Background Concentrations of Inorganic Elements … · Background Concentrations of Inorganic...

Background Concentrations of InorganicElements in Soils from the Auckland Region

AucklandRegional CouncilTE RAUHITANGA TAIAO

IIIII• Background Concentrations ofI Inorganic Elements in SoilsI from the Auckland RegionIIIIIIIIII

Auckland Regional Council

f Technical Publication No. 153, October 2001,Reprinted April 2002.ISSN1175205XPrinted on recycled paper

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TABLE OF CONTENTS

SUMMARY 31. INTRODUCTION : 5

7.7 Trace Elements in the Environment 51.2 What Does "Background" Mean? 61.3 Why Attempt to Determine Background Levels? 71.4 What is an Appropriate Methodology? 71.5 Background Concentrations and the Auckland Regional Sampling Program 7

2. SAMPLING DESIGN 92.1 Soils 92.2 Sample Collection • 92.3 Sample Preparation and Analysis 752.4 Recommended Standards of Analysis for Comparison to Background Ranges 77

3. RESULTS FROM REGIONAL SOILS 193.1 Analytical Approach 193.2 Statistical Analyses of Elements Within the Major Soil Groups for the Determination ofBackground Ranges 203.3 Arsenic 253.4 Barium 253.5 Boron 253.6 Cadmium 263.7 Chromium 263.8 Cobalt 263.9 Copper 273.10 Lead ; 273.11 Magnesium 273.12 Manganese 273.13 Mercury 283.14 Nickel 283.15 Nitrogen 283.16 Phosphorus 283.17 Potassium 293.18 Sulphur 293.19 Tin 293.20 Vanadium 293.21 Zinc 303.22 Total Organic Carbon 30

4. DISCUSSION 314.1 Volcanic Soils in the Auckland Region 314.2 Volcanic Processes and Potential Impact on Other Soil Types 314.3 The Non-Volcanic Soils Grouping 314.4 Specific Lithologies 314.5 Auckland Region Background Ranges 314.6 Background Soil Concentrations Applicability to Soil Investigations in Auckland. 33

5. RECOMMENDATIONS 356. ACKNOWLEDGEMENTS 357. REFERENCES '. 37

ARC Technical Publication No. 153

IFIGURES •Figure 1: Sample Locations in the Greater Auckland Region 10 •Figure 2: Sample Locations in the Central Auckland Region 10Figure 3: Schematic plan showing sample layout around a central point 'X' 10 mFigure 4: Linear Sample Location Layout 15 IFigure 5: Process and Decision Tree for Inclusion or Exclusion of Outlier and Extreme Data Values 24Figure 6: Definition of Outliers and Extremes 25

TABLES •

Table 1: Laboratory Detection Limits for 1999 Samples 16 •Table 2: Laboratory Detection Limits for 2001 Samples 17 |Table 3: Background Ranges of Trace Elements in Auckland Soils 32

APPENDICES |Appendix 1: Sampling Site LocationsAppendix 2: Sample Analytical Results _Appendix 3: Statistical Analyses •


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SummaryThe objective of this Auckland Regional Council (ARC) study was to establishbackground total recoverable levels of a number of trace elements in soil samplesfrom major soil groups of the Auckland Region. Soil samples were collected from 91locations in May 1999 from publicly owned rural and urban land on soils derived fromthe major lithological units of the region. In October 2001, to confirm the validity ofoutlier data obtained during the 1999 survey, fifteen of these sites were revisited, andsampled for further analysis.

The survey's design comprised geographically directed near-surface sampling withcategories being based on underlying rock type. Sites were selected to berepresentative of the lithological units, with specific sites chosen based on evidenceof minimal surface disturbance and ease of access. Samples of surficial soils (0-150mm) were collected and analysed by varying methods for total recoverable arsenic(As), barium (Ba), boron (B), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu),lead (Pb), magnesium (Mg), manganese (Mn), mercury (Hg), phosphorus (P),potassium (K), nickel (Ni), nitrogen (N), sulphur (S), tin (Sn), vanadium (V), zinc (Zn),and total organic carbon (TOC).

Environmental investigation threshold levels should be related to the local or regionalbackground levels of the elements. Certain environmental investigation thresholdlevels need to be reconsidered for the Auckland context in view of these results. TheAustralian and New Zealand Guidelines for Assessment and Management ofContaminated Sites (ANZECC/NHMRC 1992) recommends the evaluation ofbackground levels as a consideration in the determination of remediation goals. Thedata collected in this survey of total recoverable trace elements in soils of theAuckland Region can be used in this context, with the general background datareported by this study substantiated by site specific information where required.


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1. Introduction

In the absence of New Zealand-based criteria for determining whether theinvestigation of contaminants in soils is required, there has emerged a reliance on theresponse of overseas authorities'to the management of contaminated land. Thepractice of consultants and health and environmental authorities using offshoreinformation in the absence of New Zealand soil and groundwater quality orbackground standards has resulted in the application of criteria based on soil types,climate, hydrogeology and a groundwater consumption pattern not especially relevantto the New Zealand situation. The promotion and development of a site-specific, risk-based approach to the assessment of the health and environmental effects of soil andgroundwater quality presents the opportunity for the investigation of criteria relevantto New Zealand.

The Resource Management Act, 1991, (RMA) promotes effects-based considerationof environmental quality, prioritising a need to know the background levels and theircorresponding effects, prior to consideration of detected levels and their effects onthe environment or human health. The introduction of appropriate investigation ortrigger levels for contaminants must be carried out with an awareness of backgroundlevels of those contaminants in New Zealand, or sub-regions of the country. Tracemetal levels and some corresponding inorganic trace elements are the mostcommonly studied due to their ease of determination and will form the focus of thisreport.

There is little published specific information on background levels of trace elements inAuckland soils although a large corpus of information resides in University theses,consultancy and soil laboratory archives and various governmental department files.The on-going redevelopment of land and increasing numbers of investigations ofsuspect sites being conducted are describing levels of metals, the significance ofwhich may be difficult to interpret without knowledge of local background values.

The development of a site-specific, risk-based approach to the assessment ofcontaminants in land needs soil criteria relevant to the Auckland context andestablishing background levels of contaminants in soils is basic information requiredfor this task.

1.1 Trace Elements in the EnvironmentConcentrations of trace metals in surface soils are primarily the result of localgeological and soil forming factors. Accumulation or dilution of trace elements withinthe environment occurs due to physical deposition, or other geo- or hydro-chemicalprocesses. Redistribution from subsurface mineral deposits into the surfaceenvironment, commonly associated with urbanisation, agricultural and industrialactivities, has also resulted in the accumulation of these elements in near-surfacesoils and sediments. Historically therefore, human exposure to some trace elementconcentrations in soil would have been lower than those detected today.

The effects of such changes in soil quality and the resulting increase in exposure overlong time-scales are unknown. In considering "background" concentrations of traceelements in soils, particularly heavy metals, we must take note of the variable anddispersed emissions that occur in urbanised areas. Additionally the long half-lives ofuncomplexed metal contaminants in soils must also be considered.

The Auckland urban environment may have levels of heavy metals and othercontaminants that are elevated compared to those found in natural, pristine soils.Any elevated levels tend to be trace element specific, such as the contribution ofvehicle emissions and removal of lead-based paints to lead levels in urban soils.


I1.2 What Does "Background" Mean? •There is always a range of concentration values associated with, or typical of an area »for any trace element investigated. The Australian and New Zealand Guidelines forthe Assessment of Management of Contaminated Land (ANZECC/NHMRC, 1992) •define background levels as "ambient levels of a contaminant in the local area of the £site under consideration." Background may be taken to be "pristine" soils unaffectedor relatively so by human activity. Due to the development history of the AucklandRegion, and global transport of contaminants even in the hinterlands, pristine •background areas may be rare. •

The definition of "background level" used in this report is "concentrations of an _element in soils which can not be attributed to any identifiable event or activity other •than normal lithological processes and is considered representative of the levels to be •found wherever relatively undisturbed soil derived from an identifiable parent rockmaterial exists at or near the surface". •

Soils at or near sites known to be contaminated due to nearby activities would be ™excluded as part of this survey regardless of other elements being within"background" concentrations. Decisions as to where point source effects end and •ambient levels begin made in the course of this exercise have been somewhat garbitrary but are based on knowledge of activities and contaminated sites throughoutthe Auckland Region held by the ARC. _

A statistical evaluation of analytical data distributions and characteristics of the soil £that differentiate trace element sources is required in order to comprehensivelyunderstand the meaning of background concentrations. While urban soilconcentrations may have contributions from regional and local urban activities, •elevated rural soil levels are equally likely to arise from incremental additions of soil •amendments as a result of rural activities. Regional scale effects such as leachingdue to acid rain and resultant transport of heavy metals through soil are much less •relevant in New Zealand than in the Northern Hemisphere. Very low, but detectable •levels of trace element deposition do occur from Australia but these are thought to berelatively uniform and are not considered separately.

Background values of heavy metals commonly reflect variations in the composition of J|parent rock material that can be quite localised, e.g. in the Auckland Region theisthmus volcanic field has a naturally high level of nickel, generally exceedingpublished investigation levels. •

Interpretation of ambient soil metal concentration data requires an understanding ofhow sample site selection, sample depth, sample preparation and analyticaltechnique, bias analytical determinations. This is important where a range of •sources, metal species and soil particle size distributions contribute to metal mconcentrations but is beyond the scope of this report.

Geographic scale of an investigation may render studies incomparable from place to Wplace so some account of data distributions should be investigated prior to designing mstudies to determine what levels may be representative of large areas. When soil-type background concentrations are related to specific areas of contaminated land,local background concentrations should also be assessed, where possible.

ARC Technical Publication No.153

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1.3 Why Attempt to Determine Background Levels?In 1992 the Australian and New Zealand Environment and Conservation Council(ANZECC) and the National Health and Medical Research Council (NHMRC) jointlydeveloped technical guidelines for use as a framework for the assessment andmanagement of contaminated sites. These Guidelines have been adopted by the NewZealand Government for guidance only; they do not have statutory force, however theyhave become widely used throughout New Zealand, and are the basis for a number ofother guideline documents.

Information on background soil levels is required to provide a baseline on which siteremediation can be based. The ANZECC/NHMRC (1992) guidelines recommend theevaluation of background levels as a consideration in the determination of sitespecific clean up and that such guidelines will have regional and site specific uses.The ANZECC/NHMRC (1992) background soil concentrations were compiled fromAustralian soil data derived from parent rock types significantly distinct from Aucklandrock types. Compiled data from this study will therefore be used to place Auckland'sregional soil inorganic element concentrations into context, giving a realistic reflectionof inorganic element distributions in soils specific to the Auckland region.

1.4 What is an Appropriate Methodology?Sample site selection, sampling methodology, and analytical protocols need to becarefully considered in order for investigations of background values to havemeaning. Distances from point, linear and non-point (diffuse) sources of traceelements may all influence concentrations determined in soils. Determinations ofaverage soil concentrations of an area are not universally meaningful. Any dataobtained will only have meaning if there is an accurate description of surveymethodology.

Averages obtained can be meaningless, particularly in environmental data sets thatare commonly significantly skewed. Additional measures of distribution and centraltendency such as median and geometric means can be useful depending on theparticular issues being dealt with. For soils there needs to be confidence in theidentification of the soil type sampled to confirm that the relevant information isapplied to the sample and interpreted from its results.

While interpretations of soil surveys using only total metal extraction techniques onsingle measured soil intervals may have limited practical value beyond the localsetting, such information provides the basis for further more detailed studies includingindividual location sampling, vertical interval sampling, metal speciation studies and.bioavailability assessment. In this study only total metals values have been reported.

1.5 Background Concentrations and the Auckland RegionalSampling ProgramA key requirement for obtaining background levels is to find soils which have beenrelatively undisturbed since their formation. Given that anthropogenic disturbance isubiquitous across the Auckland Region, soils that have not been significantlydisturbed for a significant period was the best alternative. All sampling locations wereassessed for the likelihood of anthropogenic disturbance in the last 50 years. Whereit was considered disturbance had not occurred or was unlikely, samples wereacquired.

Soils were not sampled in urban situations where there were nearby anthropogenicsources of trace metals from local industries likely to provide spurious outliers in thedata set. Analytical results for the uppermost 150 mm of soil have been emphasisedas this represents a commonly investigated initial or screening sample interval.

Localised dustfall or stormwater ponding could focus concentration of elements at thesurface in certain locations. For this reason low-lying areas and sites near to

ARC Technical Publication No.153

Isignificant dust generating sites were avoided where possible. Soil organic and clay £matter can intercept and retain trace elements so soil carbon levels were collected forassessment, however particle size analysis was not considered in these studies. _

Contaminant concentrations within soils derived from similar geological parent £materials may show some heterogeneity both within a localised area and over longdistances. Single "point" samples were collected from each site in the 1999 .investigation, giving a range of concentrations within a single soil type across the •Auckland Region. Insufficient samples were collected during the 1999 study to ™delineate the variation within soils at each sampling locality. The purpose of theOctober 2001 investigation was to both re-sample sites where 'outlier' or 'extreme' •concentrations of individual elements were recorded, and to collect additional psamples for analysis to gauge variability of trace element concentrations within alocalised area. —

To further assess the impact of anthropogenic sources on soils sampled as p"background" and undisturbed, a vertical profile of trace element concentrationsshould be established. Stratification of trace elements results from air deposition of ^particulates, which, if present, would be present in higher concentrations in the upper •;•soil layer than lower ones. ;™


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2. Sampling Design

2.1 SoilsBaseline data for trace element concentrations were determined on 91 undisturbedsoil samples believed to be only minimally contaminated by human activity. Thesewere all collected from Parks, Forests and public lands from the 8 predominant soilgroups in the Auckland Region.

The eight major soil groups are: Volcanic (Isthmus and South Auckland VolcanicFields, as well as one sample from Kerikeri Volcanics at Ti Point), Waitemata GroupFlysch, Quaternary Sedimentary Deposits, Sands, Greywacke, Limestone, OnerahiChaos Breccia and Manukau Breccia. These are commonly recognised names formajor geological units within the Auckland Region and sampling locations wereselected from 1:250,000 Geological Maps of New Zealand assisted by topographicalinformation from NZMS260 series maps.

In 1999, a total of 91 different sites were examined, and at each site a single 150 mmcubic soil monolith was taken at a single point location. Due to budgetary constraintsthe values represent single sample maxima and no statistical confidence could begiven to values obtained. Fifteen selected sites were re-visited in October 2001 toenable the validation of outliers reported in the 1999 data set. To gauge thevariability of trace element concentrations at individual sites, and to gain statisticalconfidence and improve data quality, composite sampling was undertaken. Thevalidation samples comprised four samples from each sampling location, with eachsample consisting of four soil cores over a local area (refer to Section 2.2 for samplecollection methodologies). Exact locations were made with the aid of map co-ordinates. The sampling locations are shown on Figures 1 and 2.

