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CHAPTER III

TRACE METALS

3.1 INTRODUCTION

Heavy metals are metallic elements which have high atomic weight and have

much higher density at least 5 times than that of water. Heavy metals include most of

the metals with atomic number greater than 20. The expression ‘Trace elements’ is

applied to designate the heavy metals which occur in small concentrations in the

natural and biological systems. Heavy metal compounds are water soluble, non-

biodegradable toxic pollutants. The untreated industrial effluents which directly

converse with water bodies consist of metals like copper, zinc, lead, mercury, iron,

manganese and chemicals like acids and alkalis (Southwick, 1976).Trace metals

associated with aqueous systems and their concentrations under different conditions

were investigated by several researchers. Of the various pollutants, heavy metals form

an important toxic substance released into the aqueous ecosystems from industrial and

sewage wastes. Heavy metals are inorganic elements essential for plant growth in

traces or very minute quantities. They are toxic and poisonous in relatively higher

concentration. The common sources of heavy metals are from dead and decomposing

vegetation, animal matter, wet and dry fallouts of atmospheric particulate matters and

from man’s activities. Heavy metals in the aquatic environment exist in sediment and

suspended particulate. They are stable elements and, they cannot be metabolized by

the body and are bio-accumulative and passed up the food chain to the higher animals

in the food chain. There are over 50 elements classified as heavy metals but only 17

of them are considered to be both very toxic and relatively accessible. In India, water

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sources are polluted approximately 20% by industrial effluents and the rest by

untreated sewage (Sabata et al., 1995). They are highly toxic and can cause damaging

effects even at very low concentrations. Increasing urbanization has also increased the

levels of trace metals, especially heavy metals in water ways.

The growth of science and technology over the world has led to the

establishment of various industries and helped industrial, technological and

agricultural development of many nations. As a result, pollution of our environment

with waste generated from these industries has become a problem of major

environmental concern. Heavy metals pollution is one of these problems because

these metals tend to persist in nature, and are non-biodegradable, highly toxic and

tend to accumulate causing different health problems to plants, animals and humans.

(Ceribasies and Yetis 2001). In recent years there has been an increasing interest in

trace metal concentration in estuaries, rivers, lakes and the path way by which they

are introduced into the system. Though metals have been used since the dawn of

civilization, the use of metal has increased considerably with the phenomenal growth

of industries. The increased use of metals has resulted in the wide spread

contamination of the environment.

These wastes affect the physico-chemical quality of water, making it unfit for

use of livestock and other organisms (Diwedi et al., 2002).The metal ions are

abundant in nature and readily available as soluble species. The role of metal ions in

the living systems follows the pattern of the availability and abundance of such metals

in nature (Vahrenkamp, 1973, Williams 1967). Evidences show that no organic life

can develop and survive without the participation of metal ions. To facilitate life

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processes the living organisms including man require many metals and hence many of

the metals are essential for all life forms. As heavy metals cannot be degraded, they

are continuously being deposited and incorporated in water, sediment and aquatic

organisms. (Linnik and Zubenko., 2000). Contaminated sediments can threaten

creatures in the benthic environment, exposing worms, crustaceans and insects to

hazardous concentrations of toxic chemicals. Some kinds of toxic sediments kill

benthic organisms, reducing the food available to larger animals such as fish.

Some contaminants in the sediment are taken up by benthic organisms in a

process called bio-accumulation. When larger animals feed on these contaminated

organisms, the toxins are taken into their bodies, moving up the food chain in

increasing concentrations in a process known as biomagnifications. As a result, fish

and shellfish, water-fowl, and fresh-water and marine mammals may accumulate

hazardous concentrations of toxic chemicals. Contaminated sediments do not always

remain at the bottom of a water body. Anything that stirs up the water such as

dredging, can resuspend sediments. Resuspension may mean that all of the animals in

the water, and not just the bottom dwelling organisms, will be directly exposed to

toxic contaminations.

Different aquatic organisms often respond to external contamination in

different ways, where the quantity and form of the element in water, sediment or food

will determine the degree of accumulation. The region of accumulation of heavy

metals within fish varies with route of uptake, heavy metals, and species of fish

concerned. Their potential use as biomonitors is therefore significant in the

assessment of bioaccumulation and biomagnifications of contaminants within

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ecosystem. Many dangerous chemical elements, if released into the environment,

accumulate in the soil and sediments of water bodies. The lower aquatic organisms

absorb and transfer them through the food chain to higher trophic levels, including

fish. Under acidic conditions, the free divalent ions of metals may be absorbed by fish

gills directly from the water.

Hence, concentrations of heavy metals in fish are determined by the level of

pollution of the water body. Chemical elements are accumulated in the sediment, thus

soil or sediment can become a secondary source of heavy metal pollution (Abida

Begum et al., 2009). The heavy metals in the brackish water phase generally deposit

on the sediment bed or remain in dissolved state in the water column, depending on

the nature of the chemical species which are influenced by factors like aquatic

salinity, pH etc (Chakraborty et al., 2009). Thus the study of toxic and trace metals in

the environment is more important in comparison to other pollutants due to their non-

degradable nature, accumulation properties and long biological half lives

(Sadasivan and Tripathi.,). Heavy metal toxicity can result in damaged or reduced

mental and central nervous function, lower energy levels, and damage to blood

composition, lungs, kidneys, lever and other vital organs. Long-term exposure may

result in slowly progressing physical, muscular and neurological degenerative

processes that mimic Alzheimer’s disease, Parkinson’s disease, muscular dystrophy

and multiple sclerosis. Allergies are not uncommon and repeated long-term contact

with some metals or their compounds may even cause cancer (International

Occupational Safety and Health Information centre 1999).

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The association of symptoms indicative of acute toxicity is not difficult to

recognize because the symptoms are usually severe, rapid in onset, and associated

with a known exposure or ingestion cramping, nausea and vomiting, pain, sweating,

headaches, difficulty in breathing, impaired cognitive, motor and language skills,

mania and convulsions. The symptoms of chronic exposure are easily recognized;

however they are very similar to symptoms of other health conditions and often

develop slowly over months or even years. Lead and Mercury exact their most

devastating toll on the developing brain. Children with above average mercury

exposures have learning difficulties. The metals introduced into the system do not

remain in water column. Dissolved metallic ions get precipitated or adsorbed by

suspended particulate matters. Trace metals transported by rivers to the coastal and

estuarine system are in dissolved, colloidal and particulate forms. The magnitude of

the problems associated with chemical discharges into sea and river came with the

diagnosis of Minamata and Itai-Itai diseases due to mercury (Irukayama et al., 1961)

and Cadmium (Kobayashi, 1970) poisoning respectively.

Copper compounds are used in fungicides, insecticides and in fertilizers as a

nutrient to support growth. Copper is essential for proper functioning of enzymes such

as superoxide dismutase, ceruloplasmin, cytochrome-c oxidase, tyrosinase,

monoamine oxidase. The lethal dose of copper lies between 43 and 400mg of copper

(II) per kg body weight. Maximum contaminant level goals from Safe Drinking Water

Act 1974, says 1.3 mg/l or 1.3ppm is the maximum permissible limit for copper in

fresh water.

