BAYWIDE WATER QUALITY MONITORING PROGRAM MILESTONE REPORT...

i

BAYWIDE WATER QUALITY MONITORING PROGRAM

MILESTONE REPORT NO. 4

September 2009

BAYWIDE WATER QUALITY MONITORING PROGRAM — MILESTONE REPORT NO. 4

EXECUTIVE SUMMARY

Port Phillip Bay (PPB) is a large, shallow, almost landlocked bay under the influence of

substantial urbanisation. Maintaining the key environmental processes of PPB is essential for

sustainability.

Water quality is important to a variety of assets, values and uses of PPB. There are several

factors that can influence water quality in PPB, including:

• Exchanges between the water column, sediment and atmosphere

• Tidal flushing from Bass Strait

• Freshwater inflows, particularly from the Yarra River

• Discharges from industry and other users.

These influences are reflected in the spatial and temporal variability of water quality parameters

such as toxicants, nutrients and turbidity. This is the context for the Water Quality Baywide

Monitoring Program (WQBMP) associated with the Channel Deepening Project (CDP).

The WQBMP has been monitoring water quality in PPB on a monthly basis since November

2007, three months prior to the commencement of dredging activities for the CDP. Almost

without exception, the results of water quality monitoring in PPB over this period are within

natural variability and the expected effects of the CDP, as determined by historical range and

associated statistical analyses. For the most part, water quality was within levels of accepted

guidelines.

EPA identified no major areas of concern from assessment of the six month reporting period,

February – July 2009. The results reported here are consistent with an understanding of water

quality in PPB derived from earlier studies and other Baywide Monitoring Programs. They

describe a system affected by prolonged drought, which has led to a decline in inputs of fresh

water, nutrients, toxicants and sediments. There have been changes in water quality at specific

sites attributed to dredging in 2009, but these non persistent changes were all within the

predictions identified in the Supplementary Environmental Effects Statement (SEES) for the

CDP.

The results from this and other Baywide Monitoring Programs designed to monitor the health of

PPB have indicated that changes in key environmental processes and assets are within the

natural variability expected for PPB. Water quality throughout the majority of PPB remains as

high as it has been for at least the past 20 years, and is sufficient for maintaining assets and

beneficial uses.


Table of Contents Executive Summary ..................................................................................................................................... ii

1 Introduction.........................................................................................................................................6

2 Port Phillip Bay Dynamics ..................................................................................................................8

3 Discussion ..........................................................................................................................................9

4 Conclusion........................................................................................................................................16

5 References .......................................................................................................................................18

Appendix 1 - Background...........................................................................................................................22

Appendix 2 - Methods ................................................................................................................................26

Appendix 3 - Results..................................................................................................................................33

Appendix 4 - QA/QC data and discussion..................................................................................................59

Appendix 5 - Results outside of natural/expected variability ......................................................................65

Appendix 6.- Control chart data (November 2007 – July 2009) .................................................................69

A6.1 Control chart data for secchi disc depth .............................................................................70

A6.2 Control chart data for dissolved oxygen .............................................................................73

A6.3 Control chart data for chlorophyll-a ....................................................................................76

A6.4 Control chart data for ammonium.......................................................................................82

A6.5 Control chart data for nitrate plus nitrite .............................................................................88

A6.6 Control chart data for total nitrogen...................................................................................94

A6.7 Control chart data for phosphate.....................................................................................100

A6.8 Control chart data for total phosphorous ..........................................................................106

A6.9 Control chart data for arsenic ..........................................................................................112

A6.10 Control chart data for cadmium........................................................................................117

A6.11 Control chart data for chromium.......................................................................................120

A6.12 Control chart data for copper............................................................................................123

A6.13 Control chart data for lead................................................................................................126

A6.14 Control chart data for mercury..........................................................................................129

A6.15 Control chart data for nickel .............................................................................................132

A6.16 Control chart data for zinc ................................................................................................135

A6.17 Control chart data for TBT................................................................................................138

Appendix 7. - Summary Statistics (August 2008 – July 2009)..................................................................139

List of Tables

Table A1. 1 SEPP objectives and ANZECC trigger values ........................................................................25

Table A2. 1 Locations and corresponding SEPP segments.......................................................................26

Table A2. 2 EWMA control limits for listed water quality parameters .........................................................30

Table A2. 3 Shewhart control limits for listed water quality parameters .....................................................31


Table A3. 1 Field sampling dates and weather conditions (February – July 2009) ....................................33

Table A3. 2 Summary of Exception Reports (February – July 2009) .........................................................34

Table A3. 3 Summary of exceedence of control limits for physico-chemical data and nutrients (February – July 2009).........................................................................................................................................36

Table A3. 4 Summary of exceedence of control limits for metals (February – July 2009)..........................38

Table A3. 5 Comparison of chlorophyll-a concentrations and phytoplankton cell counts at Yarra River at Newport (February – July 2009) .......................................................................................................53

Table A3. 6 Chlorophyll-a exceedences (February – July 2009)................................................................53

Table A4. 1 ALS results outside of MU (February – July 2009) .................................................................62

Table A4. 2 Inconsistent CTD depth recordings (February – July 2009)....................................................62

Table A5. 1 PoMC Assessment (February – June 2009)...........................................................................66 List of Figures

Figure 1 Water Quality Monitoring Program sampling sites in PPB .............................................................7

Figure A3.1 Turbidity measurements at the Yarra River at Newport (February – July 2009).....................39

Figure A3.2 IMOS turbidity measurements (February – July 2009) ...........................................................40

Figure A3.3 Surface salinity measurements at Central Bay (November 2008 – July 2009).......................40

Figure A3.4 Surface salinity measurements at Long Reef (November 2008 – July 2009) .........................41

Figure A3.5 IMOS salinity measurements (February – July 2009).............................................................41

Figure A3.6 Interpolated temperature data (February - July 2009) ............................................................42

Figure A3.7 Temperature stratification Yarra River at Newport (March 2009) ...........................................43

Figure A3.8 Temperature stratification Long Reef (July 2009)...................................................................43

Figure A3.9 Salinity difference over depth at Yarra River at Newport (July 2009) .....................................44

Figure A3.10 Victorian rainfall deficiencies (February – July 2009) ...........................................................44

Figure A3.11 Daily rainfall at Viewbank (Yarra River) (February – July 2009) ...........................................45

Figure A3.12 Weekly River flow at Fairbank (Yarra River) (February – July 2009)....................................46

Figure A3.13 Daily rainfall at Moorabbin (Patterson River) (February – July 2009) ...................................46

Figure A3.14 Surface DO at Hobsons Bay (November 2008 – July 2009) ................................................47

Figure A3.15 CTD profile of salinity, temperature and DO at Central Bay (April 2009)..............................48

Figure A3.16 CTD profile of salinity, temperature and DO at Central Bay (May 2009) ..............................48

Figure A3.17 Nutrient Cycling DO measurements at Central Bay (March - May 2009) .............................49

Figure A3.18 Total Phytoplankton at all sites in PPB and the Yarra River (January 2008 – July 2009).....50

Figure A3.19 WTP flows and NOx concentrations (February – July 2009) ................................................50

Figure A3.20 Hobsons Bay phytoplankton (January – July 2009)..............................................................51

Figure A3.21 Nutrient Cycling Chlorophyll-a measurements (February - July 2009). ................................51

Figure A3.22 IMOS chlorophyll-a measurements (February – July 2009) .................................................52

Figure A3.23 Simpson Diversity Index for phytoplankton (February – July 2009)......................................52

Figure A3.24 Historical and current nitrate plus nitrite concentrations in Corio Bay (February 1994 – July 2009) ................................................................................................................................................55

Figure A3.25 Silicate concentrations at all sites in PPB and the Yarra River (February – July 2009)........56

Figure A4. 1 Inconsistent CTD depth recordings (March 2009) .................................................................63


List of Abbreviations

ANZECC Australian & New Zealand Environment Conservation Council

Guidelines for Fresh and Marine Water Quality (2000)

BMP Baywide Monitoring Program

CDBMP Channel Deepening Baywide Monitoring Programs

CDP Channel Deepening Project

DO Dissolved Oxygen

DPI Department of Primary Industries (Victoria)

EES Environment Effects Statement

EPA Environment Protection Authority

EWMA Exponentially Weighted Moving Average

IMOS Integrated Marine Observing System

LOR Limit of Reporting

MU Measurement Uncertainty

NATA National Association of Testing Authorities

PAR Photosynthetic Active Radiation

PoM DMG Port of Melbourne Dredge Material Ground

PoMC Port of Melbourne Corporation

PPB Port Phillip Bay

PR Progress Report

QA Quality Assurance

QC Quality Control

SEES Supplementary Environment Effects Statement

SEPP (WoV) State Environment Protection Policy (Waters of Victoria)

SOP Standard Operating Procedure

TBT Tributyl tin

VSOM Victorian Shellfish Operations Manual

WQBMP Water Quality Baywide Monitoring Program

WTP Western Treatment Plant


1 INTRODUCTION

1.1 Water Quality Baywide Monitoring Program

Water quality is important to a variety of assets, values and uses of Port Phillip Bay (PPB). There

are several factors that influence water quality in PPB such as tidal flushing from Bass Strait,

freshwater inflows, particularly from the Yarra River, and discharges from industry. Exchanges

between the atmosphere, water column, aquatic plants and animals and sediment are also

important. The combination of these factors affects a range of water quality parameters, including

contaminants, nutrients and turbidity, which can be variable in space and time.

For interpreting PPB water quality, important considerations include:

• PPB is relatively enclosed and has limited tidal exchange

• PPB is under the influence of substantial urbanisation within the catchment

• PPB is considered to be nitrogen limited in terms of trophic status

• Historically, nitrogen fixing blue-green algae have been very limited in their extent and

significance in PPB

• With respect to eutrophication, the ‘health’ of PPB is highly dependent upon sediment

metabolic processes involving benthic infauna and areas of adjacent oxic and anoxic

sediment. This favours nitrification / denitrification processes which allow nitrogen to be

lost from PPB more rapidly than tidal exchange would achieve (Harris et al. 1996).

The Water Quality Baywide Monitoring Program (WQBMP) undertakes monthly monitoring of

selected water quality parameters at 11 fixed sites in PPB (Figure 1) as part of the Channel

Deepening Baywide Monitoring Programs (CDBMP) of the Channel Deepening project (CDP).

Background to the WQBMP, including details of the EPA role in monitoring water quality in PPB is

provided in Appendix 1. Further information about the selection of all 11 sites is outlined in

Appendix 2, Table A2.1.

The parameters monitored and associated limits of reporting for the WQBMP are listed in section

4.1.2 and 4.1.3 of the Detailed Design Water Quality – Detailed Design CDP_ENV_MD_023 Rev

2.0, 27 May 2009 (PoMC 2009a). Algal indicators to be measured are listed in section 4.1.1 of the

Algal Blooms-Detailed Design CDP_ENV_MD_012_Rev 2.0, 27 May 2009 (PoMC 2009b).

The objective of the WQBMP is to:

‘Detect changes in water quality outside expected variability’.

‘Expected variability’ refers to changes in the monitored indicator/s that are expected due to

‘natural variability’ (i.e. background based on historical data) and the anticipated CDP - related

changes as predicted by the Supplementary Environment Effects Statement (SEES).

1.2 Methods and Results

Details of the water quality sampling and data assessment methods and results are presented in

Appendices 2 and 3, respectively. To identify changes outside of natural variability, results are

compared against derived EWMA and Shewhart control limits and, where applicable, to

SEPP/ANZECC objectives. A discussion on QA/QC is provided in Appendix 4. An assessment of


the results identified as outside expected variability is available as Appendix 5. Previous results

for the WQBMP have been reported by EPA (EPA 2008l, m; EPA 2009k).

Figure 1 Water Quality Monitoring Program sampling sites in PPB

1.3 Purpose of this Report

Milestone Report # 4 (this report) is required under the Water Quality Detailed Design (PoMC

2009a) and describes the water quality monitoring component of the BMP for the six month

reporting period from February – July 2009 inclusive, while also reflecting on the program to date

(November 2007 – July 2009).

Its function is to provide an overall appreciation of the status of water quality in PPB for the stated

reporting period. The report summarises and interprets the information gained during the field

sampling events and documented in the monthly progress reports (EPA 2008a-k; EPA 2009a-h)

and consolidates results in the context of longer-term trends, background conditions, SEPP

objectives and control chart limits, concurrent external influences (i.e. rainfall/ river flow) and other

relevant studies (including other CDBMP).


2 PORT PHILLIP BAY DYNAMICS

Port Phillip Bay (PPB) is shallow (<25 m deep) and large (2,000 km2) in relation to its catchment

(about 10,000 km2). It is almost land-locked, with the narrow entrance to Bass Strait and

associated sand banks (the Sands) greatly restricting exchange of water between PPB and Bass

Strait.

The WTP supplies about half of the nutrients entering PPB, a smaller proportion of toxicants, and

discharges treated water to PPB on a year-round basis, with highest flows in winter. Other

nutrient and toxicant sources include rivers (principally the Yarra and Maribyrnong Rivers),

streams and drains, with minor inputs from the atmosphere. Most of the riverine delivery of

nutrients and toxicants to PPB occurs during storms (Harris et al. 1996; Parslow et al. 1999;

Sokolov and Black 1999). Storm wash-off rate depends on the intensity of the surface run-off and

on the mass of transportable chemical available within the catchment that builds up between

storm events. Maximum concentrations of chemicals occur early in the first storm after prolonged

dry periods.

Nutrients and toxicants are subject to a range of physical processes once they enter PPB. These

include:

• Water circulation: wind and tides drive the movement of water in PPB with tidal currents

dominating on and south of the Sands;

• Evaporation and stream flow: generally water loss from evaporation is nearly equal to

freshwater inflows in PPB, so that except near discharges, salinity is similar to oceanic

levels. Prevailing drought conditions can result in higher salinity in PPB as stream flows

are reduced and evaporation is enhanced;

• Residence times: the theoretical residence time for water in the centre of PPB is about

one year, which is long enough for nutrients entering PPB to be taken up and recycled

through the plankton many times before they could be flushed to Bass Strait. Flushing

times are much shorter on and south of the Sands.

The WTP discharge is predominately wind-driven once it enters PPB, and may move toward

Hobsons Bay under south and westerly winds or toward Corio Bay under north and easterly

winds. The Yarra/Maribyrnong Rivers typically discharge flows down the eastern coast of PPB.

Past studies indicate that the increased plankton growth arising from these nutrient inputs might

reflect these spatial patterns. Depending on the strength of the circulation, the impacts of nutrient

inputs may occur some distance from the location of the input (Longmore 2006).

The food supply of all animals in PPB depends on the production of plants, and associated

nutrient supply. Too little nutrient may lead to restricted growth, while too much may lead to

undesirable impacts from explosive growth, including aesthetic, ecosystem and human health

impacts. Nitrogen (N) has been identified as the key nutrient limiting plant growth in PPB.

Offshore from Werribee and Hobsons Bay receive the largest N loads from land-based sources,

and are thus two of the most highly productive areas of PPB as indicated by phytoplankton

biomass (Longmore 2006).

Ultimately almost all of the annual N input to PPB is thought to be lost from the system as N2 gas.

The process leading to this loss takes place in the sediment, and arises from the coupling of two


microbial processes, called nitrification and denitrification. Maintenance of high efficiency for

these processes is essential for maintaining high water quality in PPB (Longmore 2006).

3 DISCUSSION

Physico-chemical Parameters

Physico-chemical parameters of interest in PPB include salinity, temperature, dissolved oxygen,

turbidity, suspended solids, Secchi disc depth, and light. Salinity data are useful as they may give

information about the size and amount of fresh water inputs, stratification, circulation within PPB

and exchange with Bass Strait. Temperature is important for control of plant growth, and as a

contributing factor to stratification of the water column. Dissolved oxygen is essential for

respiration for all living plants and animals. It also plays a key role in supporting nitrification and

suppressing denitrification. Total suspended solids (TSS), turbidity and secchi disc depth are

related and measured because of their impact on light availability for plants as well as aesthetics.

Salinity, temperature, dissolved oxygen

Seasonal factors and the effects of the ongoing drought have been the key factors affecting

salinity and temperature in PPB. There was a severe deficiency of rainfall in the catchment

surrounding PPB in the reporting period (Figure A3.10) that contributed to the prevailing drought

conditions that began in south-eastern Australia in 1997.

Water temperature results followed predictable seasonal patterns (Figure A3.6). Analysis of more

detailed in situ measurements since 2002 (Longmore 2006) indicated the minimum temperature

can be expected in early August, and the maximum in mid-February. The measurements reported

by the WQBMP during the reporting period are consistent with this pattern.

Prevailing drought conditions in the catchment have reduced freshwater inflows and enhanced

evaporation, resulting in PPB being consistently more saline than Bass Strait (Figure A3.5). The

continuous in situ monitoring of salinity carried out by DPI (Longmore and Nicholson 2009a-c)

confirms this (Figure A3.3 Figure A3.4), as does the Integrated Marine Observing System (IMOS)

data collected using a marine monitoring system on board the ‘Spirit of Tasmania I’ (Figure A3.5;

IMOS 2009).

