CHAPTER 4 PHYSICO-CHEMICAL AND ......Chapter 4 Physico-chemical and bacteriological analysis of...

Chapter 4 Physico-chemical and bacteriological analysis of water

An Ecological study of the Macrophytic Vegetation of the Kuttanad Ecosystem 67

CHAPTER – 4

PHYSICO-CHEMICAL AND BACTERIOLOGICAL CHARACTERISTICS OF WATER

4.1 Introduction

Water is the universal solvent and the most and precious life giving liquid on this planet

is essential for the survival of every living organisms. Nowadays, most of the water bodies are

polluted mainly due to anthropogenic activities and their conservation is an impediment for

human kind (Sangodoyin and Sanyaolu, 1995; King, 1998; Akpan, 2004; Cerqueira et al., 2008).

Due to anthropogenic activities and the population pressure, most of the wetlands are being

extinct or nearly threatened. Inadequate infrastructure to properly treat and dispose of the

sewage, lack of sanitary condition, poverty, tourism and over exploitation of natural water has

resulted in the discharge of considerable quantities of untreated waste into the natural wetlands

(Borrego & Figueras, 1997; Costanza et al., 1997). Direct discharge of domestic waste, leaching

from poorly maintained septic tanks, and improper management of farm wastes are suspected as

the major sources of bacterial contaminants in wetlands and other water bodies (Huttly, 1990).

Wetlands have highly significant role in purifying the polluted water from municipal

sewage, agricultural run-off and other industrial effluents (Keddy, 2000; Mitsch and Gosselink,

2000; Maggioni et al., 2009). Aquatic macrophytes are purifying the water and removes major

pollutants from the polluted water (Pietsch, 1972; Kohler, 1982; Arts et al., 1990; Melzer, 1999;

Peakall & Burger, 2003; Hrivnak et al., 2006; Rybicki and Landwehr, 2007). Wetlands are

known as the ‘kidneys of nature’. The changes in the quality of water will affect the distribution

and survival of different organisms in wetlands. Water quality monitoring of wetlands is a vital

aspect for assessing the pollution status because it is an ideal tool for establishing baseline data

for critical water pollutants and presiding basis for guiding the implementation of corrective

plans against pollution.

4.1.1 Scope and Significance of the study

Water quality studies are important for the conservation and management of wetlands.

In Kuttanad, very few studies have been conducted for the determination of physico-chemical

and bacteriological parameters. Studies of Thomas et al. (2001) and Padmakumar et al. (2002)

have given a brief outline of the water quality of canal systems and Kayal lands of Kuttanad.

Other reported studies have been confined to Vembanad Lake (Kurup and Samuel, 1987; Nair

and Balachand, 1993; Nair and Unni, 1993; Padmakumar et al., 2004). Studies on the bacterial

population and dynamics by Lakshmanaperumalsamy et al. (1981), Chandrika (1983), Hatha et



al. (2004) and Abhirosh et al. (2008) are confined to the Vembanad Lake and there are no studies

on the microbial pollution in the different systems of Kuttanad.

After the construction of Thaneermukkom barrage and Thottappilly spillway, the

salinity intrusion into Kuttanad is prevented and this helps the prevalence of bacterial diseases

and other ecological problems (MSSRF, 2007). During summer season (premonsoon), there is

no flow and stagnant condition prevails in this wetland system. The runoff from the paddy

fields, domestic sewage and other wastes carrying by the rivers accumulating in the water

bodies. These changes in the ecosystem reflect in the physico-chemical characteristics of water.

Hence the present study aims to find out the seasonal changes of physico-chemical

characteristics of water from different systems of Kuttanad. The study also carried out with an

objective to examine the seasonal occurrence of indicator and pathogenic microorganisms such

as facecal coliform, faecal streptococci, V. cholera Like Organisms (VCLOs), V. parahaemolyticus

Like Organisms (VPLOs’) and Pseudomonas spp. in the different systems of Kuttanad wetland

ecosystem.

4.2 Review of literature

4.2.1 Physico-chemical parameters

Water quality study is an integral part of evaluation of health of any wetland ecosystem.

In general, the riverine ecosystem, while traversing through hills, before reaching plains,

maintain unpolluted water quality due to less human activities and can be regarded as good and

potable water and suitable for sustenance of aquatic life (Stormer et al., 1996; Shyamalendu et

al., 2001; Akpan, 2004; Cerqueira et al., 2008).

Multivariate analysis and ordination by Principal Component Analysis of the physico –

chemical variables and phytoplankton density of river Mahanadi at Durg was studied by Unni

and Pawar in 2000. They reported high BOD from a distillery impacting the river water and was

found negatively correlated with DO concentration.

Bellandur lake is one of the major lakes of Banglore city and is subjected to severe

pollution stress from the Urban community. Impact of urbanization on Bellandur lake have

extensively been studied by Lokeshwari and Chandrappa (2005). The addition of effluents from

urbanized Bangalore city has changed the characteristics of the Lake from being a natural

ecologically healthy lake to an artificial reservoir of domestic sewage and industrial effluents.

The DO of the Bellandur lake water ranged from 3.8 - 6.3 mgO2/L and the COD values are

above the permissible limit. They also revealed that if the present stage of affairs continues for

long, the Bellandur lake may soon become an ecologically inactive Lake.



The physico chemical characters of the water samples of lake Vellayani in

Thiruvananthapuram district, from ten stations were studied by Radhika et al. in 2000.

Temperature, turbidity, pH, conductivity, dissolved oxygen, biochemical oxygen demand, total

solids, total suspended solids, total dissolved solids, alkalinity, chloride, hardness, nitrate,

phosphate and silicate were found higher during pre-monsoon. Although all the parameters

examined here remained within the permissible levels, the higher concentration for most of the

factors was found at or near shore station.

Water quality studies on Karamana River, Thiruvananthapuram district, Kerala was

done by Jayaraman et al. (2003). Study observed that COD and BOD were higher during pre

monsoon suggesting strong indication of organic matter contamination and discharge of sewage

effluents. In general, DO concentration remained within the range of the values of water quality

statistics for Karamana River by Central Pollution Control Board. In 2004, Piyankarage et al.

studied the water quality of Bundala Ramsar site of Sri Lanka. Agricultural operations input the

total nitrogen and phosphorus in the wetland especially during the paddy cultivation period.

Assessment of seasonal changes in surface water quality is an important aspect for

evaluating temporal variations of pollution due to natural or anthropogenic inputs of point and

non – point sources. Analysis shows that a parameter that is most important in contributing to

water quality variation for one season may not be important for another season (Ouyang et al.,

2006).

In 2007, Panigrahi et al. studied the anthropogenic impact on water quality of Chilika

lagoon in Orissa using statistical approach. They investigated the spatiotemporal variability of

water quality parameters like transparency, salinity, dissolved oxygen, nutrients viz. NH3-N,

NO2-N, NO3 –N, PO4-P, total nitrogen, total phosphorous and chlorophyll-a. Addition of

nitrogen and phosphorous compounds to the lagoon mainly occurred through the drainage from

agricultural lands and river run off during the early months of paddy cultivating seasons. The

only estuarine system for a comparison of physico-chemical aspects is that of Chilika lake which

is an estuary similar to Kuttanad; however there are significant differences between the two

systems. Chilika is alkaline (27 -189 mg/L), well oxygenated (6.4 mg/L and above), high

calcium (160 - 330 mg/L), magnesium (53 -233 mg/L), pH (6.8 – 9.6) and the rainfall received

the region is only 1200 – 1600 mm, almost half of the rainfall received in the Vembanad-

Kuttanad wetland ecosystem.

In 2009, Nikhil and Azeez studied the spatial and temporal changes of water chemistry

of Bharathapuzha using Principal component analysis. They found that the spatial and temporal

variation of water chemistry is mainly due to the land use changes in the catchment area as well

as impact of dams on river.



In 2009, Joseph and Ouseph analysed the nutrient status of Cochin estuary using

multivariate analysis based on the data of different seasons from the years 2001 to 2004. They

found that the nutrients like nitrate, nitrite, phosphate and inorganic phosphate are playing a

significant role in the system. These nutrients mainly come from the drainages and industrial

pollution from Cochin urban area.

4.2.2 Bacteriological analysis

In 1981, Lakshmanaperumalsamy et al. studied the microbiological indicators and

pathogens near the mouth regions of Vembanadu lake. They reported that the backwater system

contains a considerable number of indicators and pathogens, which will pose a potential public

health risk and any further deterioration in the microbial quality of water would adversely affect

the fishery and recreational activities in the estuarine system.

Row (1981) found that the low level of bacterial pollution in Mandovi and Zuary

estuaries of Goa. The coastal fishing villages of Madras coast have increased faecal pollution

and the role of tidal waters in the flushing of estuary was highlighted (Azariah and

Subramanian, 1982). From an eco-physiological point of view, Chandrika (1983) studied the

seasonal variations of faecal indicator bacteria at several stations in Vembanad Lake and other

estuaries in south east coast of India.

The prevalence and risk assessment of faecal indicator bacteria from Kumarakom lake

was studied by Lekha in 2002. The study reported that most probable value of faecal

streptococci were consistently high at all sampling stations mean while other two indicators

faecal contamination varied among the stations. The study reported that source of faecal

contamination using FC/FS ratio, less than 4.4 indicating faecal pollution source is non-human.

In 2004, Hatha et al. studied the prevalence of indicators of faecal pollution such as

faecal coliform and faecal streptococci in Cochin estuary. Consistently the high load of faecal

indictor bacteria at all sampling stations were recorded and the seasonal variations in the

prevalence level of these organisms showed a higher load of indicator organisms during the

monsoon seasons. The high FS count indicating a higher land run off during the study period

and they also suggest that the high faecal contamination may pose threat to fishing and

recreation of the Cochin estuary.

Abhirosh et al. (2006) studied the distribution of faecal indicator bacteria in Vembanad

Lake on both sides of Thanneermukkom Barrage at Kumarakam. Ten stations were intensively

sampled for microbial indicators of faecal pollution at both sides of barrage, which exhibited

different degrees of faecal pollution. The result showed that high FC in all stations, value range



between MPN 90 - 11000/100 ml. E. coli was isolated consistently from all the stations. The

high prevalence of E. coli throughout the study area suggested a chronic pollution problem and

potential health risk to those who use this water resource for various purposes.

4.3 Objectives of the study

1. To study the various physico-chemical characteristics of water from four different

systems i.e. rivers, canals, cultivated field and abandoned field which form separate

entities but interrelated and interconnected within in the system.

2. Temporal and spatial variation of water quality of different systems during different

seasons over two years.

3. To analyse the bacteriological quality like Faecal coliform, faecal streptococci, VCLOs’,

VPLOs’ and Pseudomonas spp. in the water samples collected from different systems

during premonsoon, monsoon and postmonosoon season.

4. To compare the seasonal variation of bacteriological parameters in water samples from

different systems during premonsoon, monsoon and postmonosoon season.

4.4 Materials and Methods

4.4.1 Water sampling

Water samples were collected monthly for two years from January, 2006 to December,

2007 covered different season viz. premonsoon (PRE), monsoon (MON) and postmonsoon

(POST). For physico-chemical analysis, water samples were collected in one litre polyethylene

cans. To avoid possible contamination, the cans were first rinsed with dilute HCl, then cleaned

using soap solution and finally washed thoroughly using tap water. At the sampling location,

the cans were again rinsed with the water to be sampled and labelled properly.

For bacteriological analysis, water samples were collected seasonally from the selected

systems of Kuttanad. The average values of all locations of AC Canal (ACC 1 to ACC 6), Kayal

lands (S1 to S4), Pallom (P5 and P6) and Vanam (VA1 and VA2) were given in the results.

Samples were collected separately in 500 ml sterile polyethylene bottles and labelled properly for

further analysis.



Table 4.1A: Details regarding the physico-chemical analysis of water

Sl.No. Parameters Analysed Unit Method/Instruments Reference

A. Physico-chemical parameters

1. Air Temperature oC Thermometer -

2. Water temperature oC Thermometer -

3. TDS ppm TDS meter -

4. Conductivity mS Conductivity meter -

5. Turbidity NTU Turbidity meter APHA,

1998 6. pH - pH meter -

7. Acidity mgCaCO3/L Titrimetry ,,

8. Alkalinity mgCaCO3 /L Titrimetry ,,

9. Chloride mg/L Argentometry ,,

10. Hardness mg/L EDTA titrimetry ,,

11. DO mgO2/L Winkler Method ,,

12. BOD mgO2/L 5 day BOD test ,,

13. COD mgO2/L Open reflux method ,,

14. Nitrate mg/L Brucine method ,,

15. Phosphate mg/L Stannous chloride method ,,

16. Potassium mg/L Flame photometry ,,

17. Sulphate mg/L Turbidimetric method ,,

B. Bacteriological parameters

18. Faecal coliform MPN/100ml Multiple Tube fermentation ,,

19. Faecal streptococci ,, ,, ,,

20. VCLO and VPLO. cfu/ml Spread plate

21. Pseudomonas spp. ,, ,, ,,

Box plot was used to express the seasonal variation of water quality in different systems

of Kuttanad and the sampling stations were indicated by the following code numbers;

Table 4.1B: Sampling stations and their codes

River systems Canal systems Cultivated Field systems Abandoned Field

No. Code No. Code No. Code No. Code No. Code

1 KV 1 10 KV 2 20 VA 1 30 KV 3 38 P 1

2 TH 3 11 TH 1 21 VA 2 31 TH 2 39 N 2

3 P 3 12 P 5 22 KR 3 32 P 2 40 KR 2

4 P 4 13 P 6 23 ACHIN 33 KR 4

5 ACC 4 14 ACC 1 24 THRP 34 PILA

6 KR 1 15 ACC 2 25 KARU 35 PURA

7 VPM 16 ACC 3 26 S 1 36 S 2CF

8 THOT 17 ACC 5 27 S 2 37 S4 CF

9 KODI 18 ACC 6 28 S3

19 N 1 29 S 4



4.2.2 Physico- chemical characteristics of water quality

a. Temperature: The temperature was recorded by using a digital thermometer

b. Conductivity: It was measured by conductivity meter (TDS – Conductivity meter, Model 308,

Systronics, India).

c. Turbidity: Turbidity is measured using Nephelometric turbidity meter (Model 132, Systronics,

India)

d. Total Dissolved Solids: Total dissolved solids were measured using a digital TDS meter. The

instrument was calibrated using 0.01M KCl.

e. pH: It was measured by using a digital pH meter ( µpH system - Model 361, Systronics, India)

f. Acidity: Acidity was estimated by titrating the sample with a strong base such as NaOH using

methyl orange or phenolphthalein as indicator.

g. Alkalinity: Alkalinity was estimated by titrating the sample with a strong acid such as HCl,

using phenolphthalein or methyl orange as indicator.

h. Chloride: For the determination of chloride, Argentometric method was used. Silver nitrate

reacts with chloride to form very slightly soluble white precipitate of AgCl. At the end point

when all the chlorides get precipitated, free silver ions react with chromate to form silver

chromate of reddish brown colour.

i. Total Hardness: It was determined by complexometreic titration using Ethylene Diamine Tetra

Acetic Acid (EDTA) as titrant and Eriochrome Black – T (EBT) as indicator.

j. Dissolved Oxygen (DO): DO was measured by the Winkler method with azide modification.

k. Biochemical Oxygen Demand (BOD): BOD was analyzed by incubation of water sample for 5

days in a BOD bottle. Incubation is done in a BOD incubator at 20 + 50C. On the 5th day, the

DO of the sample was analyzed. The difference of the initial and the final DO was calculated as

BOD5.

l. Chemical Oxygen Demand (COD): It was determined by open reflux method. The sample was

refluxed with K2Cr2O7 and H2SO4 in presence of mercuric sulphate to neutralize the effect of

chlorides and silver sulphate catalyst. The excess of K2Cr2O7 is titrated against ferrous

ammonium sulphate using ferroin as indicator. The end point is indicated by a colour change

from blue to reddish brown.

m. Sulphate: It was determined by turbidimetric method using a double beam spectrophotometer

(Model 2203, Systronics, India)



n. Nitrate: Nitrate was determined by the Brucine method. Nitrate and brucine react to produce

a yellow colour and the intensity of the colour was measured at 410 nm using a double beam

spectrophotometer (Model 2203, Systronics, India)

o. Phosphate: It was determined by using a double beam spectrophotometer (Model 2203,

Systronics, India) as per the methods prescribed in APHA (1998).

p. Potassium : It was measured by using Flame Photometer (Model 126, Systronics, India)

4.2.3 Bacteriological Analysis

For bacteriological analysis, water samples were collected in sterile plastic bottles of

500ml capacity from a depth of one foot. Water samples were transported to the laboratory in

an icebox and subjected to bacteriological examination with in four hours of collection.

a. Analysis of Faecal Coliform (FC): Faecal coliform load of water sample was determined by

three-tube dilution method (Multiple tube fermentation method) using lactose broth. The

Procedural Flow chart for the enumeration of faecal coliform from water samples as follows;

Figure 4.1: Procedural Flow chart for the enumeration of Faecal coliform from water samples

3 x 1 ml 3 x 10 ml

Inoculated into

3 x 10 ml DSLB

3 x 0.1 ml

Water Sample

Incubated at 44.5oC for 24 to 48 hours

Checked the gas production in the

inverted Durham’s tubes in the lactose

broth

Referred the three tube MPN table to

find out the MPN index of FC/100 ml

Noted the tubes with gas production in 10 ml, 1 ml, and 0.1 ml samples

Inoculated into

3 x 10 ml SSLB Inoculated into

3 x 10 ml SSLB



3 x 1 ml 3 x 10 ml

Inoculated into

3 x 10 ml DSADB

Inoculated into

3 x 10 ml SSADB

3 x 0.1 ml

Water Sample

Incubated at 37oC for 24 to 48 hours

Checked the growth (indicated as

turbidity of the medium)

Referred three tube MPN table to find

out the MPN index of FS/100 ml

Noted the tubes with growth in 10 ml,

1 ml, and 0.1 ml samples

Inoculated into

3 x 10 ml SSADB

Note down the

tubes with gas

production in 10

ml, 1 ml, and 0.1

ml samples

b. Analysis of Faecal Streptococci (FS): Faecal streptococci load of the water sample was

determined by three-tube dilution method (Multiple tube fermentation method) using Azide

dextrose broth (Himedia, Bombay). The procedural Flow chart for the enumeration of faecal

streptococci from water samples as follows;

Figure 4.2: Procedural Flow chart for the enumeration of Faecal streptococci from water

samples

Azide Dextrose Broth (HIMEDIA) is a selective medium for detection of streptococci in water,

sewage, food and other materials suspected of sewage contamination

c. Analysis for Vibrio cholerae like organisms (VCLO’s) and Vibrio parahaemolyticus like organisms

(VPLO’S)

By adopting spread plate method using Thiosulphate Citrate Bile Sucros (TCBS) agar

medium (HI MEDIA) for the selective isolation and cultivation of Vibrio cholerae and other

enteropathogenic Vibrios in water samples. Colonies with yellow colour counted as Vibrio

Cholerae like organisms and colonies with green colour counted as Vibrio parahaemolyticus like



Water Sample

0.2 ml water sample spread plate on Thiosulphate

Citrate Bile Sucrose (TCBS Agar)

Checked the presence of green and yellow coloured

colonies

Incubated at 37oC for 24 Hours

Counted the yellow coloured colonies as VCLO’S and green coloured colonies as VPLO’S and expressed the number of VCLO’S and VPLO’S per ml of the water

sample

organisms from the plate. The procedural Flow chart for the enumeration of Vibrio like

organism from water samples as follows;

Figure 4.3: Procedural Flow chart for the enumeration of Vibrio like organisms from water samples

d. Pseudomonas Species

Pseudomonas species were isolated by adopting spread plate method on pseudomonas

agar (HI MEDIA) plate. The procedural Flow chart for the enumeration of Pseudomonas species

from water samples as follows;

Figure 4.4: Procedural Flow chart for the enumeration of Pseudomonas species from water samples

Water sample

Spread plate 0.2 ml on Pseudomonas Agar

Checked for the presence of typical Pseudomonas like colonies

Incubated at 37oC for 24 Hours

Counted the typical colonies and expressed as number of Pseudomonas per ml



4.5 Results

4.5.1 Physico-Chemical Parameters of water

a. Air Temperature (oC)

The atmospheric temperature in different river systems of Kuttanad ranges from 27.2 to

35oC (Table 4.2). The minimum value recorded from ACC 4 site (River Manimala at

Kidangara) during the monsoon season and the maximum value recorded from KV1 (river

Manimala at Kavalam) during the premonsoon season. In canal systems, atmospheric

temperature varied from 25.7 to 35.5oC. The minimum value recorded from KR3 (Kumarakom)

during the monsoon season followed by THRP (Thriperumthura) with 26oC during the same

season. The maximum value recorded from ACC3 (AC canal – Daivamthara) during the

premonsoon season. The maximum average value, 33oC recorded from TH1 (Thakazhy) and

the minimum recorded from ACC6 (Onnamkara) with 29.6oC. In cultivated fields, the

minimum value, 25.1oC recorded from PURA (Purakkad) during the monsoon season and the

maximum value, 35.2oC recorded from P2 (Pallom CF) during the premonsoon season. The

seasonal maximum mean value recored from TH1 (Thakazhy) site with 32.5oC. In abandoned

fields, the atmospheric temperature ranged from 29 to 36.8oC. The minimum value recorded

from KR2 (Kumarakom) during the monsoon season and the maximum value recorded from P1

(Pallom) during the premonsoon season. The mean maximum was recorded from the P1 site.