Zinc is an essential and beneficial element for human beings. Zinc acts as

Levis acid catalyst in all life processes. Meat and fish provide the best sources of zinc.

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It is a vital component of many metallo-enzymes such as carbonic anhydrase which

regulates CO2 exchange (Shukla et al., 1992). Zinc may also be involved in stress

response by influencing glucose metabolism. It is a very important element in the

reproductive cycle of species. The most important sources of zinc in ground water are

discharge of smelter slag; mine tailing, coal and bottom fly ash. Concentration of zinc

beyond the permissible limit in water may create opalescent state and develop a

greasy film on boiling (Shrivastava, 2010). Zinc chloride can cause nose and throat

irritation, cough, chest pain and fever (ITII, 1998). However above 5 mg/l causes

bitter taste to water (Schenker et al., 1981). High dose of zinc in water is also toxic to

plants. Zinc has many biological functions, the best known being that of a cofactor in

the enzyme carbonic anhydrase. Excessive studies have been carried out on the uptake

of Zn by marine organisms. Some species take up rapidly several thousand times the

concentration of that of the surrounding sea water. There is a little knowledge of the

form in which Mn and Zn occur in sea water or in which they are utilized by

organisms. An understanding of the limiting effects of these elements on growth in

the sea and the mechanism of geochemical deposition requires identification of the

chemical forms and the total amounts present.

Iron is the fourth abundant transition element on earth. It can enter into a water

system by leaching natural deposits and acidic mine drainage. Water containing iron

greater than 2 mg/l causes staining of clothes, corrosion to plumbing works, gives

odour to drinking water, imparts unpleasant bitter astringent taste to water and

encourages the growth of iron-bacteria (Chaturvedi et al., 1999). Iron in trace quantity

is essential for nutrition. Iron deficiency leads to anemia and hence larger doses are

taken for therapeutic reason. Iron is important for cell respiration, reduction of nitrate

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and sulphate in nitrogen assimilation (Tandon, 1993). The adult daily requirement of

iron is 1 to 2 mg.

The weathering of iron and manganese bearing minerals and sewage effluents

are the main sources of iron and manganese content in water (Berner et al., 1987).

Manganese ion is likely to be related from minerals along with Fe2+

(Liprot, 1989).

Manganese is dissolved from shale and sand stone. It is an essential trace nutrient for

plants and animals. Manganese is important for nitrogen metabolism and CO2

assimilation (Tandon, 1993). WHO (1984) estimates an average daily requirement of

3 to 5 mg for normal physiological function. The relative concentrations of these

elements in ground water are controlled by the solubility of their sources (Mahan,

1966). Manganese deficiency is characterized by defective growth and abnormalities

in mammals. Measurements of the concentration of Manganese in the overlaying sea

water will help to explain the source of origin of the concentration of Mn in deep

ocean sediments. Trace elements are probably precipitated to at the bottom through

chemical and biological processes. The wide distribution of Mn in biological

materials indicates that it is necessary for biological functions, (Harvey, 1955).

Nickel is a metal of wide spread distribution in the environment: there are at

most 100 minerals of which it is an essential constituent and has many industrial and

commercial uses. Nickel and nickel compounds belong to the classic noxious agents

encountered in industry but are also known to affect non-occupationally exposed

individuals. The general population may be exposed to nickel in the air, water and

food (Cempel, Nickel 2006). Inhalation is an important route of occupational

exposure to nickel in relation to health risks. Most nickel in the human body

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originates from drinking water and food; however, the gastro intestinal route is of

lesser importance, due to its limited intestinal adsorption (WHO/UNEP, 1989). The

toxicity and carcinogenicity of some nickel compounds is found (in the nasal cavity,

larynx and lungs) in experimental animals, as well as in the occupationally exposed

population are well documented.

Lead is one of the oldest metals known to man and is discharged in the surface

water through paints, solders, pipes, building material, gasoline etc. Lead is a well

known metal toxicant and it is gradually being phased out of the materials that human

beings regularly use. Combustion of oil and gasoline account for greater than 50% of

all anthropogenic emissions and thus form a major component of the global cycle of

lead. Atmospheric fallout is usually the most important source of lead in fresh water

(Ayele et al, 1993). The excess of lead content is also due to the runoff from

agricultural fields where phosphorus fertilizers are applied, in which lead is one of the

impurities (Ramachnadra, 2006). Lead salts enter the environment through the

exhaust of cars as particulates and the larger particles will drop to the ground

immediately. The smaller particles will travel a longer distance through the air and

remain in the atmosphere. When it rains, part of this lead will fall back on earth and

this Pb-cycle resulted from human production is more extended than the natural Pb-

cycle (Edwards 2010). Lead poisoning has various long-term negative health effects.

It is important to identify the sources of such pollution and to devise methods to

eliminate the contributing factors. Lead content in water as per various surveys and

investigations conducted by organizations such as “Quality Council of India”, shows

the presence of lead in water in India. The WHO standards for lead content in water

should be less them 10ppb.

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Surface waters are sinks for heavy metals that continuously wash off rocks and

soils that are directly exposed to surface waters. The common sources of heavy metals

are from dead and decomposing vegetation, animal matter, wet and dry fallouts of

atmospheric particulate matters and from man’s activities. The role of trace metals in

biochemical life processes of aquatic plants and animals and their presence in trace

amounts in aquatic environment are essential. However, at high concentrations, these

trace metal become toxic. Heavy metals in the aquatic environment exist in sediment

as suspended particulate. In the present study, an effort has been made to assess the

extent of pollution in the few fresh water tourist spots and few coastal tourist areas of

Kanyakumari District of Tamil Nadu. The trend of heavy metal pollution in

Kanyakumari District is on the increase day by day. As the inhabitants of

Kanyakumari District depend on the river system for irrigation, drinking, bathing and

other requirements, an environmental monitoring particularly in relation to chemical

pollutants becomes highly imperative. The water and soil samples collected from

different stations were analyzed to find out the concentration of copper, iron, nickel,

zinc, manganese, lead, chromium, mercury and cadmium.

3.2 REVIEW OF LITERATURE

There is voluminous accumulation of literature on the toxicity of heavy metals

in fresh water. Toxic chemicals attack the active sites of enzymes and inhibit essential

enzyme function (De, 1994). Lot of literature are available in the detailed

investigations of heavy metal contamination in the groundwater samples and their ill-

effects on humans. Heavy metal poisoning has been reported to give rise to a quite

number of chemical syndromes. The contribution of Brooks et al. (1967) was

noteworthy in the field of methodology development for the study of heavy metal

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distribution in water and biota.Rehina et al. (1989) compared the water quality of

Kuttiadi river basin and Mananchira pond and stated that iron and aluminum in

Kuttiadi and aluminium in Mananchira exceeded the permissible limit and reported

that water from Kuttiadi river was not ideal for drinking water. Ouseph and Nair

(1989) carried out their work in Cochin estuary and reported the concentration of

dissolved and particulate heavy metals and its relation with salinity and they reported

higher concentrations of heavy metals during premonsoon season. Tarvainen (1997)

noted the increase in concentrations of cadmium, arsenic, chromium, zinc and nickel

than copper and reported the high concentration of lead and manganese in the small

lakes than in the stream.