Where practicable, samples were collected on topographic highs where the soilprofile was relatively thin and only weakly developed. Collection of samples in low-lying areas was deliberately avoided as these soils could have higher than normalbackground levels as a result of leaching of trace elements from the surroundinghillsides. Pristine soil sample collection was considered unnecessary andimpracticable given the historic development of the region. The criterion of"estimated greater than 50 years since soil profile disturbance" was subjective butcommonly involved sampling in areas where access by mechanical diggers etc.would be restricted and where vegetation or other indicators suggested this asrealistic. Soil surfaces were observed for signs of disturbance and once a hole hadbeen dug for sampling the soil profile was assessed for signs of disturbance such asinterrupted stratigraphy or anthropogenic inclusions.

2.2 Sample CollectionIn the initial 1999 survey, soil samples were collected from the surface to a depth of150 mm. Soils were commonly dug to approximately 0.5 m at each site to assess thesoil profile. A polyester-coated garden spade was used for digging and all thematerial (0 to 150 mm), including soil adhered to surface grass, was collected anddouble bagged for further preparation at the laboratory.

Soil samples were collected as a monolith by delineating an area of approximately150mm square at the soil surface and excavating, as a single piece where possible,all soil to a depth of 150mm. The resulting monolith, weighing between 1.5 and 3kgwhen bagged, had been only minimally disturbed during excavation and had aminimum of surficial contamination. The spade was double washed and rinsed withclean tap water and allowed to air dry between each sample collection.


15 m

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In the October 2001 survey, the 1999 sampling sites were relocated using the givenmap co-ordinates, and their suitability for sampling was visually assessed. Selected «locations were rechecked for potential anthropogenic impact. Since sample localities Ineeded an area large enough to support the collection of samples from 4 locations, ™spaced approximately 15 m apart, some sample sites were relocated when moreappropriate sampling localities existed within a 1 km radius and remained within the •same soil type. |

At the selected validation sampling sites, four sample locations were pegged out(where possible, in cardinal directions from the original 1999 sample site), at ttapproximately 15 m spacing (see Figures 3 and 4). From each of these sample |locations (SL01, SL02, SL03, SL04), four individual soil cores were collected atapproximately 1.0 m spacing (e.g. SL01-01, SL01-o2, SL01-o3, SL01-04). The four •samples were subsequently composited at the laboratory to provide the composite •sample. Soil samples were collected using a stainless steel push-tube soil sampler, *which collects samples from 0-150 mm depth. Clean latex gloves were worn at eachsite when handling the soils. Green vegetation was removed from the samples, ftwhich were collected into 350 ml glass jars with polyethylene seals as supplied by the |analytical laboratory. At one location at each site, a polyester-coated garden spadewas used to dig four holes to 300 mm depth, to log the soil profile and collect samples «from 150 - 300 mm depth. These samples are intended for subsequent analyses for •further assessment of the impact of anthropogenic sources on the soils. ™

All sampling equipment was decontaminated between sites by washing and rinsing ^with clean tap water, and allowing to air dry between each site. •

Figure 3: Schematic plan showing sample layout around a central point 'X' fl

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The 4 main sample locations (SL01 to SL04) were spaced approximately 15 m apart, •with 4 individual cores (o1, o2, o3 and o4) collected at each location spacedapproximately 1.0 m apart.

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FIGURE 1 ASample Locations in the Greater Auckland Region

•t,

Riteakawarau

PebblebrookRd©

Long Bay Regional Park©

For Detail • See Figure 2f}

OrerePtgj

Tapapakanga Hill

Awhitu Central (a)

Awhitu Central (

Patumahoe Reserve (Rutherford Rd (a)

AucklandRegional CouncilIE SAUHITAHCA IAIAO

Produced by GIS UnitOctober 2001

Digital Cadastral Database, LINZCrown Copyright Reserved

0 5 102T

1:400000

15 20 Kilometers

© Volcanics© Waitematas© Quaternary Sediments© Sands

• Greywacke® Limestone© Onerahi Chaos Breccia© Manukau Breccia

Lake Pupuke (Killamey Stp^

FIGURE 2 ASample Locations in the Central Auckland Region

flakapuna Grammar

North Head

Mt Albert

/•Auckland Domain (bj

AucMandDoma'nXa).1 ,

Mi-Eden ^M® •

Orakei Baari /

tEden(b) MtE

/ M t J

Three KingsOne Tree Hill (TCLP) (a)

y Cape Horn

Puketutu I

Kepa Bush-park—' 0

Mt Mangere

Mt Smart (TCLR)

-Pt.E

Pt England Res (b)®~

MtWelliiington (TOT

MtRichn

Pigeon Mountain

Highland Pk-©-

Greenmpunt (a) Greenm?'unt (b>

©

Ihumatao (a)

O Ihumatao (b)

hunui Criiter

Mahuteu City

Mclaughlins Mt-' "'

Redoubt Rd©

Produced by GIS UnitOctober 2001

Digital Cadastral Database, LINZCrown Copyright Reserved

4 Kilometers

LEGEND

© Volcanics© Waitematas© Quaternary Sediments© Sands

• Greywacke® Limestone© Onerahi Chaos Breccia© Manukau Breccia

T / /

AucklandRegional CouncilIt RAUHIHNGA TAIAO


Figure 6: Linear Sample Location Layout

SL01 SL02 SL03 SL04

ol 15m ol 15m ol 15m ol

2o -fy- o3 < ^o -$- o3 ^ ^o -$- o3 ^ ^2 o •$- o3

o 4 o 4 o 4 o 4

The linear sampling layout was used when the sampling location area could notaccommodate the cardinal sample layout (Figure 3).

2.3 Sample Preparation and AnalysisFor the samples collected in May 1999, Watercare Services Laboratory Limited, ofAuckland, were contracted for sample preparation and analyses! The baggedsamples were composited using a quartering technique except where the monolithwas intact. 600-800g of sample was retained for trace element analysis and 50-150gfor total organic carbon analysis. The sample was then dried and passed through a 2mrrrsieve. An aliquot was taken and pulverised in a ball mill.

For total soil trace element levels a 2g aliquot of sample was digested to USEPA3051 a standards (microwave digestion), and the resultant sample was analysedusing inductively coupled plasma optical emission spectroscopy (ICP-OES) for boron,phosphorus, lead, sulpher and tin, atomic absorption spectroscopy (AAS) for barium,cadmium, cobalt, chromium, copper, potassium, magnesium, manganese, nickel,vanadium and zinc, AAS/hydride for arsenic, AAS cold vapour for mercury, titrimetricanalysis for total nitrogen and Leco FP2000 for total organic carbon .

For toxicity characteristic leaching procedure (TCLP) analyses a 2g aliquot of samplewas extracted by USEPA 1312 (TCLP). The resulting sample analysed by ICP-OESfor boron, barium, cadmium, cobalt, chromium, copper, magnesium, manganese,nickel, lead, sulphur, tin, vanadium and zinc, by AAS for potassium, AAS/hydride forarsenic, AAS cold vapour for mercury, digestion/SFA for nitrogen and phosphorusand Leco FP2000 for total organic carbon.

Quality assurance, in addition to standard quality control procedures, involved the useof a secondary standard, and NBS certified soil standard with each batch of samplesanalysed. All data were reported in milligrams per kilogram (mg/kg). Detection limits(in mg/kg) are summarised in Table 1.

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Table 1: Laboratory Detection Limits for 1999 Samples

Parameter (Total Recoverable) Detection Limit (mg/kg)

Arsenic (As)

Barium (Ba)

Boron (B)

Cadmium (Cd)

Chromium (Cr)

Cobalt (Co)

Copper (Cu)

Lead (Pb)

Magnesium (Mg)

Manganese (Mn)

Mercury (Hg)

Nickel (Ni)

Nitrogen (total, N)

Phosphorus (P)

Potassium (K)

Sulpher(S)

Tin (Sn)

Vanadium (V)

Zinc (Zn)

Total Organic Carbon (TOC)

0.025

0.5

3

0.1

1

1.5

1

1.5

5

0.5

0.03

0.7

10

0.5

2

1

1

5

0.15

0.0002%

For the samples collected in the October 2001 survey, RJ Hill Laboratories Ltd, ofHamilton, were contracted for sample preparation and analysis. The samples wereair dried overnight in a forced air oven at 35°C. The dried samples were then handground using a mortar and pestle and passed through a 2 mm sieve. Compositeswere made from individual samples by quartering each sample, then selectingopposite quarters that are placed in a 'composite' tray. The composite is thoroughlymixed before being placed in a container.

Weighed subsamples are digested using US EPA Method 200.2. One gram ofsample plus 7 mL of nitric/hydrochloric/water (1.5:3.5:5) is heated in a water bath at85°C for 45 minutes, made to 20 mL with Type 1 water, filtered or centrifuged and thefiltrate/centrifugate analysed by Inductively Coupled Plasma-Mass Spectrometry(ICP-MS).

The analyses for total sulphur were sub-contracted to SGS, Waihi. Analysis wascarried out by LECO SC32 Sulphur Determinator, high temperature furnace, infra-reddetector, ASTM 4239.

The respective detection limits reported are summarised in Table 2. The analyticalmethods used in the 2001 survey are more commonly used for contaminated landreporting, and the detection limits are well within the thresholds required.




Table 2: Laboratory Detection Limits for 2001 Samples

Parameter (Total Recoverable) Detection Limit (mg/kg)

Arsenic (As)

Barium (Ba)

Boron (B)

Cadmium (Cd)

Chromium (Cr)

Cobalt (Co)

Copper (Cu)

Lead (Pb)

Mercury (Hg)

Nickel (Ni)

Phosphorus (P)

Sulphur (S)

Tin (Sn)

Vanadium (V)

Zinc (Zn)

0.2

0.02

2

0.01

0.2

0.04

0.2

0.04

0.01

0.2

40

400

0.1

10

0.4

2.4 Recommended Standards of Analysis for Comparison toBackground Ranges

Standard preparation methods are required for comparison to the backgroundconcentrations given in this document. It is recommended that soils for analysis aredried overnight at about 30°C and passed through a 2 mm sieve. The digestion andanalysis of the samples may be carried out by any standard method that gives resultscomparable to reference standards. The analytical method used should have ademonstrable 95% precision of 20% or better and the laboratory should be able to showsatisfactory performance in a suitable Interlabbratory Comparison Programme (e.g.Wageningen) for analyses of .inorganic elements in soils samples. Detection limitsshould be 10 times lower than the minimum background values given in Table 3. Wherethe minimum value is preceeded by the '<' symbol, this value is the appropriate detectionlimit.


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3. Results from Regional Soils

A list of the sample site locations for each of the eight major soil types is given inAppendix 1, and includes sample identification numbers and NZMS 260 mapreferences for each sample site. A summary of the complete analytical results (i.e. allraw data) for all soil samples is given in Appendix 2.

Identification of statistically outlier and extreme values provides grounds to questionthe representitiveness of those results, and to determine whether these values werelikely to be part of the actual background soils data set, or whether they may havebeen affected by anthropogenic input, and therefore should be excluded from thebackground soils data set.

3.1 Analytical ApproachThe method used for validating soil data and determining background ranges forthese elements is described below. The following are definitions for the data setsobtained and used in this report:

Raw Data Set. The full set of results for all soil samples obtained from all sites fromboth the 1999 and 2001 investigations (included in Appendix 2).

Site Data Set: The total set of data from a single site that was re-sampled in 2001(these sites now have a total of five analyses, 1 from 1999 and 4 from 2001). Thesedata sets were utilised for the purpose of comparing anomalous results obtained inthe 1999 investigation and validating them with the additional results from the samesite obtained in the 2001 investigation.

Partially Evaluated Data Set: The raw data set with values removed which failed thesite data set validation. This data set still includes anomalous results that weresubsequently validated by the 2001 investigation (i.e. 'Special Case' sites) andoutliers and extremes identified in the 1999 investigation where the site in questionwas not revisited. This data set was used to calculate the statistics given in Appendix3. .

Validated Background Soils Data Set: The partially evaluated data set with thestatistical outlier and extreme values above the 'npn-outlier' volcanic range and the'special case' sites removed, to include only those values deemed as background.This data set was summarised to give the background ranges in Table 3.

The principal process used to assess and validate the collected soil data is describedbelow and illustrated in the flow chart given in Figure 5. Details of the statisticalanalysis used, including definition of outlier and extreme values, are given in Section3.2.

A key approach adopted was to include any non-volcanic soil outlier or extremevalues that lay within the non-outlier range for their respective volcanic soils. Thiswas based on:

i) the potential for a component of volcanic ash to occur within any soil type due tothe natural processes of volcanic eruptions, whereby ash is deposited by aerialdistribution, and

ii) that the greatest range of trace element concentrations were frequentlyexhibited by the volcanic soils.

In 2001, re-sampling of outlier and extreme values at sites identified from the 1999data set was undertaken to provided a set of five data points per locality. Thisenabled a site- specific statistical evaluation of site sample variability and anassessment of the validity of these values at the given site.

ARC Technical Publication No.l53 • 19

iii) Assessment of the validity of the identified outliers and extremes to bebackground values, involving:

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IThe principal steps involved in analysing the soils data set, including the process of Qoutlier and extreme value validation is described below.

i) Site specific verification of the re-sampled sites, using statistical methods to Ivalidate or exclude values. V

ii) Statistical analysis of each trace element within the resultant partially evaluated Adata set to determine the elements' distributions and to identify any remaining •outlier or extreme values within each data set.