Generally, atmospheric temperature showed comparatively low values during the

monsoon season and high during the premonsoon season (Figure 4.5). Analysis of variance

showed that there is significant difference between seasons (p<0.01) but there is no significant

variation between systems (p>0.05).

b. Water Temperature (oC)

The water temperature in different river systems of Kuttanad ranges from 27 to 34oC

(Table4.2 ). The minimum value recorded from ACC 4 site (River Manimala at Kidangara)

during the monsoon season and the maximum value from THOT (river Achenkovil at

Thottapally) during the premonsoon season. In canal systems, water temperature varied from

25.5 to 34.8oC. The minimum was recorded from P6 (Pallom polluted canal) during the

monsoon season followed by P5 (Pallom north end) with 26.4oC during the same season. The

maximum recorded from KARU (Karumady) during the premonsoon season. In cultivated

fields, the minimum value of 27oC recorded from P2 (Pallom) during the postmonsoon season

and the maximum value, 35.50C recorded from TH2 (Thakazhy CF) during the premonsoon

season. The seasonal maximum mean value recorded from KR4 (Kumarakom) site with

34.03oC. In abandoned fields, the water temperature ranged from 27.3oC to 32oC. The minimum



was recorded from KR2 (Kumarakom) during the postmonsoon and the maximum from N2

(Neendur) during the premonsoon season. The mean maximum was recorded from the N2 site.

It was generally noted that water temperature is comparatively higher during the

premonsoon season in all the systems studied (Figure 4.6). Water temperature at Thottappally

site showed comparatively higher temperature than the atmospheric temperature. Statistical

analysis showed that there is significant variation of water temperature between seasons

(p<0.01, F=38.69) and systems (p<0.05, F=3.50). Water temperature showed negative

correlation with DO (r=-0.56, p<0.01), and nitrate (r = - 0.37, p<0.05). It showed positive

correlation with BOD (r=0.54, p<0.01).

Table 4.2 Atmospheric and Water temperature (mean values) variation in

Kuttanad Wetland ecosystem during study period

Sites

Atmospheric Temperature (0C) Water Temperature (0C)

Pre Mon Post Mean±SD Pre Mon Post Mean ±SD

River

KV 1 35 28.6 30 31.2±3.36 32.8 28 30.5 30.43±2.4

TH 3 34 32.1 31 32.36±1.52 32 31.6 31.5 31.7±0.26

P 3 32 30.1 31 31.03±0.95 32.6 29.4 30 30.67±1.7

P 4 32 31.1 31 31.36±0.55 31 30.8 30 30.6±0.53

ACC 4 34.2 27.2 30.5 30.63±3.5 31.5 27 32 30.17±2.75

KR 1 32.5 28.5 30.8 30.6±2.01 32 30.2 29.9 30.7±1.14

VPM 34.5 28 31 31.16±3.25 30.5 28 30.5 29.67±1.44

THOT 33.5 28.1 30 30.53±2.74 34 29.9 31 31.63±2.12

KODI 31 30 31.5 30.83±0.76 32 29.6 32 31.2±1.39

Canal

KV 2 34 30 29 31±2.65 32.5 30.5 29.5 30.83±1.53

TH I 35 31 33 33±2 33 30 31.5 31.5±1.5

P 5 31.2 31.4 28 30.2±1.91 29.6 26.4 29 28.33±1.7

P 6 31.2 31.4 30.5 31.03±0.47 28.8 29.4 25.5 27.9±2.1

ACC 1 35 27.6 35 32.53±4.27 31.5 26.7 32.5 30.23±3.1

ACC 2 34.5 26.5 33 31.33±4.25 32 27 31.5 30.17±2.75

ACC 3 35.5 26.7 31 31.06±4.4 33 27 32 30.67±3.21

ACC 5 33 29.4 30.5 30.96±1.84 32.5 30.1 30 30.87±1.42

ACC 6 32.5 26.8 29.5 29.6±2.85 32 27.6 30.5 30.03±2.24

N 1 31.5 30.4 32.1 31.3±0.86 32 28.8 28.6 29.8±1.91

VA 1 32.5 31.3 34.4 32.73±1.56 32 31.7 29 30.9±1.65

VA 2 33 31.7 32 32.23±0.68 33 30.7 29.5 31.07±1.78

KR 3 32 25.7 33.3 30.33±4.06 33 28.3 29.4 30.23±2.46

ACHIN 32.5 30.6 31.2 31.43±.97 33 31.2 30.2 31.47±1.42

THRP 34.5 26 31 30.5±4.27 32 27.9 29 29.63±2.12

KARU 33.5 26.6 30 30.03±3.45 34.8 29.7 31 31.83±2.65

S 1 31.5 30 31 30.83±0.76 30 29 33.5 30.83±2.36

S 2 33 30.2 33 32.07±1.62 32.3 30 31.5 31.27±1.17

S 3 32.5 29 31 30.83±1.76 33 29 33 31.67±2.31

S4 32 30 31.5 31.17±1.04 33 27 33 31±3.46



Cultivated Field

KV3 34.7 30 32 32.23±2.36 33 31.5 32 32.17±0.76

TH 2 34.5 31.2 32 32.57±1.72 35.5 31.6 33 33.37±1.98

P 2 35 30.1 31.5 32.2±2.52 34 30.6 27 30.53±3.5

KR 4 33.4 27.8 32.4 32.2±2.99 35 34.1 33 34.03±1

PILA 33.5 26.5 32 32.2±3.69 30.5 28.3 31 29.93±1.44

PURA 33 25.1 29.5 32.2±3.96 35 29 30.5 31.5±3.12

S 2CF 33 30 32 32.2±1.53 31.2 30 30.6 30.6±0.6

S 4 CF 33 30 33 32.2±1.73 32.4 31 28.2 30.53±2.14

Abandoned Field

P 1 36.8 29.6 36 34.13±3.95 30.5 29.4 29.5 29.8±0.61

N 2 33 30.5 32.1 31.87±1.27 32 29.3 28.6 29.97±1.8

KR 2 33 29 32.2 31.4±2.12 29.5 30.2 27.3 29±1.51

c. Total Dissolved Solids (ppm)

Among the different river systems studied, river Manimala at Kidangara (ACC4)

recorde the least TDS value of 25.3 ppm during postmonsoon season and the maximum value

(1810 ppm) recorded from the Achenkovil river (THOT) site during postmonsoon season (Table

4.3).

Out of the 20 different canal systems studied, minimum TDS value of 17.5 ppm was

recorded from S4 site (Kayal land) during monsoon and the maximum value of 1657 ppm was

recorded from VA2 (Vanam kari land site) during premonsoon season. But the mean highest

value of 1058 ppm was recorded from ACHIN (Achinakom) site.

In the cultivated fields, the maximum value of 1456 ppm was recorded from KR4 during

the premonsoon season and the minimum value of 30 ppm from Pilapuazha during monsoon.

Purakkad site recorded the highest seasonal mean value of 710 ppm (Table 4.3). In abandoned

Figure 4.5: Seasonal variation (mean) of Atmospheric

temperature (0C)

Figure 4.6: Seasonal variation (mean ) of Water temperature (

0C)

SYSTEMS

ABFCFCanalRiver

38

36

34

32

30

28

26

24

Premonsoon

Monsoon

Postmonsoon

35

37

SYSTEMS

ABFCFCanalRiver

38

36

34

32

30

28

26

24

Premonsoon

Monsoon

Postmonsoon

2612

13

25



fields, the TDS concentration ranged between 47.6 and 1868 ppm. The least value was recorded

from KR2 during monsoon and the highest from N2 site during premonsoon season. N2 site

also showed the highest mean of 814.3 ppm.

During premonsoon, all the sites have higher TDS concentration. Generally TDS and

conductivity are higher during the premonsoon season and both canal and river systems

recorded high TDS and conductivity than other two systems (Figure 4.7). Statistical analysis

showed that there is significant variation of TDS between season (p<0.01, F = 44.2) and there is

no significant variation between systems (p>0.05, F=0.44). TDS is highly correlated with

conductivity (r=0.93, p<0.01), turbidity (r=0.44, p<0.01), acidity (r=0.341, p<0.05), chloride

(r=0.74, p<0.01), hardness (r=0.65, p<0.05), COD (r=0.61, p<0.05), nitrate (r = 0.38, p<0.05),

potassium (r=0.43, p<0.01) and sulphate (r = 0.53, p<0.01).

d. Conductivity (mS)

Among all the river systems, peak value of 2.38 mS was recorded from KODI (river

Kodurar at Kodimatha - upstream) river site during premonsoon season and the minimum value

of 0.05mS was recorded from ACC4 site (river Manimala at Kidangara) during monsoon

season. The highest mean was recorded from THOT site with 2.57mS and the least recorded

from ACC4 site with 0.04 mS (Table 4.3). In canal systems, it ranged from 0.04 to 3.64mS. The

least observed from ACC 3 site during monsoon season and the peak value recorded from VA2

site during premonsoon season (Table 4.3). The highest mean value, 1.61 mS was registered

from ACHIN site. In cultivated fields, the values ranged from 0.064 mS at Pilapuzha during

monsoon to 1.88 mS at S4 during premonsoon season. The highest mean was found at PURA

site with 1.17 mS. In abandoned fields, it ranged from 0.10 mS at KR2 site during monsoon to

2.12mS at N2 site during premonsoon season.

Generally high conductivity values were observed during premonsoon in all the systems

studied (Figure 4.8). Analysis of variance showed that there is significant variation of TDS

between season (p<0.01, F = 30.44) and there is no significant variation between systems

(p>0.05, F=0.26). Conductivity showed positive correlation with turbidity (r =0.54, p<0.05),

acidity (r =0.39, p<0.05), alkalinity (r = 0.35, p<0.05), chloride (r =0.77, p<0.01), hardness (r

=0.66, p<0.01), COD (r =0.50, p<0.05), potassium (r =0.44, p<0.01) and sulphate (r =0.59,

p<0.01). It showed negative correlation with pH (r =-0.35, p<0.05).

e. Turbidity (NTU)

Turbidity ranged from 0.2 NTU at P4 during postmonsoon to 40.2 NTU at P6 canal site

during postmonsoon season and the highest mean value was recorded from P6 site with 28.2

NTU (Table 4.3). Among all river systems, P4 site recorded minimum value during post-



monsoon and the peak value (20.7) recorded at VPM (River Pampa at Veeyapuram) during

monsoon. The highest mean value of 9.57 NTU was recorded from KR1 followed by 7.97 NTU

at VPM. Polluted canal site at Pallom (P6) recorded the maximum (40.2 NTU) during post-

monsoon and the minimum of 0.4 NTU from TH1 site during monsoon. In cultivated fields, the

values ranged from 1.42 NTU at PILA site during premonsoon to 32 NTU at S4 site during

monsoon season. S2 and S4 sites (Kayal lands) recorded the highest mean of 21 NTU. Highest

turbidity of 32 NTU was reported from abandoned field at Pallom (P1) during premonsoon and

minimum value, 4.4 NTU was recorded from the same site during the monsoon season.

During monsoon, both canal and river systems have high turbidity in comparison to

other two seasons (Figure 4.9). Among the systems, abandoned field has high turbidity values

throughout the year followed by cultivated field. Turbidity recorded an increasing pattern from

river sites to abandoned field during summer and monsoon. There is significant variation of

turbidity between seasons (p<0.05, F=3.6) and between systems (p<0.05, F=3.95). Turbidity

showed positive correlation with alkalinity (r =0.34, p<0.05), chloride (r =0.50, p<0.01),

hardness (r =0.49, p<0.01), BOD (r =0.49, p<0.05), COD (r =0.40, p<0.05) and potassium (r

=0.40, p<0.01). It showed significant negative correlation with DO (r =0.33, p<0.05).

Table 4.3: Variation (mean values) of TDS, Conductivity and Turbidity in water samples of

Kuttanad wetland ecosystem during the study period.

Sites

TDS (ppm) Conductivity (mS) Turbidity (NTU)

Pre Mon Post Mean +SD Pre Mon Post Mean±SD Pre Mon Post Mean±SD

River systems

KV 1 270 58.6 51.4 126.67±124.18 0.45 0.13 0.12 0.2±0.188 3.1 1.2 1.2 1.83±0.9

TH 3 80 40.5 143 87.83±51.67 0.12 0.08 0.32 0.17±0.129 2.8 1.6 1.2 1.87±0.68

P 3 748 40 273 353.67±360.83 1.02 0.13 0.6 0.58±0.445 3.2 2.4 2.5 2.7±0.36

P 4 520 46 222 262.67±239.6 0.86 0.13 0.47 0.47±0.365 6.6 3.1 0.2 3.3±2.62

ACC 4 44 36.4 25.3 35.23±9.404 0.08 0.05 0.05 0.06±0.017 2.8 3.2 0.3 2.1±1.28

KR 1 960 46.9 142 382.97±321.98 1.24 0.1 0.3 0.57±0.609 8.6 17.2 2.9 9.56±5.88

VPM 60 29.7 29.9 39.87±17.436 0.08 0.06 0.05 0.06±0.015 1.4 20.7 1.8 7.97±9.01

THOT 214 1130 1810 1051.33±800.9 0.22 1.38 1.39 2.57±1.175 1.1 19.5 1 7.2±8.7

KODI 1320 44 86 483.33±724.88 2.38 0.08 0.12 0.86±1.317 6.8 7.2 3.4 5.8±1.7

Canal systems

KV 2 180 124 44 116±68.352 0.29 0.25 0.1 0.23±0.1 4.2 2.8 6.2 4.4±1.4

TH 1 66 47.5 44.7 52.73±11.57 0.08 0.1 0.1 0.09±0.012 4.4 0.4 3.1 2.63±1.67

P 5 480 68 215 254.33±208.8 0.84 0.18 0.45 0.49±0.332 5.8 6.8 5.5 6.03±0.56

P 6 440 120 1480 680±711.06 0.81 0.24 3.13 1.39±1.531 34.6 6.8 43.2 28.2±15.5

ACC 1 60 42 67 56.33±12.89 0.08 0.06 0.14 0.09±0.042 6.4 5.2 3.1 4.9±1.36

ACC 2 40 40 72.7 50.9±18.88 0.07 0.05 0.15 0.09±0.053 4.1 4.4 14.3 7.6±4.74

ACC 3 30 36 26.6 30.867±4.75 0.06 0.04 0.06 0.05±0.012 3.1 2.1 5.5 3.57±1.43

ACC 5 86 44 115 81.67±35.69 0.09 0.06 0.25 0.13±0.102 4.4 4.1 6.1 4.87±0.88

ACC 6 80 38 81.8 66.6±24.785 0.09 0.05 0.17 0.10±0.061 3 2 4.5 3.17±1.03

N 1 1210 69.3 182 487.1±628.58 1.02 0.14 0.39 0.57±0.453 6.1 15.9 2.1 8.03±5.8

VA 1 1256 167 850 757.67±550.34 1.03 0.35 1.81 1.06±0.73 4.4 15.2 2.8 7.47±5.51



Sites

TDS (ppm) Conductivity (mS) Turbidity (NTU)

Pre Mon Post Mean +SD Pre Mon Post Mean±SD Pre Mon Post Mean±SD

VA 2 1656.8 167 284.4 702.73±828.33 3.64 0.35 0.24 1.41±1.932 8.2 15.2 4.4 9.27±4.47

KR 3 1210 53.8 123 462.27±648.48 1.02 0.11 0.27 0.47±0.486 10.4 18.9 16.7 15.33±3.6

ACHIN 1400 144 1630 1058±799.86 1.05 0.29 3.49 1.61±1.672 7.2 16.1 8.6 10.63±3.91

THRP 110 36.7 34.5 60.4±42.969 0.24 0.07 0.08 0.13±0.095 3.1 3.7 1.4 2.73±0.97

KARU 166 301 172 213±76.269 0.28 0.63 0.38 0.43±0.18 3.1 17.1 1.1 7.1±7.12

S 1 1410 61.5 240 570.5±732.49 2.42 0.12 0.5 1.01±1.233 2.8 30.3 4.4 12.5±12.6

S 2 1400 52.5 106 519.5±763 2.42 0.09 0.2 0.90±1.315 2.4 28.8 3.1 11.43±12.3

S3 1440 39.8 86.6 522.133±795.24 2.43 0.08 0.12 0.87±1.345 2.8 35.4 2.2 13.47±15.5

S 4 1456 17.5 66.2 513.23±816.82 2.43 0.08 0.14 0.88±1.34 2.2 34.3 12.2 16.23±13.4

Cultivated Field systems

KV 3 248 115 66 143±94.175 0.07 0.25 0.34 0.22±0.137 6.8 2.4 2.2 3.8±2.12

TH 2 66 90 68 74.67±13.317 1.86 0.2 0.32 0.79±0.92 16 5.1 4.2 8.43±5.36

P 2 420 146.6 164 243.53±153.06 0.8 0.26 0.35 0.47±0.289 16.3 5.1 19.2 13.53±6.08

KR 4 1456 90.6 134 560.2±776.09 1.58 0.24 0.22 0.68±0.779 12.4 17.3 10.2 13.3±2.97

PILA 124 30 256 136.67±113.53 0.26 0.06 0.58 0.3±0.262 1.4 14.8 3.2 6.47±5.94

PURA 986 331 815 710.667±339.74 1.02 0.65 1.85 1.17±0.615 4.4 19.5 28 17.3±9.76

S 2CF 680 39.8 88 269.27±356.52 1.56 0.08 0.24 0.67±0.812 12.8 28.5 22 21.1±6.44

S4 CF 842 46.6 40.4 309.67±461.02 1.88 0.08 0.22 0.77±1.001 14 32 17 21±7.87

Abandoned Field systems

P 1 300 80.6 94 158.2±122.99 0.48 0.16 0.21 0.28±0.172 32 4.4 17.4 17.93±11.3

N 2 1868 202 373 814.33±916.5 2.12 0.42 0.8 1.13±0.892 12 17.9 6.3 12.07±4.74

KR 2 1100 47.6 616 587.87±526.76 1.01 0.1 1.32 0.81±0.634 9.1 18.7 5.6 11.13±5.54

f. pH

Among the river systems, Pampa at Veeyapuram (VPM) registered the mean maximum

pH (6.5-6.8) followed by Kodurar at Pallom (P3) with 6.13 - 6.3. Manimala river has recorded

the lower pH of 6.17 to 6.3 which is similar to Kodurar and Achenkovil (THOT) recorded the

pH similar to Pampa (Table 4.4 and Figure 4.10).