Alain et al. (1994) in his work on Lot rivers of south western France

generalized that the river water was significantly contaminated with zinc, lead and

cadmium at low concentration. The physico-chemical and biological impact of rubber

factory effluents was assessed by Thampi Jayaraj (1996) and he reported that the

concentrations of heavy metals like copper, zinc, iron and manganese were found to

be high in Pazhayar river at Keeriparai, a high land region.

Rashmi and Jain (1998) investigated heavy metal contamination in

Kerwandam water at Bhopal and found that the presence of iron and lead were more

than the permissible limit which may be due to acid battery manufacturing industries,

lead bearing paints and municipal wastes in and around the area. Occurrence of heavy

metal in lentic water of Gwalior region has been calculated by Kaushik et al. (1991).

Seasonally lowest and highest values of all the parameters (except arsenic) were

recorded during summer and in rainy seasons. They explained that the values of all

the heavy metal concentrations were found to be below the limit.

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Evans et al. (1973) studied the release of trace metals to the overlying water

column due to desorption process. Coombs (1975) discussed the significance of multi

element analysis in metal pollution studies. Goyal et al. (2004) analysed metal content

in drinking water samples from Aligarh District. The chemistry of heavy metals and

their influence on the chemistry of suspended particles in the Mediterranean Sea was

reported by Chesselet et al. (1979). Their report strongly supported the assumption

that the solubility of zinc, cadmium, copper and nickel are greatly enhanced and

controlled by the formation of bisulphide and polysulphide complexes.

Variations in chemical forms of iron, manganese and zinc in the suspended

sediment were investigated by Schoer et al. (1983). Heavy metals play an important

role in the environmental pollution (Moore et al., 1984). Pragatheeswaran et al.

(1986) reported increased metal concentration in coastal areas and this was due to the

discharge of agricultural and domestic wastes. Industrialization, especially industries

located near the river and coastal areas, poses a threat by the discharged effluents

thereby affecting the quality of groundwater (Goyal et al., 2004).

Many studies relating to the toxicity of heavy metals have been reported from

India. ITII (1988) emphasized the ill-effects of zinc in Toxic and Hazardous Industrial

Chemicals Safety manual for Handling and Disposal. Sankaranarayanan et al. (1998)

observed high concentrations of copper and zinc during summer and lowest during

monsoon in Cochin backwaters.

Gupta et al. (2012) studied the presence of copper, zinc and iron in water of

the Bawalis. Rehina et al. (1989) compared the water quality of Kuttiadi river basin

and stated that iron and aluminium exceeded the permissible limit and reported that

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water from Kuttiadi River was not fit for drinking. Tarvainen (1997) noticed high

concentrations of cadmium, arsenic, chromium, zinc, nickel, copper, lead and

manganese in small lakes than in the streams. Heavy metals indicate the lack of

uniform distribution of metals within the water sample. A similar variation of this

magnitude has also been reported by Obodo (2002) in the bioaccumulation of heavy

metals in fishes from Anambra River. Abulude et al. (2003) in the determination of

trace elements in different water samples in Nigeria and Obodo (2004) in the

bioaccumulation of heavy metals in fish from the River Niger also cited the same

explanation. Adeyeye et al. (2002) in their studies on assessment of physico-chemical

status of a textile industrial effluent and its environment pointed that low degree of

hardness of water encouraged the dissolution of heavy metals.

3.3 MATERIALS AND METHODS

Grab water samples were collected for analysis from all study areas in 1.5

litre, polyethylene bottles, which were pre-washed with 10% nitric acid and de-

ionized water. Before sampling, the bottles were rinsed at least three times with water

from the sampling site. The bottles were immersed to about 20cm below the water

surface to prevent contamination of heavy metals from air. All water samples were

immediately brought to the laboratory where they were filtered through Whatman No:

41 filter paper. The samples were acidified with 2ml concentrated Nitric acid to

prevent precipitation of metals, reduce adsorption on the walls of containers and to

avoid microbial activity. Then, water samples were stored at 4°C until the analysis.

Before analysis the sample is well mixed and 100 ml aliquot is taken in a beaker or

flask. 5ml of redistilled HCl is added. The sample is heated to near boiling for 15

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minutes and then filtered. The volume of the filtrate is made up to 100ml with

distilled water and subsequently analysed by A.A.S.

3.4 RESULT AND DISCUSSION

Organic manures, municipal wastes and some fungicides often contain high

concentrations of heavy metals. Soil receiving repeated applications of organic

manures, fungicides and pesticides have exhibited high concentration of extractable

heavy metals which subsequently increase their concentration in runoff. While falling

as rain, water picks up small amounts of gases, ions, dust and particulate matter from

the atmosphere. These impurities may give water a foul taste, colour, odour,

corrosiveness, staining etc. The toxicity of metals is dependent on their solubility

which in turn depends on pH and the presence of different types of anions and cations.

Moreover the many factors affect the concentrations, such as: the flow of dredged

materials from upper regions of the river, dilution and increase of water flow, direct

drainage from farmlands, factories. Sewage disposal, plants, dissolution of sediments,

increase in number of phytoplankton in water, bioaccumulation, chemical adsorption

on sediment and complexes with organic matter.

3.4.1 Copper

The results obtained for monthly variation of dissolved copper at stations

Kalikesham, Tirparapu, Sucindram, Kanyakumari, Chothavilai and Muttom during

the period of study are presented in table 3.1. The longitudinal variations of copper,

the annual mean of copper and its seasonal variation are graphically represented in

figure 3.1a, 3.1b and 3.1c respectively.

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The levels of copper in almost all the stations were within the limit of 1 mg/l

permitted by WHO for drinking water. The maximum value of copper at Kalikesham

was 0.9 mg/l (January 2012), Tirparapu 1.22 mg/l (May 2012), Sucindram 1.67 mg/l

(April 2012), Kanyakumari 0.138 mg/l (December 2011), Chothavilai 0.072 mg/l

(October 2011), Muttom 0.072 mg/l (March 2012, April 2012). The highest value

throughout the study period was found at Sucindram 1.67 mg/l (April 2012) and the

lowest value was recorded at Chothavilai 0.012 mg/l (August 2012). The highest

values of Tirparapu and Sucindram exceeded the WHO permissible limit of 0.5-1

mg/l. Annual mean was found maximum at Sucindram, 0.505 mg/l and the minimum

was found at Chothavilai, 0.045 mg/l. In the premonsson season the maximum was

observed at Sucindram 1.67 mg/l (April 2012) and the minimum was observed at

Chothavilai with 0.029 mg/l (May 2012). In the post monsoon season the maximum

was observed at Kalikesham 0.9 mg/l (January 2012) and minimum was observed at

Muttom 0.015 mg/l (October 2012). During the monsoon the maximum was observed

at Sucindram, 0.52 mg/l (September, 2012) and minimum was observed at

Chothavilai, 0.012 mg/l (August 2012).