From vertical profiles, salinity differences with depth were negligible at most sites. Notable

exceptions were a difference of 7.5 at Newport in July 2009 (Figure A3.9), where the lowest

surface salinity of 27.8 was recorded in the month of highest rainfall. There were also two very

small (0.1) increases in salinity in the bottom metre of the water column at the Central Bay site in

April and May 2009 (Figure A3.15 and Figure A3.16). In these months, a 1-2 m deep layer at the

seafloor of the Central Bay site was up to 0.2 °C colder than the overlying water. These salinity

and temperature observations in April and May 2009 were accompanied by declines in DO

saturation of 5 and 10% respectively. These results are significant for several reasons:

• They demonstrate that in deeper parts of PPB, even small changes in salinity and

temperature are sufficient to impede the transfer of DO to the sediment;


• The observations collected at the same time from the DPI in situ loggers at 3 and 18 m

did not detect such changes. This is because the deeper logger was at 18 m depth, 2-3 m

above the colder, more saline layer. In a series of reports (e.g. Longmore 2006), the in

situ observations at 3 and 18 m have been used to infer the structure of the entire water

column at Central PPB. The EPA observations indicate these inferences may not always

be true;

• These observations are significant for what they imply about conditions at the sediment

surface at the time of measurement that are critical for nutrient cycling. DO declines

toward the sediment surface because it is being consumed in the sediment.

Measurements of 85-90% above the sediment surface indicate much lower

concentrations in the sediment.

Harris et al. (1996) have argued that maintenance of an oxic sediment surface is important for

nitrification, the microbial step which precedes denitrification. A decline in the sediment oxic layer

may affect the fauna that are thought to be important in transferring nutrients and oxygen

throughout the sediment. Longmore (2006) has attributed efficient denitrification at the Central

PPB site to an oxic sediment layer and abundant fauna. Unusually high DO and ammonium

fluxes were found in benthic flux measurements at this site several weeks after the EPA

observations (Longmore and Nicholson 2009c), although the DO concentration a few centimetres

above the sediment surface was high (>95%).The flux observations are consistent with sub-oxic

processes dominating at the sediment surface, although denitrification efficiency did not appear to

be affected (Longmore and Nicholson 2009c).

From February to July 2009, mean DO between sites varied from 94-98% in near-surface waters.

SEPP DO objectives were met at all sites, except the Yarra River at Newport in June and July

2009 (Appendix 6, A6.2). There is an anomaly within the northern boundary of SEPP (WoV)

Schedule F6 such that the latitude/longitude puts this site in the Hobsons segment, whereas

‘Eastings and Northings’ put this site in Schedule F7 Yarra Port segment. For the purpose of this

report, objectives for both Schedules F6 and F7 values are considered for the Yarra River at

Newport site. The F7 objective (>60%) that applies to the Yarra Port was met, but not the F6

objective (>90%) that applies to Hobsons Bay. Continuous DO monitoring in Hobsons Bay since

2002 by Longmore (2005; 2008) has observed frequent excursions below 90%. These

observations indicate the difficulty in accurately assessing compliance of a highly-dynamic

variable like DO from widely-spaced (monthly) measurements.

Water clarity and total suspended solids

Turbidity and Secchi disc depth are the measures of water clarity for which SEPP objectives are

set in Schedules F7 and F6 respectively.

Water clarity (as indicated by Secchi disc depth) at the Yarra River at Newport site did not meet

the SEPP F6 objective of greater than two metres during each of the months from February to

June 2009, continuing the trend seen during the previous six months (Table A3.3; Appendix 6,

A6.1). It was expected that water clarity would decrease during dredging periods. The SEPP

objective was not always met prior to the commencement of dredging, as the Yarra River is one

of the major sources of particulates and suspended solids entering into PPB (SKM 2007).

Turbidity levels as set in Schedule F7 were met at this site with the median (5.9 NTU) and 90th


percentile (15.3 NTU) values well below the SEPP objectives of <20NTU and <50 NTU (Appendix

7).

The TSS SEPP F7 objectives for Yarra River at Newport (median < 25 mg L-1

and 90th percentile

< 60 mg L1) were met during 2009 although dredging was occurring in the Yarra River for most of

the year. When compared to the long-term means (which excludes Yarra River at Newport since

there is no long term data available), measurements in 2009 were only elevated in Hobsons Bay.

High values in February and June 2009 in the Yarra River at Newport and Hobsons Bay

coincided with rough weather conditions and dredging in the Yarra River.

Water clarity objectives were generally met at all other sites. Natural and site specific processes

including wind, storms, local currents and tides and increased phytoplankton growth influenced

Secchi disc depth measurements at some sites during the reporting period as did dredging

activities. These were short term exceptions and not considered biologically significant.

Nutrients

Because plant growth in PPB is nitrogen-limited, there is a hierarchy of interest in considering the

various nutrient forms. Of particular interest in terms of plant growth are the dissolved inorganic

nitrogen forms, ammonium, nitrite and nitrate, because they are the most readily taken up by

plants. Silicate is also of interest, because historically under certain conditions (off the Werribee

coast) it may limit growth of the most abundant plankton type (diatoms) (Longmore et al. 1996).

Orthophosphate, although in a form readily taken up by plants, is of lower interest because it is

present in excess in PPB compared to inorganic nitrogen. The organic and particulate forms of

nitrogen (N) and phosphorus (P) are also of lesser interest, as they are not readily available for

uptake by plants.

Nutrient concentrations in PPB over the current sampling period were generally consistent with

historical conditions. As described by Harris et al. (1996) in the Port Phillip Bay Environmental

Study, there is pronounced spatial and temporal variability in nutrient concentrations in PPB. This

is attributed to changes in climatic conditions affecting the amount of nutrients being delivered

from freshwater sources to PPB. These findings regarding the distribution of nutrient

concentrations are also consistent with long term trends identified and described by EPA (2002)

for the period 1984 - 1999. These studies, in conjunction with more recent results from the

Nutrient Cycling BMP, indicate that the nutrient status of PPB is in “good health”, for a number of

reasons, including:

• Efficient denitrification processes in the sediments of PPB prevent soluble and available

nitrogen in the form of ammonium and nitrate from accumulating in the water column,

removing about 80 - 90% of the nitrogen input to PPB.

• The overall shallowness and relative clarity of PPB waters allow light to penetrate to the

sediment where microphytobenthos flourish. These benthic algae intercept inorganic

forms of nutrients in the sediment before they diffuse to the overlying water column.


Nitrogenous compounds

The control limits derived for ammonium reflect historic trends in concentrations with the limits for

the Werribee area set much higher than the Yarra River, followed by Hobsons Bay (Table A2.2

andTable A2.3). Ammonium values at all sites were generally below the control limits during the

study period. The exceptions were Port of Melbourne Dredge Material Ground (PoM DMG) in

February and March 2009, and Dromana from November 2007 to July 2009 (Table A3.3;

Appendix 6, A6.4). The PoM DMG measured value in February was a transient exceedence that

was within the historic range from the nearby Central Bay site. The control limit exceedences at

this site are not considered to present a risk to the ecology of PPB. Similarly the exceedences of

the Dromana EWMA control limit do not appear to present a risk to the ecology of PPB with

evidence to indicate that the control limit for this site is too low. The Dromana EWMA control limit

is 5 µg/L, which is the lowest limit for all sampling locations (EWMA control limits for other

locations range from 6.2 to 219 µg/L). This was calculated on a limited historical data set that

included 22 records in the period 1994 - 1996 and eight records from 2004 to 2006. In

comparison, the ammonium EWMA control limit for the Central Bay site (based on over 100

records from 1994 to 2007) is 9.9µg/L, nearly double that of Dromana. The ammonium

concentrations in the centre of PPB are theoretically expected to be lower than those that are

inshore, as these sites are subject to more direct influences of nutrient rich, freshwater inflows

from rivers and storm water drains (Murray and Parslow 1997; PoMC 2008a). Ammonium

concentrations at Long Reef and in Hobsons Bay were always well below the control limit due to

reduced inputs from both the WTP and the Yarra River (Appendix 6, A6.4), particularly since

2004 (Longmore 2006). Ammonium EWMA values in the Yarra River at Newport and the PoM

DMG show a steady increase from March 2008, when dredging in the Yarra River and disposal at

the DMG commenced (Appendix 6, A6.4). As predicted in the Supplementary Environment

Effects Statement (SEES), nutrient concentrations are expected to increase during dredging but

return to background levels following the completion of dredging (Longmore 2006).

Control limits for nitrate plus nitrite (NOx) were exceeded at Corio Bay, Yarra River at Newport

and in the south of PPB at Dromana, Middle Ground Shelf and Sorrento Bank during the current

reporting period (Table A3.3; Appendix 6, A6.5).

There has been a steady increase in EWMA values for NOx at Corio Bay since the beginning of

the program, with a number of EWMA control limit exceedences occurring in the past six months

(Appendix 6; A6.5). This has been driven by an increasing trend in uncensored NOx

concentrations. A similar historical increasing trend followed by a rapid decrease in NOx

concentrations was observed during 2002-2003 (Figure A3.24). The significance of this increase

to the overall health of PPB is low. NOx concentrations remain below Shewhart control limits and

there is no evidence to suggest that the increasing NOx trend in Corio Bay has led to an increase

in chlorophyll-a concentration.

The increase in NOx observed at the Yarra River at Newport in July 2009 coincided with

increased streamflow. NOx concentrations approached 15-20 µg L-1

in Bass Strait in May-July

2006 (Gibbs et al. 2007), and the increases at Popes Eye, Middle Ground Shelf and Sorrento

Bank in May-August 2008 and Middle Ground Shelf, Sorrento Bank and Dromana in June – July

2009 (Appendix 6, A6.5) could have been brought in from Bass Strait on an inflowing tide. The

increases in 2008 did not coincide with dredging in South Channel while the increases in 2009

were coincident with dredging activities. At all sites except Yarra River at Newport and Long Reef,

and particularly in Central Bay and Corio Bay, NOx concentrations were always below 28µg N L-1

,

an important level that indicates nutrient limitation of plankton growth (Fisher et al 1992).


Total N is the sum of dissolved inorganic N, organic N and particulate N. The latter two groups

include a wide range of compounds from terrestrial and aquatic plant production such as plankton

cells. They are present throughout PPB in much higher concentrations than the dissolved

inorganic (readily available) forms, but are thought to be resistant to decomposition to forms

readily available for plant growth. Total N control limits show the expected spatial pattern, with

highest concentrations near known inputs (WTP, Yarra River, and Patterson River) and lowest

concentrations in southern PPB. This pattern was observed in 2009, with control limits being met

at all sites (Appendix 6, A6.6). A short term peak in March 2008 at Sorrento Bank was isolated to

that site and month, and was not accompanied by any change in chlorophyll-a concentration. A

peak in July 2009 at Yarra River at Newport coincided with an increase in streamflow and was

also coincident with dredging in the Yarra River, and was caused by N attached to sediment

particles, either washed in from the catchment, or resuspended from the riverbed by dredging.

Phosphorous compounds and silicate

The historical spatial distribution for orthophosphate differs from the nitrogenous nutrients with

concentrations decreasing in the order Long Reef, Corio Bay, Yarra River at Newport and

Hobsons Bay, Central Bay and near shore PPB, and south of the Sands. Only a small proportion

of the orthophosphate discharged to PPB is taken up by plants, and the spatial distribution

reflects dilution of inputs with receiving waters, and eventual flushing to Bass Strait.

Concentrations at all sites were below the control limits, and at most sites there appeared to be a

downward trend in concentration over the past year (Appendix 6; A6.7). This may reflect lower

inputs from the catchment due to the drought. As orthophosphate concentration is so high

throughout PPB compared to concentrations likely to limit plankton growth (<6 µg P L-1

,

Longmore et al. 1996), even large declines in orthophosphate concentration have no impact on

plant production in PPB.

Total P is the sum of dissolved inorganic P (orthophosphate), organic P and particulate P. In

contrast to nitrogen, orthophosphate concentrations dominate the organic and particulate forms

throughout PPB. The spatial gradient for Total P is the same as for orthophosphate. All Total P

concentrations were within the control limits, and at most sites the downward trend over time

noted for orthophosphate was also seen for Total P (Appendix 6, A6.8).

Mean silicate concentrations over the period February to July 2009 declined in the order Yarra

River at Newport, Corio Bay, Long Reef, Hobsons Bay, Central Bay and near shore PPB and

south of the Sands. This indicates that the Yarra River is a more important source of silicate than

the WTP. In areas remote from shoreline inputs, the remineralisation of sedimented

phytoplankton is also a significant source of silicate, leading to peaks in concentration in late

summer, and troughs in early spring (August to October) from plankton uptake (Harris et al.

1996). The summer peaks were observed in February to March 2009 at all sites except those

adjacent to rivers (Yarra River at Newport, Hobsons Bay and Patterson River) which peaked in

June and July 2009 (Figure A3.25). Mean concentrations at all sites were below the means from

previous studies (Longmore et al. 1996; Gibbs et al. 2007), as a result of lower freshwater inputs

due to drought. Concentrations at Popes Eye and Sorrento were, almost always, below the level

that indicates silicate limitation of diatom growth (56 µg L-1

). At all other sites, silicate

concentrations were high enough that silicate limitation was unlikely, and even at Popes Eye and

Sorrento, inorganic nitrogen levels were low enough to limit growth before silicate.


Phytoplankton and chlorophyll-a

Phytoplankton is the most significant primary producer in PPB accounting for the majority of net

primary production (Beardall and Light 1997). Despite this, biomass is generally low compared to

similar estuaries and bays within Australia and internationally (Harris et al. 1996). It was

suggested by Beattie et al. (1997) that the phytoplankton biomass within PPB is maintained at

these low levels by zooplankton grazing, thereby providing a rapid flow of the products of

photosynthesis into the food chain.

Although low, phytoplankton biomass within PPB is highly variable across space and time.

Available nutrients, light and temperature are considered the most important factors influencing

phytoplankton growth in PPB (Wood and Beardall 1992). Greater biomass generally occurs within

Hobsons Bay and the Yarra River and lower biomass is generally recorded in the south of PPB,

reflecting the distribution of available nutrients. Temporal trends in phytoplankton biomass are

more difficult to characterise, but biomass is generally higher during summer / autumn months

than over winter, reflecting seasonal patterns of light and temperature (Beardall et al 1997).

The pattern of chlorophyll-a concentrations (indicative of phytoplankton biomass) over the six

month period February to July 2009, was consistent with historical trends of spatial and temporal

variability. SEPP water quality objectives for chlorophyll-a are based on annual medians and 90th

percentiles to integrate seasonal variability. Annual medians and 90th percentiles for chlorophyll-a

calculated over the period August 2008 to July 2009 were within SEPP objectives at all sites

(Appendix 7). The two events within the six month sampling period where individual results

exceeded SEPP 90th percentile values (Corio Bay and Yarra Newport) were within historical

records for the two sites and reflect temporal variability. Similarly, the minor exceedence of long-

term control limits (EWMA limits) at these two sites and Sorrento Bank in autumn 2009 most likely

reflects the high temporal variability and seasonal trends in phytoplankton biomass that occurs

within PPB. These control values for chlorophyll-a are not seasonally weighted due to limited data

availability for a number of sites and the highly variable and unpredictable nature of

phytoplankton growth in PPB (Emphron 2009).

Across the north-west of PPB there was an increase in phytoplankton biomass during April 2009

before there was an expansion through the rest of the Bay (Figure A3.23). This can be seen in

the phytoplankton cell counts (Figure A3.18), the in-situ chlorophyll-a measures of the Nutrient

Cycling BMP (Figure A3.21; Longmore and Nicholson 2009a-c); the chlorophyll-a data collected

through IMOS (Figure A3.22; IMOS 2009) and the EPA Beach Monitoring Program (Figure A3.20;

EPA 2009i-j). This peak in phytoplankton was preceded by moderate rainfall (Figure A3.11) and

increased Yarra River and WTP flows in March (Figure A3.12 and Figure A3.19). This may have

helped instigate the increased phytoplankton activity after an abnormally low rainfall and

catchment flow period, and significant catchment burn-off due to the bushfires in February. The

increase was minor, and mostly of the diatom Skeletonema japonicum/pseudocostatum, a

species that is not known to be harmful and did not persist beyond a single sampling event and

not considered to have any negative ecological consequences.


Metals

Heavy metals in the waters of PPB, with the exception of arsenic, are low compared to ranges

found in estuaries and close to values for coastal waters (Fabris and Monahan 1995). Metals

from the catchment are transported through the rivers, streams and drains that discharge into

PPB, with the greatest loads received in the first few hours following heavy rain. The majority of

metals occur in particulate form and sedimentation removes a significant proportion of the

incoming load from the water column (Fabris and Monahan 1995). The sediment acts primarily as

a sink for heavy metals, but shipping, storm events and dredging can result in disturbance of the

sediment and re-suspension of metals into the water column (Fabris et al. 1995).

The results from February to July 2009 are consistent with this understanding of heavy metals in

PPB. The majority of samples contained very low concentrations of metals. In the small number

of samples where concentrations exceeded guideline values, the metal in question was found to

be predominantly in particulate form. In the particulate state, metals pose a lower ecological risk

as they cannot be taken up directly by organisms and toxicity is reduced (Goossens and

Zwolsman 1996).

Arsenic concentrations remained above the long term control limit at Dromana and Patterson

River during the sampling period (Appendix 6, A6.9). This is a trend that has continued since the

beginning of the sampling program. A statistical analysis of historical and current arsenic data by

Emphron (2009) assessed whether the exceedence of the control limit was a product of the

statistic upon which the control limit has been calculated. It concluded that data collected in the

current sampling program is higher than that collected historically, and changes at all sites are

fundamentally the same and represent a Baywide phenomenon. Emphron (2009) also suggested

that this was more likely to be caused by the change in analytical laboratories and analytical

methods that occurred in the WQBMP (compared to historical data collection) than an actual

increase in arsenic in PPB. The absence of data between the end of 1999 and start of 2008 make

it difficult to discriminate between effects of laboratory change and what could potentially be

Baywide effects.