Among the 20 different canal systems studied, the acidic pH of 3.2 was recorded from

VA2 (Vanam kari land site) during the premonsoon season. An unusual alkaline pH of 8.8 was

recorded from N1 (Neendur) during the postmonsoon. All the canal sites, except N1showed

acidic pH throughout the season (Table 4.4 and Figure 4.10).

In the cultivated fields, the pH ranged from 5.4 to 6.8. The least value recorded from

KV3 (Kavalam) during premonsoon season and the maximum value recorded from PILA

(Pilapuzha) during the monsoon season (Table 4.4). All the cultivated fields showed acidic pH

throughout the season. In abandoned fields, the pH ranged from 5.2 to 7.3. The least value

recorded from N2 (Neendur) during the premonsoon season and the maximum value recorded

from the same site during the postmonsoon season.



Figure 4.9: Seasonal variation of Turbidity (mean values in NTU) in water

samples of Kuttanad wetland ecosystem during the study period.

SYSTEMS

ABFCFCanalRiver

50

40

30

20

10

0

-10

Premonsoon

Monsoon

Postmonsoon

15

22

13

13

Figure 4.8: Seasonal variation of Conductivity (mean values in mS)

in water samples of Kuttanad wetland ecosystem during the study period.

SYSTEMS

ABFCFCanalRiver

4

3

2

1

0

-1

Premonsoon

Monsoon

Postmonsoon

3520

13

23

8

3525

8

9

Figure 4.7 : Seasonal variation of TDS (mean values ppm) in water samples of


SYSTEMS

ABFCFCanalRiver

ppm

3000

2000

1000

0

-1000

Premonsoon

Monsoon

Postmonsoon

3520

13

23

8

3525

1

8



The abandoning of cultivation resulted in increase of pH. In general the water of

Kuttanad are acidic in nature and the mean pH vary between 6.0 to 6.5 with unusually lower

mean ranges from 3 to 5 at Vaikom kari land due to formation of H2SO4. The acidity confirms

the above findings.

Statistical analysis showed that there is no significant spatial and temporal variation of

pH in Kuttanad except Vaikom and Purakkad kari land sites. Both Vaikom and Purakkad kari

land sites (VA1, VA2 and PKD) showed high acidic values than other sites especially during

premonsoon season. pH showed significant negative correlation with acidity (r = -0.78 , p<0.01)

and sulphate (r = -0.54, p<0.01).

g. Acidity (mgCaCO3/l)

Comparing the different river systems flowing through Kuttanad, Pampa reported the

least mean acidity (10 mgCaCO3/L). The range increased in Manimala to 12 mgCaCO3/L and

13 mgCaCO3/L in Achenkovil, followed by Kodurar with 16 mgCaCO3/L. The maximum

recorded from KODI site (Kodurar) during premonsoon season and THOT (Achenkovil) during

monsoon season (Table 4.4 and Figure 4.11).

Among canal systems, majority of the mean values range between 10 and 18

mgCaCO3/L and ACC3 only reported below this range. Greater acidity values were observed in

the canal sites at Pallom (P6) and ACC6 receiving wastes. The high acidity values were

recorded from kari land sites like VA1 and VA2. Both VA1 and VA2 sites showed acidity more

than 100 mgCaCO3/L throughout the season (Table 4.4 and Figure 4.11).

In the cultivated fields, the acidity ranged from 8 to 40 mgCaCO3/L similar to canal

systems. The minimum was recorded from PILA (Pilapuzha) during premonsoon and the

maximum from P2 (Pallom) during postmonsoon. Among the abandoned fields, P1 recorded

the least acidity with 8 mgCaCO3/L during monsoon and maximum of 40 mgCaCO3/L from

KR2 site during both premonsoon and postmonsoon season.

Acidity showed higher values in the Vanam canal sites (VA1 and VA2) and there is no

significant variation of acidity between seasons and systems of Kuttanad (p>0.05). Acidity

showed significant positive correlation with phosphate (r =0.65, p<0.01) and sulphate (r =0.63,

p<0.01).

h. Alkalinity (mgCaCO3/l)

In river systems, the mean alkalinity ranged between 14 and 30 mgCaCO3/L. The least

mean was recorded from ACC4 (river Manimala) during monsoons season (6 mgCaCO3/L) and

the mean maximum was recorded from KR1 ( river Meenachil) with 48 mgCaCO3/L during

premonsoon season (Table 4.4).



The alkalinity ranged from 10 to 52 mgCaCO3/L in different canal systems of Kuttanad.

The least value recorded from both ACC2 and ACC5 during monsoon season. The maximum

of 52 mgCaCO3/L was recorded from ACHIN (Achinakom) during the premonsoon season.

During premonsoon, most of the canal systems have comparatively high alkalinity than other

systems (Table 4.4 and Figure 4.12).

In the cultivated fields, the alkalinity seasonally ranged from 8 to 92 mgCaCO3/L. The

minimum value recorded from P2 (Pallom) during monsoon season and the maximum value

recorded from PURA (Purakkad) during postmonsoon season. In abandoned fields, the least

alkalinity 8 mgCaCO3/L recorded from P1 site during monsoon season followed by KR2 site

during the same season with 20 mgCaCO3/L. The maximum value of 62 mgCaCO3/L recorded

at N2 (Neendur) site during premonsoon season. In abandoned fields, alkalinity showed

comparatively low values during monsoon season (Table 4.4 and Figure 4.12).

It was generally found that the alkalinity was comparatively higher during the

postmonsoon season in all the systems. The alkalinity have shown high significant variation

between seasons (p<0.01, F=10.49) and between systems (p<0.05, F=3.64). It showed

significant positive correlation with BOD (r =0.33, p<0.05), COD (r =0.38 , p<0.05) and nitrate

(r =0.35 , p<0.05). It shows negative correlation with DO (r =0.34, p<0.05).

Table 4.4: Variation (mean values) of pH, Acidity and Alkalinity in water samples of


Sites pH Acidity (mgCaCO3/L) Alkalinity (mgCaCO3/L)

Pre Mon Post Mean±SD Pre Mon Post Mean(±SD) Pre Mon Post Mean(±SD)

River systems

KV 1 6.2 6.6 5.7 6.17±0.45 16.00 12.00 8.00 12.00±4.00 24.00 20.00 24.00 22.67±2.31

TH 3 6.3 6.8 6.5 6.53±0.25 12.00 12.00 8.00 10.67±2.31 20.00 24.00 36.00 26.67±8.33

P 3 6.4 6.4 6.2 6.33±0.12 18.00 8.00 16.00 14.00±5.29 24.00 8.00 20.00 17.33±8.33

P 4 5.5 6.4 6.3 6.07±0.49 16.00 16.00 16.00 16.00±0.00 16.00 12.00 16.00 14.67±2.31

ACC 4 6.2 6.5 6.3 6.33±0.15 16.00 8.00 12.00 12.00±4.00 24.00 6.00 12.00 14.00±9.17

KR 1 6.4 5.5 6.5 6.13±0.55 12.00 16.00 12.00 13.33±2.31 48.00 12.00 24.00 28.00±18.33

VPM 7.1 7 6.3 6.80±0.44 16.00 10.00 8.00 11.33±4.16 16.00 16.00 44.00 25.33±16.17

THOT 6.6 6.7 6.3 6.53±0.21 12.00 20.00 8.00 13.33±6.11 20.00 20.00 40.00 26.67±11.55

KODI 6 6.2 6.7 6.30±0.36 20.00 10.00 12.00 14.00±5.29 40.00 22.00 28.00 30.00±9.17

Canal systems

KV 2 5.8 5.7 6 5.83±0.15 20.00 12.00 8.00 13.33±6.11 28.00 24.00 52.00 34.67±15.14

TH1 6 6.2 5.9 6.03±0.15 8.00 10.00 16.00 11.33±4.16 24.00 28.00 36.00 29.33±6.11

P 5 6.6 6.3 6 6.30±0.30 24.00 28.00 12.00 21.33±8.33 36.00 32.00 20.00 29.33±8.33

P 6 6.4 6.2 6.6 6.40±0.20 56.00 32.00 56.00 48.00±13.86 44.00 24.00 40.00 36.00±10.58

ACC 1 6.8 6.4 5.8 6.33±0.50 20.00 12.00 12.00 14.67±4.62 36.00 18.00 20.00 24.67±9.87

ACC 2 6.3 6.5 5.9 6.23±0.31 12.00 16.00 8.00 12.00±4.00 28.00 10.00 16.00 18.00±9.17

ACC 3 6 6.5 6.3 6.27±0.25 12.00 4.00 12.00 9.33±4.62 24.00 16.00 16.00 18.67±4.62



Sites pH Acidity (mgCaCO3/L) Alkalinity (mgCaCO3/L)

Pre Mon Post Mean±SD Pre Mon Post Mean(±SD) Pre Mon Post Mean(±SD)

ACC 5 6.4 6.5 6 6.30±0.26 24.00 12.00 8.00 14.67±8.33 28.00 10.00 32.00 23.33±11.72

ACC 6 6.3 6.7 5.9 6.30±0.40 12.00 60.00 12.00 28.00±27.71 28.00 20.00 20.00 22.67±4.62

N 1 7.8 5.7 8.8 7.43±1.58 12.00 12.00 20.00 14.67±4.62 32.00 16.00 20.00 22.67±8.33

VA 1 5.2 4.2 6.2 5.20±1.00 320.00 120.00 212.00 217.33±100.11 40.00 16.00 20.00 25.33±12.86

VA 2 3.2 4.1 3.9 3.73±0.47 320.00 120.00 212.00 217.33±100.11 22.00 12.00 16.00 16.67±5.03

KR 3 6.4 5.9 6.5 6.27±0.32 16.00 16.00 12.00 14.67±2.31 32.00 20.00 32.00 28.00±6.93

ACHIN 6.5 4.8 6.2 5.83±0.91 24.00 12.00 8.00 14.67±8.33 52.00 16.00 20.00 29.33±19.73

THRP 6.8 6.7 6.2 6.57±0.32 12.00 14.00 8.00 11.33±3.06 20.00 20.00 28.00 22.67±4.62

KARU 6.4 6.4 6.2 6.33±0.12 4.00 20.00 12.00 12.00±8.00 28.00 16.00 40.00 28.00±12.00

S 1 5.6 6.5 6.2 6.10±0.46 16.00 20.00 6.00 14.00±7.21 28.00 24.00 12.00 21.33±8.33

S 2 6.6 6.9 6.6 6.70±0.17 16.00 16.00 8.00 13.33±4.62 28.00 24.00 20.00 24.00±4.00

S 3 6.4 6.2 6.2 6.27±0.12 24.00 20.00 12.00 18.67±6.11 52.00 24.00 20.00 32.00±17.44

S4 6.1 6.4 6 6.17±0.21 16.00 10.00 14.00 13.33±3.06 28.00 12.00 16.00 18.67±8.33

Cultivated fields

KV 3 5.4 6.6 6.7 6.23±0.72 16.00 12.00 16.00 14.67±2.31 24.00 32.00 24.00 26.67±4.62

TH 2 6.6 6.1 6.6 6.43±0.29 20.00 12.00 16.00 16.00±4.00 56.00 28.00 36.00 40.00±14.42

P 2 6 6.6 5.9 6.17±0.38 24.00 8.00 40.00 24.00±16.00 20.00 8.00 48.00 25.33±20.53

KR 4 6.2 6.4 6.7 6.43±0.25 16.00 14.00 14.00 14.67±1.15 24.00 12.00 20.00 18.67±6.11

PILA 6.6 6.8 6 6.47±0.42 8.00 10.00 8.00 8.67±1.15 20.00 24.00 24.00 22.67±2.31

PURA 6.5 6.1 6.3 6.30±0.20 12.00 12.00 14.00 12.67±1.15 24.00 12.00 92.00 42.67±43.14

S2 CF 5.6 6.7 6.6 6.30±0.61 20.00 16.00 16.00 17.33±2.31 28.00 24.00 24.00 25.33±2.31

S4CF 5.6 6.6 6.2 6.13±0.50 18.00 12.00 12.00 14.00±3.46 32.00 20.00 24.00 25.33±6.11

Abandoned Fields

P 1 5.7 6.8 5.3 5.93±0.78 20.00 8.00 16.00 14.67±6.11 44.00 8.00 32.00 28.00±18.33

N 2 5.2 5.8 7.3 6.10±1.08 28.00 12.00 16.00 18.67±8.33 62.00 42.00 48.00 50.67±10.26

KR 2 6.4 5.5 6 5.97±0.45 40.00 26.00 40.00 35.33±8.08 52.00 20.00 24.00 32.00±17.44



Figure 4.12: Seasonal variation of Alkalinity (mean values in mgCaCO3/L) in water


SYSTEMS

ABFCFCanalRiver

100

80

60

40

20

0

Premonsoon

Monsoon

Postmonsoon

35

31

2328

9

6

Figure 4.11: Seasonal variation of Acidity (mean values in mgCaCO3/L) in water


SYSTEMS

ABFCFCanalRiver

300

200

100

0

Premonsoon

Monsoon

Postmonsoon34

32

13

2021

3236

18

2021

13

Figure 4.10: Seasonal variation of pH (mean values) in water samples of


SYSTEMS

ABFCFCanalRiver

10

9

8

7

6

5

4

3

2

Premonsoon

Monsoon

Postmonsoon

21

19

1

2021

6

21

19

4

7



i. Chloride (mg/l)

Chloride concentration in river systems ranged from 11.3 to 1843.40 mg/L. The least

value recorded from ACC4 during monsoon season and the maximum value recorded from

KODI site during premonsoon season. It was generally noted that during monsoon season, all

the river systems have low chloride values than other two seasons. Kodur river at Kodimatha

recorded the high chloride (1843.4 mg/l) during premonsoon but the down stream points (P3

and P4) the concentration declined to one fifth of the upstream, 368.4 mg/l at the same season

(Table 4.5 and Figure 4.13).

Among the 20 different canal systems studied, the maximum chloride value,

3715.2mg/L recorded from ACHIN site during postmonsoon season and the minimum value,

14.2 mg/L recorded from TH1 site during monsoon season. Kayal land sites like S1, S2, S3 and

S4 have shown high chloride values more than 2000mg/L during premonsoon season. Kari land

sites like VA1, VA2 and ACHIN also showed high chloride values during premonsoon season


In cultivated fields, the chloride concentration ranged from 28.4 to 2338.66 mg/L. The

minimum value recorded from TH2 during the monsoon season and the maximum value

recorded from S4CF during the premonsoon season. Sites like PURA, S2 and S4 sites have

shown high values of chloride throughout the season.

Among the abandoned fields, P1 showed the least value of 19.90 mg/L during the

monsoon season and the N2 site recorded the maximum value, 1248.80 mg/L during the

premonsoon season. All the abandoned fields showed high chloride values during the

premonsoon season than other two seasons (Table 4.5 and Figure 4.13).

It was generally noted that the chloride values were higher during premonsoon season

and showed comparatively low values during monsoon season. Chloride has significant

variation between seasons (p<0.01, F=18.56) and no significant variation between systems

(p>0.05, F=0.71). Chloride showed significant positive correlation with hardness (r = 0.90,

p<0.01), TDS (r = 0.74, p<0.01), conductivity (r =0.77, p<0.01), potassium (r =0.42, p<0.01),

sulphate (r = 0.60, p<0.01) and COD (r =0.32, p<0.05).

j. Hardness (mg/l)

Among the river sites, the peak value of 600 mg/L recorded from river Kodurar at

Kodimatha during premonsoon resulted from sewage outflow from Kottayam town. Absence of

hardness was recorded during monsoon from the river sites like Pampa at Thakazhy (TH3) and

river Manimala at Kavalam (KV1) (Table 4.5 and Figure 4.14).



In canal sites, the hardness value ranged from 0 to 700mg/L. The absence of hardness

was recorded from TH1 site during monsoon season and the maximum value recorded from S2

(Kayal land) site during premonsoon season. Kayal land sites like S1, S2, S3 and S4 recorded

high hardness values during premonsoon season (Table 4.5 and Figure 4.14).

Among the different cultivated field sites, the least hardness of 8 mg/L was recorded

from KV3 site during monsoon and the maximum of 380 mg/L from S4CF (Kayal land) site

during premonsoon followed by S3 site with 360 mg/L during premonsoon season.

During premonsoon, all the systems have shown high hardness and canal systems

exhibited comparatively greater values during the same season (Figure 4.14). Statistical analysis

showed that there is significant variation of hardness between seasons (p<0.01, F=35.71) and no

significant variation between systems (p>0.05, F=0.59). Hardness showed positive correlation

with chloride (r = 0.90, p<0.01), TDS (r=0.65, p<0.05), conductivity (r =0.66, p<0.01), turbidity

(r =0.49, p<0.01), sulphate (r =0.51, p<0.01) and potassium (r =0.37, p<0.05).