Naturally copper occurs in most natural waters at low levels. Presence of high

concentration of copper in water gives disagreeable taste to the water (Manivasakam,

1996). Increase in concentrations of copper in natural system may be due to the

sources such as domestic and industrial wastes and land runoff. Although the

suspended particles contain a large fraction of copper (Troup et al, 1975). The

significance of the particulate fraction with rest of copper cycling is small, since much

of the copper remains fixed in a crystalline form. In aqueous system, the particles of

copper are in the form of Cu(OH)2 and Cu(OH)Cl. Shuman et al (1977) suggested

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that in fresh water system copper is complexed with dissolved organic matter. Kumari

Nithi et al (2007) reported 0.3mg/l of dissolved copper in the ponds of Jharta Town

Dhanbad. Copper in water of Bawalis was found in the range of 0 mg/l to 3.176 mg/l

(Gupta et al., 2012). In general, the value of dissolved copper is high in fresh water

zone, where addition of more fresh water enhanced the copper content. The present

study registered a low value of dissolved copper in saline water which is 0.012 mg/l at

Chothavilai (August 2012) to 0.138 mg/l at Kanyakumari (December 2011) than fresh

water which is 0.02 mg/l at Thirparpu (October 2012) to 1.67 mg/l. at Sucindram

(April 2012). This coincides with the findings of Turekian (1971) and Rema Devi

(1994). The lower values in the saline water may be due to the transfer of metallic

copper into its particulate during mixing with saline water. Nair (1997) reported the

inverse relation of dissolved copper with salinity.

In the present study, the dissolved copper content was high during the pre

monsoon season and low during monsoon. Highest value was reported in Sucindram

0.94 mg/l (May 2012) and that might be due to stagnation and evaporation. Ouseph et

al (1989), Shamin Ahmad et al (1996) and Sankarnarayanan et al (1998) reported the

same at Cochin estuary, freshwater ponds and Cochin back waters respectively.

Corrosion of metallic pipes and use of excess fungicides might be an source of copper

in fresh water. Similar findings were reported by Gupta et al (2009). The river in

particular is stagnant in lots of places.

Copper in the river water had positive correlation with Mg, salinity, Fe, Ni and

Zn during monsoon and post monsoon seasons. The same was reported by Kataria et

al (2012). In the present investigation, the riverine stations had high level of copper

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concentrations. Copper anamolies in streams can be partly by the areas of arable land

in the catchment area. Clay deposits have higher copper content than coarser soil.

Copper enriched fertilizers applied to the fields also increased copper content

(Kauranne et al 1992). The river bank soil was clayey and coastal soil coarser.

Throughout the study the copper content in Kalikesham was well within the range of

0.5 to 1.0 mg/l for uncontaminated fresh water and 0.12 mg/l to 0.85 mg/l where clay

deposits are there (Moore et al 1984). In the saline water stations very low copper

concentration were recorded. This is because of the salinity in sea water, (Rema Devi,

1994). Sholkovitz (1976) found that 40% of total dissolved copper was trasfered to its

particulate during mixing with sea. He also suggested that copper was bound to

colloids by physico-chemical process, the flux of copper to the ocean from the river

was less than 40%. The alkaline pH of the water medium can also be the cause of low

levels of copper as heavy metals are precipitated as their salts at high pH and are

deposited as sediments, (Kalaivani, 2013). Copper comes mainly from corrosion and

leaching of plumbing, fungicides (cuprous chloride), pigments, wood preservatives,

agrochemical (copper acetoarsenate) and antifouling paints, copper is used in

electronics, plating, paper, textile, rubber, fungicides, printing, plastic bases and other

alloy industries and it can also be emitted from various small commercial activities

and ware-houses (Neethu Patil et al 2014).

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Table 3.1: Longitudinal distribution of Copper (mg/l)

Stations /

Months Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Mean

Kalikesham 0.45 0.35 0.15 0.9 0.6 0.85 0.82 0.12 0.08 0.25 0.03 0.06 0.388

Tirparapu 0.02 0.12 0.22 0.07 0.15 0.12 0.93 1.22 0.1 0.19 0.03 0.09 0.272

Sucindram 0.55 0.48 0.29 0.32 0.32 0.52 1.67 0.84 0.152 0.29 0.11 0.52 0.505

Kanyakumari 0.016 0.055 0.138 0.062 0.072 0.068 0.078 0.042 0.021 0.055 0.021 0.035 0.055

Chothavilai 0.072 0.062 0.039 0.047 0.054 0.063 0.063 0.029 0.034 0.022 0.012 0.044 0.045

Muttom 0.015 0.054 0.048 0.032 0.066 0.072 0.072 0.045 0.046 0.031 0.023 0.056 0.047

Mean 0.187 0.187 0.148 0.239 0.21 0.282 0.606 0.383 0.072 0.14 0.038 0.134

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Figure 3.1a: Longitudinal variation of Copper (mg/l)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Kalikesham Tirparapu Sucindram Kanyakumari Chothavilai Muttom

Cop

per (

mg/

l)

Stations

Oct Nov Dec Jan

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8


Copper

(mg/

l)

Stations

Feb Mar Apr May

0

0.1

0.2

0.3

0.4

0.5

0.6


Copper

(mg/

l)

Stations

Jun Jul Aug Sep

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Figure 3.1b: Annual Mean of Dissolved copper (mg/l)

Figure 3.1c: Seasonal Variations of Dissolved copper (mg/l)

0

0.1

0.2

0.3

0.4

0.5

0.6


Co

pper (m

g/l)

Stations

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Agu Sep

Cop

per (m

g/l)

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3.4.2 Zinc

The results obtained for monthly variation of dissolved zinc at stations


the period of study are presented in table 3.2. The longitudinal variations of Zinc, the

annual mean of Zinc and its seasonal variation are graphically represented in figure

3.2a, 3.2b and 3.2c respectively.

Zinc concentration in almost at the stations exceeded the limit of 0.5 mg/l,

permitted by WHO 1993 for drinking water. The maximum value of zinc at

Kalikesham was 1.52 mg/l (June, 2012), Tirparapu 1.20mg/l (September, 2012),

Sucindram 1.07mg/l, (March, 2012), Kanyakumari 1.36mg/l (February, 2012),

Chothavilai 1.24mg/l (February, 2012), Muttom1.21 mg/l (February, 2012). The

highest value throughout the year was observed at Kalikesham, 1.52mg/l (June 2012)

and the minimum value was recorded at Tirparapu, 0.03 mg/l, (October, 2011). The

highest values of all the six stations exceeded the WHO permissible limit. The annual

mean was found to be maximum at Kanyakumari, 0.686mg/l and minimum was found

at Tirparapu, 0.44 mg/l. In the premonsson seasons maximum was observed at

Kanyakumari, 1.36 mg/l (February, 2012) and the minimum was observed at

Kalikesham, 0.04 mg/l (May, 2012). In the post monsoon season the maximum was

observed at Kalikesham, 1.07 mg/l (December, 2012) and the minimum was the

observed at Tirparapu, 0.03 mg/l (October, 2012). During the monsoon the maximum

was observed at Kalikesham, 1.52mg/l (June, 2012) and minimum was observed at

Kalikesham, 0.022 mg/l (September, 2012). All the maximum values exceed the

permissible limit.