Ia) including all non-volcanic outliers and extremes which lie within their

equivalent volcanic soils range.

b) excluding the remaining volcanic soil outliers and extremes that lie outsidethe non-outlier volcanic soils range (except of the major elements K, Mg, N,P, S, TOC)

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c) tagging the data excluded above for further work or, where relevant,identifying a 'Special Case' locality. •

In some instances, validation testing at sites confirmed elevated concentrations,however, the complete set remained outside expected ranges. This situation was —

identified in volcanic soils at Ti Point (Cr), Mt Smart (Pb, Sn), and the Franklin Basalts •(Sn), and within Awhitu Mineral Sands (Mn, V). It is likely that these concentrations ™are a reflection of the mineralogy of the parent material, although at Mt Smartanthropogenic activities may have had some effect. The values obtained from these Asites have been excluded from the statistical analyses in Appendix 3, and the |resultant background ranges, however it is recognised that soils from these locationsneed to be considered individually. _

It was not considered feasible to place any real confidence on the status of the £outliers or extreme values identified in magnesium, nitrogen, phosphorus, potassium,sulphur or total organic carbon ranges since these are all major earth elements, are _commonly found in soil additives and fertilisers, and total organic carbon is simply a •reflection of the organic matter present in soil. •

3.2 Statistical Analyses of Elements Within the Major Soil Groups *for the Determination of Background Ranges m

To ascertain appropriate background ranges for each trace element, statistical ™analyses were carried out for each data set for 6 of the 8 major soil groups. Due toonly 2 samples being taken for both Onerahi Chaos Breccia and Manukau Breccia Bsoil types, no statistics have been calculated and descriptions do not apply to them 0unless specified. For the purpose of this report, statistics for five of the non-volcanicsoil types have been included individually (Waitematas, Quaternary Sediments, ASands, Greywacke and Limestone), as well as categorised together as 'non-volcanic', •for comparison to volcanic soil types. Where results were less than the limit of ™detection, a value of half the limit of detection was assigned to enable statisticalanalysis. flj

Many statistical methods assume the data sets have a normal distribution. The abilityto undertake distribution analysis of the soils data sets is limited due to the smallsample sizes of the soil type categories. A Shapiro-Wilkes test for normality was flcarried out on the larger volcanic data set for each element analysed. This test |concluded with a 95% probability that each element, with the exception of nitrogenand total organic carbon, was not normally distributed. As environmental data is Moften negatively skewed, a log-normal distribution was then applied to each volcanic . •

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Figure 5: Process and Decision Tree for Inclusion or Exclusion of Outlier and Extreme Data Values Within the Background Soils Data Set

Trace element range determined for the 8 majorsoil types from 1999 Soil Investigation results

Outliers defined as:Data point value > UBC * OC x (UBV - LBV)

Extreme values defined as:Data point value > UBV + (2 x OC) x (UBV • LBV)

[See Section 3.2]

_L| Review of outlier/extreme values obtained In 1999, (or selection of sites for validation sampling In 2001 [

IObserved that volcanic soil samples obtained frequently exhibited the greatest concentrations andlargest ranges of trace elements. Given the potential for all soil types In the Auckland region to beInfluenced by volcanic ash, values are not considered Invalid If they fall within the volcanic range.

Is the 1999 SoilInvestigation value an'outlier' or 'extreme'

concentration from avolcanic soil?

Does the 'outlier' or 'extreme'value (excluding the volcanic soils

group) fall within the volcanicsoils non-outlier range ?

Retain Value withinPartially Evaluated Data

Set

Revisited site (15 In total) In 2001. Note: some sites withoutliers were not able to be revisited In the 2001 Investigation

Site potentially does not reflectbackground values - remove site

from sample site location list(Appendix 1) and data from RawData Set (Appendix 2) and locate

new sampling location

Does site informationindicate potential for

anthropogenic effects andexhibit'outliers'and'extremes' for many

elements?

Was the sitein questionre-visited?

Resample site and analyse for elements Inquestion.

Results failed site verificationsampling - exclude extremeand/or outliar values from

Partially Evaluated Data Set,but still included In the Raw

Data Set (Appendix 2).

For the set of data now collatedfor each individual site (now 5

concentration values for each),Are any of the values outliers orextremes for the Site Data Set?

Retain non-outlier valuesas part of the PartiallyEvaluated Data Set

Peform new statistical analysis on revisedPartially Evaluated Data Set

Do any outlier or extremevalues (excluding the 'all

non-volcanic soils'group) exist within each

Individual soil type ?

Is the soiltype

volcanic?

Is the outlier or extremevalue an 'outlier' or 'extreme

value when considered aspart of the whole

Non-Volcanic Group?

Does value fall withinthe non-outlier

volcanic range ?

Trace element consideredanomolous

Exclude from Validated Soils DataSet.

Is the excluded traceelement concentrationdata grouped (rather

than a single point) andfrom a single site orspecific lithology?

Future further workrequired to establish

the validity of value toenable Inclusion

within the BackgroundValidated Soils

Data Set



data set, and the Kolmogorov-Smirnov test was performed to determine the"goodness of fit" to a 95% level of confidence. As an alternate method for validatingthe log-normal distribution of the volcanic data, a Shapiro-Wilkes test for normalitywas applied to a log transformation of the original data set. While analyses show thedistribution of most elements in volcanic soils is log-normal, a normal distributionmust be assumed for the other soil types until enough data is collated to proveotherwise.

To identify values obtained from soils that lie outside the expected distribution rangebased on the total sample set, box and whisker plots were constructed (see Appendix3). The median values are represented by the small central box, while the large outerbox represents the 25th to 75* percentile range, and the whiskers represent the 'non-outlier range', which is defined here as 1.5 times the large outer box height (i.e. theinterquartile range, see Figure 6). Values that exceed the expected distribution rangeare referred to as outliers and extreme values.

A data point is deemed to be an outlier if the following conditions hold:

data point value > UBV + OC x (UBV - LBV)

A data point is deemed to be an extreme value if the following conditions hold:

data point value > UBV + (2 x OC) x (UBV - LBV)

where UBV is the upper value of the box in the box plot (i.e. the 75thpercentile);

LBV is the lower value of the box in the box plot (i.e. the 25th percentile); and

OC is the outlier coefficient (1.5 is used for this data set).

A visual interpretation of outlier and extreme values is shown in Figure 6.

This definition of outliers and extremes, calculated using a co-efficient of 1.5, isbought about by the use of the median as the mid-point rather than the mean. If themean were employed, the standard deviation would be used to calculate outlier andextreme values, instead of the interquartile range. Thus the value of 1.5 * theinterquartile range approximates 2 standard deviations (i.e. 97.7%, values abovewhich are 'outliers') and 3 * the interquartile range approximates 3 standarddeviations (i.e. 99.9%, values above which are 'extremes'). The median is used inthis investigation because of the potential non-normal distribution of the data, asdiscussed below.

Outliers and extreme values are measurements that are extremely large or smallrelative to the rest of the data, and therefore are suspected of misrepresenting thepopulation from which they were collected. They may represent analytical orsampling errors, or true elevated values of a distribution (e.g. hotspots), indicatingmore variability in the population than was expected. Not removing true outlier andextreme values, and removing false outlier and extreme values both lead to adistortion of estimates of population parameters.

ARC Technical Publication No. 153 ' 23

Figure 6: Definition of Outliers and Extremes

MEDIAN VALUE

LLJ^— fj)

1 1 1 —

icoCCUJ

O

\UJOz

GCUJ_J

0zOz

UJ

O

2W

trEi

A

A

O

O

\_Q

OOOAA

'

in•_(-

X

Iiq

UBV(75%)

LBV(25%)

Outlier and extreme values require further investigation. It is good practice not todiscard any data based solely on the statistical test. However, if a sound reason isfound to support that the data point is in error or non-representative of background,then the value should be excluded from further analysis. In this investigation, thedata points were excluded when further sampling and analysis from that sample sitecould not validate the outlier or extreme value (indicating possible sampling oranalytical error, or the presence of a 'hotspot'), or when the sample site itself wassuspected of recent disturbances that may have interfered with background elementlevels. The potential for a component of volcanic ash to occur within any soil typehas also been noted as a source of outlier and extreme measurements in these soiltypes, as discussed above.

In the 2001 investigation, not all sites with outlier or extreme values were re-visited,and hence these sites were unable to be validated and evaluated. Where the outliersand extremes were within the non-outlier range for volcanic soils they were includedin the validated background soils data set. As the aim of this investigation is toidentify background concentration ranges for soil types in the Auckland Region,spurious outlier and extreme values were removed from the validated backgroundsoils data set, and tagged for further work.

The outlier and extreme definition given above, and shown in Figure 6 was obtained,and the statistical analyses performed in this investigation, using STATISTICAVersion 6 software developed by Statsoft Inc.

The box and whisker plots in Appendix 3 show the normal distribution spreads for allnon-volcanic soil types, while the volcanic box and whiskers were created using thelog transformed data and then replotted to fit the original concentrations on the y-axis.The log normal transformation has the effect of including what in a normallydistributed data set were outlier and extreme values, within the non-outlier range.




3.3 ArsenicArsenic concentrations in all soil types in the 1999 survey ranged between 0.41 -17.83 mg/kg. The outlier of 17.83 mg/kg in the Quaternary deposits at Waiau Pa wasresampled in the October 2001 survey, and the sampling site relocated to Waiau PaDomain Reserve. A limited variance between 8.2 and 10.6 mg/kg was obtained fromthe four 2001 samples, indicating the 17.83 mg/kg value as an outlier in the site dataset, and as such the 17.83 value was excluded from the resultant validatedbackground soils data set. It is understood that concentrations of this order havebeen observed in Holocene Sands in the Auckland Region, however to date nosupporting data exists. Therefore the current background range of arsenicconcentrations for all soil types is 0.4-12 mg/kg.

Geometric mean values ranged between 1.65 - 6.51 across all soil types.

Further analyses for arsenic concentrations in sand-derived soil types arerecommended, and also the assessment of the validity of outliers in Waitemata soilsat Cape Horn (11.54 mg/kg) and McKenzie Rd (10.16 mg/kg).

3.4 BariumThe 1999 survey found barium concentrations in all soil types ranged from 8.7 - 803mg/kg. Barium outliers at Auckland Domain (691 mg/kg), Greenmount (786 mg/kg)and Point England Reserve (803 mg/kg) were re-sampled in 2001, and gave bariumconcentrations of between 77 - 112 mg/kg, 128 - 193 mg/kg, and 287 - 325 mg/kgrespectively. The 1999 values have therefore been removed from the validatedbackground soils data set as extreme values, refining, the background range for allsoil types as 8 - 350 mg/kg.

The geometric mean of the volcanic soils is 155 mg/kg, and ranges from 45 - 105mg/kg for the other non-volcanic soil types.

Further work is required to assess the validity of the 313 mg/kg concentrationrecorded in Waitemata Group sediments at McKenzie Rd in the Hunua Ranges.Should this value not be validated, a distinct difference in volcanic and non-volcanicbackground ranges becomes apparent, with volcanic soils ranging from 30 - 350mg/kg, and all other soil types ranging from 8-215 mg/kg.

3.5 BoronThe 1999 survey found boron concentrations in volcanic soils ranged from 2 - 839mg/kg, and in all other soil types ranged from 2-63 mg/kg. To verify the statisticallyextreme concentration detected in the volcanic soil at Paparata Rd in the 1999 survey(839 mg/kg) the site was re-visited in 2001. The four composite samples all recordedboron concentrations of <2 - 3 mg/kg. Therefore the 1999 Paparata Rd result hasbeen removed from the validated background soils data set as an extreme value,resulting in a refined background range for volcanic soils of <2 - 260 mg/kg.

The 1999 boron outlier of 63.3 mg/kg in the Awhitu Sands was also resampled in2001, all four composite samples for this site gave values of 2 mg/kg. The 1999results have therefore been removed from the validated background soils data set,resulting in a refined non-volcanic background range of 2 - 45 mg/kg.

The geometric mean of the volcanic soils is 46 mg/kg, and ranges between 8-17mg/kg for all other soil types.


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3.6 CadmiumThirty-six of the 91 soil samples were below the limit of detection for cadmium by the •method employed (i.e. less than 0.1 mg/kg) in the 1999 survey, however cadmium |was detected in at least one sample of each soil type. The range detected in all soiltypes in the 1999 sampling was <0.1 =- 0.8 mg/kg. _

The outlier cadmium concentrations reported at Mt Smart (0.77 mg/kg) and Waiau Pa |(0.5 mg/kg) were resampled in 2001, and reported cadmium concentrations ofbetween 0.27 - 0.48 mg/kg and 0.23 - 0.33 mg/kg, respectively. The 0.77 and 0.5 _mg/kg values were outliers within their respective site data sets, and therefore each •was removed from the validated background soils data set. The refined background ™range for cadmium is <0.1 - 0.65 mg/kg for all soil types.

The geometric mean for volcanic soils is 0.23 mg/kg and 0.07 - 0.14 mg/kg for the •other soil types. ~

Further work could be carried out in the Quaternary Sands at Orere Point to .determine the validity of the 0.46 mg/kg outlier value. •

3.7 Chromium •The 1999 survey found chromium concentrations in volcanic soils ranged from.3 - |286 mg/kg, and in all other soil types ranged from 2 - 149 mg/kg. The maximumrecorded concentrations for chromium in the 1999 survey was from Ti Point Basalt _(286 mg/kg). This site was resampled and concentrations of chromium were reported •at 195-260 mg/kg. When included as part of the volcanic data set, these ™concentrations are outliers/extremes, however, the verification of the chromiumconcentrations in soils at this location likely reflects the Kerikeri Volcanics mineralogy •(with respect to the Auckland Isthmus and South Auckland Volcanic fields). |

The extreme chromium concentration obtained from Waitemata Group soils atMcKenzie Road (149 mg/kg) was unable to be accurately located and re-sampled to •verify the elevated result with respect to the Waitemata Group data set. As this value |exceeds the non-outlier range of concentrations recorded for both non-volcanic andvolcanic soil groups it has been removed from the validated background soils data —set. The refined background range for non-volcanic soils is 2 - 55 mg/kg, while the •background range for volcanic soils (excluding Ti Point/Kerikeri Volcanics) is 3 - 125 ™mg/kg.

The geometric mean for chromium in volcanic soils is 48 mg/kg, and ranged between •7.0-14 mg/kg for the other soil types. •

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3.8 CobaltThe 1999 survey found cobalt concentrations in volcanic soils ranged from 10 - 385mg/kg, and in all other soil types ranged from 0.2 - 55 mg/kg. The cobalt outliers and .extreme values at Paparata Road (385 mg/kg), Smales Quarry (228 mg/kg) and Mt •Eden (223 mg/kg) were resampled in 2001, giving cobalt values of between 10.5- *11.1 mg/kg, 13.5 - 51.8 mg/kg and 33 - 49.4 mg/kg, respectively. The 1999 valueshave therefore all been removed from the validated background soils data set, givinga refined volcanic background range of between 10-170 mg/kg.

The cobalt outlier of 54.4 mg/kg measured in sands at Awhitu in 1999 was resampledin 2001 and returned values of 24.3 - 30.4 mg/kg. The resampling results showedthe value of 54.4 mg/kg to be an outlier of the site data set, and it was thereforeexcluded from the validated background soils data set. The revised backgroundvalues for cobalt in non-volcanic soils is therefore 0.2-35 mg/kg.

The geometric mean for volcanic soils is 48 mg/kg, and ranges between 1.6 - 9.2mg/kg for the other soil types.