PPB arsenic concentrations are at the high end of those reported elsewhere in the world. The

origin of the high arsenic is not well documented, but Fabris and Monahan (1995) proposed that

some process in the sediments was releasing arsenic to the water column. There is evidence that

arsenic is naturally high in some soil profiles in Victoria (Sultan 2006). It is likely that a

combination of factors has contributed to the arsenic levels in PPB.

Although not of ecological concern, concentrations of particulate chromium above control limits

have been recorded at the Yarra River at Newport and Hobsons Bay sites (Table A3.4; Appendix

6, A6.11). The sediments within the Port of Melbourne are known to contain higher

concentrations of chromium than the wider Bay (URS 2007; Fabris et al.1995). The surrounding

catchment is considered to be the likely source of chromium deposited in the sediment, and

elevated concentrations of chromium have been recorded before in the waters of the Yarra River

and Hobsons Bay following heavy rainfall (Fabris and Monahan 1995). Chromium in the waters of

the Yarra River at Newport site from February to July 2009 could be from re-suspended

sediments (from dredging or ship movements) or from freshwater inflows.


During the sampling period there was a single incidence of a metal in the dissolved state above

the SEPP/ANZECC guideline value - zinc in the Yarra River at Newport site in July 2009 (Table

A3.4). The Port of Melbourne, and the areas adjacent to the docks and shipping channels, are

known to have high concentrations of zinc in the sediment and the water column compared to the

rest of PPB. Fabris et al. (1995) suggested that this was due to catchment inputs from the Yarra

River. There is no evidence of any unusual occurrence prior to, or on the day of, sampling and

the cause is unknown. However, as an isolated incident it is unlikely to have resulted in significant

ecological effects.

4 CONCLUSION

The WQBMP has been monitoring water quality in PPB on a monthly basis since November

2007, three months prior to the commencement of dredging activities for the CDP. Almost without

exception, the results of water quality monitoring in PPB over this period are within natural

variability and the expected effects of the CDP, as determined by historical range and associated

statistical analyses. For the most part, water quality was within levels of accepted guidelines.

Results from this program and supported by other monitoring programs show the following:

• Water clarity objectives in PPB were generally met at all sites with the exception of the

Yarra River at Newport. Dredging activities and the Yarra River have influenced water

quality at this site.

• There is pronounced spatial and temporal variability in nutrient concentrations in PPB.

This is attributed to changes in climatic conditions affecting the amount of nutrients being

delivered from freshwater sources to PPB.

• Increases and exceedences of control limits for nitrogenous compounds were observed

at some sites. Measured concentrations were not persistent and are not considered to

present a risk to the ecology of PPB.

• Phosphorous compounds appeared to show a downward trend in concentration which

may be a reflection of lower catchment inputs due to the drought.

• Silicate concentrations were highest close to the Yarra River. Peaks were observed in

February and March in areas remote from shoreline inputs indicating remineralisation of

sedimented phytoplankton.

• Phytoplankton is the most significant primary producer in PPB accounting for the majority

of net primary production. Across the north-west of PPB there was an increase in

phytoplankton biomass during April 2009 before there was an expansion through the rest

of the Bay. This increase was minor, predominately made up of a diatom that is not

harmful and is not considered to have any negative ecological consequences.

• Heavy metals in the waters of PPB, with the exception of arsenic, are within the range of

concentrations found in other near shore marine environments. The majority of samples

contained very low concentrations of metals. In the small number of samples where

concentrations exceeded guideline values, the metal in question was found to be

predominantly in particulate form and not biologically available.


• Arsenic concentrations remained above the long term control limit at several sites during

the sampling period continuing the trend see since the beginning of the program.

Statistical analyses concluded that data collected at some sites in the current program

are higher than historically. The absence of data between 1999 and 2008 make definitive

conclusions on the cause of the higher arsenic concentrations difficult.

EPA identified no major areas of concern from assessment of the reporting period. The results

reported here are consistent with an understanding of water quality in PPB derived from earlier

studies and other Baywide Monitoring Programs. They describe a system affected by prolonged

drought, which has led to a decline in inputs of fresh water, nutrients, toxicants and sediments,

and may have led to changes in the circulation of water throughout PPB. There have been

changes in water quality at specific sites attributed to dredging in 2009, but they were all within

predictions and none were persistent.

The results from this and other Baywide Monitoring Programs designed to monitor the health of

PPB have indicated that changes in key environmental processes and assets are within the

natural variability expected for PPB. Water quality throughout the majority of PPB remains as high

as it has been for at least the past 20 years and is sufficient for maintaining assets and beneficial

uses.


5 REFERENCES

ANZECC 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality

(2000), Australian and New Zealand Environment Conservation Council.

Beardall, J. and Light, B., 1997, Microphytobenthos in Port Phillip Bay: Distribution and primary

productivity, Port Phillip Bay Environmental Study, Technical Report No.30, CSIRO, Melbourne.

Beardall J., Roberts S. and Royle, R., 1997. Phytoplankton productivity in Port Phillip Bay:

seasonal and spatial distributions. Technical Report No. 35, CSIRO Port Phillip Bay

Environmental Study, ACT.

Beattie G, Redden A, Royle R 1997. Microzooplankton grazing in phytoplankton in Port Phillip

Bay, Port Phillip Bay Environmental Study, Technical Report No.37, CSIRO, Melbourne.

BoM 2009. http://www.bom.gov.au/

Emphron Informatics Pty Ltd 2009. Channel Deepening Project Water Quality Programme Algal Blooms

Incidence.

Emphron Informatics Pty Ltd 2009. Channel Deepening Project Water Quality Programme Analysis of

Trends in Arsenic Concentration.

EPA 1997 Variation of the State environment protection policy (Waters of Victoria) - insertion of

schedule F6. Waters of Port Phillip Bay. Victorian Government Gazette S 101.

EPA 1999 Variation of the state environment protection policy (Waters of Victoria) - insertion of

schedule F7. Waters of the Yarra catchment. Victorian Government Gazette S 89.

EPA 2002. Port Phillip Bay Water Quality. Long-term Trends in Nutrient Status and Clarity 1984–

1999. EPA Publication 806.

EPA 2003 Variation of the state environment protection policy (Waters of Victoria) – Schedule to

the order in council. Victorian Government Gazette S 107.

EPA 2008a. Baywide Water Quality Monitoring Program Progress Report No 1. (November 2007

– January 2008), March 2008, EPA.

EPA 2008b. Baywide Water Quality Monitoring Program Progress Report No 2. (February 2008),

April 2008, EPA.

EPA 2008c. Baywide Water Quality Monitoring Program Progress Report No 3. (March 2008),

May 2008, EPA.

EPA 2008d. Baywide Water Quality Monitoring Program Progress Report No 4. (April 2008), May

2008, EPA.

EPA 2008e. Baywide Water Quality Monitoring Program Progress Report No 5. (May 2008), June

2008, EPA.

EPA 2008f. Baywide Water Quality Monitoring Program Progress Report No 6. (June 2008), July

2008, EPA.


EPA 2008g. Baywide Water Quality Monitoring Program Progress Report No 7. (July 2008),

August 2008, EPA.

EPA 2008h. Baywide Water Quality Monitoring Program Progress Report No 8. (August 2008),

September 2008, EPA.

EPA 2008i. Baywide Water Quality Monitoring Program Progress Report No 9. (September

2008), October 2008, EPA.

EPA 2008j. Baywide Water Quality Monitoring Program Progress Report No 10. (October 2008),

November 2008, EPA.

EPA 2008k. Baywide Water Quality Monitoring Program Progress Report No 11. (November

2008), December 2008, EPA.

EPA 2008l. Baywide Water Quality Monitoring Program Milestone Report No 1. July 2008, EPA.

EPA 2008m. Baywide Water Quality Monitoring Program Milestone Report No 2. November

2008, EPA.

EPA 2009a. Baywide Water Quality Monitoring Program Progress Report No 12. (December

2008), January 2009, EPA.

EPA 2009b. Baywide Water Quality Monitoring Program Progress Report No 13. (January 2009),

February 2009, EPA.

EPA 2009c. Baywide Water Quality Monitoring Program Progress Report No 14. (February

2009), March 2009, EPA.

EPA 2009d. Baywide Water Quality Monitoring Program Progress Report No 15. (March 2009),

April 2009, EPA.

EPA 2009e. Baywide Water Quality Monitoring Program Progress Report No 16. (April 2009),

May 2009, EPA.

EPA 2009f. Baywide Water Quality Monitoring Program Progress Report No 17. (May 2009),

June 2009, EPA.

EPA 2009g. Baywide Water Quality Monitoring Program Progress Report No 18. (June 2009),

July 2009, EPA.

EPA 2009h. Baywide Water Quality Monitoring Program Progress Report No 19. (July 2009),

August 2009, EPA.

EPA 2009k. Baywide Water Quality Monitoring Program Report No 3. May 2009, EPA.

EPA 2009i. Beach Monitoring Program,

http://www.epa.vic.gov.au/water/beach_monitoring/beach_monitoring.asp

EPA 2009j. EPA Beach Report, http://www.epa.vic.gov.au/BeachReport/default.asp


Fabris, G.J. and Monahan, C.A., 1995. Characterisation of Toxicants in Waters from Port Phillip

Bay: Metals. CSIRO INRE Port Phillip Bay Environmental Study Technical Report No. 18. ISSN

1039-3218. CSIRO.

Fabris, G.J., Monahan, C.A., Werner, G.F. and Theodoropoulos, T., 1995. Impact of Shipping and

Dredging on Toxicants in Port Phillip Bay, Port Phillip Bay Environmental Study Technical Report

No. 20, CSIRO.

Fisher, T.R., Peele, E.R., Ammerman, J.W. and Harding, L.W. Jr, 1992. Nutrient limitation of

phytoplankton in Chesapeake Bay. Mar. Ecol. Prog. Ser. 82, 51-63.

Gibbs C.F., Longmore A.R., Nicholson G.J. 2007. Port of Melbourne Corporation Channel

Deepening project Baseline Water Quality Monitoring 2006-2007. Marine and Freshwater

Systems Report Series No. 22, Primary Industries Research Victoria, Queenscliff.

Goossens, H. and Zwolsman, J., 1996, An Evaluation of the Behaviour of Pollutants During

Dredging Activities, Terra et Aqua 62: 20-28.

Harris, G., Batley, G., Fox, G., Hall, D., Jernakoff, P., Molloy, R., Murray, A., Newell, B., Parslow,

J., Skyring, G. and Walker, S. 1996. Port Phillip Bay Environmental Study Final Report. CSIRO,

ACT.

IMOS 2009. Integrated Marine Observing System (IMOS) http://www.imos.org.au

Longmore, A.R. 2005. Port Phillip Bay Environmental Management Plan: Monitoring the state of

Bay nitrogen cycling (2002-2005). Marine and Freshwater Systems Report Series No. 07.

Primary Industries Research Victoria, Queenscliff.

Longmore, A.R., 2006. Supplementary Environment Effects Statement, Head Technical Report:

Nutrient cycling- current conditions and impact assessment. Marine and Freshwater Systems

Report Series No. 17. Primary Industries Research Victoria, Queenscliff.

Longmore AR 2008. Port Phillip Bay Environmental Management Plan: Monitoring the state of

Bay nitrogen cycling (2006-2007). Marine and Freshwater Fisheries Research Institute Report

Series No. 24. Fisheries Victoria, Queenscliff.

Longmore, A.R., Cowdell, R.A. and Flint, R. 1996. Nutrient Status of the Water in Port Phillip Bay.

Technical Report No. 24. Port Phillip Bay Environmental Study. CSIRO. Yarralumba, ACT.

August.

Longmore A and Nicholson G 2009a. Baywide Nutrient Cycling (Denitrification) Monitoring

Program - Milestone Report No. 4 (Sept – Nov. 2008). Technical Report No. 36, Fisheries

Victoria, March 2009. Department of Primary Industries, Queenscliff, Victoria, Australia.

Longmore A and Nicholson G 2009b. Baywide Nutrient Cycling (Denitrification) Monitoring

Program - Milestone Report No. 5 (Nov. 2008–Mar. 2009). Technical Report No. 51, Fisheries

Victoria, May 2009. Department of Primary Industries, Queenscliff, Victoria, Australia.

Longmore A and Nicholson G 2009c. Baywide Nutrient Cycling (Denitrification) Monitoring

Program - Milestone Report No. 6 (Mar. – June 2009). Technical Report No. 67, Fisheries

Victoria, August 2009. Department of Primary Industries, Queenscliff, Victoria, Australia.


Murray, A. and Parslow, J., 1997. Port Phillip Bay Integrated Model: Final Report. Technical

Report No. 44, CSIRO Port Phillip Bay Environmental Study, ACT.

Parslow J, Murray A, Andrewartha J, Sakov P 1999. Port Phillip Bay integrated model scenarios

of nitrogen load reductions and aquaculture loads. Final Report to Victorian NRE. CSIRO, Hobart.

PoMC 2008a. Water Quality Progress Report #1- 6 – Zinc and Ammonium Assessment, 15 July

2008, Port of Melbourne Corporation.

PoMC 2009a. Water Quality – Detailed Design CDP_ENV_MD_023 Rev 2.0, 27 May 2009, Port

of Melbourne Corporation.

PoMC 2009b. Algal Blooms-Detailed Design CDP_ENV_MD_012_Rev 2.0, 27 May 2009, Port of

Melbourne Corporation.

SKM 2007. Head Technical Report Water Quality, Port Phillip Bay, Channel Deepening Project

Supplementary Environmental Effects Statement, Technical Appendix 39

Sokolov, S. and Black, K.P. 1999. Long-term prediction of water quality for three types of

catchment. Marine and freshwater Research 50, 493-502.

Sultan, K., 2006. Distribution of arsenic and heavy metals in soils and surface waters in Central

Victoria (Ballarat, Creswick and Maldon), PhD. Thesis, University of Ballarat

URS 2007. Northern Channels Sediment Investigation, Port Phillip Bay, Channel Deepening

Project Supplementary Environmental Effects Statement, Technical Appendix 36

Wood, M. and Beardall, J., 1992, Phytoplankton Ecology of Port Phillip Bay, Victoria, Port Phillip

Bay Environmental Study, Technical Report No.8, CSIRO, Melbourne.


APPENDIX 1 - BACKGROUND

EPA’s Role in Monitoring Water Quality in Port Phillip Bay

EPA Victoria has been monitoring the water quality of Port Phillip Bay (PPB) since 1975 with the

Marine Fixed Sites Program commencing in 1984. The aims of this monitoring are to:

• Identify any long term trends in water quality

• Assess the general condition of PPB

• Assess the success of management actions through the compliance with environmental

objectives.

This program has been extensively reported; most recently including an assessment of the long-

term trends in nutrient status and water clarity from 1984 to 1999.1

Inputs or loads of freshwater, nutrient and sediment to PPB are reasonably well understood.

These inputs enter primarily from several rivers, most notably the Yarra, smaller streams, about

350 storm water drains and two sewage treatment plants (STPs) — Western Treatment Plant

(WTP) at Werribee and at Altona. Groundwater discharge into PPB is considered insignificant.

Within PPB, nutrient and sediment concentrations can vary greatly. Spatially, concentrations are

usually greater inshore or adjacent to major inputs.1

State environment protection policy (Waters of Victoria) (SEPP (WoV)) Schedule F6 Waters of

Port Phillip Bay, declared in 1997 is a comprehensive policy framework for the protection of water

quality in PPB.2 A key component of SEPP (WoV) is the identification of beneficial uses that the

community want to protect and which are used as the basis for maintaining environmental quality.

The beneficial uses identified for marine waters including the waters of PPB are:

• Maintenance of natural aquatic ecosystems

• Water based recreation

• Production of molluscs for human consumption

• Commercial and recreational use of edible fish and crustacea

• Industrial water use

• Navigation and shipping.

Within PPB, six (regional) segments are recognised. These are:

• Hobsons Segment: includes the mouth of the Yarra River and the City of Melbourne and

its port facilities

• Werribee Segment: the part of PPB adjacent to the WTP outfalls

• Corio Segment: All waters in Corio Bay

• Inshore Segment: covering all waters within 600m of low tide

• Aquatic reserves: those parts of the Bay afforded statutory protection as ‘protected areas’

1 EPA 2002. Port Phillip Bay Water Quality. Long-term Trends in Nutrient Status and Clarity 1984–1999.

EPA Publication 806. 2 EPA Victoria 1997, Variation of the State environment protection policy (Waters of Victoria) - insertion of

schedule F6. Waters of Port Phillip Bay. Victorian Government Gazette S 101.


• General Segment: all other waters in PPB.

These segments reflect the different types and conditions of environments, surrounding land uses

and major inputs, and therefore have different beneficial uses requiring protection. A separate

SEPP (WoV) Schedule F7 Waters of the Yarra Catchment provides the policy framework for the

protection of water quality in the Yarra River.3

Environmental quality objectives are set for each segment to ensure the protection of designated

beneficial uses. The objectives provide targets for particular indicators of the condition of the

environment in PPB. Specific objectives are set for each segment and are shown in Table A1.1.

As nutrient and toxicant objectives are not set in the SEPP, the Australian and New Zealand

Environment Conservation Council (ANZECC) trigger values are used to assist interpretation

(Table A1.1).4

A review SEPP/ANZECC objectives was undertaken in August 2009 resulting in a variation

proposal to amend the original SEPP/ANZECC table in the Detailed Design due to the following:

1. The ANZECC trigger values provided for nutrients are not applicable.

2. The values provided in the original table for the F7 segment for Yarra River at Newport

site do not reflect existing SEPP (WoV) policy.