Table 4.5: Variation (mean values) of Chloride and Hardness in water samples of


Sites Chloride (mg/L ) Hardness (mg /L)

Pre Mon Post Mean (±SD) Pre Mon Post Mean (±SD)

River systems

KV1 113.40 17.00 25.50 51.97±53.37 48.00 0.00 28.00 25.33 ±24.11

TH3 56.70 18.40 76.60 50.57±29.58 24.00 0.00 40.00 21.33±20.13

P 3 356.58 11.30 96.40 154.76±179.89 120.00 20.00 68.00 69.33±50.01

P 4 368.70 22.70 99.30 163.57±181.73 160.00 16.00 68.00 81.33±72.92

ACC 4 56.70 11.30 19.90 29.30±24.12 32.00 8.00 12.00 17.33±12.86

KR 1 482.10 127.60 99.30 236.33±213.31 184.00 16.00 36.00 78.67±91.77

VPM 45.40 85.10 17.10 49.20±34.16 8.00 12.00 12.00 10.67±2.31

THOT 212.70 467.90 442.40 646.60±218.07 28.00 160.00 412.00 100.00±98.31

KODI 1843.40 46.34 113.40 667.71±1018.73 600.00 24.00 64.00 229.33±321.63

Canal systems

KV2 85.10 38.30 25.50 49.63±31.37 48.00 8.00 32.00 29.33±20.13

TH 1 56.70 14.20 22.70 31.20±22.49 28.00 0.00 32.00 20.00±17.44

P 5 312.00 39.70 90.80 147.50±144.73 160.00 32.00 68.00 86.67±66.01

P 6 297.80 45.50 950.10 431.13±466.81 116.00 48.00 128.00 97.33±43.14

ACC 1 42.50 29.90 28.40 33.60±7.74 80.00 16.00 32.00 42.67±33.31

ACC 2 56.70 39.70 28.40 41.60±14.25 44.00 20.00 28.00 30.67±12.22

ACC 3 42.50 19.90 14.20 25.53±14.97 16.00 8.00 12.00 12.00±4.00

ACC 5 70.90 82.30 19.90 57.70±33.23 24.00 52.00 32.00 36.00±14.42

ACC 6 56.70 70.90 36.90 54.83±17.08 20.00 8.00 32.00 20.00±12.00

N 1 950.20 212.70 76.50 413.13±470.07 280.00 24.00 40.00 114.67±143.41

VA 1 1361.30 269.40 439.60 690.10±587.47 360.00 48.00 152.00 186.67±158.86

VA 2 1372.88 269.40 446.68 696.32±592.59 68.00 48.00 60.00 58.67±10.07

KR 3 737.40 170.60 51.00 319.67±366.68 272.00 22.00 52.00 115.33±136.50

ACHIN 1999.40 326.10 3715.20 2013.57±1694.59 644.00 52.00 316.00 337.33±296.58

THRP 70.90 70.90 17.10 52.97±31.06 20.00 8.00 24.00 17.33±8.33



Sites Chloride (mg/L ) Hardness (mg /L)


KARU 368.70 765.70 99.30 411.23±335.23 68.00 92.00 48.00 69.33±22.03

S1 2240.40 198.50 130.50 856.47±1199.00 644.00 12.00 86.00 247.33±345.51

S2 2353.90 141.80 153.90 883.20±1273.68 700.00 12.00 56.00 256.00±385.14

S3 2368.10 156.00 218.40 914.17±1259.53 680.00 8.00 96.00 261.33±365.24

S4 2325.50 85.10 312.68 907.76±1233.06 692.00 20.00 84.00 265.33±370.89

Cultivated fields

KV3 28.40 36.90 34.46 33.25±4.38 52.00 8.00 48.00 36.00±24.33

TH 2 56.70 28.40 44.78 43.29±14.21 44.00 20.00 38.00 34.00±12.49

P 2 269.40 42.50 79.40 130.43±121.75 144.00 20.00 48.00 70.67±65.03

KR 4 664.68 127.60 34.78 275.69±340.06 280.00 20.00 44.00 114.67±143.68

PILA 99.30 59.60 124.80 94.57±32.86 20.00 12.00 48.00 26.67±18.90

PURA 1226.60 822.40 444.00 831.00±391.37 84.00 40.00 168.00 97.33±65.03

S2 CF 2268.89 141.80 386.72 932.47±1163.83 360.00 68.00 244.00 224.00±147.02

S4 CF 2338.66 168.99 482.10 996.58±1172.77 380.00 72.00 172.00 208.00±157.12

Abandoned fields

P 1 113.40 19.90 67.30 66.87±46.75 56.00 16.00 32.00 34.67±20.13

N 2 1248.80 538.40 212.70 666.63±529.82 214.00 52.00 76.00 114.00±87.43

KR 2 623.90 141.80 28.40 264.70±316.20 188.00 20.00 32.00 80.00±93.72

Figure 4.13: Seasonal variation of Chloride (mean values in mg/L) in water


SYSTEMS

ABFCFCanalRiver

4000

3000

2000

1000

0

-1000

Premonsoon

Monsoon

Postmonsoon

13

23

8

3525

8

9



k. Dissolved oxygen (mgO2/l)

Comparing different river systems flowing through Kuttanad, the highly polluted

Kodurar recorded least values of DO with 1 – 2 mgO2/L during premonsoon. In comparison,

Pampa, Achenkovil and Manimala reported maximum values of DO than Kodurar and river

Achenkovil at Thottapally recorded the above saturation levels (>10mgO2/L) during

premonsoon.

Anoxic condition was recorded from the polluted canal site at Pallom (P6) during both

premonsoon and postmonsoon. The maximum of 8.8 mgO2/L was recorded from ACC2 during

monsoon followed by 7.60 mgO2/L from ACC3 during both premonsoon and monsoon seasons


In cultivated field systems, the DO ranged from 0 to 10 mgO2/L. Anoxic condition

recorded from P2 (Pallom) site during both premonsoon and postmonsoon season. The

maximum DO value recorded from PILA (Pilapuzha) site during postmonsoon season (Table

4.6 and Figure 4.15).

Among different systems, abandoned field with thick vegetation cover recorded least

DO levels to anoxic conditions. The Kumarakom abandoned field site (KR2) recorded the

anoxic condition and the maximum value, 4.80 mgO2/L recorded from N2 (Neendur) during

postmonsoon season (Table 4.6 and Figure 4.15). The mean maximum for DO was recorded

Figure 4.14: Seasonal variation of Hardness (mean values in mg/L) in

water samples of Kuttanad wetland ecosystem during the study period.

SYSTEMS

ABFCFCanalRiver

800

600

400

200

0

-200

Premonsoon

Monsoon

Postmonsoon

23

8

8

9



from Neendur site (N2) with 2.9 mgO2/L and even during monsoon, lack of DO was prevalent

due to vegetation cover.

Comparatively monsoon recorded slightly high dissolved oxygen values than other two

seasons. Super saturation levels of oxygen (10 mgO2/l) was recorded from Achenkovil river site

at Thottapally and cultivated field at Pilapuzha. Generally river systems have shown

comparatively greater dissolved oxygen concentration than other systems (Table 4.6 and Figure

4.15). Figure 4.15 shows most DO ranges between 2 - 6 mgO2/L while the abandoned fields

have a distinct range of 0 (anoxic) to 2.0 mgO2/L, the least out of all sites.

Statistical analysis showed that there is no significant variation of DO between seasons

(p>0.05, F=0.32) and significant variation between systems (p=0.01, F=4.05). DO showed high

negatively correlation with BOD (r = -0.80, p<0.01) water temperature (r = -0.56, p<0.01),

COD (r = -0.43, p<0.01), nitrate (r = -0.44, p<0.01), turbidity (r = -0.33, p<0.05), potassium (r

=-0.33, p<0.05) and alkalinity (r = -0.34, p<0.01).

l. Biochemical Oxygen Demand (BOD) (mgO2/l)

In river systems, the least BOD value of 0.2 mgO2/L recorded from river Kodurar at

Pallom (P3) during monsoon and the same river at Kodimatha (KODI) recorded the peak value

of 16 mgO2/L. Meenachil at Kumarakom (KR1) recorded BOD values >6 mgO2/L during

premonsoon and postmonsoon season. The high seasonal average value of 7.27 mgO2/L

recorded from Kodurar at Kodimatha (Table 4.6 and Figure 4.16).

Most canal sites have mean BOD values <5 mgO2/L and the high BOD value of 43.2

mgO2/L recorded from the polluted canal site at Pallom (P6) during postmonsoon. The least

value (0.4 mgO2/L) was recorded from THRP (Thriperumthura) canal site during monsoon

season. Both P5 and P6 canal sites showed high BOD values throughout the season (Table 4.6

and Figure 4.16).

In cultivated field, BOD ranged between 1.2 to 31.24 mgO2/L. The minimum value

recorded from S4 site (Kayal land) during monsoon season and the maximum from P2 (Pallom)

during postmonsoon. Among all abandoned fields, Pallom site (P1) recorded the maximum

range of 14-28 mgO2/L out of 3 sites studied and the minimum of 4 mgO2/L was recorded from

Neendur (N2) during postmonsoon season (Table 4.6 and Figure 4.16).

Comparatively monsoon recorded very low BOD due to dilution and outflow in all the

systems. However, lack of flow and organic decay in abandoned fields showed higher BOD

values throughout the season. During premonsoon season, all the systems have high BOD

values (Figure 4.16). Generally river systems recorded low BOD values than other systems




Analysis of variance showed that there is no significant variation of BOD between

seasons (p>0.05, F=0.56) and significant variation between systems (p<0.05, F=3.25).

Abandoned fields and canal sites like P6, S1, KR2 and KODI (river Kodur at Kodimatha)

showed comparatively high BOD values during premonsoon and postmonsoon season. BOD

showed positive correlation with water temperature (r=0.54, p<0.01), turbidity (r =0.49,

p<0.05), COD (r=0.41, p<0.01), nitrate (r =0.47, p<0.01) and alkalinity (r =0.33, p<0.05). It

showed negative correlation with DO (r = - 0.80, p<0.01).

m. Chemical Oxygen Demand (COD) (mgO2/l)

In general COD was below 100 mgO2/L in most of the systems (60%) with fluctuations

around the year 140 to 200 in 15% and higher ranges exceeding 200 was also observed in some

sites. The least value (10 mgO2/L) recorded from TH3 (river Pampa at Thakazhy) during

monsoon season and the maximum value (360 mgO2/L) recorded from KODI (Kodurar

upstream) during premonsoon. During monsoon, all the river sites have COD <100 mgO2/L

except THOT site where the COD recorded higher value of 280 mgO2/L (Table 4.6 and Figure

4.17).

During monsoon and postmonsoon, the values were <100 mgO2/L in most canal sites

while the premonsoon reported above 100 mgO2/L in 50% sites. Values between 200 and 400

mgO2/L were recorded during premonsoon and the maximum value of 610 mgO2/L recorded

from KR3 (Kumarakom) during the postmonsoon. Sites like P6, N1, ACC6, VA1, KR3 and

ACHIN showed high COD values (>100 mgO2/L) throughout the season. Neendur (N1) site

recorded the season’s maximum average value with 380 mgO2/L followed by KR2 site with 372

mgO2/L (Table 4.6 and Figure 4.17).

In cultivated fields, COD ranged from 10 to 304 mgO2/L. The minimum value recorded

from KR4 site during monsoon season and the maximum value recorded from PURA site

during postmonsoon season. During monsoon season, most of the sites have comparatively low

COD values than other two seasons (Table 4.6 and Figure 4.17).

In abandoned fields, the COD ranged from 80 to 460 mgO2/L. The least value recorded

from KR2 during monsoon and maximum from N2 during premonsoon season. The mean

COD was higher at N2 site with 310 mgO2/L followed by KR2 with 233 mgO2/L.

There is significant variation of COD between seasons (p<0.05, F=3.32) and between

systems (p<0.05, F= 4.39). COD showed positive correlation with BOD (r=0.41, p<0.01),

nitrate (r = 0.56, p<0.01), TDS (r=0.61, p<0.05), conductivity (r = 0.50, p<0.05), turbidity (r

=0.40, p<0.05), alkalinity (r =0.38, p<0.05) and chloride (r =0.32, p<0.05). It showed negative

correlation with DO (r = - 0.43, p<0.01).



Table 4.6: Variation (mean values) of DO, BOD and COD in water samples of


Sites DO (mgO2/L) BOD (mgO2/L) COD (mgO2/L)

Pre Mon Post Mean(±SD) Pre Mon Post Mean(±SD) Pre Mon Post Mean (±SD)

River systems

KV1 6.40 5.60 5.20 5.73±0.50 2.80 0.80 0.80 1.47±1.15 44.00 19.00 50.00 37.67±16.44

TH3 8.00 6.00 7.60 7.20±0.86 3.60 0.40 1.20 1.73±1.67 36.00 10.00 40.00 28.67±16.29

P 3 2.20 4.20 5.60 4.00±1.40 1.20 0.20 2.00 1.13±0.90 120.00 30.00 80.00 76.67±45.09

P 4 1.60 3.60 5.60 3.60±1.63 8.00 0.80 2.40 3.73±3.78 60.00 60.00 120.00 80.00±34.64

ACC 4 6.40 7.40 6.40 6.73±0.47 2.80 1.00 2.10 1.97±0.91 30.00 26.00 20.00 25.33±5.03

KR 1 1.60 5.20 2.40 3.07±1.54 6.60 0.40 6.00 4.33±3.42 180.00 20.00 340.00 180.00±160.00

VPM 5.20 5.20 7.60 6.00±1.13 0.80 1.20 1.60 1.20±0.40 30.00 60.00 50.00 46.67±15.28

THOT 10.00 5.60 6.00 7.20±1.99 7.20 0.80 1.20 3.07±3.59 320.00 280.00 30.00 210.00±157.16

KODI 1.60 6.00 4.80 4.13±1.86 16.00 3.60 2.20 7.27±7.60 360.00 40.00 80.00 160.00±174.36

Canal systems

KV 2 3.20 4.00 5.60 4.27±1.00 4.40 1.60 2.40 2.80±1.44 60.00 26.00 26.00 37.33±19.63

TH1 5.20 6.40 4.40 5.33±0.82 2.80 1.60 0.80 1.73±1.01 86.00 20.00 36.00 47.33±34.43

P 5 0.80 2.00 1.20 1.33±0.50 24.00 11.00 22.00 19.00±7. 80.00 260.00 70.00 136.67±106.93

P 6 2.00 0.80 0.00 0.93±0.82 18.40 14.00 43.20 25.20±15.7 180.00 370.00 180.00 243.33±109.70

ACC 1 5.20 2.40 3.20 3.60±1.18 4.00 6.00 6.10 5.37±1.18 60.00 120.00 80.00 86.67±30.55

ACC 2 6.40 8.80 6.00 7.07±1.24 1.60 2.40 3.80 2.60±1.11 46.00 40.00 60.00 48.67±10.26

ACC 3 7.60 7.60 6.40 7.20±0.57 3.20 2.00 2.20 2.47±0.64 40.00 24.00 40.00 34.67±9.24

ACC 5 6.40 2.80 6.20 5.13±1.65 4.00 10.00 3.00 5.67±3.79 80.00 80.00 390.00 183.33±178.98

ACC 6 6.80 6.50 6.80 6.70±0.14 2.00 2.50 4.80 3.10±1.49 120.00 60.00 180.00 120.00±60.00

N 1 6.00 3.60 3.60 4.40±1.13 4.40 6.00 0.40 3.60±2.88 240.00 480.00 420.00 380.00±124.90

VA 1 5.20 2.80 3.20 3.73±1.05 4.00 8.00 1.20 4.40±3.42 280.00 100.00 80.00 153.33±110.15

VA 2 5.20 2.80 3.20 3.73±1.05 4.00 6.00 2.20 4.07±1.90 320.00 100.00 80.00 166.67±133.17

KR 3 6.00 0.60 6.80 4.47±2.75 4.80 16.00 5.60 8.80±6.25 266.00 240.00 610.00 372.00±206.52

ACHIN 7.20 4.00 5.20 5.47±1.32 5.20 2.00 2.80 3.33±1.67 140.00 100.00 300.00 180.00±105.83

THRP 3.20 6.00 5.20 4.80±1.18 0.80 0.40 1.60 0.93±0.61 40.00 30.00 20.00 30.00±10.00

KARU 6.00 4.80 6.00 5.60±0.57 1.20 0.80 0.40 0.80±0.40 84.00 10.00 80.00 58.00±41.62

S1 2.00 2.80 6.40 3.73±1.91 14.40 5.60 1.20 7.07±6.72 420.00 20.00 40.00 160.00±225.39

S 2 6.80 6.00 6.40 6.40±0.33 3.60 2.00 1.20 2.27±1.22 140.00 20.00 170.00 110.00±79.37

S3 5.60 5.60 5.60 5.60±0.00 2.40 2.80 1.40 2.20±0.72 126.00 60.00 80.00 88.67±33.84

S 4 6.00 6.40 5.60 6.00±0.33 2.00 4.20 2.20 2.80±1.22 96.00 140.00 86.00 107.33±28.73

Cultivated fields

KV3 4.00 3.20 4.80 4.00±0.65 3.40 4.00 2.00 3.13±1.03 80.00 34.00 66.00 60.00±23.58

TH 2 6.40 7.60 5.20 6.40±0.98 1.60 1.60 3.20 2.13±0.92 120.00 40.00 80.00 80.00±40.00

P 2 0.00 3.60 0.00 1.20±1.70 26.00 4.00 31.20 20.40±14. 110.00 90.00 160.00 120.00±36.06

KR 4 6.60 9.20 6.60 7.47±1.23 3.20 2.40 2.80 2.80±0.40 56.00 10.00 42.00 36.00±23.58

PILA 8.80 4.40 10.00 7.73±2.41 4.00 2.40 6.00 4.13±1.80 60.00 40.00 50.00 50.00±10.00

PURA 6.40 4.40 0.80 3.87±2.32 2.80 1.60 16.00 6.80±7.99 186.00 20.00 304.00 170.00±142.67

S2 CF 6.00 5.20 6.00 5.73±0.38 1.20 1.60 1.60 1.47±0.23 120.00 30.00 86.00 78.67±45.45

S4 CF 6.00 6.00 5.60 5.87±0.19 1.20 1.20 1.60 1.33±0.23 240.00 56.00 50.00 115.33±108.01

Abandoned fields

P 1 0.00 0.40 0.40 0.27±0.19 28.4 14.00 21.60 21.33±7.20 140.00 110.00 140.00 130.00±17.32

N 2 0.80 3.20 4.80 2.93±1.64 18.2 6.60 4.00 9.60±7.56 460.00 100.00 370.00 310.00±187.35

KR 2 0.00 2.40 1.20 1.20±0.98 16.0 8.60 12.00 12.20±3.70 240.00 80.00 380.00 233.33±150.11



Figure 4.15: Seasonal variation of Dissolve Oxygen (mean values in mgO2/L)


SYSTEMS

ABFCFCanalRiver

12

10

8

6

4

2

0

-2

Premonsoon

Monsoon

Postmonsoon

6

4

5

32

34

12

Figure 4.16: Seasonal variation of Biochemical Oxygen Demand (mean values in mgO2/L)


SYSTEMS

ABFCFCanalRiver

50

40

30

20

10

0

-10

Premonsoon

Monsoon

Postmonsoon

32

12

13

6

22

9

32

26

13

12

9

Figure 4.17: Seasonal variation of Chemical Oxygen Demand (mean values in

mgO2/L) in water samples of Kuttanad wetland ecosystem during the study period.