3.9 CopperThe 1999 survey found copper concentrations in all soil-types ranged from 20 - 111mg/kg. The copper outliers identified within the volcanic soils at Rutherford Road(111 mg/kg), and sand-derived soils at Awhitu (33 mg/kg) were resampled in 2001.The volcanic soils at Rutherford Rd returned copper values of between 51 -60mg/kg, therefore the 111 mg/kg value has been removed from the validatedbackground soils data set.

The Awhitu sands recorded copper concentrations of 20.2 - 27.1 mg/kg at three ofthe four locations, with one location reporting the highest level detected of 135 mg/kg.The 135 mg/kg concentration from sand-derived soils at Awhitu was removed fromthe validated soils data set as an extreme value, although further work isrecommended to be undertaken to ascertain whether higher background copperlevels specific to the Awhitu sands exist. The refined background range of copperconcentrations for volcanic soils is at 20 - 90 mg/kg, and for all other soil types is 1 -45 mg/kg.

The geometric mean of copper in volcanic soils is 44.5 mg/kg, and ranges from 3.6 -17.2 mg/kg in other soil types.

3.10LeadThe 1999 survey found lead concentrations in all soil types ranged from 0.5 - 1280mg/kg. The outlier lead concentrations reported in Ti Point (1280 mg/kg) and MtSmart (475 mg/kg) and Ihumataq (128 mg/kg) volcanic soils were resampled in the2001 survey, and reported lead concentrations of 13.4 - 15.8 mg/kg, 61.7 - 143mg/kg and 14.3 - 33.7 mg/kg respectively. The 1999 values were therefore removedfrom the validated background soils data set as extreme values.

The 2001 concentrations of 88.5 - 143 mg/kg obtained at Mt Smart are the fourgreatest lead concentrations recorded within volcanic soils. While they are not outlieror extreme values given the log-normal distribution of lead in volcanic soils, it isunclear if these values are specific to the Mt Smart basalts or whether they are aresult of anthropogenic effects. The Mt Smart data has therefore been removed fromthe validated background soils data set, and the background range for lead in all soiltypes shall remain at <1.5 - 65 mg/kg until further works can be conducted. Verticalsoil profiling is recommended at Mt Smart.

The lead concentration reported in the 1999 survey for Awhitu sands was an outliervalue for the sand soil type (31.4 mg/kg). The site was resampled in 2001, andreturned lead concentrations of 15.1 - 38.3 mg/kg at three of the four locations, withone location reporting 538 mg/kg. The 538 mg/kg concentration from sand-derivedsoils at Awhitu was removed from the validated background soils data set as anextreme value.

The geometric mean of lead concentrations ranges between 5.6 - 25 mg/kg in all soiltypes.

3.11 MagnesiumThe 1999 survey found magnesium concentrations in volcanic soils ranged from 190- 76,600 mg/kg, and in all other soil types ranged from 470 - 10,300 mg/kg. Volcanicsoils have a geometric mean of 7024 mg/kg and a 95th percentile of 47,300 mg/kg,while all the other soils have a geometric mean around 1500 mg/kg.

3.12 ManganeseThe 1999 survey found manganese concentrations all soil types ranged from 20 -8500 mg/kg. The outlier of 8496 mg/kg in the sand-derived soils at Awhitu wasresampled in 2001 and returned values of between 3390 - 5890 mg/kg, indicating thepresence of mineral sands at this location. This set of values remain extreme inrelation to the overall concentration of manganese in sand, therefore the manganese

ARC Technical Publication No.l53 27

Ibackground range has been refined to exclude the Awhitu sand data, which appears |to be specific to only this lithology. The revised manganese backgroundconcentration range is 10 - 2,500 mg/kg for all soil types, excluding the Awhitu _sands. ' •

The geometric mean concentration in volcanic soils is 1075 mg/kg, while thegeometric mean concentration ranges from 86-417 mg/kg across the other soil —types. •

Further work could be carried out in the Okahukura Peninsula sand-derived soils todetermine the validity of the extreme manganese value of 1704 mg/kg recorded at _this locality. Should this value not be validated, a difference in volcanic and non- •volcanic background ranges becomes apparent, with volcanic soils ranging from 360 ™- 2,500 mg/kg, and all other soil types ranging from 10 - 1460 mg/kg.

3.13 Mercury ™The 1999 survey found mercury concentrations in all soil types ranged from <0.03 - _2.3 mg/kg. Most soil samples recorded mercury concentrations above the detection •limit of 0.025 mg/kg. The 1999 survey recorded extreme mercury concentrations of ™2.3 mg/kg at One Tree Hill, which was resampled in 2001 and recorded mercuryconcentrations of between 0.08 - 0.11 mg/kg. Hence the 1999 mercury •concentration was removed from the validated background soils data set, confirming |the background range of <0.03 - 0.45 mg/kg in all soil types.

The geometric mean concentration range of mercury for all soil types is 0.07 - 0.2mg/kg. I3.14 Nickel •The 1999 survey found nickel concentrations in volcanic soils ranged from 4 - 320 •mg/kg, and in all other soil types ranged from 0.9 - 35 mg/kg. Concentrations ofnickel are generally higher among the volcanic soils of the Auckland isthmus. •

Although not initially recorded as an anomalous value, the 317 mg/kg nickel ™concentration reported in the 1999 investigation from Mt Smart was removed from thevalidated background soils data set when the 2001 validation testing (for a full suite of •elements) returned nickel concentrations of between 28.7 - 104 mg/kg. J|

The geometric mean for nickel concentrations in volcanic soils is 87 mg/kg, andranges between 2.7 - 9.0 mg/kg in all other soil types. •

3.15 NitrogenThe 1999 survey found total nitrogen concentrations in all soils ranged from 320 - •8430 mg/kg. The geometric mean for nitrogen concentrations ranged from 1375 - ™3200 mg/kg in soil types across the Auckland Region.

Further work could be undertaken to assess the validity of the volcanic outlier of 8422 Img/kg observed at Mt Smart. ™

3.16 Phosphorus gPhosphorus levels in soil samples indicated that there are higher levels in volcanicderived soils than in all other soil types. The 1999 survey found phosphorusconcentrations in volcanic soils is 245 - 3730 mg/kg, and the range for non-volcanicsoil types is 75-1220 mg/kg.

The geometric mean for phosphorus concentrations in volcanic soils is 1180 mg/kg,and ranges between 220 - 530 mg/kg in all other soil types.

Further work could be undertaken to assess the validity of the volcanic outlier of 3729mg/kg observed at Mt Smart.

ARC Technical Publication No.]53 28


3.17 PotassiumThe 1999 survey found potassium concentrations in all soil types ranged between226 - 5840 mg/kg, with geometric means of between 713 - 1275 mg/kg.

The extreme potassium concentration of 5840 mg/kg obtained from the Waihekegreywackes soils exceeds the non-outlier range of concentrations recorded for boththe 'all non-volcanic soils group' and the volcanic soils group, and has therefore beenremoved from the validated background soils data set. The refined background rangefor potassium in all soil types is therefore 226 - 3660 mg/kg until further work can beconducted to assess the validity of the 5480 mg/kg extreme value.

3.18 SulphurThe 1999 survey found sulphur concentrations in all soil types ranged from 85 - 2513mg/kg. The geometric mean of sulphur concentrations in soils varied between 333and 740 mg/kg.

To verify the outlier sulphur concentration of 2513 mg/kg reported at Kumeu Heightsin 1999, the site .was resampled in 2001, and returned values of 400 - 500 mg/kg.The 2513 mg/kg value was therefore excluded from the validated background soilsdata set, giving a revised background range of 85 - 2,300 mg/kg for all soil types.

Further work could be undertaken to assess the validity of the volcanic outlier of 2288mg/kg observed at Puhinui Crater.

3.19 TinThe 1999 survey found tin concentrations in all soil types ranged from <0.7 - 11.5mg/kg. Concentrations of tin detected in soils in the Auckland Region were generallylow to below the analytical detection limit (0.7 mg/kg in the 1999 survey). The 1999survey reported an extreme value at Ti Point (411 mg/kg), which was resampled andreported tin concentrations of between 0.8 - 1.0 mg/kg. The 411 mg/kg value wastherefore excluded from the validated background soils data set.

Two site specific sets of outlier and extreme tin values in volcanic soils have beenidentified; four locations within a 5 km radius in the Franklin Basalts (Glenbrook, KiwiRd, Puni and Patumahoe) recorded tin concentrations between 1.85 - 3.44 mg/kg,while tin values obtained from Mt Smart soils in 2001 ranged from 1.8 - 5.5 mg/kg.

The values of 11.5 mg/kg and 7.48 mg/kg obtained from Quaternary sediments atNew Lynn and Hobsonville Airbase respectively, are statistically extreme and outliervalues for their own soil type, and are outside the non-outlier volcanic soils datarange. These values have therefore been removed from the data set, resulting in arefined range of 0.35 - 4 mg/kg for all soil types. Further work could be undertaken toascertain the validity of the extreme values measured at New Lynn and HobsonvilleAirbase.

The geometric mean of tin concentrations ranged between 0.4 - 1.9 mg/kg in all soiltypes.

3.20 VanadiumThe 1999 survey found volcanic soils recorded a wide distribution of vanadiumconcentrations particularly within the Auckland isthmus basalts. South Aucklandbasalts showed limited variance, with concentrations of 147 to 181 mg/kg recorded,compared to a range of 15.6 to 603 mg/kg for all other volcanic samples. The outliervanadium concentrations reported in the Auckland Domain (603 mg/kg) and OneTree Hill (508 mg/kg) volcanic soils were resampled in 2001, and reported vanadiumconcentrations of 50 - 68 mg/kg, and 116 - 137 mg/kg respectively. The 1999values were therefore removed from the validated background soils data set. Therevised background range for vanadium concentrations in volcanic soils is therefore15-370 mg/kg.


ITo assess the extreme vanadium concentration measured in Awhitu sands (303 •mg/kg) the site was resampled in 2001. Vanadium concentrations were measuredbetween 271 - 320 mg/kg, indicating that the data is valid and possibly lithology _specific. These values are outliers within the sand-derived soil type, and as part of Ithe non-volcanic group as a whole, therefore they were removed from the validated ™background soils data set, resulting in background vanadium concentrations in non-volcanic soil types between 8-160 mg/kg, with the exception of Awhitu (mineral) Asands. g

The geometric mean for vanadium concentrations in volcanic soils was 133 mg/kg,and ranged between 27 - 57 mg/kg in other soil types. •

3.21 ZincA wide distribution of zinc concentrations was recorded in volcanic soils in 1999, •particularly within the Auckland isthmus basalts. South Auckland basalts showed 'limited variance, with concentrations of 70 to 166 mg/kg recorded (althoughPukekohe Hill recorded a concentration of 789 mg/kg), compared to a range of 54 to •1160 mg/kg for all other volcanic samples. The 1999 survey found zinc j|concentrations in all other soil types ranged from 9.2 - 179 mg/kg.

The geometric mean for zinc concentrations in volcanic soils was 252 mg/kg, and •ranged between 18-59 mg/kg in other soil types. . fj

3.22 Total Organic Carbon •The analysis of total organic carbon was undertaken to provide some measure of the ™variability of carbon levels in surficial soils in undisturbed environments of theAuckland region. The identification and assessment of any relationship between •anomalous trace element levels and either elevated or depressed carbon levels is |beyond the scope of this report. The 1999 samples from all soil types recordedvalues of between 0.6-14 % dry weight. _


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4. Discussion

4.1 Volcanic Soils in the Auckland RegionResults obtained from volcanic soils in the Auckland region indicate that for manyparameters (barium, boron, cadmium, chromium, cobalt, copper, magnesium,manganese, nickel, phosphorus, vanadium and zinc) the distribution of levels of thetrace element is elevated compared to other derived soil types. In addition, thevolcanic centres - Auckland Isthmus (central), Franklin Basalts (south) and KerikeriVolcanics (north), are often geochemically distinct from each other; for example, theelevated chromium concentrations in the Ti Point Basalts, or the low concentrationsand low variance of vanadium distribution in the Franklin Basalts.

4.2 Volcanic Processes and Potential Impact on Other Soil TypesConsideration of each of the soil types as having a distinct geochemical range wouldbe useful in the setting of acceptable background concentrations for the AucklandRegion for a number of parameters. However, due to the geologically young age ofthe volcanic deposits and the explosive nature of their formation, the surficial layer ofother geological deposits (and indeed to greater depths in Holocene Sands andQuaternary Sediments) have the potential to be affected by the presence of airfalltephra. It is therefore recommended that the ranges reported for a given soil type arecompared to the ranges listed for that soil type, however, if exceedences occur withinthat soil type, that consideration be given to the potential for a significant volcaniccomponent within the given soil type.

4.3 The Non-Volcanic Soils GroupingIt is recognised that there is little validity in grouping the non-volcanic soil typestogether, as each of the parent lithologies are potentially chemically very different.However, for the purpose of statistical analysis in this report the grouping is made tocompensate for the small number of samples within each of the non-volcanic soil datasets currently collated. Volcanic soils have a minimum of 33 samples for eachelement, while minimum sample sizes for the non-volcanic soils are as follows:Waitematas (19), Quaternary (12), Sands (12), Greywackes (6), Limestone (4),Onerahi Chaos Breccia (2) and Manukau Breccia (2).

As the number of samples for each of the non-volcanic soil types increases, the 'allnon-volcanic soils' grouping may be reconsidered in favour of ranges for each of thenon-volcanic soil types individually.

4.4 Specific LithologiesValidation testing has confirmed elevated concentrations (above the backgroundranges for their own soil types) of certain elements in the following lithogies: Volcanicderived soils at Ti Point (Cr), Mt Smart (Pb, Sn), and Franklin (Sn), and sand-derivedsoils at Awhitu (Mn, V).

It is likely that these concentrations are a reflection of the mineralogy of the parentmaterial, although at Mt Smart anthropogenic activities may have had some effect.While the values obtained from these sites have been excluded from the statisticalanalyses in Appendix 3, and the resultant background ranges, it is recognised thatsoils from these locations need to be considered individually.

4.5 Auckland Region Background RangesTable 3 summarises the background ranges for trace elements in Auckland soilsbased on the statistical analysis of results from soils analysed in the 1999 and 2001studies. In some cases, a single range is given to include both volcanic and non-

ARC Technical Publication No. 153 : JT

volcanic soil types. When the range of concentrations in volcanic soils is greater thanthat of non-volcanic soils, to the extent that the volcanic median value isapproximately equal to or greater than the non-volcanic soils maximum non-outliervalue, a range for each type (volcanic and non-volcanic) is given.