The amended table has been used for reporting purposes from August 2009. The amended table

of SEPP/ANZECC objectives will be included in all subsequent Milestone Reports.5

EPA has historically sampled water quality approximately monthly at six fixed sites in PPB (see

Appendix 2, Table A2.1 for details):

• Hobsons Bay

• Central Bay

• Long Reef

• Corio Bay

• Dromana

• Patterson River.

Historically, Central Bay and Dromana were considered reference sites for the purpose of

calculating nutrient and suspended sediment trigger values. Information relating to coastal land

use developments adjacent to Dromana indicates that this site is also likely to be influenced by

various human activities similar to the other four sampling sites:

• Hobsons Bay site is approximately 800m from shore and is primarily influenced by

discharge from the Yarra River

• Long Reef site is located approximately 1km from the WTP

3 EPA Victoria 1999. Variation of the state environment protection policy (Waters of Victoria) - insertion of

schedule F7. Waters of the Yarra catchment. Victorian Government Gazette S 89.

4 ANZECC 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000),

Australian and New Zealand Environment Conservation Council. 5 EPA 2009. Filenote Channel Deepening Project – Detailed Design discrepancies, 27

th August 2009.


• Patterson River site is located about 300m from shore and to the south of Patterson River

• Corio Bay site is close to domestic and industrial inputs to Corio Bay.

As part of the establishment of the Water Quality component of the Channel Deepening Baywide

Monitoring Programs (CDBMP) for the CDP, five additional sites to improve the spatial coverage

across key areas of PPB augmented EPA’s water quality monitoring program. These additional

sites are:

• Yarra River at Newport

• PoM DMG

• Middle Ground Shelf

• Sorrento Bank,

• Popes Eye.

The location of all eleven sampling sites for the Water Quality Baywide Monitoring Program

(WQBMP) is provided in Figure 1.


25

Table A1. 1 SEPP objectives and ANZECC trigger values

Attenuation

of PAR

Sampling Site

SEPP (WoV)

schedule &

segment

ANZECC

Level of

ProtectionM

in fo

r 1

m b

elo

w s

urf

ace

Min

1m

ab

ove

bo

tto

m

Lo

we

r lim

it fo

r 9

0th

pe

rce

ntile

Min

pe

rce

nta

ge

co

nce

ntr

atio

n

Sa

linity v

ari

atio

n

Te

mp

era

ture

( o

C)

Se

cch

i d

isc d

ep

th (

m)

An

nu

al 9

0th

pe

rce

ntile

NT

U

An

nu

al 5

0th

pe

rce

ntile

An

nu

al 9

0th

pe

rce

ntile

An

nu

al 5

0th

pe

rce

ntile

An

nu

al 9

0th

pe

rce

ntile

Ch

loro

ph

yll-

a (

ug

/L)

An

nu

al 9

0th

pe

rce

ntile

Am

mo

niu

m (µ

g /L

)

Nitra

te p

lus n

itri

te (µ

g/L

)

To

tal n

itro

ge

n (µ

g/L

)

Ph

osp

ha

te (µ

g/L

)

To

tal P

ho

sp

ho

rus (µ

g/L

)

Ars

en

ic (µ

g/L

)

Ca

dm

ium

(µ

g/L

)

Ch

rom

ium

(µ

g/L

)

Co

pp

er

(µg

/L)

Le

ad

(µ

g/L

)

Me

rcu

ry (µ

g/L

)

Nic

ke

l (µ

g/L

)

Zin

c (µ

g/L

)

TB

T (µ

g/L

)

F6 Hobsons >90% >90% N ± 5% N ± 1 >2 0.5 0.5 - 10 2.5 4.0 15 5 120 10 25 <3 5.5 <5 1.3 4.4 0.4 70 <10 0.006

F7 Yarra Port >60% N ± 2 <20 <50 <25 <60 15 5 120 10 25 50 0.2 10 3 1 0.05 15 5 0.006

Hobsons Bay F6 Hobsons >90% >90% N ± 5% N ± 1 >2 0.5 0.5 - 10 2.5 4.0 15 5 120 10 25 <3 5.5 <5 1.3 4.4 0.4 70 <10 0.006

Corio Bay F6 Corio >90% >90% N ± 5% N ± 1 >3 0.45 0.5 - 10 1.5 2.5 15 5 120 10 25 <3 5.5 <5 1.3 4.4 0.4 70 <5 0.006

Long Reef F6 Werribee >90% >90% N ± 5% N ± 1 >3 0.45 0.5 - 10 2.5 4.0 15 5 120 10 25 <3 5.5 <5 1.3 4.4 0.4 70 <5 0.006

Central Bay F6 General >90% >90% N ± 5% N ± 1 >4 0.35 0.5 - 10 1.0 2.0 15 5 120 10 25 <3 <0.15 <5 0.3 2.2 0.1 7 <5 0.0004

PoM DMG F6 General >90% >90% N ± 5% N ± 1 >4 0.35 0.5 - 10 1.0 2.0 15 5 120 10 25 <3 <0.15 <5 0.3 2.2 0.1 7 <5 0.0004

Patterson River F6 Inshore >90% >90% N ± 5% N ± 1 >3 0.45 0.5 - 10 1.5 2.5 15 5 120 10 25 <3 <0.15 <5 0.3 2.2 0.1 7 <5 0.0004

Dromana F6 Inshore >90% >90% N ± 5% N ± 1 >3 0.45 0.5 - 10 1.5 2.5 15 5 120 10 25 <3 <0.15 <5 0.3 2.2 0.1 7 <5 0.0004

Middle Ground

ShelfF6 General >90% >90% N ± 5% N ± 1 >4 0.35 0.5 - 10 1.0 2.0 15 5 120 10 25 <3 <0.15 <5 0.3 2.2 0.1 7 <5 0.0004

Sorrento Bank F6 General >90% >90% N ± 5% N ± 1 >4 0.35 0.5 - 10 1.0 2.0 15 5 120 10 25 <3 <0.15 <5 0.3 2.2 0.1 7 <5 0.0004

Popes Eye F6 General >90% >90% N ± 5% N ± 1 >4 0.35 0.5 - 10 1.0 2.0 15 5 120 10 25 <3 <0.15 <5 0.3 2.2 0.1 7 <5 0.0004

SEPP Waters of

VictoriaN=natural background Limit of reporting is above SEPP objective

ANZECC trigger values not highlighted

Yarra River at

Newport

95%

99%

SEPP Schedule F6 - Waters of Port Phillip Bay, and

SEPP Schedule F7 - Waters of the Yarra Catchment objectives

Channel Deepening PARAMETER

Policy Categories

Dissolved Oxygen

(% saturation) Turbidity

Suspended

Solids (mg/L)

Chlorophyll-a

(ug/L)

Notes Schedule F7 (Waters of the Yarra Catchment) is included for comparison of water quality objectives at the Yarra River at Newport site, as this site has been determined to be in a crossover area between schedules F6 and F7. Both schedule segments can be applicable to the site dependent on tide cycle and flow conditions in the Yarra mouth


APPENDIX 2 - METHODS

Sampling Locations

The Water Quality Monitoring Program sampling schedule is monthly, at 11 fixed sampling sites

across PPB (Figure 1). Table A2.1 provides further information relating to the selection of the

sites and corresponding SEPP segments.

Table A2.1 Locations and corresponding SEPP segments

Site name

Site no. (PoMC)

Segment Historical

Data Purpose

Yarra River at Newport

8005

Yarra Port

segment of

Schedule F6/F7*

PoMC data 2004-2005 and 2006-

2007

This samples Yarra River water prior to entering PPB. Sediments here contain contaminants that may be mobilised by storms, shipping and dredging. It is near a popular fishing area known as the ‘Warmies’.

Hobsons Bay

7007

Hobsons segment

of Schedule

F6

PoMC 2004-5 and 2006-

7. ; EPA 1994 to present

Hobsons Bay is a recreational area and home to a Little Penguin colony. It is the interface between the Yarra River and PPB.

Corio Bay 4321 Corio (F6)

EPA 1994 - present

This is a recreational area and supports seagrass beds.

Long Reef

4310 Werribee

(F6) EPA 1994 -

present

This area is influenced by the WTP. Links to other Baywide Monitoring programs in same area.

Dromana 2808

General, bordering ‘Inshore’

(F6)

EPA 1994-1996

and2005 - present

This is an important recreational area.

Patterson River

4604

General, bordering ‘Inshore’

(F6)

EPA 1994-1996 and

2005-present

This site is near Patterson River which is a significant input to PPB.

PoM DMG

4503 General

This is at the centre of the PoM Dredged Material Ground, to confirm that placement and storage of contaminated material does not result in significant impacts to water quality.

Central Bay

4514 General

EPA 1994 – present.

PoMC nearby

(4519) 2004-2005 and

2006-2007

This site is indicative of water quality across large central area of PPB. Links to other Baywide Monitoring programs in same area.

Middle Ground Shelf

2719 General

Nearby (2710) PoMC

2004-2005 and 2006-

2007

This is on the edge of the Great Sands area. Links to other Baywide Monitoring programs in same area.

Sorrento Bank

2006 General PoMC 2004-

2005 and 2006-2007

Key recreational area and seagrass beds. Links to other Baywide Monitoring programs in same area.

Popes Eye

2301 General PoMC 2004-

2005 and 2006-2007

This is near the boundary of a marine national park, and is strongly influenced by tidal exchange with Bass Strait.


27

*There is an anomaly within the northern boundary of SEPP (WoV) Schedule F6 such that the latitude/longitude puts the ‘Yarra River at Newport’ site in the Hobsons segment, whereas ‘Eastings and Northings’ put this site in Schedule F7 Yarra Port segment. For the purpose of this report, objectives for both Schedules F6 and F7 values are considered for the Yarra site, although for Progress Reports # 1 & 2, only Schedule F6 values were considered.

Field Sampling

EPA personnel, who are trained in the sampling methodology, conduct all field sampling.

Fieldwork involves both in-situ monitoring and the collection of water samples for laboratory

analysis.

A summary of the methods for in-situ monitoring and the collection of water quality and algal

samples are provided below. Descriptions of the methods are provided in the following EPA

Standard Operating Procedures (SOPs):

• In-situ Monitoring

• Water Quality Sampling

• Algal Sampling

• Sample Handling and Custody.

Detail on sample and equipment preparation is also contained in the SOPs. This includes

sourcing sample containers from laboratories, marking up sample containers, checklists for

equipment and supplies and equipment maintenance and inspection. The SOPs are incorporated

into the Quality System for delivery of the WQBMP.

Field sampling is undertaken monthly within a 2-week window starting from the second week of

the month. This is preferably conducted over three consecutive days, however flexibility in timing

is required due to logistical and OH&S constraints.

In-situ Monitoring

A CTD Profiler is used to measure the in-situ parameters at each site including conductivity,

depth, temperature, dissolved oxygen (% saturation), photosynthetic active radiation (PAR),

fluorescence and turbidity. Further detail on operation, calibration and QC checks for the CTD

profiler are provided in the ‘In-situ Monitoring’ SOP.

Water Quality

Water samples are collected using a peristaltic pump with medical grade silicone tubing. Samples

are collected at the near surface (~0.5 m) of the water column and sub-samples withdrawn for

total nutrients, total metals, TBT and suspended solids. Sub-samples are filtered through 0.45µm

membrane filters and stored for dissolved nutrient and dissolved metal analysis. Chlorophyll-a

samples are collected by gravity filtration of seawater through a glass fibre filter, and stored on

ice.

The need for a bottom water sample is determined based on whether salinity stratification (a

change with depth of more than 10 units) is identified by the profiler.


Sample containers, sampling and preservation methodologies, and sample handling and storage

are provided in the ‘Water Quality Sampling’ SOP.

Algal Sampling

At each site an integrated water sample is taken for algal enumeration and a net tow sample is

collected for algal identification. Full detail including sample containers, sampling and

preservation methodologies and sample handling and storage is provided in the ‘Algal Sampling’

SOP.

Sample blanks and replicates

Field sampling quality control measures include the collection of field blanks and replicates. This

includes:

• Two freshwater field blanks per cruise to test for contamination during sample collection/

treatment/ storage.

• One seawater field blank per cruise to test for laboratory precision.

• Two field replicates to test for contamination during sample collection/treatment/storage,

site heterogeneity and laboratory precision. These are two randomly selected sites per

monthly sampling cycle in each of the north and south of PPB, and are analysed for

each of the parameters normally tested for each location. Replicate sample sites are

selected in advance on a random basis so they will remain blind as far as the

laboratories are concerned. Where a replicate is taken, a filtered replicate is also

collected for required parameters.

Sample handling and custody

Sample storage requirements and holding times are provided in the ‘Sample Handling and

Custody’ SOP. Chain of Custody forms accompany all samples.

Quality Assurance for field sampling

The 2009/2010 EPA Quality Plan6 is the key document that outlines all relevant QA/QC

specifications for the EPA WQBMP. This includes the QA/QC requirements for the fieldwork as

outlined below.

QA/QC for fieldwork includes:

• Sampling for metals, nutrients and TBT is carried out using powder-free, plastic

disposable gloves to minimise contamination

• Sampling equipment is left open to the water column for approximately five minutes

allowing it to sufficiently rinse prior to taking a sample

• All samples are stored on ice and transported to the laboratories within 24 hours of

sample collection

• Collection of field blanks and replicates as described in Section 2.1.4

6 EPA 2009, EPA Victoria Baywide Water Quality Monitoring Program Quality Plan


29

• The EPA Field Scientist provides field records for the profiler to the EPA Project Manager

for the QA file including serial number, when new equipment is used, where used and

details of calibration checks. These records will show if any clear ‘steps’ in the data can

be tracked and attributed to changes in instrumentation,

• Chain of Custody forms are created and forwarded with the samples to the laboratories.

Laboratory Analysis

The laboratory analysis of samples is contracted to Ecowise Australia for metals and TBT

analysis, Department of Primary Industries (DPI) Queenscliff for nutrients (and some physico-

chemical parameters) and MicroAlgal Services for algal analysis. DPI Queenscliff analyses

samples for physico-chemical parameters such as suspended solids, dissolved oxygen, salinity,

dissolved nutrients, total N and P, particulate N (and dissolved organic N), silicate and algal

pigments (chlorophyll-a and phaeophytin-a).

Reports are provided by the laboratories detailing their QA/QC programs while the EPA also

conducts cross laboratory analyses to ensure quality control for laboratory results.7

Data Assessment Methods

In order to detect changes in water quality outside expected variability in PPB, two control

charting techniques (CSIRO/Emphron 2007)8 have been employed in the analysis of the

WQBMP results:

• An Exponentially Weighted Moving Average (EWMA) control chart is used for

assessment of longer-term changes in baseline results. The EWMA is a statistic that

averages the data in a way that gives less weight to data as they are further removed in

time. To do this EWMA applies weighting factors which decrease exponentially over

time. This gives relatively greater importance to recent observations while still not

discarding older observations entirely. EWMA is being used in this context to detect

persistent changes from a baseline ‘target’ concentration, usually the historical mean of

the data, which may reflect long term changes in water quality. An upper control limit for

the EWMA has been calculated to assist in deciding whether a persistent change from

the target value may have occurred (Table A2.2).

• A Shewhart control chart is used to detect changes in the number or size of peak

events for nutrients, total metals and TBT. These changes will reflect short-term

changes in water quality (Table A2.3).

7 EPA 2009, EPA Victoria Baywide Water Quality Monitoring Program Quality Plan

8 CSIRO/Emphron 2007. Channel Deepening Project Bay-Wide Monitoring Programme Water Quality,

Emphron Informatics Pty Ltd, December 2007.


Table A2.2 EWMA control limits for listed water quality parameters

Ammonium Nitrate plus

Nitrite Total Nitrogen Phosphate

Total Phosphorus

Chlorophyll-a

Arsenic Sampling site

µg/L µg/L µg/L µg/L µg/L µg/L µg/L

Yarra River at Newport 32.42 39.52 278.39 86.19 108.01 2.0 3.23

Hobsons Bay 19.45 39.53 266.22 85.72 105.32 3.9 2.98

Central Bay 9.90 3.61 168.10 72.32 84.08 1.1 2.86

PoM DMG 6.16 9.92 176.47 66.31 83.99 1.0 3.10

Corio Bay 10.70 2.31 224.48 100.12 115.66 1.4 3.66

Long Reef 219.05 83.74 629.12 238.83 305.50 6.8 3.20

Patterson River 13.65 42.75 243.10 69.75 89.34 2.2 2.59

Dromana 5.00 4.29 170.20 56.93 70.12 1.6 2.52

Middle Ground Shelf 7.02 2.29 156.09 50.94 63.85 0.8 N/A

Sorrento Bank 8.16 4.93 143.10 36.40 45.74 0.8 N/A

Popes Eye 8.20 12.73 145.12 36.75 120.94 0.8 N/A

Notes

NA – Not available due to lack of historical data.

Source: Table 4 CDP_ENV_MD_023 Rev 2.0 (available on the CDP website www.channelproject.com).