SYSTEMS

ABFCFCanalRiver

700

600

500

400

300

200

100

0

-100

Premonsoon

Monsoon

Postmonsoon

35

17

19

22

6

32

13

19

8

26



n. Nitrate (mg/l)

In river systems, nitrate ranged from 0.04 to 6.44mg/L. The least value recorded from

KV1 (river Manimala at Kavalam) during postmonsoon and the maximum value recorded from

the same river at Kidangara (ACC4 site) during monsoon season (Table 4.7 and Figure 4.18).

River systems like Manimala, Meenachil and Kodurar have recorded high mean values >2

mg/L. It was generally noted that the nitrate was comparatively high in different river systems

of Kuttanad during monsoon. River Meenachil at Kumarakom (KR1) showed the maximum

seasonal average value of 3.22 mg/L.

Among the canal systems, nitrate ranged from 0.04 to 12.40 mg/L. The minimum value

recorded from N1 (Neendur) during premonsoon and the maximum value recorded from KR3

(Kumarakom) during postmonsoon season. Like river systems, nitrate showed comparatively

higher values during monsoon season.

In cultivated fields, the nitrate ranged from 0.06 to 5.32 mg/L. The least value recorded

from Pilapuzha (PILA) during premonsoon and maximum value recorded from the same site

during monsoon season. Monsoon season recorded comparatively high nitrate values than other

two seasons in cultivated fields (Table 4.7 and Figure 4.18).

Among the abandoned fields, high nitrate value of 16.30 mg/L recorded from N2 site

during postmonsoon season and the least value of 0.44mg/L recorded from KR2 site during

premonsoon (Table 4.7 and Figure 4.18).

Nitrate values were higher during the monsoon in all the systems except abandoned

fields (Table 4.7 and Figure 4.18). Statistical analysis showed that there is significant variation of

nitrate between seasons (p<0.01, F=5.1) and between systems (p<0.01, F=6.29). Nitrate

showed positive correlation with BOD (r =0.47, p<0.01), COD (r = 0.56, p<0.01), TDS (r=

0.38, p<0.05) and alkalinity (r =0.35, p<0.05). It showed negative correlation with water

temperature (r= - 0.37, p<0.05) and DO (r = - 0.44, p<0.01).

o. Phosphate (mg/l)

The phosphate concentration in river systems ranged from 0.02 to 1.42 mg/L. The least

value recorded from river Pampa at Veeyapuram (VPM) site during postmonsoon season and

the maximum value recorded from Kodurar at Pallom (P4) during the same season.

In canal systems, the phosphate concentration ranged from 0.02 to 13.79 mg/L. During

premonsoon season, Vanam (VA1) site recorded the peak value and the least value recorded

from KV2 during the post monsoon season. Mean maximum value of 4.88 mg/L recorded from

VA1 site followed 1.27 mg/L from P5 site.



Among the cultivated field sites, the least value of 0.04 mg/L recorded from KV3 site

during monsoon season and the maximum value recorded from S4 CF (Kayal land) during

postmonsoon season (Table 4.7 and Figure 4.19).

The phosphate concentration in abandoned field sites ranged from 0.03 to 2.60 mg/L.

The minimum value recorded from N2 (Neendur) site during monsoon and the maximum from

KR2 (Kumarakom) during premonsoon. Among the abandoned fields, KR2 site recorded

comparatively high values of phosphate (Table 4.7 and Figure 4.19).

It was generally noted that the phosphate values were higher during premonsoon season

and low during monsoon season (Figure 4.19). Statistical analysis showed that there is

significant variation of phosphate between seasons (p<0.05, F=4.49) and no significant variation

between systems (p>0.05, F=0.62). Phosphate showed positive correlation with acidity (r =0.65,

p<0.01) and sulphate (r = 0.46, p<0.01).

Table 4.7: Variation (mean values) of Nitrate and Phosphate in water samples of


Sites Nitrate (mg/L) Phosphate (mg/L)

Pre Mon Post Mean(±SD) Pre Mon Post Mean (±SD)

River systems

KV1 3.18 3.19 0.04 2.14±1.82 0.49 0.31 0.06 0.29±0.22

TH 3 0.10 1.24 0.05 0.46±0.27 0.08 0.98 0.06 0.37±0.53

P 3 0.56 3.72 0.80 1.69±1.76 0.08 0.62 0.14 0.28±0.30

P 4 0.59 4.34 1.78 2.24±1.92 1.42 0.52 0.06 0.67±0.69

ACC 4 0.05 6.99 0.62 2.55±3.85 1.04 0.98 0.06 0.69±0.55

KR 1 2.42 3.18 4.07 3.22±0.83 0.05 0.04 0.36 0.15±0.18

VPM 1.06 2.03 0.70 1.26±0.69 0.57 0.34 0.02 0.31±0.28

THOT 0.35 1.77 3.10 1.74±1.38 0.31 0.07 0.24 0.21±0.12

KODI 2.66 1.66 2.12 2.15±0.50 0.17 0.02 0.06 0.08±0.08

Canal systems

KV 2 0.45 0.44 0.74 0.54±0.17 0.61 0.08 0.02 0.24±0.32

TH 1 0.11 1.42 0.78 0.77±0.66 0.31 0.04 0.05 0.13±0.15

P 5 0.50 9.21 0.53 3.41±5.02 2.20 1.53 0.09 1.27±1.08

P 6 0.44 6.47 3.72 3.54±3.02 2.08 1.34 0.07 1.16±1.02

ACC 1 0.47 3.01 0.89 1.46±1.36 1.38 0.44 0.14 0.65±0.65

ACC 2 0.54 2.30 1.94 1.59±0.93 0.96 0.67 0.20 0.61±0.38

ACC 3 0.44 4.87 0.35 1.89±2.58 0.98 0.44 0.06 0.49±0.46

ACC 5 0.54 3.10 0.53 1.39±1.48 1.77 0.31 0.06 0.71±0.92

ACC 6 0.44 4.20 0.88 1.84±2.06 1.38 0.41 0.07 0.62±0.68

N 1 0.04 2.08 2.56 1.56±1.34 0.37 0.31 0.31 0.33±0.03

VA 1 0.53 2.22 6.11 2.95±2.86 13.79 0.25 0.61 4.88±7.72

VA 2 0.64 5.50 6.20 4.11±3.03 0.32 0.25 0.14 0.24±0.09

KR 3 0.89 2.75 12.40 5.35±6.18 0.37 0.04 1.04 0.48±0.51

ACHIN 0.62 1.50 6.11 2.74±2.95 0.31 0.31 0.77 0.46±0.27

THRP 1.86 1.11 1.15 1.37±0.42 0.10 0.07 0.14 0.10±0.04

KARU 0.12 2.22 1.01 1.12±1.05 0.07 0.13 0.11 0.10±0.03

S1 0.47 1.86 1.15 1.16±0.70 0.49 0.18 1.04 0.57±0.44



Sites Nitrate (mg/L) Phosphate (mg/L)

Pre Mon Post Mean(±SD) Pre Mon Post Mean (±SD)

S2 1.77 0.44 1.52 1.24±0.71 0.14 0.21 0.06 0.14±0.08

S 3 0.59 1.50 2.74 1.61±1.08 0.37 0.13 0.14 0.21±0.14

S 4 0.46 2.40 2.44 1.77±1.13 0.22 0.37 0.22 0.27±0.09

Cultivate field systems

KV3 0.12 0.54 0.68 0.45±0.29 0.38 0.04 0.12 0.18±0.18

TH2 0.12 0.54 0.36 0.34±0.21 1.23 0.14 0.34 0.57±0.58

P 2 0.53 3.15 2.70 2.13±1.40 1.16 0.64 0.11 0.64±0.53

KR 4 0.66 2.42 0.56 1.21±1.05 0.22 0.14 0.08 0.15±0.07

PILA 0.06 5.32 0.88 2.09±2.83 0.56 0.13 0.06 0.25±0.27

PURA 0.47 4.07 1.86 2.13±1.82 0.26 0.13 0.14 0.18±0.07

S 2 CF 1.44 1.54 0.66 1.21±0.48 0.16 0.08 0.12 0.12±0.04

S 4 CF 1.04 0.86 0.97 0.96±0.09 0.28 0.13 1.44 0.62±0.72

Abandoned Field systems

P 1 0.52 12.80 2.28 5.20±6.64 0.35 0.77 0.26 0.46±0.27

N 2 9.88 1.68 16.30 9.29±7.33 0.22 0.03 0.31 0.19±0.14

KR 2 0.44 1.86 1.95 1.42±0.85 2.60 0.24 0.31 1.05±1.34

Figure 4.18: Seasonal variation of Nitrate (mean values in mg/L) in water samples of


SYSTEMS

ABFCFCanalRiver

20

10

0

-10

Premonsoon

Monsoon

Postmonsoon

32

22

12

5

251119222724



p. Potassium (mg/l)

There are three ranges of potassium levels in the Kuttanad rice field mainly due to

addition of this element as fertilizer to the rice crop. The values below 5 mg/L are observed in

17 out of 40 sites. Values between 5 to10 mg/L were observed at 13 sites and more than 10

mg/L recorded from 10 sites.

Potassium in river systems ranged from 0.6 to 14.20 mg/L. The minimum value was

recorded from river Pampa at Veeyapuram (VPM) during premonsoon and the maximum

recorded from Kodurar at Kodimatha (KODI) during postmonsoon. Achenkovil at Thottapally

(THOT) recorded the seasonal maximum average value of 7.63 mg/L (Table 4.8 and Figure

4.20).

In canal systems, potassium seasonally between ranged from 0.80 to 56.72 mg/L. The

peak value recorded from the polluted canal site ACC1 during premonsoon season and the

minimum value recorded from Thriperumthura (THRP) site during monsoon season.

Generally, monsoon season showed comparatively low values of potassium than other two

seasons (Table 4.8 and Figure 4.20).

In the cultivated fields, potassium ranged from 1 to 24.2 mg/L. The minimum value

recorded from S4 (Kayal land) site during premonsoon and the least value recorded from TH2

site during monsoon. All the cultivated fields showed comparatively higher values of potassium

during the premonsoon and low values were recorded during the monsoon season (Table 4.8

and Figure 4.20).

Figure 4.19: Seasonal variation of Phosphate (mean values in mg/L) in


SYSTEMS

ABFCFCanalRiver

16

14

12

10

8

6

4

2

0

-2

Premonsoon

Monsoon

Postmonsoon

37

20232622

630

32

1312

20

4



In abandoned fields, potassium ranged from 2.40 to 14.60 mg/L. The maximum value

recorded from N2 (Neendur) during premonsoon season and the minimum value recorded from

KR2 during monsoon season (Table 4.8 and Figure 4.20).

Seasonal variation of potassium concentration showed that the peak values were

recorded during premonsoon season in all the systems. The maximum values were recorded

from cultivated fields and canal systems due to the addition of fertilizers in rice fields which flow

in to the surrounding canals. Analysis of variance showed that there is significant variation

between seasons (p<0.01, F=20.65) and no significant variation between systems (p>0.05,

F=0.85). Potassium showed significant positive correlation with TDS (r=0.43, p<0.01),

conductivity (r =0.44, p<0.01), chloride (r =0.42, p<0.01) and hardness (r =0.37, p<0.05).

Potassium showed negative correlation with DO (r = - 0.33, p<0.05).

q. Sulphate (mg/l)

Among the river systems, Pampa recorded the least sulphate value (4 mg/L) at VPM

(Veeyapuram) during premonsoon followed by the same river at Thakazhy (TH3) with 8 mg/L

during same season. The peak value of 380 mg/L was recorded from river Meenachil during

premonsoon season.

Among the canal sites, high sulphate value (422 mg/L) recorded from VA1 site during

premonsoon season and the Vaikom Kari land sites (VA1 and VA2) showed high sulphate

values ranged from 160 to 400 mg/L, which is comparatively higher than other sites of

Kuttanad. The minimum value of 2 mg/L recorded from THRP site during monsoon season.

Sites like P5, P6 (Kayal lands), VA1, VA2 and ACHIN (lies in Vaikom Kari land) have shown

no significant variation of sulphate throughout the season (Table 4.8 and Figure 4.21).

In cultivated systems, the mean sulphate values ranged between 10 and 165 mg/L. The

minimum value recorded from PILA (Pilapuzha) site during monsoon season and the

maximum value recorded from S4 (Kayal land) during premonsoon season (Table 4.8 and

Figure 4.21).

The sulphate concentration in abandoned fields ranged from 12 to 154 mg/L. The

minimum value was recorded from P1 site during postmonsoon season and the maximum value

recorded from N2 (Neendur) during premonsoon season (Table 4.8 and Figure 4.21).

Generally sulphate was higher during premonsoon season in all systems (Figure 4.21).

High values were recorded in canal and cultivated field systems. Statistical analysis showed that

there is significant variation of sulphate between season (p<0.01, F=14.56) and no significant

variation between systems (p>0.05, F=1.57). Sulphate showed significant positive correlation



with TDS (r = 0.53, p<0.01), conductivity (r =0.59, p<0.01), acidity (r =0.63, p<0.01), chloride

(r = 0.60, p<0.01), hardness (r =0.51, p<0.01), phosphate (r = 0.46, p<0.01). It showed

significant negative correlation with pH (r = - 0.54, p<0.05)

Table 4.8: Variation (mean values) of Potassium and Sulphate in water samples of


Sites

Potassium (mg/L) Sulphate (mg/L)


River systems

KV1 4.00 1.60 1.50 2.37±1.42 85.00 20.00 36.00 47.00±33.87

TH3 1.50 1.20 3.10 1.93±1.02 8.00 20.00 25.00 17.67±8.74

P 3 8.30 1.30 5.30 4.97±3.51 186.00 22.00 160.00 122.67±88.14

P 4 8.90 2.00 5.00 5.30±3.46 200.00 56.00 140.00 132.00±72.33

ACC 4 1.80 0.90 1.10 1.27±0.47 25.00 200.00 12.00 79.00±104.99

KR 1 12.80 2.10 3.70 6.20±5.77 380.00 14.00 30.00 141.33±206.85

VPM 0.60 1.90 0.80 1.10±0.70 4.00 14.00 12.50 10.17±5.39

THOT 4.30 5.40 13.20 7.63±4.85 62.00 32.00 196.00 96.67±87.32

KODI 3.10 2.20 14.20 6.50±6.68 24.00 12.00 140.00 58.67±70.69

Canal systems

KV 2 3.40 2.90 2.10 2.80±0.66 38.00 26.00 28.00 30.67±6.43

TH1 2.10 1.10 1.90 1.70±0.53 18.00 44.00 24.50 28.83±13.53

P 5 7.00 3.90 4.20 5.03±1.71 145.00 120.00 150.00 138.33±16.07

P 6 10.50 4.60 34.80 16.63±16.01 125.00 140.00 120.00 128.33±10.41

ACC 1 86.70 3.30 5.90 31.97±47.42 68.00 120.00 32.00 73.33±44.24

ACC 2 4.70 2.10 3.00 3.27±1.32 70.00 46.00 52.00 56.00±12.49

ACC 3 1.20 0.90 1.20 1.10±0.17 4.00 220.00 125.00 116.33±108.26

ACC 5 1.60 1.50 2.70 1.93±0.67 16.00 220.00 36.00 90.67±112.45

ACC 6 1.50 1.20 5.20 2.63±2.23 12.00 235.00 37.50 94.83±122.06

N 1 18.80 2.50 4.10 8.47±8.98 260.00 16.00 58.00 111.33±130.45

VA 1 2.00 2.20 10.10 4.77±4.62 422.00 160.00 180.00 254.00±145.84

VA 2 12.40 4.50 11.20 9.37±4.26 398.00 160.00 180.00 246.00±132.02

KR 3 15.30 1.80 3.30 6.80±7.40 260.00 18.00 42.00 106.67±133.33

ACHIN 38.00 4.40 14.40 18.93±17.25 136.00 86.00 320.00 180.67±123.23

THRP 2.10 0.80 1.20 1.37±0.67 80.00 0.00 22.00 34.00±41.33

KARU 8.20 1.40 2.70 4.10±3.61 190.00 42.00 27.00 86.33±90.09

S 1 15.90 3.80 5.90 8.53±6.47 340.00 20.00 142.00 167.33±161.50

S2 8.10 3.40 2.80 4.77±2.90 176.00 18.00 86.00 93.33±79.25

S 3 13.60 2.60 6.50 7.57±5.58 270.00 8.00 124.00 134.00±131.29

S 4 22.70 2.80 10.60 12.03±10.03 280.00 8.00 172.00 153.33±136.96

Cultivated field systems

KV3 5.80 3.00 3.80 4.20±1.44 240.00 60.00 80.00 126.67±98.66

TH2 7.40 1.00 5.60 4.67±3.30 30.00 120.00 68.00 72.67±45.18

P 2 15.70 1.90 5.70 7.77±7.13 296.00 120.00 22.00 146.00±138.84

KR 4 14.20 2.80 2.00 6.33±6.82 68.00 16.00 34.00 39.33±26.41

PILA 2.00 1.40 4.20 2.53±1.47 20.00 2.00 8.00 10.00±9.17

PURA 9.50 4.40 13.20 9.03±4.42 220.00 92.00 30.00 114.00±96.89

S 2CF 8.40 2.60 3.60 4.87±3.10 228.00 10.00 120.00 119.33±109.00

S4 CF 24.20 2.80 6.80 11.27±11.38 320.00 8.00 168.00 165.33±156.02



Sites

Potassium (mg/L) Sulphate (mg/L)


Abandoned field systems

P 1 4.10 5.30 12.40 7.27±4.49 70.00 24.00 12.00 35.33±30.62

N 2 14.60 7.10 6.00 9.23±4.68 154.00 24.00 50.00 76.00±68.79

KR 2 14.00 2.40 5.90 7.43±5.95 124.00 16.00 38.00 59.33±57.07

Figure 4.20: Seasonal variation of Potassium (mean values in mg/L) in


SYSTEMS

ABFCFCanalRiver

100

80

60

40

20

0

-20

Premonsoon

Monsoon

Postmonsoon

35

13

89

8

23

14

Figure 4.21: Seasonal variation of Sulphate (mean values in mg/L) in


SYSTEMS

ABFCFCanalRiver

500

400

300

200

100

0

-100

Premonsoon

Monsoon

Postmonsoon

23

5

Chapter 4 Physico-chemical and bacteriological parameters


Table 4.9: Correlation matrix of physico-chemical parameters of water

AT WT TDS COND TUB pH ACD ALK CHL HAR DO BOD COD NITR PHO POT SUL

AT 1

WT 0.14 1.00

TDS -0.11 0.09 1.00

CON -0.04 0.12 0.93** 1.00

TUB 0.07 -0.15 0.44** 0.54** 1.00

pH -0.28 -0.07 -0.26 -0.35* -0.04 1.00

ACD 0.27 -0.02 0.341* .39* 0.04 -.78** 1.00

ALK 0.01 -0.01 0.30 0.35* 0.34* 0.08 -0.11 1.00

CHL -0.05 0.16 0.74** 0.77** .50** -0.22 0.18 0.19 1.00

HAR -0.02 0.17 0.65** 0.66** .49** -0.05 0.07 0.08 0.90** 1.00

DO -0.22 -0.56** -0.20 -0.22 -0.33* 0.25 -0.21 -0.34* 0.02 0.00 1.00

BOD 0.14 0.54** 0.18 0.21 0.49** -0.07 0.06 0.33* -0.07 -0.04 -0.80** 1.00

COD -0.11 -0.31 0.61** 0.50** 0.40* 0.01 0.15 0.38* 0.32* 0.29 -0.43** 0.41** 1.00

NITR 0.06 -0.37* 0.38* 0.30 0.28 -0.29 0.23 0.35* 0.15 0.05 -0.44** 0.47** 0.56** 1.00

PHO 0.21 -0.19 0.18 0.15 0.02 -0.29 0.65** -0.02 0.04 0.10 -0.24 0.20 0.12 0.11 1.00

POT 0.17 -0.11 0.43** 0.44** 0.40* -0.11 0.06 0.18 0.42** 0.37* -0.33* 0.28 0.33* 0.18 0.04 1.00

SUL 0.02 0.01 0.53** 0.59** 0.29 -0.54** 0.63** -0.14 0.60** 0.51** -0.27 0.10 0.33* 0.18 0.46** 0.31 1.00

** Correlation is significant at the 0.01 level (2-tailed).

* Correlation is significant at the 0.05 level (2-tailed).