Table 3: Background Ranges of Trace Elements in Auckland Soils(all values in mg/kg unless otherwise specified)

Element (Total Recoverable) Non-Volcanic Range Volcanic Range

Arsenic (As)

Barium (Ba)

Boron (B)

Cadmium (Cd)

Chromium (Cr)

Cobalt (Co)

Copper (Cu)

Lead (Pb)

Magnesium (Mg)

Manganese (Mn)

Mercury (Hg)

Nickel (Ni)

Nitrogen (total, N)

Phosphorus (P)

Potassium (K)

Sulphur (S)

Tin(Sn)

Vanadium (V)

Zinc (Zn)

Total Organic Carbon (TOC)

0.4-12

8-350

2-45 <2 - 260

<0.1 -0.65

2-55

0.2 - 35

1 - 45

3-125*

10-170

20-90

< 1.5-65*

470-10,300 190-76,600

10-2,500*

<0.03 - 0.45

0.9-35 4-320

300 - 8,500

75-1,220 245 - 3,730

220 - 3,660

85 - 2,300

<0.7-4*

8-160*

9-180

15-370

54-1,160

0.6-14%

2.

Notes:Background ranges for major elements (N, P, S, TOC) include statistical outlier and extremevalues outside the non-outlier volcanic soil range. All other elements do not include valuesobtained that were statistical outliers or extremes outside the non-outlier volcanic soil range.*Work suggests special cases have been found to apply for Ti Point Basalts (Cr), Mt SmartVolcanics (Pb, Sn), Franklin Basalts (Sn), and Awhitu-type Mineral Sands (Mn, V) and as suchthese lithologies need to be considered individually.

The background levels given in Table 3 are the maximum and minimum values fromthe validated background soils data set as determined by statistical analysis of thecurrent set of soil data (raw data) included in Appendix 2. Further investigations andanalysis are ongoing, and the background levels will become refined as more data iscollated. In particular the Greywacke, Limestone, Manukau Breccia and OnerahiChaos Breccia derived soil types require more data to provide for statistical analysisand refinement of their background soil ranges.




4.6 Background Soil Concentrations Applicability to SoilInvestigations in AucklandWhile the ANZECC/NHMRC (1992) Guidelines proposed setting health-based andenvironmental-based investigation thresholds, they also indicated the need to identifylocal background soil levels of trace elements to provide a suitable context fordecision making. Where soils are investigated and decisions regarding contaminantremoval or trace element treatment are considered readily available regionalbackground soil level information provides a baseline below which levels areacceptable within the region. This data may assist in minimising costly sampling orsoil removal / treatment.

Two means of identification for soils have been used in this study, the identification bygeological map and by excavation of the soil profile as well as the "fingerprint"associated with the limited range of analyses undertaken. In assessing the soils atany location in the Auckland region these should both be undertaken. This allowsidentification of the likely ranges of trace elements for a site from details in this studyas well as comparison of site samples to confirm that soils are, at least in places onor near that location, representative of the soil type described.



5. Recommendations

The ANZECC/NHMRC Guidelines for Assessment and Management ofContaminated Sites recommend the .evaluation of background levels as aconsideration in the determination of clean-up standards. The data collected in thissurvey on trace metals in soils from the Auckland Region can be used in this context.

Environmental investigation threshold levels should be related to the backgroundlevels of the elements. Certain environmental investigation threshold levels mayneed to be reconsidered dependent on the soil terrains investigated in the Aucklandsetting; in particular, those where samples considered to be undisturbed anduncontaminated soil were found to contain total recoverable levels of elements atconcentrations above the currently accepted environmental investigation levels.

Where 'site/Iithology specific' elevated concentrations were observed, further samplesfrom additional sites with soils derived from the same lithologies should be collectedto further validate the consistently elevated concentrations observed there. Thelithologies and elements to be further validated include:

1) Kerikeri Volcanics for chromium;

2) Mt Smart Volcanics for lead and tin;

3) Franklin Basalts for tin; and

4) Holocene Mineral Sands (Awhitu-type) for manganese and vanadium.

In addition the anomalous concentrations observed at the following locations shouldbe resampled and evaluated:

Volcanic soils at Mt Smart for nitrogen and phosphorus, and Puhinui Crater forsulphur;

Awhitu sands for copper and Okahukura sands for manganese;

Waitemata-derived soils at McKenzie Rd in the Hunua Ranges for arsenic,barium and chromium; at Cape Horn for arsenic;

Quaternary sediments at Hobsonville Airbase and New Lynn for tin, and at OrerePoint for cadmium;

Greywacke-derived soils at Waiheke Island for potassium.

At all future sites sampled, it is recommended that a vertical profile of the soilchemistry be established, by collecting a second sample at 150 - 300 mm depth tohelp identify any anthropogenic input to the near-surface soils.

Collection of the above data may be undertaken by either directed surveys or bycollation of independently collected data providing that in the second case the sameor similar sampling and site identification methodologies are utilised.

6. Acknowledgements

The study design, sampling, data analysis and reporting for the 2001 investigationwas conducted by URS New Zealand Ltd, in conjunction with Sharon Vujnovich of theARC. The study design, sampling, data analysis and reporting for the 1999investigation was conducted by Ramon Scoble of the ARC.

This paper has benefited from helpful suggestions from Dr Murray Wallis of URS NewZealand Ltd (formerly Woodward-Clyde (NZ) Ltd), Peter Robinson of Hill LaboratoriesLtd, Terrey Fitzgerald of Watercare Services Ltd and Eddie Grogan of the AucklandRegional Council.

ARC Technical Publication No. 153 . 35


7. References

ANZECC / NHMRC (1992) Guidelines for the Assessment and Management ofContaminated Sites, Australian and New Zealand Environment andConservation Council.

Canadian Council of Ministers of the Environment (1999), Canadian EnvironmentalQuality Guidelines.

Patil G.P., Rao, C.R. (editors), Handbook of Statistics Volume 12; EnvironmentalStatistics (1994), Elsevier Science B.V.

Ministry for the Environment and Ministry of Health (June 1997) Health andEnvironmental Guidelines for Selected Timber Treatment Chemicals.

Ministry for the Environment, (2001) Hierarchy and Application of EnvironmentalAcceptance Criteria in New Zealand. Draft Version.

Ministry for the Environment, (June 1999) Guidelines for the Assessing and Managingof Petroleum Hydrocarbon Contaminated Sites in New Zealand.

Ministry for the Environment, (August 1997) Guidelines for Assessing and ManagingContaminated Gasworks Sites in New Zealand.

Ministry of Housing, (1994) Environmental Quality Objectives in the Netherlands.Risk Assessment and Environmental Quality Division Directorate forChemicals, External Safety and Radiation Protection, and Ministry ofHousing, Spatial Planning and the Environment.

National Environment Protection Council (1999) National Environment Protection(Assessment of Site Contamination) Measure.

NZ Government (1991) Resource Management Act Government Printer

Statsoft Inc., (2001), Statistica Version 6, statistical analysis software.

Wageningan SETOC Soils ILCP, Dr V Houba, PO Box 8005, 700 EC, Wageningan,The Netherlands.

United States Environmental Protection Agency (2000), Preliminary Remediation andGoals, Region 9.

United States Environmental Protection Agency (July 2000), Guidance for DataQuality Assessment; Practical Methods for Data Analysis. EPA QA/9.


APPENDICES



Appendix 1: Sampling Site Locations(TCLP) indicates that sample was additionally submitted for TCLP testing

Soil Parent Rock Sample ID Site Name Map Reference 1

Volcanics 101

TP01-TP04

102

LP01-LP04

103

104

105

106

107

108

ME01-ME02

ME03-ME04

109

110

111

112

113

114

OT01-OT04

115

GM01-GM02

116

IH01-IH04

117

118

119

120

121

122

124

125

126

AD01-AD04

127

128

129

Ti Point

Ti Point

Smales Quarry

Lake Pupuke (Killarney St Reserve)

Mt Victoria

North Head

Riteakawarau

Mt Roskill

Mt Albert

Mt Eden (& TCLP)

Mt Eden

Mt Eden

Mt Hobson

Mt Smart (& TCLP)

Mt Wellington (& TCLP)

Mt Mangere

Mt Richmond

One Tree Hill (& TCLP)

One Tree Hill

Greenmount

Greenmount

Ihumatao

Ihumatao

Puhinui Crater

McLaughlins Mt

Three Kings

Pigeon Mountain

Orakei Basin

Panmure Basin

Puketutu Is

Mt St John

Auckland Domain

Auckland Domain

Glenbrook School

Puni School

Patumahoe Reserve

R09:715410

R09:711409

R1 1:675895

R1 1:681 891

R1 1:708846

R1 1:721 844

010:496113

R1 1:652752

R1 1:637776

R1 1:675790

R1 1:677790

R1 1:677795

R1 1:697788

R1 1:71 9743

R1 1:749771

R1 1:691 709

R1 1:743727

R1 1:693765

R1 1:689760

R1 1:7977 16

R1 1:801 71 7

R1 1:660660

R1 1:665656

R1 1:731 672

R1 1:757648

R1 1:667762

R1 1:800774

R1 1:7 16803

R1 1:750760

R1 1:663693

R1 1:690784

R1 1:684805

R1 1:6878 13

R1 2:658427

R1 2:749395

R1 2:738443

ARC Technical Publication No. 153 .41

Soil Parent Rock Sample ID Site Name Map Reference \Volcanics 130

131

132

133

RR01-RR04

134

PR01-PR04

310

PE01-PE04

Kiwi Rd

Pukekohe Hill

Adams Rd

Rutherford Rd

Rutherford Rd

Paparata Rd

Paparata Rd

Pt England Reserve

Pt England Reserve

R12:691391

R1 2:783397

R1 2:769428

R1 2:843444

R1 2:875445

R1 2:880444

R1 2:839442

R1 1:773785

R1 1:771 782Soil Parent Rock Sample ID Site Name Map Reference \Waitematas 201

202

203

204

205

206

207

KH01-KH04

208

209

KP01-KP04

211

212

213

214

215

216

217

218

219

Pakiri Reserve

Burma Rd

Kaipara Hills Rd

Green Hollows Rd

The Dome

Inland Rd

Kumeu Heights

Kumeu Heights

Whangaparaoa

Long Bay Regional Park

Kauri Point Centennial Park

Cottle Rd

Cape Horn

Kepa Bush Park

Redoubt Rd

Cyclades Reserve

Kaipara Rd

Beaver Rd

McKenzie Rd

Takapuna Grammar

R08:590538

(209:317342

Q09:424248

R1 0:5921 61

R09:563368

Q1 0:430023

Q1 0:473931

Q1 0:471 929

R1 0:693083

R1 0:640000

R1 1:628853

Q1 1:475852

R1 1:646725

R1 1:738806

R1 1:830657

R1 1:841 755

R1 2:866584

R12:865417

311:004621

R1 1:703875Soil Parent Rock Sample ID Site Name Map ReferenceQuaternary

Sediments

301

302

WP01-WP04

303

304

305

306

307

Sandspit Rd

Waiau Pa

Waiau Pa Domain Reserve

Urqhart Rd

Manukau City

Orere Point

Monument Rd

Omana Regional Park

R1 2:635395

R1 2:660501

R1 2:659504

R1 2:752563

R1 1:768659

811:106670

811:923640

811:908782



Soil Parent Rock Sample ID Site Name Map Reference 1Quaternary

Sediments

308

309

311

312

Highland Park

New Lynn

Hobsonville Airbase

Kumeu A&P Showgrounds

R1 1:803764

R1 1:600766

R1 1:590885

Q1 0:495902Soil Parent Rock Sample ID Site Name Map Reference \

Sands 401

402

403

404

405

406

407

408

409

AW01-AW04

410

411

412

South Head

Wilson Rd

Rimmer Rd Lookout

Pulpit Rd

Okahukura Peninsula

Pakiri Block Rd

Pakiri River Rd

Omaha Bay

Awhitu Central

Awhitu Central

Douglas Rd

Kariotahi School Rd

Orewa

Q09:222232

Q1 0:2631 34

Q1 0:355007

Q10:391915

Q09:273381

R08:623522

R09:654492

R09:704385

R1 2:509550

R1 2:509550

R12:541451

R1 2:597355

R1 0:6221 15Soil Parent Rock Sample ID Site Name Map Reference \Greywacke 501

502

503

504

505

506

Cape Rodney Rd

Lilburne Rd

Tapapakanga Hill

Maraetai

Waiheke

Waiheke

R09:730451

812:998521

311:119661

811:907772

511:941887

811:028840Soil Parent Rock Sample ID Site Name Map ReferenceLimestone 601

602

603

604

Marsh Rd

North Shore Aerodrome

Snells Algies

Partridge Rd

Q09:353404

R1 0:583038

R09:663293

(209:417410So/7 Parent Rock Sample ID Site NameOnerahl Chaos

Breccia

Glorit-Kaipara Hills Rd

Pebblebrook RdSo/7 Parent Rock Sample ID Site NameManukau

Breccia 802

Anawhata Rd

Goldie Bush

Map Reference(209:487313

R10:508092Map Reference

Q11:463718

Q11:418830


Appendix 2: Analytical Results

VOLCANIC SAMPLES

HD I101TP01TP02TP03TP04102LP01LP02LP03LP04103104105106107108ME01ME02ME03ME04109110MS01MS02MS03MS04111112113114OT01OT02OT03OT04115GM01GM02GM03GM04

^HMK^ H3.68.

•-.

1.67----

1.992.020.411.080.482.15

--..

7.86.614.53.74.84.81.925.822.84.33

----

3.55---

131120----

119--

. -.