135

In the present study, the annual mean of dissolved zinc in Sucindram was

higher than the other stations. The Zinc in water of Sucindram was found in the range

of 0.09 ml/l to 1.07 ml/l. This might be due to the influence of discharges from tiles

industries and domestic waste and also due to stagnation. The concentration of zinc

was high during the pre-monsoon season and low during the monsoon season. The

high value during premonsoon could be due to evaporation and stagnation. Same can

be stated for Sucindram, where in many places the river is stagnant in all the seasons.

Kaushik et al (1999) reported the same pattern at Motiheel.

Zinc exist in sea water in dissolved state or as solid precipitate or adsorbed to

particle surface Goldberg (1963) suggested that the principal species of zinc in sea is

Zn2+

and ZnSO4. Young et al (1973) reported that large quantities of Zn are released

to the coastal environment and bays lying close to densly populated regions. Dyrrsen

et al (1974) proposed that Zn is dissolved in sea water and is in the form of Zn2+

,

Zn(OH)2, ZnCl2 and ZnSO4. In the present study the annual average of Zn content of

saline stations are higher. Sebastin Raja et al (1989) reported the same. Higher values

in the fresh water region may be due to effluents reaching this water. This is

supported by the study of Preston et al (1972). High values of zinc are also most

likely to occur in acid surface waters (Alain et al 1994). The present study coincided

with the above findings, in June (2012), Kalikesham had a pH of 6.8 mg/l showing a

slight acidic nature, in the same month, the highest value 1.52 mg/l of zinc was

recorded in the study period. The same phenomenon was again seen at Kanyakumari

in August 2012 when the pH was 6.98 the concentration of zinc was 1.06 mg/l and in

September 2012 when the pH was 6.00 the Zn concentration decreases to 0.83 mg/l.

136

In the present study the dissolved Zn content was higher during permonsoon

and monsoon seasons. Higher values of Zn during premonsoon may be due to

evaporation and stagnation. Succindram showed the higher value in all the pre

monsoon months 0.99 mg/l (February 2012), 1.07 mg/l (March 2012), 0.83 mg/l

(April 2012). This may be due to stagnation and evaporation.

Studies in the monsoon seasons reveal that the zinc may be high due to high

rainfall and surface runoff. In the present study, Sucindram had values slightly

highest, 0.62 mg/l (May 2012) and 0.48 mg/l (June 2012). Shamim et al (1996).

noticed high concentration of Zn during monsoon mainly due to land drainage which

mainly bring in heavy metals both in dissolved and in their associated form in to the

river. Kaushik et al 1999 also reported the same. They reported that Zn concentration

varied from 0.065 to 0.120 mg/l. The bioaccumulation of zinc was reported on a fish

variety by Enuneku et al., (2013) in his study on river Owan, Edo State, Nigeria. He

also reported that the fish accumulates metals from water by diffusion via skin and

gill as well as oral consumption or drinking of water (Nusseyet et al 2000). Zinc

reaches aquatic ecosystems by zinc containing fungicides, viscose rayan fibres, fossil

fuel burning etc. Zinc content in our study period was higher than Juwarkar (1988),

Kiran (2005) and Leung et al (2000).

137

Table 3.2: Longitudinal distribution of zinc (mg/l)

Stations /


Kalikesham 0.12 0.16 1.07 0.23 0.08 0.78 0.23 0.04 1.52 0.63 0.32 0.22 0.45

Tirparapu 0.03 0.15 0.35 0.27 0.48 0.35 0.32 0.25 0.66 0.87 0.35 1.2 0.44

Sucindram 0.82 0.09 0.56 0.17 0.99 1.07 0.83 0.62 0.48 0.56 0.26 0.37 0.568

Kanyakumari 0.92 0.75 0.63 0.36 1.36 0.93 0.26 0.46 0.38 0.29 1.06 0.83 0.686

Chothavilai 0.72 0.53 0.46 0.65 1.24 0.85 0.34 0.56 0.43 0.34 0.94 0.72 0.648

Muttom 0.53 0.33 0.29 0.92 1.21 0.68 0.44 0.69 0.51 0.46 0.76 0.62 0.62

Mean 0.523 0.335 0.56 0.433 0.893 0.777 0.403 0.437 0.66 0.525 0.615 0.66

138

Figure 3.2a: Longitudinal variation of Zinc (mg/l)

0

0.2

0.4

0.6

0.8

1

1.2


Zin

c (m

g/l)

Stations

Oct Nov Dec Jan

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6


Zin

c (m

g/l)

Stations

Feb Mar Apr May

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6


Zin

c (m

g/l)

Stations

Jun Jul Aug Sep

139

Figure 3.2b: Annual Mean of dissolved zinc (mg/l)

Figure 3.2c: Seasonal Variation of dissolved zinc (mg/l)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8


Zin

c (

mg

/l)

Stations

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Zin

c (m

g/l)

140

3.4.3 Iron

The results obtained for monthly variation of dissolved iron at station


the period of study are presented in table 3.3. The longitudinal variations of iron, the

annual mean of iron and its seasonal variation are graphically represented in figure


Iron concentration in almost at the stations exceeded the limit of 0.3 mg/l,

permitted by WHO 1993 for drinking water. The maximum value of iron at

Kalikesham was 0.86 mg/l (March, 2012), Tirparapu 1.10 mg/l (February, 2012),

Sucindram 1.21 mg/l, (June, July, 2012), Kanyakumari 0.94 mg/l (October, 2011),

Chothavilai 0.95 mg/l (February, 2012), Muttom 0.96 mg/l (March, 2012). The

highest value throughout the year was observed at Sucindram, 1.21 mg/l (June,July,

2012) and the minimum value was recorded at Tirparapu, 0.11 mg/l, (September,

2012). The highest values of all the six stations exceeded the WHO permissible limit.

The annual mean was found to be maximum at Kanyakumari, 0.706 mg/l and

minimum was found at Tirparapu, 0.413 mg/l. In the premonsoon seasons maximum

was observed at Tirparapu, 1.10 mg/l (February, 2012) and the minimum was

observed at Muttom, 0.23 mg/l (April, 2012). In the post monsoon season the

maximum was observed at Kanyakumari, 0.94 mg/l (October, 2011) and the

minimum was observed at Kalikesham, 0.14 mg/l (November, 2011). During the

monsoon the maximum was observed at Sucindram, 1.21 mg/l (June, July, 2012) and

minimum was observed at Tirparapu, 0.11 mg/l (September, 2012). All the maximum

values exceed the permissible limit.