AT – Atmosphere temperature, WT – Water temperature, TDS – Total Dissolved solids, COND – Conductivity, TUB – Turbidity, pH, ACD- Acidity, ALK – Alkalinity, CHL- Chloride, DO – Dissolve Oxygen, BOD – Biochemical Oxygen Demand, COD- Chemical Oxygen Demand, NITR – Nitrate, PHO – Phosphate, POT – Potassium, SUL - Sulphate



4.5.2 Bacteriological parameters

a. Faecal coliform

In river systems, the faecal coliform count ranged from 7500 to 116500 MPN/100ml

(Table 4.10). The minimum was recorded from downstream of Kodurar at Pallom during

postmonsoon season and the maximum value recorded from Pampa at Thakzhy during

postmonsoon. High values of faecal coliform (>100000 MPN/100ml) were recorded from

Kodur at Kodimatha during monsoon, Kodur at Pallom downstream during postmonsoon,

Manimala river at both Kavalam and Kidangara during monsoon, Pampa at Thakazhy during

postmonsoon, Pampa at Veeyapuram during monsoon and Achenkovil at Thottapally during

monsoon season. Faecal coliform count showed higher values during monsoon season and river

Pampa showed higher values during the postmonsoon season (Table 4.10 and Figure 4.22).

Among the canal systems studied, FC values ranged from 1500 to 110000 MPN/100ml

(Table 4.11). The least value was recorded from Thakazhy site during postmonsoon and the

maximum value recorded from sites like Kavalam during both premonsoon and postmonsoon,

Pallom during monsoon, Vanam during postmonsoon, Achinakom during postmonsoon and

Kumarakom recorded throughout the season. In canal systems, the FC values are higher during

monsoon and premonsoon season than postmonsoon season (Figure 4. 22).

In cultivated fields, the FC values ranged from 4300 to 110000 MPN/100ml (Table

4.12). The least value recorded from Pilapuzha site during premonsoon season and Thakazhy

and Kumarakom sites recorded the maximum value throughout the season (Table 4.12). In the

abandoned fields, the maximum FC value of 110000 MPN/100ml recorded from Neendur (N2)

site during premonsoon and Kumarakom site on both premonsoon and monsoon season (Table

4.13 and Figure 4. 22). The least value recorded from Neendur site during postmonsoon season.

Analysis of variance showed that there is no significant variation (p>0.05, F=0.36) of

faecal coliform distribution between seasons but significant variation between systems (p<0.01,

F=4.81).

b. Faecal streptococci

In river systems, the faecal streptococci values ranged from 900 to 110000 MPN/100ml

(Table 4.10). The least value recorded from three river sites viz. Kodur downstream at Pallom

during postmonsoon, Pampa at Veeyapuram during premonsoon and Achenkovil at Thottapally

during the premonsoon season. The maximum value recorded from most of the river systems

mainly during monsoon season (Table 4.10). FS values also showed higher values in river

systems during the monsoon season (Figure 4. 22).



The FS value in canal sites ranged from 400 to 110000 MPN/100ml (Table 4.11). The

least value recorded from Thakazhy site during the premonsoon season and the maximum value

recorded from Neendur, Vanam, Achinakom and Kumarakom sites during the postmonsoon

season and Kumarakom site during monsoon season. It was generally found that during

postmonsoon season, the FS values comparatively higher in canal systems (Figure 4. 22).

In cultivated fields, the FS value ranged from 700 to 110000 MPN/100ml (Table 4.12).

The least value recorded from Kavalam (KV3) during monsoon and Pilapuzha (PILA) during

premonsoon season. The peak values were recorded from Kumarkaom during both monsoon

and postmonsoon season, Kavalam during postmonsoon and Pallom during premonsoon

season. In cultivated field systems, the FC values were exceeded the FS values throughout the

season (Figure 4. 22).

Among the abandoned fields, the FS values ranged from 930 to 110000 MPN/100ml

(Table 4.13). The least value was recorded from Kumarakom (KR2) during postmonsoon

season and the maximum value recorded from Neendur (N2) site during postmonsoon season

(Figure 4. 22). During postmonsoon season, FS showed higher values than the FC load in

abandoned fields (Figure 4.22).

Statistical analysis showed that there is significant variation of faecal streptococci

between seasons (p<0.05, F= 3.61) and between systems (p=0.05, F=2.75).

c. Vibrio cholerae like organisms (VCLOs’)

In river systems, the VCLO counts ranged from 0 to 390 cfu/ml (Table 4.10). The

absence of VCLO were recorded from river Manimala at Kavalam during monsoon season and

the maximum value recorded from Achenkovil at Thottapally during monsoon season. It was

generally found that the VCLO values are higher during the monsoon season followed by

premonsoon season (Figure 4.23).

Among the canal systems, the VCLO counts ranged from 0 to 440 cfu/ml (Table 4.11).

The absence of VCLO’s were noted fromThakazhy and Neendur sites during monsoon season

and the maximum count recorded from Karumady during monsoon season. The VCLO counts

were higher during the monsoon followed by premonsoon (Figure 4.23).

In cultivated field systems, the VCLO counts ranged from 0 to 175 cfu/ml (Table 4.12).

The absence was noted from Pilapuzha during premonsoon season and the maximum value

recorded from Pallom during monsoon season (Figure 4.23).



Among the abandoned fields, VCLO ranged from 5 to 155 cfu/ml (Table 4.13). The

least value recorded from Neendur during postmonsoon season and the maximum value

recorded from Pallom during premonsoon season (Figure 4.23).

Analysis of variance showed that there is no significant variation of VCLO between

seasons and systems.

d. Vibrio parahaemolyticus like organisms (VPLOs’)

In river systems, the VPLO ranged from 0 to 135cfu/ml (Table 4.10). The absence of

VPLO recorded from Manimala at Kidangara during postmonsoon season and the maximum

value recorded from Meenachil at Kumarakom (KR1) during premonsoon season. VPLO like

organisms were comparatively higher during premonsoon season in different systems of

Kuttanad (Figure 4.23).

Among the canal systems, the VPLO ranged from 0 to 290 cfu/ml (Table 4.11). The

absences of VPLO were recorded from Kavalam, Vanam and Achinakom during monsoon

season. The maximum value recorded from Kumarakom during postmonsoon season (Figure

4.23).

In cultivated fields, the VPLO counts ranged from 0 to 130 cfu/ml (Table 4.12). The

maximum value recorded from Pallom cultivated field during premonsoon season and the

absences of VPLO recorded from both Thakazhy and Pilapuzha during monsoon season (Figure

4.23).

In abandoned fields, the VPLO values ranged from 5 to 110 cfu/ml (Table 4.13). The

least value was recorded from both Kumarakom and Neendur sites during monsoon season.

The maximum value recorded from Pallom during premonsoon season (Figure 4.23).

Analysis of variance showed that there is no significant variation (p>0.05) of VPLO between

seasons and between systems.

e. Pseudomonas spp.

In river systems, the Pseudomonas spp. counts ranged from 0 to 260 cfu/ml (Table 4.10).

The absence of Pseudomonas spp. were recorded from river Meenachil at Kumarakom during

postmonsoon season and the maximum value recorded from river Pampa at Thakazhy during

monsoon season. It was generally noted that the Pseudomonas spp. counts were comparatively

high during the monsoon season in the river systems (Figure 4.23).

Among the canal systems, Neendur site noted the absence of Pseudomonas spp. during

postmonsoon and the maximum value of 688 cfu/ml recorded from Karumady during



monsoon. It was generally noted that Pseudomonas spp. were high during the monsoon season in

the canal systems (Table 4.11 and Figure 4.23).

In the cultivated fields, Pseudomonas spp. were ranged from 5 to 876 cfu/ml (Table 4.12).

The least value recorded from Kavalam during premonsoon season and the maximum recorded

from Pilapuzha during monsoon season (Figure 4.23).

In abandoned fields, the Pseudomonas spp. counts ranged from 0 to 280 cfu/ml (Table

4.13). The absence noted at Neendur during postmonsoon season and the maximum value

recorded at Pallom during the monsoon season. During monsoon season, the Pseudomonas spp.

were higher in the abandoned fields of Kuttanad (Figure 4.23).

Statistical analysis showed that there is significant variation of Pseudomonas spp. counts

between seasons (p<0.01, F= 4.36) and systems (p=0.05, F=2.95).

f. FC/FS Ratio

In river systems, the FC/FS ratio was higher during the premonsoon and postmonsoon

season (Figure 4.24). During monsoon season, FC/FS value is less than 2. Rivers like Pampa,

Achenkovil and Manimala have shown high FC/FS values during premonsoon and

postmonsoon season. Kodur river showed high FC/FS value during monsoon season. The high

FC/FS value of 52.4 noted from river Manimala at Kidangara during premonsoon season and

river Pampa at Thakazhy (55.48) during postmonsoon season (Table 4.10). Pampa river showed

high FC/FS value during premonsoon and postmonsoon season from both Thakazhy and

Veeyapuram. The upstream of Kodur river at Kodimatha site has high FC/FS value during

monsoon but the downstream sites at Pallom showed low values (Table 4.10).

In canal systems, the FC/FS value have shown the peak value of 122.22 at Kumarakom

site during premonsoon season (Table 4.11). During premonsoon season, all the sites have high

FC/FS value more than 4 except Vanam, where FC/FS values were lower than 4.4 throughout

the season (Table 4.11).

In cultivated field systems, the FC/FS values are more than 4.4 during both

premonsoon and monsoon seasons (Table 4.12 and Figure 4.24). Sites like Thakazhy, Purakkad

and Pilapuzha sites showed high FC/FS value throughout the season (Table 4.12).

Among the abandoned fields, high FC/FS value recorded during the premonsoon

season and the least values (<2) recorded from both Neendur and Pallom site during

postmonsoon season (Table 4.13 and Figure 4.22).



Table 4.10: Seasonal variation (Mean values) of bacteriological parameters in different

River systems of Kuttanad

Site Seasons FC

(MPN/100ml)

FS

(MPN/100ml)

VCLO

(CFU/ml)

VPLO

(CFU/ml)

Pseudomonas sp.

(CFU/ml)

FC/FS

Ratio

Meenachil

at

Kumarakom

Premonsoon 46000 2300 125 135 30 20.00

Monsoon 11000 9300 40 10 130 1.18

Postmonsoon 110000 110000 40 40 0 1.00

Kodurar

at

Kodimatha

Premonsoon 15000 21000 70 45 10 0.71

Monsoon 110000 21000 120 20 16 5.24

Postmonsoon 24000 21000 66 10 8 1.14

Kodurar

at

Pallom

Premonsoon 9300 46000 70 50 5 0.20

Monsoon 110000 110000 35 18 110 1.00

Postmonsoon 7500 900 50 15 58 8.33

Manimala

at

Kavalam

Premonsoon 93000 24000 65 5 5 3.88

Monsoon 110000 110000 5 6 80 1.00

Postmonsoon 15000 9300 14 14 38 1.61

Manimala

at

Kidangara

Premonsoon 110000 2100 20 20 10 52.38

Monsoon 11000 11000 185 35 210 1.00

Postmonsoon 9300 2300 10 0 30 4.04

Pampa

at

Thakazhy

Premonsoon 15000 2100 45 85 30 7.14

Monsoon 24000 110000 20 8 260 0.22

Postmonsoon 116500 2100 6 2 10 55.48

Pampa

at

Veeyapuram

Premonsoon 40000 900 16 4 10 44.44

Monsoon 110000 110000 55 26 4 1.00

Postmonsoon 93000 4300 10 2 4 21.63

Achankovil

at

Thottapally

Premonsoon 9300 900 20 30 22 10.33

Monsoon 110000 110000 390 30 188 1.00

Postmonsoon 24000 15000 80 20 12 1.60



Table 4.11: Seasonal variation (mean values) of bacteriological parameters in different

Canal systems of Kuttanad

Sites Seasons FC

(MPN/100ml) FS

(MPN/100ml) VCLO

(CFU/ml) VPLO

(CFU/ml) Pseudomonas sp.

(CFU/ml)

FC/FS

Ratio

Kavalam

Premonsoon 110000 9300 125 110 450 11.83

Monsoon 11000 11000 2 0 310 1.00

Postmonsoon 110000 2000 14 12 54 55.00

Thakazhy

Premonsoon 15000 400 15 5 130 37.50

Monsoon 11000 9300 0 5 40 1.18

Postmonsoon 1500 1500 6 6 2 1.00

Pallom

Premonsoon 78000 9300 143 103 43 8.39

Monsoon 110000 11000 180 43 155 10.00

Postmonsoon 11250 1600 263 63 55 7.03

AC Canal

Premonsoon 42700 2500 27 69 17 17.08

Monsoon 11000 9300 92 36 164 1.18

Postmonsoon 30580 2360 19 16 62 12.96

Neendoor

Premonsoon 7500 900 170 110 18 8.33

Monsoon 11000 9300 0 25 130 1.18

Postmonsoon 9300 110000 10 5 0 0.08

Vanam

Premonsoon 9300 4300 95 20 25 2.16

Monsoon 11000 7500 15 0 170 1.47

Postmonsoon 110000 110000 35 25 2 1.00

Achinakom

Premonsoon 46000 7500 265 85 20 6.13

Monsoon 11000 7500 100 0 40 1.47

Postmonsoon 110000 110000 95 10 10 1.00

Kumarakom

Premonsoon 110000 900 195 145 10 122.22

Monsoon 110000 110000 40 160 90 1.00

Postmonsoon 110000 110000 240 290 10 1.00

Thriperumthura

Premonsoon 46000 700 45 10 12 65.71

Monsoon 11000 9300 360 25 170 1.18

Postmonsoon 24000 9300 40 6 2 2.58

Karumady

Premonsoon 4300 700 15 5 4 6.14

Monsoon 11000 9300 440 46 688 1.18

Postmonsoon 15000 9300 5 26 24 1.61

Kayal lands

Premonsoon 15000 9300 22 4 60 16.13

Monsoon 11000 11000 50 100 80 1.00

Postmonsoon 4100 12000 21 29 2 0.34




Cultivated field systems of Kuttanad

Site Seasons FC

(MPN/100ml)

FS

(MPN/100ml)

VCLO

(CFU/ml)

VPLO

(CFU/ml)

Pseudomonas sp.

(CFU/ml)

FC/FS

ratio

Kavalam

Premonsoon 110000 24000 170 35 5 4.58

Monsoon 4600 700 2 15 130 6.57

Postmonsoon 11000 110000 22 4 56 0.10

Thakazhy

Premonsoon 110000 4300 5 5 15 25.58

Monsoon 110000 4300 15 0 320 25.58

Postmonsoon 110000 4300 6 2 12 25.58

Pallom

Premonsoon 110000 110000 46 130 180 1.00

Monsoon 110000 4300 175 20 80 25.58

Postmonsoon 7500 9300 25 60 145 0.81

Kumarakom

Premonsoon 110000 9300 26 6 44 11.83

Monsoon 110000 110000 25 80 260 1.00

Postmonsoon 110000 110000 36 44 26 1.00

Pilappuzha

Premonsoon 4300 700 0 30 12 6.14

Monsoon 110000 4300 10 0 876 25.58

Postmonsoon 24000 4300 15 6 10 5.58

Purakkad

Premonsoon 24000 900 60 45 65 26.67

Monsoon 110000 4300 6 2 860 25.58

Postmonsoon 24000 4300 15 22 38 5.58


Abandoned field systems of Kuttanad

Site Seasons

FC

(MPN/100ml) FS

(MPN/100ml) VCLO

(CFU/ml) VPLO

(CFU/ml)

Pseudomonas

sp. (CFU/ml) FC/FS

ratio

Pallom

Premonsoon 46000 9300 155 110 30 4.95

Monsoon 46000 4300 35 105 280 10.70 Postmonsoo

n 21000 46000 70 60 80 0.46

Neendoor

Premonsoon 110000 9300 36 22 24 11.83

Monsoon 11000 11000 8 5 80 1.00

Postmonsoon 9300 110000 5 20 0 0.08

Kumarakom

Premonsoon 110000 11000 22 20 46 10.00

Monsoon 110000 46000 10 5 70 2.39 Postmonsoo

n 11000 930 26 6 34 11.83

Chapter 4 Physico-chemical and bacteriological parameters of water


Figure 4.22: Seasonal variation of FC and FS in different systems (mean values) of Kuttanad

Figure 4.23: Seasonal variation of VCLO, VPLO and Pseudomonas spp. in different systems (mean values) of Kuttanad

Chapter 4 Physico-chemical and bacteriological parameters of water


0

5

10

15

20

25

30

Pre Mon Post Pre Mon Post Pre Mon Post Pre Mon Post

River Canal Cultivated field Abandoned Field

FC/FS

4.4

Figure 4. 24: Seasonal variation (mean values) of FC/FS ratio in different systems of Kuttanad


113

An Ecological study of the Macrophytic Vegetation of the Kuttanad Ecosystem

4.6 Discussion

Development of human culture started in the flood plain of major river systems of the

world. Along with the expansion of human development, these habitats did not get attention

and it is considered as „waste lands‟. But worldwide, a large number of scientific studies were

conducted and these studies highlighted the importance of wetlands which lead to its

conservation. In Kerala, wetland studies were started only recently and very few studies have

been made on the ecological aspects. “Aquatic habitats such as rivers, lakes, ponds, pools and

swamps are not ideal locations for prolonged field studies. Often they are in accessible and even

they are, no worthwhile work can be done unless one is prepared to forgo one‟s minimum

comforts” (Joseph, 2002). This approach towards wetlands by a senior Botanist who has made

significant contribution to floristic of Kerala reflect the negative approaches to study the dirty

mud and overlying water and its ecology over decades. Only the rice fields and their weed flora

have been studied to some extent and limno- chemistry has been neglected in this part of India.