31

Table A2.3 Shewhart control limits for listed water quality parameters

Sampling site

Total

Nitrogen

µg/L

Ammonium

µg/L

Nitrate plus

Nitrite µg/L

Total Phosphorus

µg/L

Phosphate

µg/L

Arsenic

µg/L

Cadmium

µg/L

Chromium

µg/L

Copper

µg/L

Lead

µg/L

Mercury

µg/L

Nickel

µg/L

Zinc

µg/L

TBT

µg/L

Yarra River at Newport 383.31 88.78 182.90 138.91 107.54 4.75 0.20 0.58 3.08 2.79 0.10 4.29 12.77 0.02

Hobsons Bay 382.82 50.61 257.50 135.51 129.08 4.43 0.25 1.17 1.70 0.95 0.13 2.28 9.13 0.01

Central Bay 206.91 21.50 7.43 106.48 112.50 4.66 * * * * * 1.95 * *

PoM DMG 217.07 7.81 28.33 107.98 76.61 4.73 * * * * * 2.82 * 0.02

Corio Bay 275.74 25.37 5.00 140.27 127.68 5.57 * NA * * * 1.90 * NA

Long Reef 1035.88 999.28 512.03 536.16 445.31 4.56 * NA * * * 2.17 * NA

Patterson River 367.57 30.57 366.52 111.81 87.58 3.56 * NA * * * 1.14 * NA

Dromana 222.84 11.03 5.71 89.64 75.42 3.58 * NA * * * 1.06 * NA

Middle Ground Shelf 185.93 10.66 2.71 96.82 65.33 NA NA NA NA NA NA NA NA NA

Sorrento Bank 168.74 11.54 9.50 63.20 48.44 NA NA NA NA NA NA NA NA NA

Popes Eye 209.84 14.74 42.71 471.38 148.04 NA NA NA NA NA NA NA NA NA

Notes

NA – Not available due to lack of historical data. * - No limit, as more than half historical data is below limits of reporting.

Source: Table 5 CDP_ENV_MD_023 Rev 2.0, (available on the CDP website www.channelproject.com)


EWMA and Shewhart charts have been generated for all parameters with chart-based limits

specified in Tables A2.2 and A2.3 respectively. Exceedence of these limits flag results as being

outside of normal background variability based on historical data. The next question is to

determine whether results are also outside of ’expected variability’, based on the predicted

effects of the CDP as defined in the SEES. Where results are considered to be outside expected

variability, PoMC leads an assessment of the significance to the environment, with the support of

EPA. If results are significant, this initiates further risk-based assessments in accordance with the

Water Quality Detailed Design CDP_ENV_MD_023_Rev 2.0, Decision Framework for

Management. 9

In cases where no Shewhart limits exist (asterisks in Table A2.3), SEPP (WoV) objectives, or

ANZECC ‘trigger values’ where no SEPP values exist (Table A1.1), are used for comparison.

Monthly progress reports and six monthly milestone reports also include a discussion of all

applicable results compared to SEPP as a general observation of water quality at the program’s

monitoring sites.

In some cases, for example nutrients, SEPP objectives do not exist but EWMA and Shewhart

limits have been derived. In other cases (e.g. some metals), either SEPP objectives are explicit

or, by default, ANZECC trigger values are used. For most metals and sites there is insufficient

historical data to derive Shewhart or EWMA limits.

Interpretation of the algal analysis (species composition and enumeration) is defined in the Algal

Blooms Detailed Design CDP_ENV_MD_012_Rev 2.0.10

Algal results are compared against a

threshold as a tool to identify change outside of expected variability. The minimum warning levels

used in the Victorian Shellfish Operations Manual (VSOM) for toxic and nuisance species have

been adopted as the threshold concentrations. These are listed in Section 4.2.1 of the Algal

Blooms Detailed Design. The Algal Blooms Detailed Design also defines the method for

interpreting chlorophyll-a results using an EWMA and associated limits.

Another requirement of the Water Quality Detailed Design is the inclusion of summary statistics,

particularly as they relate to some SEPP (WoV) water quality parameter requirements for

comparison with annual statistical derivations such as median and percentiles. When calculating

summary statistics, if a value is <LOR then it is not possible to calculate a mean. When

calculating percentiles, including the median, values <LOR are temporarily replaced with a

number that is marginally less than the LOR so as to make it distinguishable from the LOR itself

(e.g. replace <0.2 with 0.199). The percentiles and median are then calculated and any estimates

that are smaller than the LOR are replaced with '<LOR'.

9 PoMC 2009. Water Quality – Detailed Design CDP_ENV_MD_023 Rev 2.0, 27 May 2009, Port of

Melbourne Corporation. 10

PoMC 2009. Algal Blooms – Detailed Design CDP_ENV_MD_012 Rev 2.0, 27 May 2009, Port of Melbourne Corporation.


33

APPENDIX 3 - RESULTS

This Milestone Report (#4) incorporates all data collected since the inception of the program in

November 2007 with the focus primarily on this reporting period extending from February – July

2009.

Field Sampling

Field sampling was conducted monthly as outlined in Table A3.1. Strong winds and rough

conditions were experienced in February, April and June 2009.

Table A3.1 Field sampling dates and weather conditions (February – July 2009)

Progress Report

Sampling Dates

Dredge location Weather Observations

10th

February Strong 15-25kts winds; waves 1.0-1.5m No.14

11th

February Yarra River

Strong 20-25kts winds; waves 1.5-2.0m

10th

March Light 5-10kts winds increasing to 15-20 kts; waves 0.2-0.8m No.15

11th

March

Yarra River South Bay/South Channel

Very light 0-5kt winds; waves 0.1m

14th

April Hobsons Bay South Bay/South Channel

Moderate 10-15kt winds increasing to 25-35kts; waves 0.4-1.0m

15th

April Strong 25-30kts winds increasing to 35-40kts; waves 1.5-3.0m

No.16

16th

April

Yarra River South Bay/South Channel Strong 15-20kt winds increasing to 25-35kts;

waves 0.6-1.5m

12th

May Moderate 10-15kt winds decreasing to 5-10kts; waves 0.2-0.5m No.17

13th

May

Yarra River South Bay/South Channel to PoM DMG capping Moderate 10-15kt winds; waves 0.1-0.2m

9th

June Hobsons Bay South Bay/South Channel to PoM DMG capping

Strong 15-20kt winds increasing to 25-35kts; waves 1.0-1.5m

No.18

10th

June Yarra River Strong 15-20kt winds increasing to 25-30kts; waves 0.3-1.5m

7th

July Yarra River Very light 0-5kt winds; waves 0.1-0.2m

No.19 8th July

Yarra River South Bay/South Channel

No wind increasing to 10-15 kts; waves 0-0.2m

Quality Assurance/Control (QA/QC)

Field and laboratory QA/QC data and discussion relevant to this reporting period are provided in Appendix 4.

Exception reports

A number of deviations from the Detailed Design occurred during the reporting period. Formal

exception reports were provided with progress reports as a means of documenting events in each

occasion. These exception reports are referenced in relevant progress reports and help ensure

that learning’s are captured and improvements incorporated back into the program. All exception

reports from this reporting period are summarised in Table A3.2.

Table A3.2 Summary of Exception Reports (February – July 2009)

Report Number

Exception

ER090201 The Limit of Reporting (LOR) for the Yarra River at Newport TBT sample was 0.003 µg/L instead of 0.002 µg/L as stated in Table 3 of the Detailed Design.

ER090202 Progress Report #14 contained erroneous EWMA calculated values for ammonium.

ER090301 Progress Reports #7-12 contained erroneous EWMA calculated values for chlorophyll-a.

ER090302 No reliable zinc data was available for March 2009.

ER090401 Dissolved Oxygen (DO) samples collected in April 2009 were not analysed by the laboratory within specified holding times.

ER090402 PAR data for April and May 2009 was recorded using a spherical rather than flat sensor.

ER090403 The LOR for nitrate plus nitrite has been amended from 2.4µg/L to 1.2 µg/L.

ER090501 Secchi disc depths were amended for reporting in 0.1m increments.

ER090701 The July 2009 sampling event was undertaken one week prior to the scheduled date.

Results from Progress Reports

This subsection presents and discusses the data collected from field sampling events carried out

from February to July 2009, as outlined in Progress Reports # 14 -1911

The information in this subsection highlights exceedences of the program’s control limits (EWMA

and Shewhart), the criteria used to flag possible variation from historical water quality data.

Secondary comparison with SEPP (WoV) F6 and F7 objectives, or ANZECC trigger values as

applicable, are also made to assist broader interpretation of the results.

This section is presented according to the water quality parameter categories:

11

EPA 2009. Baywide Water Quality Monitoring Program Progress Reports No 14 -19, February – July 2009, EPA.


35

• Physico-chemical data

• Phytoplankton and Algal Pigments

• Nutrients

• Metals.

Where appropriate, results are also charted in the context of the Shewhart and EWMA control

limits, SEPP/ANZECC values and historical means, for each parameter (see Appendix 6).

Tables A3.3 and A3.4 summarise all exceedences of EWMA and Shewhart control limits

observed during the reporting period for physico-chemical data/nutrients and metals, respectively.

These tables also include exceedences of SEPP/ANZECC objectives where no Shewhart limit is

available.

Assessment by the PoMC of these exceedences in terms of any implications for the ecological

health of PPB and subsequently the management of this project are presented in Appendix 5,

Results outside of natural/ expected variability.

Summary statistics are provided for relevant metals, nutrients and physico-chemical parameters

for comparison against SEPP (WoV) F6 and F7 objectives, or ANZECC trigger values (see

Appendix 7). A minimum of 11 (monthly) data points are required to gain a true comparison with

SEPP objectives against an annual statistic.


Table A3.3 Summary of exceedence of control limits for physico-chemical data and nutrients (February – July 2009)

Date Site Depth Secchi disc depth Ammonium Nitrate plus Nitrite Chlorophyll-a Oxygen

(m) (m) (µg/L) (µg/L) (µg/L) (%)

Value EWMA Value EWMA Value EWMA

10/02/09 Dromana 0.5 6.9 4.4

10/02/09 PoM DMG 0.5 4.0 7.9 6.4

11/02/09 Yarra River at Newport 0.5 0.2 2.06

11/02/09 Hobsons Bay 0.5 0.9

11/02/09 Corio Bay 0.5 1.9

11/02/09 Long Reef 0.5 1.2

11/02/09 Corio Bay 0.5 2.4

10/03/09 PoM DMG 0.5 6.4

10/03/09 Dromana 0.5 6.8

11/03/09 Corio Bay 0.5 2.4


11/03/09 Long Reef 0.5 1.7

14/04/09 Middle Ground Shelf 0.5 2.5

14/04/09 Dromana 0.5 6.2

15/04/09 Yarra River at Newport 0.5 0.6 5.131 2.78

16/04/09 Corio Bay 0.5 3.0 2.541

12/05/09 Dromana 0.5 5.8

12/05/09 Sorrento Bank 0.5 0.82


13/05/09 Corio Bay 0.5 6.6 3.0 1.40

09/06/09 PoM DMG 0.5 2.4

09/06/09 Dromana 0.5 2.9 5.9 8.3

09/06/09 Middle Ground Shelf 0.5 4.6 2.6

09/06/09 Sorrento Bank 0.5 16.2 5.8 0.82

10/06/09 Yarra River at Newport 0.5 0.4 2.47 88

10/06/09 Hobsons Bay 0.5 0.3

10/06/09 Corio Bay 0.5 2.8


37

Table A3.3 cont. Summary of exceedence of control limits for physico-chemical data and nutrients (February – July 2009)

Notes

1. The chlorophyll a value is above the 90th percentile objective in SEPP (WoV) Schedule F6.

Yellow coloured cells indicate measured results above the Shewhart control limit (for ‘total’ fraction). See Table A2.3 for detail.

Orange coloured cells indicate EWMA calculated results above EWMA control limits. See Table A2.2 for detail.

Blue coloured cells indicate results above SEPP objectives where a Shewhart limit is not available. See Table A1.1 for detail.

Date Site Depth Secchi disc depth Ammonium Nitrate plus Nitrite Chlorophyll-a Oxygen

(m) (m) (µg/L) (µg/L) (µg/L) (%)

Value EWMA Value EWMA Value EWMA

08/07/09 Yarra River at Newport 0.5 0.6 51.7 2.11 90

08/07/09 Corio Bay 0.5 2.5

07/07/09 Dromana 0.5 5.7

07/07/09 Middle Ground Shelf 0.5 2.4

07/07/09 Sorrento Bank 0.5 5.5 0.81


Table A3.4 Summary of exceedence of control limits for metals (February – July 2009)

Date Site Depth Arsenic Cadmium Chromium Zinc

(m) (µg/L) (µg/L) (µg/L) (µg/L)

Value EWMA

10/02/09 Patterson River - total 0.5 2.7

10/02/09 Dromana - total 0.5 2.7

11/02/09 Yarra River at Newport - total 0.5 1.7


10/03/09 Dromana - total 0.5 2.7


14/04/09 Dromana - total 0.5 2.7



12/05/09 Dromana - total 0.5 2.6

12/05/09 Central Bay - total 0.5 7


09/06/09 Central Bay - total 0.5 0.2

09/06/09 PoM DMG - total 0.5 0.2

09/06/09 Patterson River - total 0.5 2.6 0.2 8

09/06/09 Dromana – total 0.5 2.5

09/06/09 Middle Ground Shelf - total 0.5 0.2

09/06/09 Sorrento Bank - total 0.5 0.2

09/06/09 Popes Eye - total 0.5 0.2

10/06/09 Yarra River at Newport - total 0.5 0.2 1.7

10/06/09 Hobsons Bay - total 0.5 1.4


08/07/09 Yarra River at Newport - total 0.5 0.7 14

08/07/09 Yarra River at Newport - dissolved 0.5 10

Notes

Yellow coloured cells indicate measured results above the Shewhart control limit (for ‘total’ fraction). See

Table A2.3 for detail.

Orange coloured cells indicate EWMA calculated results above EWMA control limits. See Table A2.2 for

detail.

Blue coloured cells indicate results above SEPP objectives for total metals where a Shewhart limit is not

available See Table A1.1 for detail.

Green coloured cells indicate results above ANZECC trigger values for dissolved metals (for metals,

ANZECC triggers are the default objective when no SEPP value is specified) See Table A1.1 for detail.


39

Physico-chemical data

Water Clarity - Secchi disc

Secchi disc depth is the measure of water clarity for which SEPP objectives are set in

Schedule F6. These objectives are applied as control values for water clarity as there are no

Shewhart limits available and also no EWMA applicable for these measurements.

Water clarity at the Yarra River at Newport site did not meet the SEPP objective of >2m during

each of the last 6 months, continuing the trend seen in the previous 6 month period (Appendix

6, A6.1).

Water clarity at Long Reef in February (1.2m) and March (1.7m) did not meet the SEPP

objective of >3m. This may have been influenced by rough weather during February and

increased outflows from Western Treatment Plant (WTP) in March.

Decreased water clarity was also observed at a number of other sites, particularly during

periods of strong winds and rough weather (Table A3.1 and A3.3).

Water Clarity - Turbidity

Turbidity is the measure of water clarity for which SEPP objectives are set in Schedule F7 for

the Yarra Port segment of the Yarra River. There were several months during which individual

turbidity measurements were high at the Yarra River at Newport site (Figure A3.1). A dredge

was active during each of the sampling events while strong SSW winds were evident in

February and June. The annual median (5.9 NTU) and annual 90th percentile (15.3 NTU) for

the last 12 months of monitoring were below the SEPP objectives of <20NTU and <50 NTU

respectively (Appendix 7). It should be noted that the maximum turbidity reading for this CTD

is 24.3 NTU. This has impacted on the readings in February and June 2009.

Figure A3.1 Turbidity measurements at the Yarra River at Newport (February – July 2009)

0

2

4

6

8

10

12

14

0 5 10 15 20 25 30

Turbidity (NTU)

Dep

th (

m)

Feb-09

Mar-09

Apr-09

May-09

Jun-09

Jul-09


Elevated turbidity levels in the Yarra River were also captured through the Integrated Marine

Observing System (IMOS)12

. Increased turbidity associated with dredging activity in the south of

the bay was also detected (Figure A3.2).

Figure A3.2 IMOS turbidity measurements (February – July 2009)

Salinity and Temperature

Salinity and temperature readings from both the water quality and nutrient cycling monitoring

programs show similar patterns at each of the common sampling sites (Central Bay (Figure

A3.3), Long Reef, Hobsons Bay and Middle Ground Shelf). The only exception was a

laboratory surface salinity measurement taken from Long Reef in March (Figure A3.4). This

anomaly may be a data quality error.

Figure A3.3 Surface salinity measurements at Central Bay (November 2008 – July 2009)

36.6

36.8

37

37.2

37.4

37.6

37.8

29/10/08 18/12/08 6/02/09 28/03/09 17/05/09 6/07/09 25/08/09

Sa

lin

ity (

ps

u)

DPI Nutrient Cycling Data

EPA Water Quality Data (Lab)

EPA Water Quality Data (CTD)

12

Integrated Marine Observing System (IMOS: http://www.imos.org.au/ )


41

Figure A3.4 Surface salinity measurements at Long Reef (November 2008 – July 2009)

36.2

36.4

36.6

36.8

37

37.2

37.4

37.6

37.8

38

38.2

38.4

29/10/08 18/12/08 6/02/09 28/03/09 17/05/09 6/07/09 25/08/09

Salin

ity (

ps

u)

DPI Nutrient Cycling data

EPA Water Quality Data (Lab)

EPA Water Quality Data (CTD)

The current monitoring period coincides with one of the longest droughts in the history of south

east Australia which is reflected in salinity readings across PPB. A strong salinity front at PPB

entrance has prevailed for the monitoring period (Figure A3.5). This is likely to limit tidal

flushing from Bass Strait. The streamflow events during the monitoring period are contained in

the north of PPB and do not erode the salinity gradient at the entrance to PPB indicating the

persistence of this feature.