141

Iron usually enters the aquatic systems as acid iron wastes. Banerjee et al

(2010) studied the variation in hydrochemistry of river Damodar and reported the

presence of iron in water in the range of 0.04mg/l to 4.98mg/l. Kakti et al (2010)

reported (2010) the presence of iron in drinking water in the range of 0.3 mg/l to

8.42mg/l Gupta (2012) reported in the range 0.036mg/l to 0.097mg/l. In the present

study concentration of iron ranged from 0.11mg/l in Thirparapu to 1.21mg/l in

Succindram, for the fresh surface waters. In the sea surface waters, the iron values

ranged from 0.23 mg/l in Muttom (April 2012) to a maximum of 0.95mg/l (February

2012) at Chothavilai.

The present study indicates the annual mean of dissolved iron content was

high in the coastal areas 0.706 mg/l (April 2012) to 0.654 mg/l (February 2012)

Chothavilai. The high value may be due to the discharge of industrial effluents,

sewage and land runoff. This concept was in accordance with the findings of Moyle

(1956), Pragatheeswaran et al (1986) and Kataria et al (2012). A similar type of

findings was reported by Tale et al (2010). In the present study the fresh water

stations exceeded the permissible limit of iron in drinking water as recommended by

WHO (1994) an Bis: 10500 (1991) which is 0.3mg/l.

The hydrated oxides of iron entering the aquatic system are precipitated and

drifted around as particles before settling. Reduction of natural iron III oxides induced

by light has been observed in acidic streams (Mcknight et al, 1988, Kimball et al

1992). This is of particular importance because natural oxides can scavenge trace

metals during their formation and metal absorbed as oxides might be released when

pH decreases or as a consequence of reduction and subsequent dissolution of these

142

oxides. Boyden et al (1979) reported that the dissolved iron greater than 0.45ppm may

consist of Fe (III) held in solution by complexation with organic materials.

The higher values of dissolved iron content in the fresh water stations were

associated with influx of fresh river water. Sahu (1991) noted an increase in heavy

metals content due to discharge of waste water and agricultural runoff. This is in

accordance with the present study.

In the present study, the concentration of dissolved iron was found to be high

during premonsoon and monsoon seasons. During premonsoon seasons the

concentration was high due to evaporation and stagnation. 0.71 mg/l (April 2012) at

Kalikesham, 0.33 mg/l (April 2012) Tirparapu, 0.44 mg/l Sucindram, 0.73 mg/l

Kanyakumari, 0.57 mg/l Chothavilai, 0.23 mg/l Muttom (Ouseph et al 1989). In the

monsoon season, the high concentration was due to the impact of rainfall and

increased land discharge in to the river water Chothavilai and Muttom had higher

value during monsoon, 0.79mg/l (June 2012), and 0.41mg/l (June 2012) respectively.

Azis and Nair (1987), Sathyanarayana et al (1990) reported the same in Ashtamudi

estuary and West Bay of Bengal respectively. The presence of high concentration of

iron in any water body may increase the hazard of pathogenic organisms; since most

of these organisms need iron for their growth (Tiwana et al., 2005).

143

Table 3.3: Longitudinal distribution of Iron (mg/l)

Stations /


Kalikesham 0.24 0.14 0.42 0.57 0.36 0.86 0.71 0.52 0.36 0.36 0.25 0.22 0.418

Tirparapu 0.35 0.22 0.24 0.72 1.1 0.83 0.33 0.42 0.21 0.21 0.22 0.11 0.413

Sucindram 0.24 0.39 0.16 0.75 0.99 0.49 0.44 0.51 1.21 1.21 0.89 0.66 0.662

Kanyakumari 0.94 0.63 0.51 0.83 0.78 0.89 0.73 0.92 0.42 0.51 0.65 0.66 0.706

Chothavilai 0.83 0.32 0.45 0.66 0.95 0.82 0.57 0.63 0.79 0.65 0.78 0.52 0.664

Muttom 0.86 0.41 0.62 0.81 0.81 0.96 0.23 0.46 0.41 0.72 0.88 0.68 0.654

Mean 0.58 0.35 0.4 0.72 0.83 0.81 0.5 0.577 0.57 0.61 0.61 0.48

144

Figure 3.3a: Longitudinal variation of dissolved Iron (mg/l)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Iron (m

g/l)

Stations

Oct Nov Dec Jan

0

0.2

0.4

0.6

0.8

1

1.2


Iron (m

g/l)

Stations

Feb Mar Apr May

0

0.2

0.4

0.6

0.8

1

1.2

1.4


Iron (m

g/l)

Stations

Jun Jul Aug Sep

145

Figure 3.3b: Annual Mean of dissolved Iron (mg/l)

Figure 3.3c: Seasonal Variation of dissolved Iron (mg/l)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8


Iron

(m

g/l)

Stations

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9


Iron

(m

g/l)

146

3.4.4 Manganese

The results obtained for monthly variation of dissolved manganese at station


the period of study are presented in table 3.4. The longitudinal variations of

Manganese, the annual mean of Manganese and its seasonal variation are graphically

represented in figure 3.4a, 3.4b and 3.4c respectively.

Manganese concentration in all the stations did not exceed the limit of

0.05 mg/l, permitted by WHO 1993 for drinking water. The maximum value of

manganese at Kalikesham was 0.041 mg/l (March, 2012), Tirparapu 0.048 mg/l

(April, 2012), Sucindram 0.061 mg/l, (March, 2012), Kanyakumari 0.082 mg/l

(August, 2012), Chothavilai 0.073 mg/l (January, 2012), Muttom 0.71 mg/l (May,

2012). The highest value throughout the year was observed at Kanyakumari, 0.082

mg/l (August, 2012) and the minimum value was recorded at Kalikesham, 0.0027

mg/l, (October, 2011). The highest values of all the six stations did not exceed the

WHO permissible limit. The annual mean was found maximum at Kanyakumari,

0.048 mg/l and minimum was found at Kalikesham, 0.025 mg/l. In the premonsoon

seasons maximum was observed atMuttom, 0.071 mg/l (May, 2012) and the minimum

was observed at Kalikesham, 0.0022 mg/l (February, 2012). In the post monsoon

season the maximum was observed at Chothavilai, 0.073 mg/l (January, 2012) and the

minimum was observed at Kalikesham, 0.0027 mg/l (October, 2011). During the

monsoon the maximum was observed at Kanyakumari, 0.082 mg/l (August, 2012) and

minimum was observed at Kalikesham, 0.004 mg/l (June, 2012). All the maximum

values were all within the permissible limit.

147

Manganese is an essential element for plants and the information regarding its

toxicity is limited. Manivasakam (1987) reported that a large amount of manganese

causes pneumonitis. Kataria et al (2012) noticed 0.008mg/l to 1.130mg/l in his work.

In the present study the annual mean of manganese concentration was found, high in

sea water zones. In the river water zones the variation was in between 0.00027mg/l to

0.046mg/l. In the present study high values are also reported during premonsoon

seasons. This was in accordance with Ouseph et al (1989). Kaushik (1999). In the

present study Mn was under the permissible limit in all the fresh water zones.