A literature survey on the water quality of Kerala wetlands clearly indicate this aspect as a virgin

field to make detailed scientific studies since there is an urgent needs to sustain these wetlands

under threat. Nair and Unni (1993); Thomas et al. (2001); Nair and Sankar (2002); Sooraj et al.

(2002); Padmakumar et al. (2002); Nirmala and Shoba (2003) and Nandan (2008) are the only

available studies on the wetlands of Kerala, mostly on the water quality of rivers, canals,

estuaries and lakes. However no detailed studies exists on the physico-chemical aspects of

waters of the cultivated fields, abandoned fields, Kari land and Kayal lands and it make

comparison a more difficult task. The present work is a pioneer investigation in the field. Table

4.14 illustrated limno- chemical aspects of water quality of some rivers and canals of the state

compared to the present work covering different systems of the entire Kuttanad.

Extensive agricultural activities around the wetlands can cause the nutrient enrichment

in the water especially the nitrate and phosphate. Studies of Rodrigo et al. (2002) in El Fondo

wetland Spain, Piyankarage (2004) in Bundala Ramsar site, Sri Lanka, Panigrahy et al. (2007) in

Chilika, India, Bugenyi (1987) and Bugenyi and Magumba (1996) in Lake Victoria, Schenon et

al. (2007) in Samborombon wetland in Argentina and Babu et al. (2009) in Asthamudi lake were

reported the nutrient enrichment due to agricultural run off from the catchment areas. Organic

matter decay can contribute phosphates, bicarbonate, nitrate, ammonia and dissolved solids to

the surface waters (Yidana et al., 2008). Settlement of rich organic silt, driven from the

terrigenous origin and degradation of vast aquatic weeds and algae could also act as the

contributing factor for the nutrients and ions in water (Nuccio et al., 2003 and Panigrahi et al.,

2007).


114


4.6.1 Physico-chemical parameters of water

a. Temperature

The measurement of ambient temperature in surface water is of vital importance for

calculating the solubility of oxygen and carbon dioxide, bicarbonates and carbonates

equilibrium (Shivanikar et al., 1999). Kuttanad has fairly unique tropical climate and

atmospheric temperature ranged from 27 to 320C. In the present study, there was significant

variation of water and atmospheric temperature between seasons. The river systems exhibited

water temperature range 21 to 33OC in river Chalakudy and the present work recorded higher

water temperature ranged from 27 to 35OC. Comparative assessment of water temperature with

the other wetlands of Kerala is given in Table 4.14. The present study is the first time report of

elevated water temperature exceeding 30OC in all rivers, canals and cultivated systems. During

premonsoon, the mean water temperature indicates the exceeding of water temperature (32 to

35 OC) out of the 40 samples collected all over Kuttanad. The cultivated fields are exposed to the

severe heat of the summer throughout the day and water temperature exceeded 35OC certainly

indicate a climate shift in Kuttanad.

b. Total Dissolved Solids

The decaying organic matter is responsible for high TDS, which ranged between 12 to

414 ppm in Chalakudy (Table 4.9) and 161 to 633 ppm in Parvathym Puthenaar canal system

receiving pollution from city sewage at Thiruvananthapuram, Kerala (Sooraj et al., 2002).

Kodurar exceeded the TDS in comparison to the city sewage canal of Thiruvananthapuram by

almost two times. Earlier studies (Thomas et al., 2001; Thampatty and Jose, 2005; Padmakumar

et al., 2004) also reported the similar results. In Chilika lagoon, Panigrahy et al. (2007), Pal and

Mohanthy (2004) also noted the similar observation during the premonsoon season. Both

Vembanad and Chilika are connected to the sea through bar mouth. Studies of

Sankaranarayana and Panampunnayil (1979), Sankaranarayan and Quasim (1969), Jospeh and

Kurup (1990), Balachandran (2001) also reported the seasonal increase of TDS and conductivity

due to the salinity intrusion in Cochin estuary part of Vembanad lake. High TDS values can

also be contributed by the greater organic matter decomposition resulting from high water

temperature and dissolution of elements held by decaying plants (Klumpp et al., 2002). In the

present study, during premonsoon the TDS values were exceeded 1200 ppm to the maximum of

1868 ppm at N2 which is due to increased organic matter production and also due to the

influence of salinity intrusion.


115


c. Conductivity

Conductivity depends upon the concentration of ions and nutrients. The increase of

conductivity is due to sewage and industrial effluent as noticed by Paramasivam and

Sreenivasan (1981) Unni and Naugoriya (1989), Viet and Bhargava (1989), Shukla et al. (1989)

and Singh and Singh (1990). In the present study, conductivity showed similar values as in

Chalakudy (Table 4.14) with an increasing trend during premonsoon and the seasonal salinity

intrusion was the major factor for the increased conductivity values. The correlation analysis

also proved the influence of high chloride levels on conductivity during premonsoon season.

d. Turbidity

During monsoon, both canal and river systems have high turbidity than the other two

seasons. Among the systems, abandoned field have high turbidity values due to stagnant

conditions throughout the year followed by cultivated field. Water was always turbid in

abandoned fields than other systems due to the partial decaying of aquatic macrophytes. The

stagnation of water under the mats of Ischaemum travencorense and other floating weeds

contributed the suspended organic materials in water. Experimental studies of James et al.

(2002) proved the decaying of macrophytes increases the turbidity level in aquatic systems. In

KWE, the water is black in colour due to the particulate organic matter released through

decomposition. Thomaz (2004) reported the similar observations in the Upper Parana river,

Brazil. Both river and canal systems are flowing throughout the season but significant increase

of turbidity was noticed during monsoon. During monsoon, all the rivers carry the wastes,

runoff water from upland areas and other suspended materials in to the wetland system.

Turbidity recorded an increasing pattern from river sites to abandoned field during summer and

monsoon and postmonsoon reported highest level in canals. Dewatering from rice fields resulted

in greater turbidity in canals. In the canal systems of Vaikom, Purakkad, Neendur, Karumady

and Kumarakom were mostly black in colour especially during cultivation period.

e. pH

In the present study, a wide range of pH has been recorded from different systems of

Kuttanad. In river systems, the pH ranged from 5.5 to 7.1 but in canal systems, it ranged from

3.2 to 8.8. pH of the Chalakkudy River (Nirmala and Shoba, 2003) ranged between 5.03 to 7

while in Chaliyar River (Joshil, 2003) it ranged from 5.5 to 8. The present study agrees with the

earlier reports on Kuttanad by Thomas et al. (2001) and Padmakumar et al. (2002). In Cultivated

field (CF) systems, the pH ranged from 5.4 to 6.8. Compared to other systems like river and

canals, CF showed higher values of pH.


116


The pH was alkaline in Kayamkulam wetland (7.2 - 8.2) and acidic to neutral in the

Parvathy Puthenaar canal of Thiruvananthapuram (Sooraj et al., 2002). Except the low pH

values of 2.4 reported from Karilands of Vaikom, the general trend towards the mean range of

around 6.2 to 6.5 almost throughout the year. In other wetland systems of Kerala like

Kattampally with 7.2 (Vaasu et al., 1998); Vellayani with 6.45 (Krishnakumar, 2002); Chelur

with 7.5 (Sreejith, 1996) and lake systems like Vembanad with 6.2 to 7.1 (Harilal et al., 2000;

Ouseph and Pillai, 2004) and Sathamkotta with 7.4 (Sreejith, 1996; Krishnakumar et al., 2005)

In conclusion pH of all Kuttanad wetland system ranges between 6.2 to 6.5.

f. Acidity

No studies on the acidity of any system of this part exist in literature, for a comparison.

Rivers have low acidity than cultivated fields and abandoned fields. Cultivated field showed

high acidity during the post-monsoon than other systems. Relatively high acidity in Vaikom kari

and some parts of North Kuttanad is mainly due to the leaching of acidity from the subsurface

kari soil during ploughing before cultivation (Mathew, 2004). Acidity showed an increasing

trend from river sites towards abandoned fields during summer. However postmonsoon acidity

was maximum in the canals due to dewatering from rice fields into canals for the beginning of

cultivation.

g. Alkalinity

The carbonate, bicarbonate, calcium and magnesium input resulted in high alkalinity of

Parvathy Puthenaar canal system at Thiruvananthapuram (Sooraj et al., 2002). Compared to

results (mean values) of the present study (6 to 52 mgCaCO3/L), KWE showed low alkalinity

similar to Vallayani (Krishnakumar, 2002)

h. Chloride

During premonsoon season, all the systems have comparatively high chloride value than

the postmonsoon and monsoon season which is due to the salinity intrusion from the

Vembanad lake. During monsoon season, the chloride gets diluted in all systems and showed an

increasing trend from postmonsoon to premonsoon season. Canal and cultivated systems have

comparatively high chloride value than other systems (Figure 4.13). Chloride varied between 72

to 330 mg/L in the Parvathy Puthenaar canal at Thiruvananthapuram which was highly

polluted due to city sewage (Sooraj et al., 2002). In the present study, river site at Kodimatha

(KODI) recorded 6 times greater values than the above report during premonsoon season.


117


Kayal land flushed by saline water intrusion showed chloride more than 2000 mg/L and

peak value of 2368.10 mg/L during premonsoon season. Achinakom site recorded the

maximum chloride concentration during postmonsoon season with 3715.16mg/L and this is

due to the saline water intrusion from Vembanad lake. River Kodurar at Kodimatha recorded

the high chloride (1843.4 mg/L) during premonsoon, however the downstream points (P3 and

P4), the concentration declined to one fifth of the upstream to 368.4 mg/L. This is due to the

sewage discharge of sewage from Kottayam municipality contributed to increased chloride

values.

It was generally found that the Upper Kuttanad (Thriperumthura, Pilapuzha and

Veeyapuram sites) and southern parts of Lower Kuttanad regions - Thakazhy, Kavalam,

Kidangara, Onnamkara (AC canal area) have low chloride concentration during premonsoon

season, clearly indicates lack of salinity intrusion in to these areas. The present study is in

agreement with the observations made in Cochin Backwater (Sankarnarayan and Quasim, 1969;

Manikoth and Salih, 1974), Pulicat lake (Kaliamurthy, 1973), Ashtamudi lake (Balakrishnan et

al., 1984) and Chilika lagoon (Panigrahi et al., 2007) where such constant decrease was reported

towards freshwater zones.

i. Hardness

The total hardness ranged from 0.0 to 700 mg/L. Total hardness in Parvathym

Puthenaar canal varied between 110 to 270 mg/L (Sooraj et al., 2002) and the present study

recorded 3 times greater than the reported value from Parvathy Puthenaar. According to Batram

and Ballance (1996), the total hardness is an index of water quality and is of considerable

significance in connection with the discharge of municipal and domestic sewage. In the present

study, the high value of 600 mg/L recorded from the Kodimatha site of river Kodurar. This site

receives municipal sewage and drainage from nearby workshops. Higher values of hardness

were reported in Yamuna river due to the confluence of sewage and paper mill effluents (Singh

and Gupta, 2004). Singh and Singh (1990) pointed that hardness of water can be related to the

discharge of sewage and effluent. In canal systems, it ranged from 0 to 700 mg/L. The higher

values were recorded from the Kayal land sites due to salinity intrusion during the premonsoon

season. Hardness showed highly significant correlation with chloride (r =0.90, p<0.01).

Hardness also showed low values during the monsoon season and similar observations

were made by Babu et al. (2009) in Asthamudi estuary. Thomas et al. (2001) reported that

hardness in Kayal land ranged from 17 to 562 mg/L but in the present study recorded

comparatively higher range.



Table 4.14: Comparison of water quality of Kuttanad with other wetlands of Kerala

Water quality

Parameters

Chalakudy

(Nirmala

and Shoba,

2003)

Vellayani

Lake

(Krishnaku

mar, 2002)

Vembanad

lake

(Nandan,

2005,

Kayamkulam

Wetland,

( Nandan, 2004)

Kattampal-

ly, (Vasu et

al., 1998)

Poonthura

Canal,

(Sooraj et

al., 2002)

Ashtamudy

estuary,

(Ramadevi

and Aziz,

1995)

Vembanad

lake (Ouseph

and Pillai,

2004)

Sasthamkotta

(Sreejith,

1996)

Kuttanad

(Thomas et

al., 2001)

Kuttanad

present work,

(Mean values)

Temperature

(OC) 21-33 - 29.7 26-29 - - 24 - 34 - - 33.64 27- 35

pH 5.03 -7 .9 6.45 6.8 7.6 - 8.2 7.2 6.1-7.0 1.85 - 7.55 6.2 7.4 5.01 - 6.93 5.7 - 7.1

TDS (ppm) 12 - 414 48 - 172 - 21-43 - 161- 633 - - 53.3 - 25 - 1058

DO (mg/L) 3.1 - 9.1 6.8 6.6 3.8-5.0 - 0-1.7 1.1 - 6 2.67 - 3.67 5.87 4.13 - 7.84 0 – 7.73

BOD (mg/L) 0.18 - 8.3 0.92-4.5 - - - - - 2.- 4.21 8.86 0.41 - 9.05 0.8 – 25.2

Alkalinity

(mg/L) 5 - 140 14-34.8 - - 64 104 -320 - 19.2 - - 14 - 50.67

Hardness

(mg/L) 6 - 254 14 - 28 - 3360-6300 5800 100-270 - 100 - 344 - 17.6 – 562.3 10.67 - 337.33

Nitrate

(mg/L) 0.04 - 21.8 - 0.087 0.002(µg) - 0.9-9.96 0.3 - 2.44(µg) 17.47 - 34 - 0.01 – 0.15 0.05 - 9.29

Phosphate

(mg/L) 0.002 - 4.04 0.07 0.02 0.1-0.05(µg) - 0.3-1.9 0.3 - 7.3(µg) - 2.01 0 - 0.01 0.02 - 4.88

Sulphate

(mg/L) 4.4 - 18.8 6.94 - - 2.2 2 - 64 - - 0.01 2.32 – 64.12 10 - 254

Chloride

(mg/L) 1.4 - 72 10 - 13 - - 16900 72 - 330 - - - 50 - 1500 11.3 – 2013.57

Conductivity

(mS) - 0.29 - 0.18 - 1.6 4.5 0.3 - 3.3 - 0.87 0.63 0.08 – 4.96 0.05 – 1.61

COD (mg/L) - - - 26.32

- - - - 36.8 – 353.65 10 - 380

‘-‘ No data


119


j. Dissolved Oxygen

Dissolved Oxygen is an index of the physical and biological processes in water. It is

moderately soluble in water and its solubility decreases with increase in temperature (Patil and

Goudar, 1985). Dissolved oxygen in aquatic ecosystems has the function of many

physicochemical parameters, which govern their solubility. The important biological processes

associated with oxygen distribution are photosynthesis, respiration and decomposition

(Hutchinson, 1967).

Comparatively monsoon recorded high dissolved oxygen than other two seasons due to

the mixing and dilution of flood water and rain. The saturation level of oxygen (10mgO2/L)

recorded from Neendur abandoned field and river site at Thottapally is due to the high

photosynthetic activity and liberation of oxygen by the submerged aquatic macrophytes. Even

during the premonsoon season, some sites showed high DO concentration (more than

7mgO2/L) and this is mainly due to the abundance of phytoplankton and submerged aquatic

plants in the study area which liberates high amount of oxygen in to the system. Similar

observations were made by Pal and Mohanty (2002); Panigrahy et al. (2007) at Chilika lagoon,

Kaladharan et al. (2005) in river Periyar. Generally river sites have comparatively greater

dissolved oxygen concentration than other sites, due to mixing and turbulence and water being

open, oxygen gets dissolved from atmosphere.

Anoxic condition was also reported by Sooraj et al. (2002) from Parvathy Puthenaar

canal system at Thiruvananthapuram city. In the present study, sites receiving municipal sewage

like Kodimatha (KODI) and ACC1 showed anoxic condition. Anoxic conditions have been also

recorded in abandoned fields covered by Eichhornia, Salvinia and other floating macrophytes.

The floating mats prevent the submerged macrophyte growth and the mixing of water with

atmosphere. The high decomposition of organic matter also reducing the DO level in the

abandoned fields.

k. Biochemical Oxygen Demand (BOD)

BOD is of great significance in water quality assessment and it accounts for organic

matter present in the system and the quantity of oxygen required for the stabilization. Batram

and Ballance (1996) advocated that the decomposition of organic matter is an important factor

in the consumption of DO. Kuttanad Water balance study (1989) reported that the water near

Alleppy was greatly polluted and BOD values were 10 – 20 mg O2/L. In the present study, the

BOD levels in Kuttanad were mostly less than 5 mg O2/L among 90% of the samples. It

exceeded 10 only in few samples. The peak value 43.2 mgO2/L recorded from Pallom receiving

effluents from a factory and domestic sewage. In Chalakudy river, the BOD ranged from 0.18 to


120


8.3 mgO2/L (Nirmala and Sobha, 2003). High BOD values of 30.49 mgO2/L were reported

from river Karamana by Jayaraman et al. (2003) and was due to the input of organic wastes. The

results of the present study also exceeded the values from Karamana river. Previous study of

Thomas et al. (2001) reported the maximum BOD value of 9.05 mgO2/L from the kayal land

sites of Kuttanad and the present study recorded a maximum of 14.4 mgO2/L from the same

site, indicates the higher values than the previous study.

l. Chemical Oxygen Demand (COD)

COD is the reliable parameter in judging the extent of organic pollution (Abbasi, 1997).

In river systems, the COD values ranged from 10 to 360 mgO2/L. The maximum recorded

from the Kodurar at Kodimatha site during the premonsoon season. At Pallom, it declined to

120 mgO2/L during the same season. The mean values were higher at Thottapally site, which is

located at the downstream of Achenkovil river. The river carries all the wastes into Kuttanad,

which gets later accumulated in the downstream sites and discharged through the barmouth.