Figure A3.5 IMOS salinity measurements (February – July 2009)

Average water temperature across PPB and the Yarra River followed predictable seasonal

patterns. Figure A3.6 provides a general view of the spatial variation seen in temperature data

collected for the WQBMP across PPB in the last 6 months.


Figure A3.6 Interpolated temperature data (February - July 2009)

Stratification

The Detailed Design states that stratification is deemed to occur where there is a difference of

>10 in salinity or the temperature differs by more than 0.5°C between surface and bottom

waters.13

During this reporting period temperature stratification was only observed on two

occasions at the Yarra River at Newport in March and Long Reef in July (Figure A3.7 and

A3.8). In both cases the temperature stratification corresponded with salinity. This is expected

when the stratification is a result of warmer fresh water overlying more saline water14

as seen

at the Yarra River. The opposite was seen at Long Reef with colder water on the surface

rather than the bottom. This is inherently unstable from a thermal perspective so it may have

been short-lived unless the higher salinity in the deeper water maintained it. A salinity

difference of 7.5 was observed over depth at the Yarra River at Newport site following rainfall

in July (Figure A3.9).

13

PoMC 2009. Water Quality – Detailed Design CDP_ENV_MD_023 Rev 2.0, 27 May 2009, Port of Melbourne Corporation. 14

Gibbs et al 2007 Port of Melbourne Corporation Channel Deepening Project Baseline Water Quality Monitoring 2006-2007


43

Figure A3.7 Temperature stratification Yarra River at Newport (March 2009)

0

1

2

3

4

5

6

7

8

19 19.2 19.4 19.6 19.8 20 20.2 20.4 20.6

Temperature (oC)D

ep

th (

m)

34

34.5

35

35.5

36

36.5

37

37.5

38

Salin

ity

temperature-depth

temperature-salinity

Figure A3.8 Temperature stratification Long Reef (July 2009)

0

1

2

3

4

5

9.9 10 10.1 10.2 10.3 10.4 10.5 10.6 10.7

Temperature (oC)

Dep

th (

m)

37.2

37.3

37.4

37.5

37.6

37.7

Sa

lin

ity

temperature-depth

temperature-salinity


Figure A3.9 Salinity difference over depth at Yarra River at Newport (July 2009)

0

1

2

3

4

5

6

28 30 32 34 36 38

Salinity (PSU)

Dep

th (

m)

Rainfall

Drought conditions throughout Victoria have resulted in a severe deficiency of rainfall in the

catchment surrounding PPB (Figure A3.10) resulting in reduced inflows into PPB.

Figure A3.10 Victorian rainfall deficiencies (February – July 2009)


45

The majority of nutrients and toxicants supplied by rivers to PPB are discharged during storms.15

No storm events were identified in the last six months for the Yarra River using storm event

criteria outlined in Gibbs et al (2007).16

The storm event criteria for the Yarra River is that 24-hour

rainfall must exceed 20 mm with rainfall continuing and Yarra River flow exceeds 15 m3.s-1 (~

1,300 ML d-1) and is rising. During the last 6 months, while rainfall exceeded 20mm in 24 hours

during March, April and June there was no evidence of daily river flow greater than 1300 ML d-1

(Figures A3.11 – A3.12). The storm event criterion of 24-hour rainfall exceeding 16mm for

Patterson River was reached on the 15th March and 28

th of April, however these events did not

coincide with water quality sampling (Figure A3.13).

Fairfield (riverflow) and Viewbank (rainfall) were identified in Gibbs et al (2007) as the most

relevant Melbourne Water (MW)17

and Bureau of Meteorology (BoM)18

sites for the Yarra River,

while Moorabbin was identified as the most relevant BoM rainfall site for Patterson River.

Figure A3.11 Daily rainfall at Viewbank (Yarra River) (February – July 2009)

0

5

10

15

20

25

30

35

40

1/02/09 13/02/09 25/02/09 9/03/09 21/03/09 2/04/09 14/04/09 26/04/09 8/05/09 20/05/09 1/06/09 13/06/09 25/06/09 7/07/09 19/07/09 31/07/09

Date

Ra

infa

ll (

mm

)

Rainfall

Sampling

Storm event

15

Harris et al 1996, Port Phillip Bay Environmental Study Final Report 16

Gibbs et al 2007 Port of Melbourne Corporation Channel Deepening Project Baseline Water Quality Monitoring 2006-2007 17

All river flow data obtained from Melbourne Water < www.melbournewater.com.au> 18

All rainfall data obtained from the Bureau of Meteorology <www.bom.gov.au>


Figure A3.12 Weekly River flow at Fairbank (Yarra River) (February – July 2009)

0

200

400

600

800

1000

1200

1400

1600

1/2/09 13/2/09 25/2/09 9/3/09 21/3/09 2/4/09 14/4/09 26/4/09 8/5/09 20/5/09 1/6/09 13/6/09 25/6/09 7/7/09 19/7/09 31/7/09

Date

Riv

erf

low

(M

L/d

ay)

Mean Riverflow

Sampling

Storm Event

Figure A3.13 Daily rainfall at Moorabbin (Patterson River) (February – July 2009)

0

5

10

15

20

25

30

1/02/09 13/02/09 25/02/09 9/03/09 21/03/09 2/04/09 14/04/09 26/04/09 8/05/09 20/05/09 1/06/09 13/06/09 25/06/09 7/07/09 19/07/09 31/07/09

Date

Rain

fall (

mm

)

Rainfall

Sampling

Storm event


47

Dissolved Oxygen (DO)

Under natural conditions, DO concentrations may vary greatly over a daily (or diurnal) period

depending on water temperature, salinity, photosynthetic and microbial activity.19

There were two marginal exceedences of near surface DO, 88% and 90% respectively, of the

SEPP F6 objective (>90%) at the Yarra River at Newport site (Table A3.3). The SEPP F7

objective at this site is >60%.

Results from the nutrient cycling monitoring program show the variability that can occur in DO

readings that is not evident in single samples collected for the water quality program (Figure

A3.14).

Figure A3.14 Surface DO at Hobsons Bay (November 2008 – July 2009)

0

20

40

60

80

100

120

140

29/10/08 18/12/08 6/02/09 28/03/09 17/05/09 6/07/09 25/08/09

Dis

so

lve

d O

xy

gen

(%

satu

rati

on

)

DPI Long-term Moorings

EPA Water Quality Data

During April and May at the Central Bay site, reduced oxygen concentrations at the bottom of the

profile were detected (Figures A3.15 and A3.16). Stratification occurred at depth and was

characterised by colder temperature and higher salinity.

The 18 metre deep in-situ logger that samples at this site for the Nutrient Cycling Monitoring

Program also recorded lower dissolved oxygen (~ up to 10% difference) compared to the three

metre deep sensor during the period of mid-April to mid-May (Figure A3.17).

19

ANZECC 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000), Australian and New Zealand Environment Conservation Council


Figure A3.15 CTD profile of salinity, temperature and DO at Central Bay (April 2009)

Figure A3.16 CTD profile of salinity, temperature and DO at Central Bay (May 2009)


49

Figure A3.17 Nutrient Cycling DO measurements at Central Bay (March - May 2009)

Source: Longmore (2009)

20

Phytoplankton and Algal Pigments

Total phytoplankton cells showed a peak in April at Hobsons Bay, Long Reef, and Corio Bay

(Figure A3.18). This peak in phytoplankton was preceded by moderate rainfall (Figure A3.11)

and increased Yarra River flows (Figure A3.12) as well as a doubling in WTP flows in March

2009 (Figure A3.19). This may have helped instigate the increased phytoplankton activity after

an abnormally low rainfall and catchment flow period, and significant catchment burn-off.

20 Longmore 2009 Baywide Nutrient Cycling (Denitrification) Monitoring Program–In situ Loggers Progress

Report No. 13 (Mar-May 2009).


Figure A3.18 Total Phytoplankton at all sites in PPB and the Yarra River (January 2008 – July 2009)

0

1000000

2000000

3000000

4000000

5000000

6000000

7000000

Jan-08 Feb-08 Mar-08 Apr-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08 Oct-08 Nov-08 Dec-08 Jan-09 Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09

Month

# p

hy

top

lan

kto

n c

ell

s

Yarra River at Newport Hobsons Bay Central PoM DMG

Corio Bay Long Reef Patterson River Dromana

MGS Sorrento Popes Eye

Figure A3.19 WTP flows and NOx concentrations (February – July 2009)

34

35

36

37

38

39

01/02/09 21/02/09 13/03/09 02/04/09 22/04/09 12/05/09 01/06/09 21/06/09 11/07/09 31/07/09

Date

Sali

nit

y

0

30

60

90

120

150

Co

ncen

trati

on

(u

g/L

)

Flo

w (

x10)

(ML

/day)

Long Reef salinity WTP Flow Long Reef NOx Corio Bay NOx Hobsons Bay NOx

Total phytoplankton results obtained for Hobsons Bay follow a similar trend to results from the

Baywide Beaches Monitoring Program (comparison with beaches located in Hobsons Bay

segment, consisting of Williamstown, Sandridge, Port Melbourne, Middle Park, St Kilda and

Elwood) (Figure A3.20).


51

Figure A3.20 Hobsons Bay phytoplankton (January – July 2009)

0

1000000

2000000

3000000

4000000

5000000

6000000

5/01/09 27/01/09 16/02/09 10/03/09 30/03/09 20/04/09 25/05/09 15/06/09 6/07/09 27/07/09

To

tal

Ph

yto

pla

nk

ton

(c

ell

s/L

)

Hobsons Bay (WaterQuality Program)

Hobsons beaches

average

Data from the Nutrient Cycling Monitoring Program shows evidence of plankton activity with

elevated chlorophyll-a levels from February to April with a peak in seen at Hobsons Bay in late

March (Figure A3.21). This increase is indicative of catchment inflows as seen in the salinities

from Hobsons Bay and Central Bay.

Figure A3.21 Nutrient Cycling Chlorophyll-a measurements (February - July 2009).

0

2

4

6

8

10

1/02/09 21/02/09 13/03/09 2/04/09 22/04/09 12/05/09 1/06/09 21/06/09 11/07/09 31/07/09

Date

Ch

l-a F

luo

resen

ce u

g/L

36

36.4

36.8

37.2

37.6

38

Sali

nit

y

Hobsons Bay Chl-a Central Bay Chl-a Long Reef Chl-a Hobsons Bay Salinity Central Bay Salinity

Chlorophyll-a data collected through IMOS shows a prolonged seasonal bloom event in the far

north of PPB during March-May 2009 (Figure A3.22). The intense but contained plankton activity

in the north of PPB continued to late April before there was an expansion through the rest of the

bay.


Figure A3.22 IMOS chlorophyll-a measurements (February – July 2009)

During the last six months, species richness varied considerably across sites and sampling

events. Species diversity (as measured by the Simpson Index21

) was greatest at Popes Eye

and Sorrento Bank (as denoted by a low Simpson Index) and phytoplankton communities less

diverse at Corio Bay and Long Reef (Figure A3.23). 22

Figure A3.23 Simpson Diversity Index for phytoplankton (February – July 2009)

Phytoplankton data measured during this reporting period did not exceed VSOM action levels

at any of the sites while algal pigment measures such as phaeophytin-a and fluorescence (in-

situ chlorophyll-a) do not have comparison values.

21

Simpson 1949, Measurement of diversity, Nature vol 163, April 30 1949. 22

Note that higher diversity is indicated by a lower score on the Simpson Index.


53

Chlorophyll-a is useful indicator of phytoplankton biomass in the water column.23

Results from

this reporting period did show inconsistencies in chlorophyll-a concentrations and

phytoplankton cell counts at the Yarra River at Newport site (Table A3.5). This disparity was

also observed at a number of other sites including Hobsons Bay and Long Reef and is likely

due to the different species of phytoplankton containing different amounts of chlorophyll-a

depending on their size, dominant pigments and responses to environmental variables such

as light and temperature.

Table A3.5 Comparison of chlorophyll-a concentrations and phytoplankton cell counts at Yarra River at Newport (February – July 2009)

Date Chlorophyll-a

concentration (µµµµg/L)

Total cell count (cells / L)

Feb-09 2.05 775,000

Mar-09 2.72 925,000

Apr-09 5.13 1,383,300

May-09 2.91 2,454,800

June-09 1.10 1,077,075

July-09 0.70 448,770

A number of chlorophyll-a EWMA and SEPP exceedences were reported for the Yarra River

at Newport, Sorrento Bank and Corio Bay (Table A3.6, Appendix 6).

Table A3.6 Chlorophyll-a exceedences (February – July 2009)

Month Location Chl-a value SEPP objective

(90th percentile)90th percentile

value (Aug 08 -

Jul 09)

EWMA value EWMA control

limit

16/04/2009 Corio Bay 2.54 2.5 2.17

13/05/2009 Corio Bay 1.40 1.4

12/05/2009 Sorrento Bank 0.82 0.8

09/06/2009 Sorrento Bank 0.82 0.8

07/07/2009 Sorrento Bank 0.81 0.8

11/02/2009 Yarra River at Newport 2.06 2.0


15/04/2009 Yarra River at Newport 5.13 4.0 3.90 2.78 2.0




23

ANZECC 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000), Australian and New Zealand Environment Conservation Council.


Nutrients

Control limits in the form of Shewhart and EWMA have been derived for nutrients using historic

and site specific data, and provide a reliable estimate of expected conditions in PPB. SEPP

(WoV) Schedule F6 excludes nutrient objectives (and default ANZECC values) in recognition of

the limited value current ANZECC water quality guidelines for nutrients have in PPB.24

Nutrient

discharges are deemed to be acceptable if they do not cause chlorophyll-a objectives to be

breached. The expected variation in water quality in PPB is most effectively expressed via the

control limits.

Ammonium

Most sites showed levels of ammonium to be within the range of the historical mean and

below Shewhart/EWMA control limits. (Appendix 6, A6.4). The Dromana EWMA control

continues to exceed the 5 µg L-1

EWMA control limit derived for this site.

An exceedence of the Shewhart limit was reported for the PoM DMG in February in addition to

EWMA control limit exceedences in February and March (Table A3.3).

Nitrate plus Nitrite

Levels of nitrate plus nitrite (NOx) varied across sites (Appendix 6, A6.5).

A peak in NOx concentrations was observed in the south of PPB in June 2009 with Shewhart

exceedences occurring at Sorrento Bank, Middle Ground Shelf and Dromana. Corresponding

EWMA exceedences occurred at Sorrento Bank and Middle Ground Shelf. A similar peak in

NOx concentrations was previously recorded between May and August 2008.

A spike in concentration at the Yarra River at Newport occurred in July exceeding the EWMA

but not the Shewhart limit.

Corio Bay recorded a number of EWMA exceedences in the last six months due to an

underlying increasing trend in raw values (Figure A3.24).

A slight upward trend in EWMA values is evident at Central Bay but values are still well below

the EWMA control limit.

24

EPA 2002 Port Phillip Bay Water Quality. Long-term Trends in Nutrient Status and Clarity 1984–1999.


55

Figure A3.24 Historical and current nitrate plus nitrite concentrations in Corio Bay (February 1994 – July 2009)

-2.0

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Year

NO

X (

ug

/L)

NOX (94-08)

NOX (08-09)

Shewart limit

LOR

Total Nitrogen

The results for total nitrogen at all sites were generally within the range of the historical mean

and below the Shewhart and EWMA control limits (Appendix 6, A6.6). As with NOx, a peak in

total nitrogen concentration close to the control limits was observed at the Yarra River at

Newport in July.

Phosphate

All results for phosphate were below the Shewhart and consistent with the historical mean

(Appendix 6, A6.7). Phosphate EWMA values were generally consistent across sites and

below the EWMA limit, indicating that there has not been a baseline shift in this parameter in

PPB.

Total Phosphorous

The concentrations of total phosphorous are within range of the historical mean and below the

Shewhart and EWMA control limits at all sites (Appendix 6, A6.8).

Silicate

There are no control limits or SEPP objectives for silicate. Highest silicate concentrations were

reported at the Yarra River at Newport site. Peaks in silicate were observed in February - March

2009 at all sites except those adjacent to rivers (Yarra River at Newport, Hobsons Bay and

Patterson River) which peaked in June and July 2009 (Figure A3.25).


Figure A3.25 Silicate concentrations at all sites in PPB and the Yarra River (February – July 2009)

0

50

100

150

200

250

300

350

Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09

Month

Co

ncen

trati

on

(u

g/L

)

0

100

200

300

400

500

600

700

800

900

Ya

rra R

iver

at

Ne

wp

ort

Co

ncen

trati

on

(u

g/L

)

Long Reef Corio Bay PoM DMG Central Bay

Dromana MGS Sorrento Popes Eye

Patterson River Hobsons Bay Yarra River at Newport

Metals

Many of the metal samples were below the detection limit. There were several reported

exceedences above control limits for total metals and one exceedence of a dissolved metal.

Table A3.3 provides a summary of all control limit exceedences, including SEPP and

ANZECC, where no Shewhart are available.

Summary statistics for metals have been calculated for comparison against SEPP objectives.

Regionally specific SEPP objectives apply to total metals. Where there is no regionally specific

objective in SEPP, the SEPP (ANZECC) objective is applied to dissolved metals (Appendix 7).

Summary statistics are calculated using the last 12 months of data (August 2008 – July 2009)

and include the mean, median, 90th percentile, minimum and maximum value. SEPP objectives

for metals are based on maximum values.