Sebastin Raja et al (1989) reported that in-shore samples had more Mn than offshore

samples. Turekian (1971) stated that the absorbed metals in streams and rivers always

released in contact with sea due to their displacement by major ions such as

magnesium and sodium present in sea water.

In some places higher values were also noticed. This may be due to drainage

of domestic sewage. Subrahmanyam (1986) in his study recorded higher values of

manganese at Visakapatnam harbour due to drainage of domestic sewage from city.

At Succindram 0.06 mg/l (March 2012) a slight higher value than WHO and BIS was

recorded which may be due to domestic sewage. A slight higher values at Kalikesham

0.04 mg/l (March 2012) and Tirparapu 0.048 mg/l (April 2012) and 0.043 mg/l

(August 2012) may be due to the rubber factory effluents. This was in conformity

with the results discussed by Vijayamohan et al (1984). Chemical analysis report of

rubber factory effluent showed that it contained an array of chemicals including heavy

metals. The concentration of heavy metals such as Zn, Cu, Fe and Mn in rubber

factory effluent was higher when compared with textile mill effluents (Murugesan

1988). Higher values of Mn at Sucindram attributed to the untreated sewage, collected

148

washings from nearby villages, cattle yards, small scale industries, hospitals etc. This

was in agreement with the observations made in Ganga sagar regions of Darbhanga

by Kanwar and Randhawa (1974).

A probable source of air borne inorganic Manganese pollutant is the

combustion of methylcyclopentadienyl manganese tricarbonly (MMT), particularly in

areas of high traffic density (Sierra et al, 1998). Combustion of MMT in hot car

engine leads to the emission of manganese phosphates, manganese suplhate and

manganese oxides that include manganese trioxide as a minor component (Zayed,

2001). The higher manganese concentrations might be due to the addition of sewage

and domestic waste in the river (Neal et al, 2000). This may be the reason for higher

values at sucindram, which is located at a higher vehicular congestion area.

149

Table 3.4: Longitudinal distribution Manganese of (mg/l)

Stations /


Kalikesham 0.002 0.009 0.032 0.023 0.022 0.041 0.039 0.025 0.004 0.036 0.037 0.026 0.025

Tirparapu 0.023 0.005 0.009 0.027 0.032 0.041 0.048 0.029 0.016 0.028 0.043 0.015 0.026

Sucindram 0.019 0.027 0.018 0.026 0.005 0.061 0.042 0.039 0.046 0.033 0.026 0.036 0.032

Kanyakumari 0.038 0.047 0.052 0.066 0.031 0.041 0.055 0.027 0.039 0.047 0.082 0.051 0.048

Chothavilai 0.023 0.056 0.011 0.073 0.044 0.058 0.047 0.031 0.029 0.027 0.049 0.056 0.042

Muttom 0.039 0.048 0.036 0.035 0.046 0.038 0.062 0.071 0.053 0.046 0.031 0.029 0.045

Mean 0.029 0.039 0.031 0.05 0.036 0.056 0.058 0.044 0.037 0.043 0.054 0.043

150

Figure 3.4a: Longitudinal variation of Manganese (mg/l)

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08


Man

gan

ese

(mg/

l)

Stations

Oct Nov Dec Jan

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08


Man

gan

ese

(mg/

l)

Stations

Feb Mar Apr May

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09


Man

gan

ese

(mg/

l)

Stations

Jun Jul Aug Sep

151

Figure 3.4b: Annual Mean of dissolved Manganese (mg/l)

Figure 3.4c: Seasonal Variation of dissolved Manganese (mg/l)

0

0.01

0.02

0.03

0.04

0.05

0.06


Man

gan

ese

(mg

/l)

Stations

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07


Man

ganese

(m

g/l)

152

3.4.5 Nickel

The results obtained for monthly variation of dissolved nickel at station


the period of study are presented in table 3.5. The longitudinal variations of nickel,

the annual mean of nickel and its seasonal variation are graphically represented in

figure 3.5a, 3.5b and 3.5c respectively.

Nickel concentration in all the stations did not exceed the limit of

0.02 mg/l, permitted by WHO 1993 for drinking water except Sucindram and saline

water zones. The maximum value of Nickel at Kalikesham was 0.072 mg/l (October,

2011), Tirparapu 1.66 mg/l (May, 2012), Sucindram 2.246 mg/l, (March, 2012). In all

the saline water zones nickel was found to be below the detection limit. The highest

value throughout the year was observed at Sucindram, 2.246 mg/l (March, 2012) and

the minimum value was recorded at Kalikesham, 0.001 mg/l, (June, 2012). The

highest values of all the six stations exceed the WHO permissible limit. The annual

mean was found maximum at Sucindram, 0.557 mg/l and minimum was found at

Kalikesham, 0.035 mg/l. In the premonsoon seasons maximum was observed at

Tirparapu, 1.66 mg/l (May, 2012) and the minimum was observed at Kalikesham,

0.012 mg/l (May, 2012). In the post monsoon season the maximum was observed at

Tirparapu, 0.300 mg/l (January, 2012) and the minimum was the observed at

Kalikesham, 0.014 mg/l (January, 2012). During the monsoon the maximum was

observed at Sucindram, 0.831 mg/l (July, 2012) and minimum was observed at

Kalikesham, 0.001 mg/l (June, 2012).

There are many reasons for the high concentration of Nickel in the different

stations. Many factors affect the concentrations of heavy metals: the flow of the

153

dredged materials from upper regions of the river, dilution and increase of water flow,

direct drainage from farm land, factories, sewage disposal plants, dissolution of

sediments increase in the number of phytoplanktons in water, bioaccumulation,

chemical absorption on sediments and complexes with organic matter [Kaiser et al

2004, Al-Haidrey et al 2010, Al-Haidary, 2008]. Nickel was comparatively lower in

all the sites than the other metals. Several reasons were quoted for the presence of Ni

in fresh water zone Ndeda, Manohar, (2014) reports of waste dumping activities,

agriculture, car garages, industries, construction works, car washings, human waste,

raw sewage and garbage which are the major sources of heavy metals accumulation in

dams. Nickel is one of the colouring agent in paints. The higher value in Sucindram

may be due to the temple wash out and renovation work carried on the temple during

the study period.

In the saline water sources the Ni was below detectable limit, which may be

due to the cationic exchange of metals by Na, Mg and K in sea water. In the fresh

water zones the level of Ni is higher in the pre-monsoon season. This is due to high

evaporation rate during the dry season and results in higher concentration of metals in

water compared to dilution in monsoon. (Ndeda, 2014). A study of Rai, (2008) on

heavy metals in aquatic ecosystem of tropical industrial region concluded that

comparatively lower values of all metal ions were recorded during rainy monsoon

season compared to summer, which is due to dilution by addition of rain water and

subsequent drain out from reservoir water. Analysis of heavy metals in water of lower

river in Nigeria, attributed the high levels of Zn, Cr, Cu, Mn, Ni in river water during

dry season than wet season due to decrease in the river water in the dry season

resulting in increase in concentration of metals in water [Olatunde, 2012].