66.418.523971.540.1249

----

31.857*43517

15.416343.1179

----

196---

^^^^1174----

224----

24314922028834123

----

76116

--.-

4920788197----

786*193128150139

^Hjf£ l0.32

----

0.19----

0.270.270.150.280.180.31

----

0.280.77*0.330.270.400.480.590.630.570.39

----

0.39---

^^R^^ l89.5-

• ---

228.4*51.834.722.813.590.957.4143.483.232.9223*49.245.333

41.263.645.726.324.429.837.930.512136.2119

----

124---

mm28619S19S200260124----

72.153.83.610110198.8

----

35.361.355.142.564.471.69.110515.554.5

----

73.2---

Mm82----

36.5• -

---

28.325.538

53.153.879.9

----

36.688.665.065.984.181.226.639.134.733.9

----

42.1--

• -

^ Eu5 l0.081

----

0.265----

0.2150.1460.0850.1250.060.235

----

0.0980.2710.110.060.180.130.0590.120.0842.303*0.080.110.10.090.146

---

mm903

----

751----

113012803660253015801270

----

1520498

----

681129013501480

----

1880---

mmm1151

-- --

•8612

---

376785587230341883048322612

----

3182022217

----

2338410705162734157

----

11964- •--

U2Q1826

----

2110----

13541008149810068481502

----

7682484

----

42913258771565

----

1749--'-

mm3842

----

3779---'

48173028519017625304732

----

29768422

--

. --

636650933669'5790

----

5689---

•?/•128

---

253----

3151204.6251235223

----

229317*50.828.746:710412116893.498.3

---

- -149

---

^^^ • ^^^H1260

----

804----

1259101459213252461592

----

23443729

----

1373222819921935

--

.. -2830

---

^^^H1280*14.615.813.415

23.3----

46.613.73.0413.13.3

34.1--'--

23.9475*88.561.710214311.821.915.716.3

----

32.8---

mm733

----

700----

9156011036407389805

----

4221520

----

669762539938

----

887---

Sn411.3*

0.90.90.81.0

<0.7----

<0.7<0.7<0.7<0.7<0.7<0.7

----

<0.7<0.73.11.85.54.5<0.7<0.7<0.7<0.7

----

<0.7---

V196

• ----

256----

12541.626812774.2366

----

72.2104--.-

15.629128

508*120137132116331

---

Zn84----

748.

--

3621081142801271038

-

- •-

191484*14211620525854.5549143742

--.-

1160.--

TOO •4.97

--

"--

4.39.-..

5.974.078.773.780.856.47

-- •--

3.3711.64

--.-

10.666.784.856.55

---.

6.32---


HEH116IH01IH02IH03IH04117118119120121122124125126AD01AD02AD03AD04127128129130131132133RR01RR02RR03RR04134PR01PR02PR03PR04310PE01PE02PE03PE04

BflM5.29

-.-.

0.694.142.271.994.126,611.931.6

0.62--.-

7.776.856.838.450.782.412.56

----

3.17-

• -.-

3.15.-

. .-

13155.9

-.--

19829.410735.722773

18.781243

----

54.660.961.757.3255190 .157--.-

839*<2233

190.-.-

Ba239----

12315172347142

.3016927969 r11283.877.198.523021620421313297157

----

181----

803*287325304317

Cd0.48

--•--

0.240.210.430.310.150.30.110.270.15

----

<0.10.13^0.1<0. 10.220.120.31

----

0.24----

<0.1----

Co34.7

----

13827.610561.112850

29.193.6134----

23.453.433.534.111416693.1

----

385*11.111

10.610.575.8

----

mm72.5

r

-

-

-

11438.489.146.879.653.139.711067.3

----

13.711.627.214.249.498.480.3

-- '--

64----

40.1----

mSIM28.7

----

75.922.953.251.448.555.137.241.581----

20.651

33.424.957.221.8111*56.751.351

60.346.6

i---

20.8----

msm0.167

----

0.0470.1480.1470.0930.1430.107<0.030.1690.219

---

0.3330.3770.3510.4010.1840.2080.187

----

0.202.

---

0.074----

mm1930

---- .

747128015102110216020801600927978

----

48911501200496735493275----

406----

1900----

mMm3948

---

3779535793379464998133007656417327149923594

----

14191414194175310043281750

----

860--

-4812

----

MtKM2420

.----

106310101321108812179926341436710

----

497675151620944363621480

----

685----

907----

mm5149

----

157735057237339227093730324

32403172

-•• -

--

2678214729042798434711073767

----

4118----

3750.---

•?/•84.1

• ---

1

22741.432020716413795.6223161----

13.611.930.19.717.822.7116

---

107--

•• -57.2

-'---

IEI1086

----

1152901

206825901610336612699721343

----

33336159837611223991812

----

955----

2148.---

msm128*16.833.714.315.411.255.443

19.260.239.613.123.227.4

----

26.252.131

36.921.214.113.4

----

15.4----

17.3...-

•a679----

228849610261593790649475732783

----

753801767742769313775

----

863--.-

670....

Sn<0.7

----

<0.7<0.7<0.7<0.7<0.7<0.7<0.7<0.7<0.7

----

1.853.143.443.13<0.7<0.7<0.7

----

<0.7--..-

<0.7•...

V87.9

• -.

--

3136615532631012823208603*68585057147158150151158155158----

181•----

335...-

Zn547

----

85323542172891336388.3288835

----

70.616610986.178971.470---

•87.5

---.

689....

roc6.56

---- '

1.883.949.473.914.724.431.425.424.56

--

• --

4.582.654.494.227.111.895.4----

5.83-..-

4.76....


WAITEMATA GROUP SAMPLES

Hj ^ H^ H201 2.63202 4.57203 1.58204 2.48205 1.36206 4.02207 2.12KH01KH02KH03KH04208 1.93209 1.32KP01KP02KP03KP04211 5212 11.54213 2.93214 5.17215 2.29216 1.7217 6.07218 10.16219 3.1

^^^H42.219.214.830.841.123.68.4-.-.

7.44.8.-..

20.85.830.211.58.213.634.237.316.7

Ba1882721895.33081

12.1----

16.18.7----

15.22971587418231.231353

Cd0.250.210.14<0.t0.15<0.1<0.1

-.

-.

<0.1<0.1

--.-

<0.10.14<0.1<0.1<0.1<0.1<0.10.150.17

Co23.6

318.36.25.3 .8.50.2---

0.71----

1.92.426.31.75.35.53.69.318.6

mm208.125

26.338.316.93.7

----

2.22.4----

5.57.640.414.619.84.9149'18.525.4

^•ffff ^^^Bffj ^^^^BA^^^^^BJTM I

35.3 0.113 2730 102615.7 0.18 389 8729.3 0.058 830 309521.8 0.096 2310 511029 0.13 1300 3844

16.8 0.074 3070 36012.2 0.137 520 654.

--.

.4.1 0.071 275 4744 0.131 226 743

7.1 0.066.7 0.064.9 0.075.0 0.0910.8 0.145 348 9047.5 0.092 401 59711.1 0.154 908 158513.9 0.035 2490 23944.6 0.196 724 9512.8 0.049 847 90911.7 0.048 1230 249221.3 0.313 1030 78221.5 0.067 2040 7563

•EBB876376

• 96613333433256----

33842----

28384112113606133586104

mm607432219825141193438441650

----

10831032

---.-

1626236328218051168194453231984644

•?/•

23.23.66.911.715.76.80.93

----

1.52.38

---- .

3.33.4619.511.5122.525.815

34.1

^^^ • ^^^H770454227580482531163----

9276216217185158250309417122137173237824597

^^^16.67.226.087.28

21.13.74

---.

13.910.78.268.347.369.079.6417.625.712.79.82.786.3140.98.9

mm10649024258191532661

2513'500400400400265180.-.-

1145401586103338322168748913

Sn<0.7<0.7<0.71.49<0.7<0.71.87

---.

<0.7<0.70.50.40.40.5

2.11<0.7<0.71.18<0.71.551.8

3.91<0.7

V56.349.361

91.113554.341-.-.

40.321.9....

11433.565.429

63.845.896.710541.3

Zn1064346

98.312357.111.5

--

- -.

16.39.6....

32.224.971.345.528.143.682.368.570.6

TOO •7.93

52.416.434.435.032.44

---.

2.362.05

-...

3.882.674.140.841.7

3.180.634.56.84

QUATERNARY SEDIMENTS

301 3.98302 17.83'WP01 8.2WP02 10.1WP03 10.6WP04 8.3303 6.97304 3.11305 7.07306 1.91307 3.76308 2.75309 6.09311 7.6312 9.11

^^^114.830.6.---

35.217.7219.69

17.612.129.68.7

^^^B179117.---

1989821147.247.1682818342.1

• H l<0.10.5*0.320.230.230.33<0.10.270.46<0.10.15<0.10.150.21<0.1

•jl ^H10.913.4

----

8.817.13.70.52.915.83.45.61.5

mm16.511.5

----8

21.15.43.93.928.17.911.14.8

• ^^^ ••/•' ^^ • ^^ •jYi'B20.5 0.325 1380 241123.7 0.302 447 1417....

27.4 0.337 1510 11728.3 0.11 861 23448.3 0.165 281 6457.6 0.169 777 8474.8 0.107 624 65611.5 0.106 1270 352915.2 0.247 700 111825.7 0.311 906 155517.7 0.421 648 886

•»!•389520

----

150139128483397612399639

mm41275202

----

34620703749272834163101206623276108

•?/•20.210.7

----

12.6115.95.42.723.28.5323.32.8

^^^ • ^^^H6661213

----

454457756363486632350401465

^QjH44.328.7

---.

26.721.319.311.216.412.956.252.622.6

^m8021191

----

12024757224265705625855291178

Sn2.41<0.7.--.

1.52.443.611.211.49<0.711.47'7.48'2.17

V64111.--.

11343.274

34.230.151.841.811833

Zn92.5111.--.

78,763.990

36.928.255.952.196.621

TOO •5.997.45

---.

2.142.654.923.493.893.786.673.7413.96

ARC Technical Publication No.]53 47

SANDS\ ID As B Ba

401 5.33 20.4 81402 8.34 24.1 170403 6.73 39.3 109404 3.4 17.9 47.9405 4.02 23.7 78406 7.44 3.6 13.4407 5.23 3.9 12.2408 3.92 3 11409 5.49 63.3* 202AW01 - 2AW02 - 2AW03 - 2AW04 - 2410 5.09 23.7 55411 7.56 23.6 73.5412 7.22 5.2 30

GREYWACKEI /O As B Ba

501 9.78 20.4 36502 4.74 13.2 178503 6.98 20.2 85.5504 3.91 10.9 63.1505 8.6 21.1 212506 7.01 13.4 181

LIMESTONE1 ID As B Ba

601 1.72 9.7 31.1602 2.3 22.1 120603 1.19 7.5 17604 1.57 10 63

Cd<0.1<0.1<0.1<0.10.180.11<0.1<0.10.22

-.--

<0.1<0.1<0.1

Cd0.12<0.1<0.1<0.10.170.17

Cd0.120.18<0.1<0.1

Co9.96.8

13.68.8

20.91.51.31.6

54.4*28.230.424.329.323.1172.4

Co4.25.22.72.8

31.84.4

Co0.69.30.52.1

IQHiO10.6 8.39.1 8.6

11.6 115.9 2.819.1 10.25.5 1.14.9 1.15.8 2.2

33.1 33.152.3 20.247.4 135' .48.2 26.841.3 27.120.2 7.911.1 17.24.5 3.7

jjQj QI13.3 28.26.1 12.94.8 8.48.5 7.3

23.8 44.812.1 25.6

I3HEB7.9 1.5

10.2 17.13.5 1.38.6 5.1

•>£•£•0.26 8670.296 10500.191 10200.124 3500.12 873<0.03 308<0.03 547<0.03 2590.319 1060

----

0.047 7500.198 676<0.03 436

K9K9<0.03 23800.117 15500.12 448

0.061 13800.104 5840*0.081 3500

•Z3HD10.073 8880.086 9490.063 6010.097 1160

mmm18051328208410202310583802635

2212----

310723241468

•u/f l

11711903843

1182590

2109

^Ku/7^114502487814

1539

KoHBI376 1950101 1069429 2491393 336

1704 199358 92645 150949 538

8496 42243390373040505840544 2265462 362461 1954

HZflHd453 1563337 1776179 558142 1685

1460 732924 3535

HOKI50 1028464 442728 114185 4085

icz i7.19.38.95.611.71.941.942.2118.1

-.--

9.59.63.4

msmm3

5.63

2.726.38.96

msi M2.118.290.943.32

• ^^^^^^ • T^^ l358 .10.4240 12.4548 12.8140 14.2303 9.6611 1.7196 3.04220 <1.5633 31.4

15.138.322.5538'

598 4.14505 12.7281 11.6

j ^H^QI855 26.7233 13.5316 17.8321 13.6471 25.7439 19.1

jjj Hjj ^H177 2.42448 12.6117 6.6260 4.83

D47035854532561810319785

1009-

•..

411787180

El345392349219370448

mm375755607525

Sn V<0.7 68.31 .24 80.3<0.7 95.6<0.7 72.3<0.7 81<0.7 12.2<0.7 9.6<0.7 8.6<0.7 303

320299301271

<0.7 151<0.7 129<0.7 19

Sn V1.5 26.5

1.76 47.72.71 86.10.91 46.4<0.7 17<0.7 14

Sn V<0.7 26.5<0.7 38.40.94 20.6<0.7 27

zn Tocmm95.3 3.4991.7 1.45179 4.3161.8 1.21106 2.2316.6 1.0412.8 2.1210.7 0.85158 5.39

-.-.

78.1 2.6970.4 4.9820.7 2.03

Zn TOC Mm29.8 2.0642.2 2.4243.7 0.9636.1 2.33103 3.8634 4.69

Zn TOC Mm10.5 2.8563.9 4.549.2 2.6817.7 3.2

ONERAHI CHAOS BRECCIA1 ID As B Ba

701 3.03 16.6 78702 4.88 28.7 49.5

MANUKAU BRECCIA1 ID As B Ba

801 1.49 77.8 41802 4.92 184 50.6

Cd0.2<0.1

Cd0.12<0.1

Co10.4<0.2

Co7.42.3

'Results considered anomalous and excluded from

BS^B I11.2 8.610.9 4

DHB94 53.2

13.8 49.5

••£•010.091 18900.099 1580

E9HD10.245 4340.114 1340

mmm23122504'

MM12835315

KOHEH1202 339214 1495

msntmxm117 3543193 1500

I2 B6.62.5

miMM4.965.4

the validated soils data set for statistical purposes. Bold Italic values

• ^^^^^ • ^^^1348 9.13223 13

^mmSEm420 16188 10.8

EH537255

mm767597

Sn V<0.7 14.72.16 37.4

Sn V<0.7 3623.69 506

Zn TOC •36.5 4.6327.2 2.47

Zn TOC Mm143 7.19333 2.91

: considered as lithology specific



Appendix 3 - Statistical Analysis

Samples abovedetectionArithmetic meanStandard DeviationGeometric MeanMedianMinimumMaximum

All Non-Volcanic Soils

54

5.132.834.314.871.1911.54

Volcanic

38

2.76NANA3.160.418.45

Waitematas

18

3.892.913.142.781.3211.54

Quaternary

14

6.402.845.697.021.9110.60

Sands

12

5.811.625.605.413.408.34

Greywacke

6

6.842.236.517.003.919.78

Limestone

4

1.700.461.651.651.192.30

One rah!