Arsenic

Total arsenic concentrations were below the Shewhart limit at all sites where a control limit

was available. Patterson River and Dromana continued to show EWMA exceedences (Table

A3.3; Appendix 6, 6.9). An investigation into the continued arsenic EWMA exceedences was

conducted with results reported in Emphron (2009).25

25 Emphron Informatics Pty Ltd 2009 Channel Deepening Project Water Quality Programme

Analysis of Trends in Arsenic Concentration.


57

Summary statistics based on the last 12 months of data show the SEPP F6 objective of

<3µgL-1

was not met at most sites (Appendix 7). Results from the Baywide Beaches

Monitoring Program also show arsenic concentrations exceeding the SEPP F6 objective at all

sites in the last year. The results from the last six month period in contrast show that the SEPP

objective was met at most sites with the exception of Yarra River at Newport (April), Hobsons

Bay (April) and Corio Bay (March and April).

Cadmium

Generally samples were below the limit of reporting (LOR) (0.2 µg L-1

) and within both control

limits and SEPP objectives (Appendix 6, A6.10). The exception occurred in June with positive

cadmium values (0.2 µg L-1

) at Patterson River and all sites in the F6 general segment

exceeding the SEPP objective of 0.15 µg L-1

(Appendix 7). The Baywide Beaches Monitoring

Program data also shows similar results for the inshore and general segments. When

considering the measurement of uncertainty (MU) provided by the laboratory the results were

all within the range of 0.2 ± 0.22 µg L-1

.

Chromium

The majority of chromium results were below the LOR (0.5 µg L-1

) and within both control

limits and SEPP objectives (Appendix 6, A6.11). Exceptions included a Shewhart exceedence

of total chromium at Hobsons Bay in June and Shewhart exceedences at Yarra River during

five of the last six months. The SEPP F6 objective of <5 µg L-1

for total chromium was met at

all sites.

Copper

The majority of copper results were below the LOR (1 µg L-1

) and within both control limits and

SEPP objectives (Appendix 6, A6.12). The SEPP (ANZECC) F6 objective of <0.3 µg L-1

was

not met at Middle Ground Shelf due to a dissolved value of 2.0 µg L-1

reported in December

2008 (Appendix 7).

Lead

The results for lead were generally below the LOR and/or within both control limits and SEPP objectives (Appendix 6, A6.13).

Mercury

All mercury results, with the exception of total mercury at Popes Eye in June, were below the

LOR (0.1 µg L-1

) (Appendix 6, A6.14). The SEPP (ANZECC) F6 objectives were met at all

sites.

Nickel

The results for nickel were generally below the LOR and/or within both control limits and SEPP

objectives (Appendix 6, A6.15).

Zinc

The majority of zinc results were below the LOR (5 µg L-1

) and within derived control limits

(Appendix 6, A6.16). Summary statistics based on the last 12 months of data show the SEPP

F6 objective was not met at a number of sites (Appendix 7). Beaches monitoring data also


shows total zinc to exceed the SEPP F6 objectives at most sites during the last 12 months.

The results from the last six month period in contrast show that the SEPP objective was met at

most sites with the exception of Yarra River at Newport (June and July), Central (May) and

Patterson River (June).

TBT

All TBT samples, from the Yarra River at Newport and Hobsons Bay sites, were below the

LOR and/or within both the Shewhart control limits and the SEPP (ANZECC) objectives

throughout the reporting period (Appendix 6, A6.17).


59

APPENDIX 4 - QA/QC DATA AND DISCUSSION

LABORATORY QA/QC

The respective laboratories for this monitoring program have reported their quality control for the

sample batches covered by this report to be within acceptable limits.

Phytoplankton Analysis

Microalgal Services laboratory protocols and procedures aim to comply with AS ISO/IEC 17025-

2005 (General Requirements for the competence of testing and calibration laboratories).

Equipment is calibrated to NATA traceable standards and method validation has been

undertaken.

Nutrient Analysis

Department of Primary Industries (DPI) Queenscliff laboratory’s QA/QC program includes:

• Laboratory blanks, analysed with each batch of samples;

• Laboratory spikes, analysed with each batch of samples;

• Spike recovery analysed periodically;

• Algorithm checks are carried out periodically to assure the accuracy of nutrient calculations; and

• All samples analysed in duplicate.

Metals Analysis

Ecowise employs a QAQC program as follows:

• Method Blanks, analysed with each batch of samples;

• Laboratory Duplicates, analysed with each batch of samples;

• Laboratory Control Samples (LCS), analysed with each batch of samples; and

• Matrix Spikes (MS), analysed with each batch of samples.

Australian Laboratory Services (ALS) employs a QAQC program as follows:

• 5% Method Blanks – one analysed within each process lot of 20 samples;

• 10% Laboratory Duplicates – two analysed within each process lot of 20 samples;

• 5% Laboratory Control Samples (LCS) – one analysed within each process lot of 20 samples; and

• 5% Matrix Spikes (MS) – one analysed within each process lot of 20 samples.

Tender for laboratory service providers

EPA went to tender to identify and contract the most appropriate laboratory(s) for the analysis of

samples collected for the WQBMP. Three laboratories were selected to undertake the various

analyses. Microalgal Services and DPI Queenscliff continue as the preferred laboratories to


undertake the phytoplankton and nutrient analyses respectively. A different laboratory, Ecowise,

was contracted to undertake the metals analysis.

Laboratory comparison on filtered and unfiltered nutrients

Inorganic nutrients are currently measured using filtered samples, whereas historically EPA data

was based on unfiltered samples. This means that the control limits currently being applied to

these inorganic nutrients are largely based on unfiltered results. Testing of both filtered and

unfiltered samples was undertaken from April – June 2009 to determine the magnitude of

difference between filtered and unfiltered results.

A total of 46 samples were analysed for total and filtered ammonium, nitrite, nitrate, nitrite plus

nitrate, phosphate and silicate. This comprised filtered and unfiltered samples collected at 11

sites around Port Phillip Bay in April, May and June 2009 and filtered and unfiltered freshwater

rinsate blanks, one for each day of sampling.

For each sample, the unfiltered and filtered result was plotted as a bar chart and the

measurement of uncertainty (MU) provided by the laboratory applied as error bars. The unfiltered

and filtered result was considered comparable if the error bars overlapped.

Overall, there were differences between the filtered and unfiltered results for most inorganic

nutrients analysed. It was identified that low level nitrate contamination was probably occurring

during the filtering process. Advice from DPI indicates that none of these results are considered

to be ecologically significant changes overall and there is no rationale for the continuation of

filtering nutrient samples in PPB (pers. comm. Andy Longmore 03/07/09).

A decision is pending on the whether filtering of nutrient samples will continue.

Inter-laboratory comparison on metals analysis

An inter laboratory comparison between the previous metals laboratory (ALS) and the new metals

laboratory (Ecowise) was conducted to determine if there were any differences in reporting that

may impact on the integrity of the dataset.

Split samples were collected from 11 sites around Port Phillip Bay (PPB) in April, May, June and

July 2009 and sent to both ALS and Ecowise for analysis.

Statistical differences in the datasets were found between the laboratories for arsenic and nickel.

Arsenic and nickel were the only parameters for which there were sufficient data points above the

LOR. The datasets for all parameters were graphed and the measurement of uncertainty (MU),

provided by each laboratory, were used as error bars where applicable. The results were found to

be within acceptable limits, as defined by the MU, and therefore do not impact on the integrity of

the dataset when accompanied by measurements of uncertainty.

Withheld zinc results in March 2009

On receipt of metals results from ALS in March 2009, routine QA/QC screening by EPA identified

a number of possible data issues and a re-analysis of results was requested. Review of the initial

and subsequent results highlighted the following issues:

• The dissolved zinc fractions were considerably higher than the total fractions at the

Central Bay and Yarra River at Newport sites.


61

• There was a trend of increasing total zinc in the re-analysed samples, with PoMC DMG

(replicate), Popes Eye (replicate), Sorrento and the certified reference material (CRM)

blank results all outside the MU for the corresponding original results.

• There was possible zinc contamination of samples due to zinc being present in the

analysed CRM and freshwater rinsate blanks.

Expert opinion was sought on the findings which identified a potential contamination issue. It also

highlighted that the current laboratory quality control approach for trace metal analyses was

inadequate based on the expected trace metal concentrations in PPB waters.

EPA has since contracted another laboratory to perform ultra-trace metals analysis that has

laboratory control measures more suitable to the expected concentrations found in EPA samples.

Sample blanks and replicates

Field sampling quality control measures include the collection of field blanks and replicates to test

for contamination and laboratory precision.

Field Sample blanks

The majority of field blanks analysed by the laboratories have come back with values less than

the LOR. Exceptions included:

• ALS detected zinc in the sample field blanks provided in March. All results were withheld

due to contamination concerns.

• ALS detected zinc in sample field blanks in June 2009. The results were not considered

significant as the values (2 µg L-1

) were marginally above the LOR (1 µg L-1

).

• DPI detected low levels of nitrates in most blanks. This has been attributed to filtering

cartridges and is not considered ecologically significant.

ALS is no longer analysing the metals samples for the program.

Field replicate samples

Ecowise showed very good levels of reproducibility for the metals analysis with no original

samples falling outside of the MU range of the replicate sample. ALS reported all results to be

within their QAQC criteria however when the MU was applied to results it was found that on

several occasions the original samples were different to the replicates (Table A4.1).


Table A4.1 ALS results outside of MU (February – July 2009)

Arsenic

Dissolved Total Dissolved Total Dissolved Total Dissolved

Date Sample LOR 0.5 0.5 0.5 1 1 0.5 0.5

14/04/2009 2.2 +/- 0.35 2.6 +/-0.66 1.3 +/- 0.28

14/04/2009 1.8 +/- 0.28 <0.5 0.6 +/- 0.22

14/04/2009 6.9 +/- 1.62 1.1 +/- 0.23 1.2 +/- 0.52

14/04/2009 0.6 +/- 0.31 <0.5 0.6 +/- 0.5

9/06/2009 1.6 +/- 0.25

9/06/2009 2.2 +/-0.35

10/06/2009 <1

10/06/2009 3 +/- 0.63

8/07/2009 <1

8/07/2009 2 +/- 0.42

8/07/2009 1.1 +/- 0.37

8/07/2009 <0.5

Corio Bay

Chromium Copper Nickel

Patterson River

Southern Replicate

Northern Replicate

Middle Ground Shelf

Southern Replicate

Dromana

Southern Replicate

Newport

Northern Replicate

Hobsons Bay

Northern Replicate

DPI reported that all nutrient results were correct with 95% confidence. All samples are analysed

twice with the mean value reported when the values are within 10%.

FIELD QA/QC

CTD multi sensor probe

During the last reporting period there have been a number of different people, with varying levels

of training and experience, operating the CTD during sampling events. This has resulted in a

number of inconsistencies within the data obtained using the CTD. These inconsistencies are not

considered to impact significantly on the dataset however they have been identified as areas for

improvement.

Inconsistent CTD starting depths

On 11 occasions (out of 66 casts) during the reporting period, the CTD was lowered through the

water column from a starting depth of 1.5m, reducing the likelihood of detecting surface

stratification at a given site. During February, April and June, the inconsistent starting depth for

CTD casts can be attributed to poor weather conditions which can hinder the ability to keep the

CTD stable. All other occasions were due to the relative inexperience of the operators.

Inconsistent CTD ending depths

There were two occasions when the CTD was not lowered to the maximum depth possible for

unknown reasons. This occurred during March at Yarra River at Newport and in June at

Patterson River (Table A4.2).

Table A4.2 Inconsistent CTD depth recordings (February – July 2009)

Month Yarra River at Newport Patterson River

CTD Total depth CTD Total depth

Feb-09 14.5 15.2 5.5 6

Mar-09 7.5 14.1 6 7

Apr-09 15 16.4 7.5 8.3

May-09 15 16 5.5 6.4

Jun-09 9 10 6.5 8.5

Jul-09 5.5 6.8 7.5 7


63

Natural variability in site depth can also occur at sites depending on the position of the boat, the

size of the boat, tides and position from which the CTD is lowered (must remain out of boat

shadow).

Comparability of CTD and laboratory results

A small number of discrepancies were found between the CTD and laboratory results. It is

expected that differences in results will arise due to the different methodology used in collecting

the samples and the time of the analysis. Further factors that may also cause discrepancies

include turbulence off the hull, differences in sampling times and differences in collection point of

the sample.

The only result identified of concern was DO at Hobsons Bay in March 2009 with a difference of

32.8% saturation between the laboratory and CTD. The CTD profile in Figure A4.1 shows the

unstable DO values throughout the cast while temperature and salinity remained fairly stable. It is

unknown what caused the DO values to fluctuate so widely but is likely to have been a result of

air bubbles.

Figure A4.1 Inconsistent CTD depth recordings (March 2009)

Calibration of the CTD

The regular CTD used for water quality monitoring was sent to America for an annual

manufacturer’s calibration following the March 2009 sampling.

Use of back-up CTD in April and May

A back-up CTD was used to collect in-situ data for the water quality monitoring program in April

and May 2009 while the regular CTD was undergoing annual calibration.

A scalar (spherical) PAR sensor rather than the usual planar (flat) sensor was the only available

option for recording PAR during these months. The use of the spherical sensor allows light to be

captured from all directions resulting in considerably higher PAR readings in April and May 2009


than previously recorded for the program. The resulting data collected using the back-up CTD

was therefore not directly comparable with the existing dataset. This was not considered

significant as there are no control limits for assessing PAR when expressed as micromole/m2/sec.

EPA investigated methods for comparing data from different PAR sensors and identified a simple

method that enables comparison when data is converted to attenuation (assuming R2 >0.8) rather

than micromole/m2/sec.This conversion of data to attenuation allows for assessment against the

SEPP (WoV) 90th percentile objective (schedule F6). This will occur in future milestone reports.

Comparability of regular and back-up CTD

An inter-comparison of the two CTDs used for the Water Quality Monitoring Program was

undertaken during the June 2009 sampling event. The two CTDs were lowered through the water

column side by side at each site by different operators. Overall the two CTDs showed good

comparability for most parameters. Differences were observed for turbidity and fluorescence

although they were not considered significant. Results seen at some sites may have been

influenced by handling and environmental/spatial variation within the site. Either CTD is

considered appropriate for use in collecting in situ measurements for the water quality monitoring

program. There are QA/QC protocols now in place to check the accuracy of the instruments on a

monthly basis together with annual manufacturer calibration.


65

APPENDIX 5 - RESULTS OUTSIDE OF NATURAL/EXPECTED VARIABILITY

As outlined in the Detailed Design (Decision Framework for Management) PoMC led an

assessment of results flagged as outside of natural/expected variability.

In summary, the assessment undertakes the following basic steps:

1. Are the results outside natural/expected variability? This is a two part question:

a) Are results outside of expectations based on our understanding of ‘natural’ historical

background conditions in the Bay? - This is determined by assessing results against control

limits.

b) If the results exceed control limits then they are deemed to be ‘outside of natural

variability’. Are such results outside of our expectations based on the predicted effects of the

CDP, as defined in the Supplementary Environment Effects Statement (SEES) – This

assessment is based on expert opinion.

2. If results are deemed to be ‘outside expected variability’, then a decision is made to

determine if these changes are significant to the environment. This will consider issues such as:

• The accuracy of the results

• The magnitude of deviation from expectations

• The temporal and spatial extent of changes

• The biological significance of changes.

3. Under the Decision Framework for Management, if an assessment concludes that results are

of significance to the environment then further risk-based investigations are initiated to identify

flow on effects to the ecosystem, the causal factor/s and any required management measures.

PoMC Assessment

Multiple lines of evidence are considered to assess whether the results are outside of expected

variability. All results up to June 2009 have been reviewed by the PoMC with the identification of

the following issues and outcomes summarised in Table A5.1.


66

Table A5.1 PoMC Assessment (February – June 2009)

PARAMETER SITES EXCEEDENCE TYPE DATES ASSESSMENT OUTCOME

Yarra River at Newport Feb - Jun 09

Middle Ground Shelf Apr-09

PoM DMG Dromana

Hobsons Bay Jun-09

These exceedences can be attributed to dredging as a Trailing Suction Hopper Dredger was active on the sampling days, decreasing water clarity at sites adjacent to dredging.

Hobsons Bay PoM DMG Corio Bay Long Reef

Feb-09 Natural processes, including wind, storms, local currents and tides can affect water clarity. Winds and rough conditions reported during the sampling period indicate results are insignificant.

Water Clarity (Secchi Depth and Turbidity)

Long Reef

SEPP (Secchi depth) ANZECC (Turbidity)

Mar-09 Evidence of increased phytoplankton growth reducing clarity indicates the result is biologically insignificant.

Dissolved Oxygen Yarra River at Newport SEPP Jun - Jul 09

These exceedences are likely to be short-lived and are not considered significant. These results are within the historical range and DO is influenced by a range of environmental conditions, and can vary substantially over short (hours) and large (seasonal) time scales.

Dromana EWMA Feb – Jun 09

This result is not considered to be biologically significant as ammonium concentrations at Dromana have returned exceedences of the control limits since November 2007. These exceedences are thought to be associated with a baseline shift in concentrations since the 1990's. Furthermore, the control limit is low when compared to control limits from other sites, and is based on a small historical dataset.

Ammonium

POMC DMG Shewhart Feb-09

The result exceeded the Shewhart limit and is outside of historical range which is based on a < 2 year dataset. The concentration is within the historical range of the neighbouring site, Central Bay and is therefore not considered to be biologically significant.