Among the canal sites, Kumarakom site recorded the maximum of 610 mgO2/L during

postmonsoon season. The site also lies in the downstream of Meenachil river and during

postmonsoon season, the water was almost stagnated and the salinity intrusion decays the

aquatic macrophytes. The decay of aquatic macrophytes and other organic wastes attributed the

high COD in water.

Higher values of COD were noted during premonsoon and showed a declining trend

during the monsoon. The abandoned fields recorded the maximum COD values than all other

systems of Kuttanad. The decaying of organic matter especially the macrophytes were the

reason for high COD values during premonsoon and post monsoon season. The monsoon flood

water flush out the organic materials into the Vembanad Lake resulted the low COD values

during monsoon. The higher values of COD due to organic waste were reported by Gloyna

(1971), Kudesia and Verma (1986), Saxena (1990), Gautam et al. (1989) and Gautam (1990).

COD in Kuttanad exceeded the values reported from other wetlands; 1 to 17 mgO2/L from Kol

lands of Thrissur, (Table 4.14). Previous study of Thomas et al. (2001) reported the COD value

ranged from 36.08 to 353.6 mgO2/L from Kuttanad and the present study exceeded two times

greater value of 610 mgO2/L from a polluted canal site at Pallom. In the present study, the

maximum COD value from river systems showed similar value of the previous study. Organic

waste accumulation in abandoned field resulted in the formation of floating islands in Kuttanad

(John et al., 2009).

m. Nitrate (NO3-)

Atmospheric deposition, agricultural practices, import from livestock, atmospheric N2

fixation and sewage are the main sources of nitrogen and phosphorus influx to watercourses


121


(Moreau et al., 1998). The primary source of nitrate in water systems usually comes from

nitrogen, a common plant nutrient supplied by inorganic fertilizer and animal manure (Nolan,

2002). Other sources of contamination include deposits from airborne nitrogen compounds

emitted by industry and automobiles (Nolan, 2002). Nitrate was comparatively high during the

monsoon season in river systems and was due to the runoff from the upland and the mixing of

water from the nearby paddy fields. Nitrates from the agricultural lands were carried to the

waterways through the runoff or seepage due to their high solubility and the low sorption on soil

materials (Klapper, 1991). Rainfall was supposed to be responsible for increasing the nitrates in

water (Nandan and Patel, 1992). Hussain and Ahmed (2002) made similar observations in

Pachin river, Itanagar. The similar trend also noted in the canal systems of Kuttanad. The

sources of nitrate in Kuttanad mainly due to nitrogenous fertilizers applied in the paddy fields as

well as sewage discharge (Thomas et al., 2001) and Piyankarage et al. (2007) reported the similar

observations in Bundala Ramsar site in Sri Lanka.

Nitrate in Parvathy Puthenaar canal ranged between 0.34 to 1.93 mg/L due to the

sewage inflow from Thiruvananthapuram city (Sooraj et al., 2002). Suchindan et al. (1999)

reported the nitrate value ranged from 0.17 to 0.34 mg/L from Vembanad lake near

Kumarakom and Padmakumar et al. (2002) recorded the nitrate value of 0.20 mg/L from

Vembanad lake. Compared to the previous study of Thomas et al. (2001), the nitrate

concentration in the present study showed 10 times increase which ranged from 0.05 to 16.30

mg/L (mean value of 9.29 mg/L). Previous studies are confined to the canal systems and there

were no study on abandoned fields to compare. In canal systems, the nitrate ranged from 0.04 to

12.4 mg/L, which was also higher than the previous reports. The excess application of

nitrogenous fertilizers in the paddy fields and the organic decomposition caused the high nitrate

levels in waters of Kuttanad (Nair and Varma, 2002).

Many investigators reported a gradual rise of nitrate concentration in Cochin backwaters

(Sankarnarayanan and Quasim, 1969; Devassi and Bhattathiri, 1974; Remani et al., 1983;

Lakshmanan et al., 1987; Balachandran, 2001) due to sewage and industrial effluents. However,

compared to Cochin backwaters (0.0 to 0.206 mg/L; Joseph and Ouseph, 2009), the nitrate level

in the abandoned fields of Kuttanad is comparatively high during the postmonsoon season.

Compared to other systems, abandoned fields have higher level of nitrate throughout the season.

These systems were receiving the nutrient enriched water from the paddy fields and the anoxic

condition of the system accelerates the mineralization of organic nitrogen into ammonia by the

ammonification process (Horne and Goldman, 1994) due to relatively less mixing of water and

air. The decaying of aquatic macrophytes can also increase the high level of nitrate-nitrogen in

these systems (Williams et al., 2005; Yidana et al., 2008).


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n. Phopshate (PO4-)

The primary sources of phosphate are anthropogenic activities like sewage, agricultural

run-offs and detergents (Wangsness, 1994). Phosphate is a growth limiting nutrient for plants.

Similar to nitrate, excessive phosphate in natural water bodies often spurs rapid algae growth,

resulting in eutrophication (Ramachandra et al., 2002).

Kuttanad wetland ecosystem recorded the high values of phosphate ranged from 0.02 to

13.79 mg/L. Phosphate concentration of other wetlands in Kerala were compared with present

study (Table 4.14). From Vembanad lake, Nandan (2005) reported 0.02 mg/L and much greater

values (0.002 - 4.04 mg/L) was reported from river Chalakkudy (Table 4.14). Other wetland

sites of Kerala like Asthamudi with 0.06 mg/L (Remadevi and Abdul Aziz, 1995), Vellayani

with 0.07 mg/L (Krishnakumar, 2002), Sasthamkotta with 2.01mg/L (Sreejith, 1996 and

Krishnakumar et al., 2005), Chelur with 0.03 mg/L (Sreejith, 1996) and the present study also

showed similar ranges except 2.20 to 13.79 at some sites. The nutrient enriched water from the

paddy fields were pumped out in to the nearby canal system during the cultivation is a common

practice in Kuttanad which increase the phosphate level more than 1mg/L in many sites.

Phosphate was comparatively low in river systems and the seasonal average of all sites showed

the peak concentration during premonsoon season. Mixing and dilution of water resulted in the

low concentration of phosphate in river systems. The present study is in agreement with

previous studies of Thomas et al. (2001). Abandoned fields also showed high phosphate level

during premonsoon season and was due to the organic matter decay in these systems.

o. Potassium (K)

In acidic soils potassium deficiency is common at low pH of 4.5 to 5.5. In Kari soils

(acid sulphate soils with pH<4.5) the organic carbon comprise 0.75 % combined with Fe

toxicity and K deficiency (Ponnamperuma, 1972; Ramanathan et al., 1997). Seasonal variation

of potassium concentration showed peak values during premonsoon in all the systems and the

maximum values were recorded from the cultivated field and canal systems. Potassium

concentrations in cultivated fields were comparatively high due to the application of fertilizers

and manures during cultivation and get diluted in to the water. During cultivation, this water

pumped out in to the nearby canals for maintaining the water level in fields, which causing the

high potassium in canal systems. The potassium concentration also showed the similar trend as

nitrates and phosphates which clearly indicates the sewage pollution in the canal and the

influence of agricultural runoff from the nearby paddy fields.

Sankaranarayanan and Panampunnayil (1979) attributed unabated domestic waste

disposal caused the degraded water quality in the Cochin estuary. Balachandran et al. (2005)

also pointed out that freshwater run-off from Periyar river was one of the sources of nutrients in


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the Cochin Estuary. Similar observations were made in the present study and in Kuttanad, the

domestic sewage from the households situated over the bunds discharging their wastes into the

canal systems. During premonsoon season, the stagnation and low water level increases the

pollution load in the canal systems.

p. Sulphate

The soils of Kuttanad are genrally enriched termed as acid sulphate soils enriched with

iron, aluminium and sulphate in nature (Van Breemen and Pons, 1978; Mathew et al., 2001)

which is reflected in the sulphate concentration of water especially areas where water is pumped

out from rice fields. The high concentration of sulphate is toxic to plants especially to rice

(Ponnamperuma, 1978; Mathew et al., 2001). Among the river systems, Meenachil river at

Kumarakom (KR1) showed high sulphate during premonsoon in comparison to other river sites.

Cultivated fields and canal systems have comparatively high sulphate than other systems which

can be attributed to the ploughing of subsurface soil during cultivation which liberates the

sulphate in to the soil (Mathew, 2003; Thampatti and Jose, 2005) later reaches the canal system

through pumping. In general, during premonsoon all the systems have high sulphate values

compare to other seasons. Comparatively Kari lands recorded high sulphate concentration

throughout the study. The seasonal salinity intrusion also enhances the sulphate level in water

and soil of wetlands (Ramanathan, 1997).

4.6.2 Bacteriological parameters

The faecal coliform count in all systems throughout the season was always high. The

faecal coliform counts ranged from 1100 to 116500 MPN/100 ml. Maximum faecal coliform

(FC) counts were recorded from Pampa river during postmonsoon season. FC in Pampa river

clearly indicated the high faecal pollution during the Sabarimala pilgrimage season (November

to January). During Sabarimala pilgrimage season, approximately two million people cross the

Pampa river to reach the hill shrine and the river turns into a cesspool of human waste, raw

sewage, and domestic and commercial garbage. Because pilgrims defecate on the river banks

and in the vicinity for miles together, faecal matter gets washed into the river water and sinks in

the wetlands of Kuttanad.

A very significant and distinct aspect of the present study was the very high load of FC

and FS during monsoon at most river systems (110000 MPN/100ml). During postmonsoon,

high values were reported at Pampa from both Thakazhy and Veeyapuram out of all sites.

Premonsoon recorded the least values. Nair and Varma (2002) reported maximum coliform

counts of 12000/500ml from Kumarakom during monsoon and Suchindan et al. (1999) reported

the E. coli of 5000/500ml in water samples from Kumarakom. All these values are very low


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compared to the present study. In the canals and cultivated fields, FC values were higher during

monsoon and premonsoon (110000/100ml). The results of the present study showed 10 times

greater compared to that of values (12000/100 ml) reported from Kumarakom (Nair and

Varma, 2002). Compared to canals of Thrissur, the present results exceed 100 times in monsoon

during which most of the bacterial borne diseases and viral related disease such as Dengue and

Japanese fever are prevalent every year. Thomas et al. (2001) reported the maximum faecal

coliform count of 70000 MPN/100ml from Kuttanad during May and premonsoon season

recorded the higher values of FC and E. coli. But the present study recorded the FC values

>100000 MPN/100ml from most of the sites especially during the monsoon season.

During the monsoon season, both river and canal systems have high amount of faecal

coliform and faecal streptococci counts. It was due to the increased land run off during monsoon

season resulted in the high bacterial population of the wetland system. Studies of Abhirosh et al.

(2008) in both sides of Thanneermukkom barrage in Vembanad lake also recorded the results

>12000 MPN/100ml. Another study carried out by Hatha et al. (2003) revealed that prevalence

of indicators of faecal pollution such as faecal coliform and faecal streptococci in Cochin

estuary. They observed consistently the high load of faecal indictor bacteria at all sampling

stations. Seasonal variations in the prevalence level of these organisms showed a higher load of

indicator organisms during the monsoon season, especially those of FS indicated higher land

run off during this period. The results of the present investigation revealed the high degree of

faecal pollution in Kuttanad wetland ecosystem will pose health hazards.

In Kuttanad, the abandoned fields near roadsides were became the illegal waste

dumping sites. Animal carcasses, septic tank wastes and market wastes were dumped into these

water bodies without any discrimination. This promotes the proliferation of pathogenic and

indicator bacterial population in Kuttanad. This effect reflected in the results of FC and FS at

different systems without any significant variation in its population (p>0.05). The results of the

present study were comparatively higher than those reported by Lakshmanaperumalsamy et al.

(1981) in Vembanad Lake and Mandovi Zuary estuary of Goa.

FC/FS ratio, which is a qualitative pollution index, is a useful measure in determining

the source of faecal pollution. FC/FS ratios >4.4 indicate that the faecal contamination is of

human origin (EPA, 1978). In Pampa, the FC/FS ratio was 52.38 during postmonsoon season

which indicated the human faecal contamination. During monsoon season, the FC/FS ratio less

than 4 indicated the faecal contamination were not by human origin.

V. cholerae like organisms (VCLO) were comparatively high in Achenkovil during

monsoon season with 390 cfu/ml. Generally VCLO counts were higher during premonsoon


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season in both river and canal sites while it showed higher values during premonsoon from both

cultivated and abandoned field systems. VPLO counts were higher during premonsoon season

in all the systems and peak value was recorded from cultivated field system. Pseudomonas spp.

were comparatively higher in Achenkovil river during monsoon season. Increase of Pseudomonas

spp. counts during monsoon season was reported by Pradeep and Lakshmanaperumalsamy

(1986) and Chandrika (1983) from Cochin estuary. The presence of these pathogenic bacteria

may pose serious health hazard to human population (Borrego and Figueras, 1997).

Pseudomonas aeruginosa, a dominant bacterial species can cause a wide range of diseases such as

urinary tract infections, respiratory diseases (especially people with cystic fibrosis), ear and eye

infections as well as a wide range of systemic diseases such as bacteraemia, osteomyelitis and

meningitis (EPA, 1978; ).

The bacteriological data reported by Thomas et al. (2001) showed E. coli counts between

100 to 1700/100 ml, faecal coliforms between 1300 to 70000/100 ml and Klebsiella 100 to

2300/100 ml. The Pseudomonas counts were high and ranged between 10 to 2700/100 ml. In the

present study, the results of FC, FS, VCLO, VPLO and Pseudomonas were higher than reported

values of Thomas et al. (2001) from Kuttanad and Abhirosh et al. (2008) from Vembanad lake.

The WHO Guidelines determine that usable and safe bathing water can have a

maximum of 500 coliforms per 100 ml. The water samples from Kuttanad contained an average

of over 1,600 MPN/100 ml which has not included the count for other coliforms. In addition to

gastro-intestinal diseases, specific waterborne diseases namely Enteric Fever, Typhoid,

Hepatitis, Jaundice, Weil‟s diseases (Leptospirosis), Cholera, Japanese Encephalitis and

Amoebiasis have been cited as frequent epidemics in the Kuttanad region (Padmakumar, 2007;

Gregory, 2003; Christina, 2009). These are diseases caused by faecal contaminations or via

vectors such as mosquitoes or rats. The health impacts of using such water for bathing and in

some cases drinking in Kuttanad are disturbing. In Kuttanad, water borne diseases are endemic

and they occurring mostly during the onset of monsoon (Padmakumar, 2007). As per the results

of the present study, the bacterial population was higher during the monsoon the there was

significant seasonal variations in FS and Pseudomonas spp.

A survey of 217 families in Kuttanad found that 31% of the families have no special

arrangement of waste disposals; they either litter the wastes on the premises or discard them into

the river (Gregory, 2003). In addition, only 53% of the families have septic tanks, 38% have

other kinds of latrine facilities and the remaining 9% of families have no latrine facilities at all

(Gregory, 2003). During the flood period, the hydrology level increases and it leads to the

mixing of water with the faecal matter in the septic tank. Open defecated faecal matter also

mixed with the flood water and this leads to the severe microbial pollution which causes the


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prevalence of bacterial diseases during monsoon. After the construction of Thaneermukkom

barrage and Thottappilly spillway, the salinity intrusion into Kuttanad was prevented and this

helped the prevalence of bacterial diseases and other ecological problems (MSSRF, 2007).

During summer season (premonsoon), there was no flow and stagnant condition prevailed in

this wetland system. The booming of tourism, house boat operations and indiscriminate

discharge of household wastes and faecal matter into the water bodies of Kuttanad caused the

increased level of bacterial pollution. This condition also ruins the ecological resilience of the

system.

4.7 Conclusion

The present detailed investigation of Kuttanad wetland is a pioneer study of the water

quality of the different systems covering the (1) Kayal lands comprising reclaimed lands from

Vembanad lake, (2) the two Kari lands namely Purakkad (southern) and Vaikom (northern) and

(3) Karappadoms of central Kuttanad mainly in Alappuzha and Kottayam districts.

1) The most distinct aspect of KWE was the high acidity all over the area showed declining

trend during monsoon and increasing during premonsoon which highly varied between

rivers, canals, cultivated fields and abandoned fields.

2) The water temperature showed a significant increase in the cultivated fields exceeding

35OC (mostly 33-35OC), the maximum reported from the entire Kuttanad region and this

point towards a climatic shift to higher water temperature which directly impact the

biota.

3) From very low values (29 ppm), the TDS increased 600 times (1864 ppm) in different

systems of Kuttanad and the maximum from the abandoned fields.

4) Conductivity increased several folds (36 times) between different systems and seasons

ranged from 0.05 to 3.64 mS.

5) Highly turbid water is the characteristic of this wetland due to release of organic matter

which renders a black colour to the water especially in kari lands. The variation between

seasons and systems are 30 times – maximum from cultivated fields – supporting

macrophyte vegetation year round except for 3 – 4 months of cultivation.

6) The pH was acidic in nature and the highly acidic pH of 2. 9 to 3.5 were recorded from

the Kari lands. Other sites have the range between 5.6 to 6.8.


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7) The acidity varied 80 times between the canal systems from 4 mgCaCO3/L to 320

mgCaCO3/L i.e. AC canal and Vaikom kari (VA1) sites respectively.

8) The mean alkalinity was <30 mg/L which indicating deficiency of carbonates and

bicarbonates in this system.

9) Saline water intrusion resulted in increased chloride levels at Kayal lands and Kari

lands. The hardness also recorded a similar fluctuation pattern as chloride between sites.

10) High DO levels were correlated to low BOD and vice versa at sites receiving sewage

especially at river Kodurar at Kodimatha, canal site at Pallom (P6) and ACC1 site at AC

canal.

11) The COD recorded significant variation between canals and exceeded 31 times in

comparison to other systems due to the impact of sewage and organic decomposition.

12) Compared to the previous reports, the nitrate concentration was higher in the present

study and abandoned fields recorded the peak values. The excess application of

nitrogenous fertilizers in the paddy fields and organic decomposition caused the high

nitrate levels in the waters of Kuttanad.

13) The sulphate levels in water varied 40–53 times between the different canal systems

during premonsoon and postmonsoon seasons. The high sulphate values were recorded

from the kari land and kayal land sites due to the leaching of sulphate from the acid

sulphate soil.

14) The faecal coliform and faecal streptococci load was higher during monsoon season in

river and canal systems of Kuttanad resulted due to the land run off and sewage

pollution.

15) VCLO and VPLO counts were higher during the premonsoon season and Pseudomonas

counts exhibited higher values during monsoon season.

16) FC/FS ratio showed that the human faecal contamination was the major factor behind

the bacteriological pollution in Kuttanad especially during the premonsoon and

postmonsoon season.

17) The booming of tourism, house boat operations and indiscriminate discharge of

household wastes and faecal matter into the water bodies of Kuttanad caused the

increased level of bacterial pollution. This condition also ruins the ecological resilience

of the system.

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