2

3.034.88

Manukau Brec

2

1.494.92

All values In mg/kg

Distribution (percentiles)102550759095

1.712.664.877.188.9610.12

0.751.953.164.806.847.77

1.511.982.784.897.3010.37

2.863.827.028.289.8010.28

3.934.825.417.287.557.91

4.335.307.008.209.199.49

1.301.481.651.872.132.21

Box & Whisker Plot for Arsenic In Auckland Soils

14

12

10

.further.wp|k...

o-Cape Horn; Rd

Wait Quat Sand Lime Non-VoleGrey

Soil Type

Non-Outlier Range O Outliers

Vole

. D Median I 125%-75%

Cumulative Arsenic Distribution of Auckland Soils

I

100

80 -

60

4 6 8

Arsenic (mg/kg)

•Volcanic

- Waitematas

- Quaternary

-Sands

-Greywacke

- Limestone


"-• O»WIUM All Non--' Barium Volcanic SoilsSamples above R1detectionArithmetic mean 90.0Standard Deviation 72.7Geometric Mean 61 .7Median 68Minimum 8.7Maximum 313

All values In mg/kg

Distribution (percentiles)10 1525 3150 6875 14590 19895 212

400

350

300

|> 250

|- 200

1 150

100

50

n

Volcanic Waitematas Quaternary Sands Greywacke Limestone Onerahi ManukauBrec

43 18 11 12 6 4 2 2

154.6 83.5 110.8 73.6 125.9 57.8NA 85.7 70.2 61.3 73.2 45.7150 51.0 89.1 50.1 104.8 44.7157 55.5 98 64.3 131.8 47.134 8.7 28 11 36 17 49.5 41347 313 211 202 212 120 78 50.6

76 14 42 12 50 21114 28 47 26 69 28157 56 98 64 132 47227 92 181 88 180 77298 197 198 164 197 103316 232 205 184 204 111

Box & Whisker Plot for Barium in Auckland Soils

Further work$ McKenzie Road

0I

n

1

1

D

1

: •_!_.

. .T^TTI n

. jD

D

D-. p

— :Walt Quat Sand Grey Lime

Soil Type

Non-Vole Vole

n Median I—125%-75% Non-Outlier Range o Outliers

Cumulative Barium Distribution of Auckland Soils

<D

50 100 150 200

Barium (mg/kg)

250 300 350

- Volcanic

- Waitematas

- Quaternary

- Sands

- Greyw acke

- Limestone




§MI|i? prQfj( Volcanl'cSolls Volcanic Waitematas Quaternary Sands Greywacke Limestone Onerahi Manuteu

Samples above _. ...detection M

Arithmetic mean 17.1 45.5Standard Deviation 11.0 NAGeometric Mean 13.0 29.2Median 15.8 60.9Minimum 2 <2Maximum 42.2 255

All values In mg/kg

Distribution (percentiles)10 3.7 3.025 8.5 18.750 15.8 60.975 23.6 16390 33.2 22795 38.0 243

260

240

220

200

180

o> 160

|> 140

1" 120

(§ 100

80

60

40

20

0

18 11 15 6 4 2 2

20.6 18.7 13.1 16.5 12.312.6 9.4 12.1 4.5 6.616.7 16.7 7.6 16.0 11.318.0 17.6 5.2 16.8 9.94.8 8.7 2 10.9 7.5 16.6 77.842.2 35.2 39.3 21.1 22.1 28.7 184

6.9 9.0 - 2.0 12.1 8.29.2 10.9 2.5 13.3 9.218.0 17.6 5.2 16.8 9.930.7 25.3 23.7 20.4 13.038.4 30.6 23.9 20.8 18.541.3 32.9 28.7 20.9 20.3

Box & Whisker Plot for Boron in Auckland Soils

fr— —1 — 1 —Cn •• a

— i — >

Walt Quat

" LT

.

n*

I Y I | £ j u r

D

Sand Grey Lime Non-Vole Vole

D Median I—I 25%-75%

Soil Type

Non-Outlier Range o Outliers

Cumulative Boron Distribution of Auckland Soils

50 100 150

Boron (mg/kg)

200 250

-Volcanic

• Waitematas

- Quaternary

-Sands

-Greywacke

-Limestone


1\, Cadmium All Non-Volcanic Soils Volcanic Waitematas Quaternary Sands Greywacke Limestone One rah!

ManukauBrec

Samples above .. „detectionArithmetic mean 0.12 0.23Standard Deviation 0.09 NAGeometric Mean 0.09 NAMedian O.OS 0.27Minimum 0.05 0.05Maximum 0.46 0.63

All values In mg/kg

Distribution (percentiles)10 0.05 0.0825 0.05 0.1550 0.05 0.2775 0.17 0.3390 0.23 0.4895 0.29 0.57

0.7

0.6

1

S 0.3"O

80.2

0.1

nn

18 14 12 6

0.10 0.19 0.08 0.100.07 0.13 0.06 0.060.08 0.14 0.07 0.090.05 0.18 0.05 0.0850.05 0.05 0.05 0.050.25 0.46 0.22 0.17

0.05 0.05 0.05 0.050.05 0.05 0.05 0.050.05 6.18 0.05 0.090.15 0.26 0.07 0.160.18 0.33 0.17 0.170.22 0.38 0.20 0.17

Box & Whisker Plot for Cadmium in Auckland

I c

1

•4t

. ....

'

>

'

.

4 2 2

0.100.060.090.0850.05 0.05 0.056.18 0.2 0.12

0.050.050.090.140.160.17

Soils

• i

., — —

-

-

' Further workOrere Poi it

"

\

..., f

L" '

' rL_D I ._

i "" n

i i ii i i

— c

V

it

Wait Quat Sand Grey Lime Non-Vole Vole

So// Type

n Median I 125%-75% I Non-Outlier Range o Outliers A Extremes

Cumulative Cadmium Distribution of Auckland Soils

<D••J3

100

80

60

40

20

0.00 0.10 0.20 0.30 0.40 0.50

Cadmium (mg/kg)

0.60 0.70

- Volcanic

-Waitematas

- Quaternary

-Sands

- Greyw acke

- Limestone






54

15.412.911.210.92.252.3

Volcanic*

37

48.5NA

43.461.33.6124

Waltematas

17

16.5' 12.0

11.716.92.2

40.4

Quaternary

11

11.17.89.08

3.928.1

Sands

16

20.717.614.411.44.552.3

Greywacke

6

11.46.99.910.34.8

23.8

Limestone

4

7.62.97.08.33.510.2

One rani

2

10.911.2

ManukauBrec

2

413.8

All values In mg/kg

Distribution (percentiles)10 4.125 S.650 10.975 20.290 36.795 43.4

14.039.761.380.3102.6110.8

3.25.516.92531.138.7

3.95.181421.124.6

5.25.911.435.247.849.2

5.56.710.31318.621.2

4.86.88.399.710.0

•Specific lithology data removed for statistical analysis

Box & Whisker Plot for Chromium in Auckland Soils300

250

200

150

100

50

•*r

Further workMcKenzie Rd

Ti Point ftasalts -

iA

•a-


n Median Q25%-75% I Non-Outlier Range o Outliers A Extremes

Cumulative Chromium Distribution of Auckland Soils

100

80<D

•43

50 100

Chromium (mg/kg)

150 200

- Volcanic

- Waitematas

- Quaternary

-Sands

- Greyw acke

- Limestone


.>*„,' ^Cobalt All Non-Volcanic Soils


Samples abovedetectionArithmetic meanStandard DeviationGeometric MeanMedianMinimum, Maximum

All values In mgfkg

54

9.49.25.195.40.231.8

47

47.5NA

43.945.710.5166

18

7.868.184.235.30.226.3

11

7.605.925.045.60.517.1

15

14.6110.849.2313.61.3

28.2

6

8.5211.455.344.32.731.8

3.134.181.561.350.59.3

0.210.4

2.37.4


1.12.45.4152429

18.530.245.792126137

0.92.05.39.120.124

1.53.25.6121616

1.54.613.6242930

2.83.24.35

18.525

0.50.61.43.97.18.2

Box & Whisker Plot for Cobalt In Auckland Soils

5

COo6

IOU

1fil"l

•i/in

19D

mn

or-)

fin

40

Ol-lzu

n

c

I c

i

—3 I

1

c

- —

i 1

—

— i

c

1

]

L

" r

r

i

t==i r1^!

i 1

c!

c]

c]

Walt Quat Sand Grey Lime Non-Vole Vole

Soil Type

n Median 25%-75% Non-Outlier Range o Outliers A Extremes

Cumulative Cobalt Distribution of Auckland Soils

100

50 100

Cobalt (mg/kg)

150

-Volcanic

- Waitematas

- Quaternary

-Sands

- Greyw acke

- Limestone




fgl-£i>plSamples abovedetectionArithmetic meanStandard DeviationGeometric MeanMedianMinimumMaximum

All values In mgfkg


58

13.110.19.39.81.1

44.8

Volcanic

42

44.5NA

43.548.520.688.6

1

Waitematas

22

11.79.08.98.42.235.3

Quaternary

11

15.58.0013.515.24.827.4

Sands

15

12.110.47.58.61.1

33.1

Greywacke

6

21.214.517.219.37.344.8

Limestone Onerahl

4 2

6.37.43.63.31.3 417.1 8.6

ManukauBrec

2

49.553.2


2.65.09.8

20.427.229.6

24.933.948.557.28182

4.04.98.416.121.828.6

7.68.315.222.125.726.6

1.53.38.618.727.028.9

7.99.519.327.636.540.7

1.41.53.38.113.515.3

Box & Whisker Plot for Copper In Auckland Soils

pi

CD

!

Q>'43

100

80

60


So// Type

n Median O25%-75% I Non-Outlier Range o Outliers A Extremes

Cumulative Copper Distribution of Auckland Soils

- Volcanic

-Waitematas

- Quaternary

-Sands

-Greywacke

- Limestone20 40 60

Copper (mg/kg)

80 100


• / -: , •' Lead All Non-Volcanic Soils Volcanic* Waitematas Quaternary Sands Greywacke Limestone Onerahi Manukau

BrecSamples abovedetectionArithmetic meanStandard DeviationGeometric MeanMedianMinimumMaximum

All values In mg/kg

Distribution (percentiles)

58

15.612.211.612.7<1.556.2

39

19.8NA18.117.33.060.2

22

11.458.529.488.622.7840.9

1128.415.724.822.611.256.2

15

13.310.58.812.4<1.538.3

6

19.45.718.718.513.526.7

6.64.35.65.72.412.6

9.1313

10.816

102550759095

4.07.512.720.729.541.4

12.814.217.331.943.752.4

6.17.28.612.220.825.5

12.917.922.636.552.654.4

2.26.912.414.727.833.5

13.614.718.524.026.226.5

3.14.25.78.110.811.7


Box & Whisker Plot for Lead in Auckland Soils

IUU

140

120

r°-§, 80

aj^ 60

40

20

n

i

>

\iI rji I

o

11

\iXT

O--] D [

: I c

Mt'Smaor AnthnFurther v

_

t Basalts -ipogenic?vork f

^C

i

,— n1 1 |

•- C

i

3

!

]

20


Soil Type

o Median I 125%-75% I Non-Outlier Range o Outliers A Extremes

Cumulative Lead Distribution in Auckland Soils

- Volcanic

• Waitematas

- Quaternary

-Sands

• Greyw acke

-Limestone10 20 30 40

Lead (mg/kg)

50 60




' f/Maj ium All Non-Volcanic Soils

Volcanic Waitematas Quaternary Sands Greywacke Limestone One rani ManukauBrec


All values In mg/kg


51 34 18 11 12

190517681457141747410261

7024NA6206858519476564

260127001683126847410261

1507904

1302.3611726453529

1640796144416375833107

1300594118511775902109

1572690145814958142487

23122504

12835315

102550759095

6458451417233435294477

104633538585225133407045693

6378051268347558467968

6568671172195024112970

6529661637223723232676

7179251177172320062058

100512911495177622032345

Box & Whisker Plot for Magnesium in Auckland Soilsouuuu

70000

60000

oJ•§, 50000£

1 40000'55<D

| 30000§

20000

10000

0

fI,

-

•

I n I r-==l1

•

•

.

'

'

:

A

Walt Quat Sand Grey Lime Non-Vole

0

Vole

a Median 25%-75%

Soil Type

Non-Outlier Range o Outliers A Extremes

Cumulative Magnesium Distribution of Auckland Soils

10000 20000 30000

Magnesium (mg/kg)

40000 50000

-Volcanic

-Waitematas

- Quaternary

-Sands

-Greywacke

• Limestone


Volcanic Waitematas Quaternary Sands* Greywacke Limestone Onerahi


All values In mg/kg


50

364460190308131704

34

1075NA105610763622484

32534915923313

1121

11

364395210284391391

11

384479201376451704

6

5835144173951421460

157206866828464

141202

117193

102550759095

39603084609281270

5357871075150120102214

3257233382903989

39902844596121002

49603764465441124

16121939580611921326

354568180350407

*Specific lithology data removed for statistical analysis

Box & Whisker Plot for Manganese in Auckland Soils

ouuu

8000

7000

6000

5000

4000

3000

2000

1000

0I t

• •

a i

i , _

i$o

i

4

A

>'

L-A

'

. Puillier.wi^ Okahukua

1

---if-- -

1 a I

-

.

-.

rkPeninsular

; .b

t

•

1

•

:j_

^

4AL.

^Avvhitu

...I... . .T^D 1

-•

rSands

L

rc]:• : , . - -_.

_J ;

Wait Qiiat Sand Grey Lime Non-Vole Vole

Soit.Type

Median d]25%-75% I Non-Outlier Range o Outliers A Extremes

Cumulative Manganese Distribution in Auckland Soils

- Volcanic

- Waitematas

- Quaternary

-Sands

- Greyw acke

- Limestone

500 1000 1500

Manganese (mg/kg)

2000 2500




^ / /Mercury All Non-Volcanic Soils



55

0.130.100.100.107<0.030.421

41

0.13NANA

0.143<0.030.401

22

0.110.060.090.0910.0350.313

11

0.240.110.210.2470.1060.421

12

0.130.120.070.122<0.030.319

6

0.080.040.070.093<0.030.12

4

0.08<0.030.080.080.0630.097

2

0.0910.099

2

0.1140.245

All values in mg/kg

Distribution (percentiles)"102550759095

0.0400.0650.1070.1750.3070.321

0.0600.0900.1430.2020.2710.351

0.0500.0620.0910.1360.1770.195

0.1070.1380.2470.3180.3370.379

0.0130.0130.1220.2140.2920.306

0.0370.0660.0930.1140.1190.119

0.0660.0710.0800.0890.0940.095

"where values are less than the analytical detection limit of 0.03 mg/kg, a value of half that was used (0.015 mg/kg) for statistical purposes

Box & Whisker Plot for Mercury in Auckland Soils\J**\J

. • •

O oc

l«~5 0 20Q)

iO 'tC

0 -1 r>. ID

.05

n nn

0

, . _ _ „ i _

D

ii!

c3

j

D

1.