67


Shewhart May-09

Jan - Mar 09 Corio Bay EWMA

May - Jul 09

Exceedences are due to a small underlying trend of increasing NOx which has also been seen in previously (May 2002 - June 2003). Results are unlikely to be biologically significant as they are within the historical range but will be further assessed if trend continues.

Middle Ground Shelf Shewhart Jun-09

Sorrento Bank EWMA Jun - Jul 09

Although the concentrations are outside of historical range, small datasets are informing these sites. Peaks have occurred previously (May, July and August 2008) at these sites and although lower concentrations were shown in July, these peaks are still influencing EWMA values. Results are therefore considered not to be biologically significant.

Nitrate plus nitrite

Dromana Shewhart Jun-09 This result is within the historical range and is thought to be transitory as the July result is below control limits.

Yarra River at Newport EWMA Feb - Jul 09

Corio Bay EWMA May-09 Chlorophyll-a

Sorrento Bank EWMA May - Jul 09

Conditions were localised and annual median and 90th percentile results were below the SEPP objectives. All raw results were within the historical range except at Sorrento Bank. The evidence indicates results are not biologically significant.

Filtered and unfiltered nutrient comparison

All sites N/A Apr - Jun 09 An investigation is underway to determine the magnitude of difference between unfiltered and filtered results and the possible impact on using control limits based on historical (unfiltered) data to assess filtered data.

Arsenic Patterson River

Dromana EWMA Jan - Jun 09

Investigation concluded that results are affected by systematic sampling and/or analysis-based difference that occurred in the late 1990's on the EWMA limits at these two sites.

Yarra at Newport Jan 09

Apr - Jun 09 Chromium

Hobsons Bay

Shewhart

Jun-09

These results are within historical range and as the total and dissolved fractions below the SEPP objective they are not considered to be biologically significant.

Mercury Popes Eye ANZECC Jun-09

The total mercury concentration was 0.1 µg/L, which is equal to the ANZECC trigger value. As the dissolved (bio-available) mercury concentration was <0.1µg/L, it is not considered biologically significant and was identified as a transient elevation.


68


Yarra at Newport Shewhart

Cadmium

PoM DMG Central Bay

Sorrento Bank Middle Ground Shelf

Popes Eye Patterson River

SEPP Jun-09

In all instances the cadmium concentration exceeded the limit/SEPP objective by small margins and in all cases would be within the accuracy of the laboratory reporting. The July 2009 results were below the LOR at each of the sites indicating that the positive results in June were transient.

Central Bay May-09

Zinc

Patterson River

SEPP

Jun-09

The dissolved (bio-available) concentrations were below the SEPP objective (<5 µg/L). It is not considered biologically significant and was identified as transient elevations.

Withheld zinc results based on the review of laboratory QAQC results.

All sites N/A Mar-09 Missing data will not impact on long term assessments.


69

APPENDIX 6. CONTROL CHART DATA (NOVEMBER 2007 – JULY 2009)

Notes: Where the historical mean is plotted below the limit of reporting (LOR), data without imposed reporting limits was used in calculations.

Legends on control charts have been generated using the EPA WIMS database. Additional clarification around labels is provided. Curr </> LOR: For all parameters (except Secchi disc depth) the result is below the LOR.

For Secchi disc depth the Secchi disc was visible on the bottom. Hist mean: EPA historical mean Hist*mean: Historical mean value was obtained from Emphron (2007)

26

26 Emphron Informatics Pty Ltd 2008 Channel Deepening Project Bay-wide Monitoring Programme Water Quality (Report 2007/172)


70

A6.1 Control chart data for secchi disc depth


71


72


73

A6.2 Control chart data for dissolved oxygen


74


75


76

A6.3 Control chart data for chlorophyll-a


77


78


79


80


81


82

A6.4 Control chart data for ammonium


83


84


85

ANZECC F6 and F7 value are the same


86


87


88

A6.5 Control chart data for nitrate plus nitrite


89


90

The Shewhart limit is equal to ANZECC F6


91



92


93


94

A6.6 Control chart data for total nitrogen


95


96


97



98


99


100

A6.7 Control chart data for phosphate


101


102


103



104


105


106

A6.8 Control chart data for total phosphorous


107


108


109



110


111


112

A6.9 Control chart data for arsenic


113


114

SEPP F6 value equals the historical mean


115


116


117

A6.10 Control chart data for cadmium


118


119


120

A6.11 Control chart data for chromium


121


122


123

A6.12 Control chart data for copper


124


125


126

A6.13 Control chart data for lead


127


128


129

A6.14 Control chart data for mercury


130


131


132

A6.15 Control chart data for nickel


133


134


135

A6.16 Control chart data for zinc


136


137

SEPP F6 is equal to the historical mean SEPP F6 is equal to the historical mean


138

A6.17 Control chart data for TBT


139

APPENDIX 7. - SUMMARY STATISTICS (AUGUST 2008 – JULY 2009)

Note: SEPP (WoV) Schedule F6/F7 exceedences are highlighted in blue.

Table A7.1 Yarra River at Newport summary statistics – Schedule F7 Yarra Port Segment Objectives

Dissolved

Arsenic

Dissolved

Chromium

Dissolved

Zinc

Dissolved

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Total

Mercury

SEPP objective µµµµg/L 50 10 5 0.2 3 15 1 <0.05

Mean 2.3 0.9

Median 2.2 <0.5 <5 <0.2 <1 0.8 <0.2 <0.1

90th percentile 2.9 <0.5 9 <0.2 <1 1.2 <0.2 <0.1Minimum 1.8 <0.5 <5 <0.2 <1 0.7 <0.2 <0.1

Maximum 3.1 <0.5 10 <0.2 <1 1.4 0.6 <0.1

N 12 12 11 12 12 12 12 12

Dissolved Oxygen

Dissolved

Oxygen Salinity Temperature Turbidity Turbidity

Suspended

Solids

Suspended

Solids

%sat

SEPP objective

%sat mg/L deg C NTU

SEPP

objective

NTU mg/L

SEPP objective

mg/L

Mean 94 34.7 16.6 7.5 12.1

Median 92 35.5 16.8 5.9 <20 9.6 <25

90th percentile 100 36.3 22.1 15.3 <50 24.9 <60

Minimum 87 >60 27.8 10.1 2.1 3.5

Maximum 106 36.8 22.9 24.3 29.1

N 12 12 12 12 12


140

Table A7.2 Yarra River at Newport summary statistics – Schedule F6 Hobsons Segment objectives

Total

Arsenic

Total

Chromium Total Zinc

Dissolved

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury Tributyl Tin

SEPP objective µµµµg/L <3 <5 <10 <5.5 <1.3 <70 <4.4 <0.4 <0.006

Mean 2.6 0.9

Median 2.6 <0.5 <5 <0.2 <1 0.8 <0.2 <0.1 <0.002

90th percentile 3.1 1.6 11 <0.2 <1 1.2 <0.2 <0.1 <0.002Minimum 1.9 <0.5 <5 <0.2 <1 0.7 <0.2 <0.1 <0.002

Maximum 3.2 1.7 14 <0.2 <1 1.4 0.6 <0.1 <0.003

N 12 12 11 12 12 12 12 12 12

Dissolved

Oxygen

Dissolved

Oxygen Salinity Temperature

Secchi

Depth Secchi Depth Chlorophyll-a Chlorophyll-a

%sat

SEPP

objective

%sat mg/L deg C metres

SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 94 34.7 16.6 1.1 2.12

Median 92 35.5 16.8 1.1 1.82 2.5

90th percentile 100 36.3 22.1 1.9 3.90 4.0

Minimum 87 >90 27.8 10.1 0.2 >2 0.70

Maximum 106 36.8 22.9 1.9 5.13

N 12 12 12 12 12


141

Table A7.3 Hobsons Bay summary statistics

Total

Arsenic

Total

Chromium Total Zinc

Dissolved

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury Tributyl Tin

SEPP objective µµµµg/L <3 <5 <10 <5.5 <1.3 <70 <4.4 <0.4 <0.006

Mean 2.7

Median 2.8 <0.5 <5 <0.2 <1 0.7 <0.2 <0.1 <0.002

90th percentile 3.0 1.4 <5 <0.2 <1 0.8 <0.2 <0.1 <0.002Minimum 2.2 <0.5 <5 <0.2 <1 <0.5 <0.2 <0.1 <0.002

Maximum 3.2 3.0 <5 0.2 <1 0.9 0.3 <0.1 <0.002

N 12 12 11 12 12 12 12 12 12

Dissolved

Oxygen

Dissolved


Secchi


%sat

SEPP

objective


SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 97 36.9 16.0 2.6 1.50

Median 96 36.8 16.4 2.9 1.25 2.5

90th percentile 100 37.5 20.3 3.8 2.18 4.0

Minimum 88 >90 35.3 9.4 0.3 >2 0.97

Maximum 105 37.6 21.6 4.3 2.31

N 12 12 12 12 12


142

Table A7.4 Corio Bay summary statistics

Total

Arsenic

Total

Chromium Total Zinc

Dissolved

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury

SEPP objective µµµµg/L <3 <5 <5 <5.5 <1.3 <70 <4.4 <0.4

Mean 2.8

Median 2.8 <0.5 <5 <0.2 <1 0.8 <0.2 <0.1

90th percentile 3.4 0.7 <5 0.2 <1 1.1 <0.2 <0.1Minimum 2.4 <0.5 <5 <0.2 <1 <0.5 <0.2 <0.1

Maximum 3.8 1.7 <5 0.2 <1 1.1 <0.2 <0.1

N 12 12 11 12 12 12 12 12

Dissolved

Oxygen

Dissolved


Secchi


%sat

SEPP

objective


SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 96 38.1 15.5 3.9 1.04

Median 96 37.9 16.2 4.0 0.80 1.5

90th percentile 102 38.7 20.4 5.1 2.17 2.5

Minimum 92 >90 37.5 9.8 1.9 >3 0.23

Maximum 105 38.7 21.4 5.6 2.54

N 12 12 12 12 12


143

Table A7.5 Long Reef summary statistics

Total

Arsenic

Total

Chromium Total Zinc

Dissolved

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury


Mean 2.7

Median 2.7 <0.5 <5 <0.2 <1 0.8 <0.2 <0.1

90th percentile 2.9 0.6 <5 <0.2 <1 1.0 <0.2 <0.1Minimum 2.3 <0.5 <5 <0.2 <1 <0.5 <0.2 <0.1

Maximum 3.0 1.9 <5 0.2 <1 2.1 <0.2 <0.1

N 12 12 11 12 12 12 12 12

Dissolved

Oxygen

Dissolved


Secchi


%sat

SEPP

objective


SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 97 37.4 15.6 4.3 1.13

Median 96 37.3 15.8 4.8 1.04 2.5

90th percentile 103 37.9 21.0 5.7 1.57 4.0

Minimum 91 >90 36.4 9.1 1.2 >3 0.47

Maximum 109 38.2 21.2 5.9 2.57

N 12 12 12 12 12


144

Table A7.6 Central Bay summary statistics

Total

Arsenic

Total

Chromium Total Zinc

Total

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury


Mean 2.7

Median 2.8 <0.5 <5 <0.2 <1 0.6 <0.2 <0.1

90th percentile 3.0 <0.5 7 <0.2 <1 0.9 <0.2 <0.1Minimum 2.3 <0.5 <5 <0.2 <1 <0.5 <0.2 <0.1

Maximum 3.1 0.6 7 0.2 <1 0.9 0.3 <0.1

N 12 12 11 12 12 12 12 12

Dissolved

Oxygen

Dissolved


Secchi


%sat

SEPP

objective


SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 97 37.2 15.7 7.0 0.74

Median 96 37.1 16.1 6.7 0.73 1.0

90th percentile 99 >90 37.6 19.5 8.4 1.05 2.0

Minimum 93 >90 36.8 10.2 4.2 >4 0.25

Maximum 100 37.6 22.0 12.1 1.45

N 12 12 12 12 12


145

Table A7.7 POM DMG summary statistics

Total

Arsenic

Total

Chromium Total Zinc

Total

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury


Mean 2.6

Median 2.5 <0.5 <5 <0.2 <1 0.6 <0.2 <0.1


Maximum 3.1 0.7 <5 0.2 <1 0.8 0.3 <0.1

N 12 12 11 12 12 12 12 12

Dissolved

Oxygen

Dissolved


Secchi


%sat

SEPP

objective


SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 96 37.2 15.7 5.8 0.73

Median 96 37.1 16.1 4.9 0.72 1.0

90th percentile 100 >90 37.6 19.3 8.4 1.10 2.0

Minimum 93 >90 36.9 10.8 2.4 >4 0.24

Maximum 100 37.7 22.1 11.6 1.25

N 12 12 12 12 12


146

Table A7.8 Patterson River summary statistics

Total

Arsenic

Total

Chromium Total Zinc

Total

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury


Mean 2.6

Median 2.7 <0.5 <5 <0.2 <1 0.7 <0.2 <0.1

90th percentile 2.9 <0.5 6 <0.2 <1 0.9 <0.2 <0.1Minimum 2.3 <0.5 <5 <0.2 <1 <0.5 <0.2 <0.1

Maximum 2.9 1.0 8 0.2 <1 1.1 <0.2 <0.1

N 12 12 11 12 12 12 12 12

Dissolved

Oxygen

Dissolved


Secchi


%sat

SEPP

objective


SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 97 36.9 16.0 5.0 0.87

Median 97 36.9 16.9 5.2 0.81 1.5

90th percentile 100 37.4 19.5 7.1 1.31 2.5

Minimum 90 >90 35.5 10.1 2.8 >3 0.35

Maximum 100 37.4 21.8 8.2 2.32

N 12 12 12 12 12


147

Table A7.9 Dromana summary statistics

Total

Arsenic

Total

Chromium Total Zinc

Total

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury


Mean 2.6

Median 2.7 <0.5 <5 <0.2 <1 <0.5 <0.2 <0.1


Maximum 3.0 2.2 76 <0.2 <1 1.8 <0.2 <0.1

N 12 12 11 12 12 12 12 12

Dissolved

Oxygen

Dissolved


Secchi


%sat

SEPP

objective


SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 98 36.8 16.0 5.3 0.73

Median 97 36.9 16.4 5.5 0.68 1.5

90th percentile 101 37.3 19.8 6.8 1.10 2.5

Minimum 94 >90 36.2 11.1 2.9 >3 0.28

Maximum 106 37.4 21.4 7.1 1.52

N 12 12 12 12 12


148

Table A7.10 Middle Ground Shelf summary statistics

Total

Arsenic

Total

Chromium Total Zinc

Total

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury


Mean 2.6

Median 2.5 <0.5 <5 <0.2 <1 0.5 <0.2 <0.1


Maximum 3.2 0.7 <5 0.2 2 0.7 <0.2 <0.1

N 12 12 11 12 12 12 12 12

Dissolved

Oxygen

Dissolved


Secchi


%sat

SEPP

objective


SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 97 36.9 15.8 6.3 0.68

Median 97 36.9 16.1 5.9 0.67 1.0

90th percentile 100 >90 37.3 19.8 9.2 1.07 2.0

Minimum 94 >90 36.5 10.2 2.5 >4 0.27

Maximum 101 37.3 21.2 9.3 1.21

N 12 12 12 12 12


149

Table A7.11 Sorrento Bank summary statistics

Total

Arsenic

Total

Chromium Total Zinc

Total

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury


Mean 2.2

Median 2.2 <0.5 <5 <0.2 <1 <0.5 <0.2 <0.1

90th percentile 2.5 <0.5 <5 <0.2 <1 0.6 <0.2 <0.1Minimum 1.8 <0.5 <5 <0.2 <1 <0.5 <0.2 <0.1

Maximum 3.1 <0.5 10 0.2 <1 1.3 <0.2 <0.1

N 12 12 11 12 12 12 12 12

Dissolved

Oxygen

Dissolved


Secchi


%sat

SEPP

objective


SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 97 36.2 15.8 3.3 0.76

Median 98 36.2 15.9 3.3 0.72 1.0

90th percentile 100 >90 36.6 19.8 3.8 1.05 2.0

Minimum 93 >90 35.9 11.1 2.7 >4 0.41

Maximum 104 36.6 20.2 4.0 1.41

N 12 12 12 12 12


150

Table A7.12 Popes Eye summary statistics

Total

Arsenic

Total

Chromium Total Zinc

Total

Cadmium

Dissolved

Copper

Dissolved

Nickel

Dissolved

Lead

Dissolved

Mercury


Mean 2.0

Median 2.0 <0.5 <5 <0.2 <1 <0.5 <0.2 <0.1

90th percentile 2.2 0.7 <5 <0.2 <1 <0.5 <0.2 <0.1Minimum 1.6 <0.5 <5 <0.2 <1 <0.5 <0.2 <0.1

Maximum 2.7 1.0 <5 0.2 <1 <0.5 <0.2 <0.1

N 12 12 11 12 12 12 12 12

Dissolved

Oxygen

Dissolved


Secchi


%sat

SEPP

objective


SEPP objective

metres µµµµg/L

SEPP objective

µµµµg/L

Mean 97 35.9 15.9 9.0 0.58

Median 97 35.7 16.2 8.5 0.49 1.0

90th percentile 101 >90 36.4 18.9 10.9 0.87 2.0

Minimum 93 >90 35.6 12.1 7.0 >4 0.31

Maximum 102 37.3 19.6 13.3 1.04

N 12 12 12 9 12

BAYWIDE WATER QUALITY MONITORING PROGRAM MILESTONE REPORT...

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