154

Table 3.5: Longitudinal distribution Nickel of (mg/l)

Stations Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Mean

Kalikesham 0.072 0.045 0.063 0.014 0.065 0.046 0.020 0.012 0.001 0.022 0.040 0.015 0.035

Tirparapu 0.025 0.072 0.015 0.300 0.710 1.020 1.520 1.660 0.024 0.056 0.001 0.047 0.454

Sucindram 0.273 0.172 0.108 0.065 0.872 2.246 1.421 0.072 0.042 0.831 0.256 0.321 0.557

Kanyakumari bd bd bd bd bd bd bd bd bd bd bd bd

Chothavilai bd bd bd bd bd bd bd bd bd bd bd bd

Muttom bd bd bd bd bd bd bd bd bd bd bd bd

Mean 0.123 0.096 0.062 0.126 0.549 1.104 0.987 0.581 0.022 0.303 0.099 0.128

155

Figure 3.5a: Longitudinal variation of Nickel (mg/l)

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Kalikesham Tirparapu Sucindram

Nic

kel (

mg/

l)

Stations

Oct Nov Dec Jan

0

0.5

1

1.5

2

2.5


Nick

el (m

g/l)

Stations

Feb Mar Apr May

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9


Nic

kel (

mg/

l)

Stations

Jun Jul Aug Sep

156

Figure 3.5b: Annual Mean dissolved Nickel (mg/l)

Figure 3.5c: Seasonal Variation dissolved Nickel (mg/l)

0

0.1

0.2

0.3

0.4

0.5

0.6


Nic

kel (

mg

/l)

0.00

0.20

0.40

0.60

0.80

1.00

1.20


Nic

kel (

mg

/l)

157

3.4.6 Lead

The results obtained for monthly variation of dissolved lead at station


the period of study are presented in table 3.6. The longitudinal variations of lead, the

annual mean of lead and its seasonal variation are graphically represented in figure


Lead concentration in all the stations did not exceed the limit of

0.3 mg/l, permitted by WHO 1993 for drinking water. The maximum value of Lead at

Kalikesham was 0.033 mg/l (December, 2011), Tirparapu 0.034 mg/l (October, 2011,

April, 2012), Sucindram 0.047 mg/l, (October, 2011), Kanyakumari 0.047 mg/l

(January, 2012), Chothavilai 0.038 mg/l (October, 2011), Muttom 0.036 mg/l (April,

2012). The maximum value throughout the year was observed at Sucindram, 0.047

mg/l (October, 2011) and Kanyakumari 0.047 mg/l (January, 2012) and the minimum

value was recorded at Muttom, 0.008 mg/l, (August, 2012). The highest values of all

the six stations did not exceed the WHO permissible limit. The annual mean was

found maximum at Sucindram, 0.0345 mg/l and minimum was found at Tirparapu,

0.0236 mg/l. In the premonsoon seasons maximum was observed at Sucindram, 0.044

mg/l (March, 2012) and the minimum was observed at Kalikesham, 0.0089 mg/l

(March, 2012). In the post monsoon season the maximum was observed at Sucindram,

0.047 mg/l (October, 2011) and Kanyakumari 0.047 mg/l (January 2012) and the

minimum was observed at Muttom, 0.009 mg/l (December, 2011). During the

monsoon the maximum was observed at Sucindram, 0.037 mg/l (July, 2012) and

minimum was observed at Muttom, 0.008 mg/l (August, 2012). All the maximum

values were within the permissible limit.

158

During higher dry season levels of heavy metals depend upon the

physicochemical properties of water, such as pH, temperature, salinity, conductivity

and dissolved oxygen levels (Idodo-Umeh, 2002), (Yayintas, 2007). In the present

study of Pb the sea water regions had lower values compared to the fresh water zones.

Pb content showed negative correlation with salinity. Similar pattern was reported by

Qvarfort (1977). Satyanarayana and Prabhakara Murthy (1990) in their study on trace

metal distribution in marine environment recorded higher concentration of Pb in

inshore waters which were accompanied by relatively lower salinities and higher

nutrients. Nair (1995) in Beypore estuary recorded a decrease in lead content with

increase in salinity. In the present study, the values were comparatively higher at the

fresh water zone, Sucindram. Heavier traffic may also result in elevated levels of lead

(Aryas and Niskavaara, 1992). In the fresh water zone Tirparapu also recorded slight

higher values which may be due to tourist population on vacation, (October 2011)

0.034mg/l, (April 2012) 0.24mg/l, (May 2012) 0.21mg/l, (September 2012)

0.029mg/l. The tourist population increases traffic discharge and increase the Pb

content in the sample sites (Joshua N. Edokpayi, 2014) The high concentration

observed could be due to leaching of Pb containing materials and runoff from garages

and roads around the river (Joshua N. Edokpayi, 2014) (Jennings et al., 1996).

The study on the pH correlation of river water Riyadh water revealed, heavy

metal especially lead precipitation in the form of carbonate is possible. High

wastewater pH also promotes the precipitation of metals as oxides and hydroxides:

(Corbitt, 1990). The concentration observed at Sucindram could be due to leaching of

Pb containing materials and runoff from garages and roads around the river. This was

reported by Joshua N. Edokpayi in Dzindi River in South Africa (2014).

159

Table 3.6: Longitudinal distribution Lead of (mg/l)

Stations Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Mean

Kalikesham 0.025 0.021 0.033 0.026 0.03 0.0089 0.032 0.022 0.011 0.018 0.031 0.032 0.0242

Tirparapu 0.034 0.015 0.011 0.033 0.017 0.024 0.034 0.031 0.019 0.02 0.016 0.029 0.0236

Sucindram 0.047 0.026 0.033 0.026 0.028 0.038 0.044 0.032 0.025 0.037 0.05 0.028 0.0345

Kanyakumari 0.024 0.015 0.0098 0.047 0.021 0.032 0.0099 0.025 0.027 0.032 0.036 0.029 0.0256

Chothavilai 0.038 0.031 0.019 0.024 0.028 0.022 0.035 0.017 0.026 0.033 0.034 0.019 0.0272

Muttom 0.031 0.025 0.009 0.025 0.032 0.031 0.036 0.022 0.03 0.015 0.008 0.024 0.0240

Mean 0.033 0.022 0.019 0.030 0.026 0.026 0.032 0.025 0.023 0.026 0.029 0.027

160

Figure 3.6a: Longitudinal variation of lead (mg/l)

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05


Lead

(m

g/l)

Stations

Oct Nov Dec Jan

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05


Lead

(m

g/l)

Stations

Feb Mar Apr May

0

0.01

0.02

0.03

0.04

0.05

0.06


Lead

(m

g/l)

Stations

Jun Jul Aug Sep

161

Figure 3.6b: Annual Mean of dissolved of lead (mg/l)

Figure 3.6c: Seasonal Variation of dissolved lead (mg/l)

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04


Lead (m

g/l)

Stations

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035


Lead

(mg/l

)

chapter iii trace metals - shodhgangashodhganga.inflibnet.ac.in/bitstream/10603/68275/9/09_chapter...

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