1 o |

s

ri

cj


Soil Type

Median [Z]25%-75% I Non-Outlier Range o Outliers

Cumulative Mercury Distribution of Auckland Soils

100

o>

40

20

0.0 0.1 0.2

Mercury (mg/kg)

0.3 0.4

- Volcanic- Waitematas

- Quaternary

-Sands

•Greywacke

- Limestone


~< *'< - Nickel w i?H °2L-u Volcanic Waitematas Quaternary Sands Greywacke Limestone Onerahi ^T"^8"*. " > , volcanic oous orec

SoSnabOV6 51 38 18 11 12 6 4 2 2Arithmetic mean 9.4 87.3 11.1 11.5 7.4 8.3 3.7Standard Deviation 7.9 NA 9.6 7.6 4.8 9.2 3.2Geometric Mean 6.5 73.9 7.2 9.1 5.9 5.6 2.7Median 7.1 118 9.2 10.7 8 4.3 2.7Minimum 0.9 4.6 0.9 2.7 1.9 2.7 0.9 2.5 4.96Maximum 34.1 v 320 34.1 23.3 18.1 26.3 8.3 6.6 5.4

All values In mg/kg

Distribution (percentiles)10 2.1 16.4 2.1 2.8 2.0 2.9 1.325 3.0 47.7 3.3 5.7 3.1 3.0 1.850 7.1 118 9.2 10.7 8.0 4.3 2.775 11.9 219 15.5 16.4 9.5 8.1 4.690 23.2 252 24.0 23.2 11.5 17.6 6.895 24.6 315 27.0 23.3 14.6 22.0 7.5

350

300

250

"SiH 200

1 150ig

100

50

0

Box & Whisker Plot for Nickel In Auckland Soils

i

1 n 1 1 E_

.•

3 1 r-H?

<;

_

;>hi 1 -*

ii

i

•

•

n•

i

8—f-

Walt Quat Sand Grey Lime Non-Vole

Sort Type

n Median [Z]25%-75% I Non-Outlier Range o Outliers

Cumulative Nickel Distribution in Auckland Soils

Vole

~~ \$f

fin III/

n c

^^

^

n M

^^

"\r\ M

-"^

=n 01

^^^

•\n r>t

» •

:r> 11

— *

tn 11

• Volcanic

— • — Waitematas

A Quaternary

0 Sands

—A— Greywacke

-n — e — Limestone

Nickel (mg/kg)




^ -Nitrogen



51

2340.101448.701869.03

19823366108

Volcanic

34

3745.181769.173198.083699.5

3248422

Waitematas

18

2260.891433.391838.10

19395325141

Quaternary

11

3203.641592.942668.79

31013466108

Sands

12

1906.581166.291539.40

1952336

4224

Greywacke

6

1641.501059.501374.85

1624558

3535

Limestone

4

2670.251836.962146.08

261310284427

One rani

2

14953392

ManukauBrec

2

15003543

All values In mgfkg


60711121982347643224893

163328253700479657606671

74611041939310444194719

206621993101393852025655

57710331952232235113894

6459401624175326563095

106211132613417143244376

9000

8000

7000

6000

5000

4000

3000

2000

1000

Box & Whisker Plot for Nitrogen In Auckland Soils

Further workjMt Smart

Wait Quat

100


Soil Type

n Median O25%-75% I Non-Outlier Range o Outliers A Extremes

Cumulative Nitrogen Distribution in Auckland Soils

- Volcanic

-Waitematas

- Quaternary

-Sands

- Greyw acke

- Limestone2000 4000 6000

Total Nitrogen (mg/kg)

8000


, PhosphorusAll Non-

Volcanic SoilsVolcanic Waitematas Quaternary Sands Greywacke Limestone Onerahi

ManukauBrec


All values In mg/kg


51 34 18 11 12 6 4 2 . 2

411 1180 358 568 386 439 251230 NA 233 250 181 222 144347 1141 284 530 345 401 222401 1265 280 465 331 380 21976 246 76 350 140 233 117 223 188

1213 3729 824 1213 633 855 448 348 420

140 383 113 363 198 275 135235 914 166 428 235 317 162401 1264 280 465 331 380 219540 1978 519 649 561 463 307666 2513 649 756 610 663 392797 3007 778 985 621. 759 420

Box & Whisker Plot for Phosphorus In Auckland Soils.innn

•annn

"3•12500

to

o-c8-° 1500

CL

innn

500

n

c

|

5

— i —

D 'L_ " 1

'

— i1 —

D

— ! —1 c

c

Further workMt Smart *

•

.

i

l_ i ~ ' i o° — 1 — !


Soil Type

n Median I 125%-75% I Non-Outlier Range o Outliers

Cumulative Phosphorus Distribution in Auckland Soils

500 1000 1500 2000 2500 3000 3500

Phosphorus (mg/kg)

- Volcanic

- Waitematas

- Quaternary

-Sands

- Greyw acke

- Limestone




All Non-Volcanic Soils Volcanic Waitematas Quaternary Sands Greywacke Limestone One rani Manukau

BrecSamples abovedetectionArithmetic meanStandard DeviationGeometric MeanMedianMinimumMaximum

All values In mg/kg

51

113710068658672265840

34

1118NA109112752753660

18

12049188938782263070

11

8553887717772811510

12

6832986157132591060

6

25161925189719654485840

9002318759196011160

15801890

4341340


348534867128523802900

4947481275159521012283

326431878185525622781

447636777108813801445

31241571391010471055

91414231965322046705255

687816919100210971128

Box & Whisker Plot for Potassium in Auckland Soils(UUU

6000

5000

i 4000

I% 30003§.

2000

1000

n

D

1

- •— ir—

D

,,,.— -j

D

1

•

D

i

i

i

—"i D r-

i

cf

.L Further work

VWalheke.

>•i60

D

— -1

•-

r

.'

D

i

Wait Quat

100


Soil Type

D Median d]25%-75% I Non-Outlier Range o Outliers A Extremes

Cumulative Potassium Concentrations of Auckland Soils

- Volcanic

- Waitematas

- Quaternary

-Sands

- Greyw acke

- Limestone1000 2000 3000 4000

Potassium (mg/kg)

5000 6000


Sti/#u*fSamples abovedetectionArithmetic meanStandard DeviationGeometric MeanMedianMinimumMaximum

All Non-

50

565.74331.81467.72

50085

1532

Volcanic

34

740NA -7317583132288

Waitematas

17

621.88401.11490.90

5861031532

Quaternary

11

749.27301.64699.40

5854261202

Sands

12

424.00281.51333.10384.5

851009

Greywacke

6

353.8375.98345.92359.5219448

Limestone

4

565.50158.71548.06

566375755

Onerahi

2

255537-

ManukauBrec

2

597767

All values In trig/kg

Distribution (percentiles]10 18025 34650 50075 753.2590 1072.195 1185.15

43765475884810331545

175.23225869021096.41222.4

475545.558599011911196.5

110.7192.75384.5563.25770.1886.9

282346359.5386.5420434

420487.5ceoODD644710.6732.8

Box & Whisker Plot for Sulphur In Auckland Soils

2200

-•c

800

400

Further work A•Buhimif Crater- -


Soil Type

n Median Q25%-75% 1 Non-Outlier Range o Outliers A Extremes

Cumulative Sulphur Distribution in Auckland Soils

100

80i

I

20

- Waitematas

- Quaternary

- Sands

- Greyw acke

500 1000

Sulphur (mgfltg)

1500 2000

IIIIIIIIIIIIIIII


II


•^"m^TftSamples abovedetectionArithmetic meanStandard DeviationGeometric MeanMedianMinimumMaximum


530.940.890.650.350.353.91

Volcanic*

330.420.180.390.350.35

1

Waitematas

220.890.910.620.3750.353.91

Quaternary

91.731.051.351.5

0.353.61

Sands

120.420.260.390.350.351.24

Greywacke

61.260.920.961.2050.352.71

Limestone

40.500.300.450.350.350.94

One rah!

2

0.352.16

ManukauBrec

2

0.353.69

All values In mg/kg

Distribution (percentiles)"102550759095

0.350.350.351.492.162.5

0.350.350.350.3511

0.350.350.381.411.862.10

0.351.211.502.412.673.14

0.350.350.350.350.350.75

0.350.491.211.702.242.47

0.350.350.350.49750.7630.8515

'Specific lithology data removed for statistical analysis"where values are less than the analytical detection limit of 0.7 mg/kg, a value of half that was used (0.35 mg/kg) for statistical purposes

Box & Whisker Plot for Tin In Auckland SoilsD

4

I,•5..g

•i

n

t,

c

f

3

C]

/

.

r•h

.

\

• .,..i....1

1 r?

V

r

fi,

3

i•

,L

{i

i

.

r

,->

,

\ j

"'

.Mt SmartVolcanics

K FranklinBasalts

100

0.0


So// Type


Cumulative Tin Distribution in Auckland Soils

- Volcanic

-Waitematas

- Quaternary

•Sands

- Greyw acke

- Limestone0.5 1.0 1.5 2.0

Tin (mg/kg)

2.5 3.0 3.5


' „ Vanadium.' j"Samples abovedetectionArithmetic meanStandard DeviationGeometric MeanMedianMinimumMaximum


50

58.736.247.448.58.6151

Volcanic

40

123NA11614215.6366

Waitematas

18

63.631.956.755.321.9135

Quaternary

11

64.934.257.451.830.1118

Sands*

11

66.149.143.872.38.6151

Greywacke

6

39.626.932.636.514

86.1

Limestone

4

28.17.4

27.426.820.638.4

Onerahi

2

14.737.4

ManukauBrec

2

362506

All values In mg/kg


18.830.848.580.8113124

4974142199314331

32.241.155.384.7108117

333851.892.5113116

9.615.672.388.3129140

15.519.436.547.466.976.5

22.425.026.829.935.036.7


Box & Whisker Plot for Vanadium in Auckland Soils'HJtuI

350

300

H 25°.§

E 200'•6«t>| 150

100

50

n

D

i

--

-i—

G

;

--

Axal

.

Mjsa rAwhFtu

Sands

n

•'

L .- J

•u i^l"""" ;

J. i n i

A£.

A

?r-

.

' D

-

D


Soil Type


Cumulative Vanadium Distribution in Auckland Soils

•Volcanic

- Waitematas

- Quaternary

-Sands

- Greyw acke

- Limestone100 150 200 250

Vanadium (mg/kg)

300 350




.-Svii-Mf f'tSm^WMlzimfi-^ri-f > *'4(KivjL-.\ Jt'f'j? '&&'''; v 'V-.i'"'1-'' - f-s ..'.-iv Vj't

.. ,AI' ^°o~ ,, Volcanic Waitematas Quaternary Sands Greywacke Limestone Onerahl Ma£^ u

VOICantC OO1IS DrBC


All values In mg/kg


1200

1000

800

1H 600

N400

200

0

51

58.739.145.352.19.2179

12.828.252.186.2106117

3 8 1 8 1 1 1 2 6 4 2 2

252 54.3 66.1 75.1 48.1 25.3NA 33.1 30.0 55.5 27.4 26.0233 43.7 58.7 52.3 43.7 18.2247 45.8 63.9 74.3 39.2 14.154.5 9.6 21 10.7 29.8 9.2 27.2 1431160 123 111 179 103 63.9 36.5 333

80 14.9 28.2 13.2 31.9 9.6110 29.1 44.5 19.7 34.5 10.2246 45.8 63.9 74.3 39.2 14.1654 71.1 91.3 98.0 43.3 29.3840 100.6 96.6 152.8 73.4 50.0931 108.6 103.8 167.5 88.2 57.0

Box & Whisker Plot for Zinc in Auckland Soilsn

L

6

p1

A

I _ I /

D I ° =£>•* I r

i

D_ p

i — I o | — I —-i ' 1 ' •

Walt Quat Sand Gray Lime Non-Vole Vole

Soil Type

D Median d]25%-75% I Non-Outlier Range O Outliers A Extremes

Cumulative Zinc Distribution in Auckland Soils

<bfi

100

80

60

40

20

200 400 600

Zinc (mg/kg)

800 1000

- Volcanic

-Waitematas

- Quaternary

-Sands

- Greyw acke

- Limestone


Total Organic/' : Carbon

All Non-Volcanic Soils Volcanic Waitematas Quaternary Sands Greywacke Limestone One rani Manukau

Brec

Samples abovedetection bn

Arithmetic mean 3.66Standard Deviation 2.31Geometric Mean 3.05Median 3.2Minimum 0.63Maximum 13.96

34

5.202.414.604.740.85

1 8 1 1 1 2 6 4 2 2

3.69 5.33 2.65 2.72 3.322.04 3.30 1.55 1.34 0.843.08 4.66 2.24 2.42 3.253.53 3.89 2.175 2.375 3.0250.63 2.14 0.85 0.96 2.68 2.47 2.91

11.64 7.93 13.96 5.39 4.69 4.54 4.63 7.19

All values in%drywt.

Distribution (percentiles)10 1 2125 2.18550 3.275 4.61590 6.4395 7.145

2.118 1.442 2.65 1.057 1.51 2.7313.9725 2.3725 3.615 1.39 2.1275 2.80754.74 3.53 3.89 2.175 2.375 3.025

6.43258.272

4.875 6.33 3.695 3.5 3.5356.553 7.45 4.913 4.275 4.138

9.8865 7.0035 10.705 5.1645 4.4825 4.339

Box & Whisker Plot for Total Organic Carbon in Auckland Soils

14

"oj 4*)_>^ i f-

^ 100-s8 8.0

g> 6^

"3 <4\~. t

n

J ' Y" ' '

C

~^

o

1

••

r ~

_T±- -

o1

61

. •"•

r — n

G D

n n ! .

i i 1 1


Soil Type

n Median Q25%-75% I Non-Outlier Range o Outliers A Extremes

Cumulative Total Organic Carbon Distribution in Auckland Soils

on

AH

40 -

on

t

y/is1 «

y

ftfUl*Jr5 ,

»&r „

^^

/

<\ 1

-~^

^

: <

•*r ""

3 1n -i

• Volcanic

—•—Waitematas

—A — Quaternary

0 Sands

—A — Grey w ac ke

n — e — Limestone

Total Organic Carbon (% dry weight)



Background Concentrations of Inorganic Elements … · Background Concentrations of Inorganic...

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