Organochlorine Pesticide Residues Analysis in Rapti River Water and Fishes


India is predominantly an agricultural country. In India almost 50% of the potential of food grain production is lost annually due to insect/ pests, pathogen etc. Pesticide plays an important role for control of pests in agriculture and public health programmes. India at present is the largest manufacturer as well as consumer of pesticide chemical in southern Asia.

Pesticide possesses potential health-hazard not only to livestock and human beings but also to aquatic flora and fauna. The biomagnifications and bioaccumulation of the pesticide in food chain of fishes of serious concern.

In India, many organochlorine pesticides are being used. However, there is very little information available regarding the pesticide contamination of Indian River water and fishes. Unfortunately no work has so for done regarding the pesticide contamination of aquatic body’s in Eastern part of Uttar Pradesh. In order the assess of the status of pollution load of the pesticides both in Rapti and Gandak rivers as well as in the fishes of both these rivers the present study were undertaken.


Material and Methods

Water Sample :

The water samples were collected in the pre and post monsoon period (1999-2000) from two different spots (S1 and S2) as well as along the banks of rivers of Rapti and Gandak (B1 and B2). Water samples in replicate of five were used for analysis. One litre water sample was taken in two litre separator funnel mixed with 3 x 150 ml distilled n-hexane and shaken for 30 minutes. The organic phase was separated from aqueous phase. The extractions were repeated and the combined extracts were repeated and the extracts were concentrated to 10 ml with vacuum rotator evaporator at 50°C which was dissolved in 25 ml n-hexane and there after the combined n-hexane were concentrated to 10 ml.

The sample so obtained was purified by applying it over a mixed phase chromatographic column containing 1×5 cm bed of anhydrous sodium sulphate at the bottom followed by 1 x 10 cm activated charcoal in about 600 mg. celite 545 and eluted with 40 ml. 5% benzene/hexane. The benzene system was changed to n-hexane and then applied to 1 x 25 cm bed of 2% activated silicagel and eluted with n-hexane. The fractions containing pesticides were collected and made to 2. 0 ml with n-hexane.


Fish Samples :

80 Adults fishes of 5 different species were trapped each during pre and post monsoon season (1999-2000) from Rapti and Gandak rivers. The fishes collected were of the following types.

1. Channa punctatus

2. Clarias batrachus


3. Heteroponstes fossilis

4. Channa striatus

5. Mystsus tengara

These fishes were acclimatized to laboratory condition for a week in tap water having the following characteristics.


Temperature 20 ± 1°C

PH 6.8 – 7.0

Dissolved oxygen 6.4 – 7.2 mg/litre

Alkalinity 95 – 100 mg/litre


Hardness 118 – 120 mg/litre

After a week’s time the fishes were removed, thoroughly washed and tissues removed, washed and dried. The tissues (Gills, kidney, liver and intestine) were kept in the medium containing hexane: acetone (80:20) for determination of DDT and Hexane: Ether (90:10) for determination of HCH pesticides. These samples were centrifuged and chilled in ethanol and decanted. After one hour the extracts were used for TLC experiments using silica gel 6 plates of 250 µ thickness activated at 100°C in an oven. The following solvent systems were used:

(i) For DDT estimation:-

(a) Chloroform: Methanol (90:10)

(b) Benzene: Ethyl Acetate (90:10)

(ii) For HCH estimation:-

(a) Hexane

(b) Hexane: Acetone (95:5)

The locating reagents used were as follows:

i. DDT-5% acidified palladium chloride

ii. HCH-2% Alcoholic Solution of dianisidine

The pesticide residues were determined by TLC method.

Results and Discussion

These results reveal that water samples collected from above rivers showed contamination with HCH and DDT residues.

Rapti river water is considerably polluted with the presence of excess amount of residues of HCH pesticide during post monsoon period. The increased level of α-HCH was significant compared to other pesticide such as ß-HCH, λ-HCH and DDT.

In a likewise manner the Gandak river water was also found to be contaminated with excess level of residues of α-HCH during post monsoon season as compared to residues of another isomer of HCH. Organ chlorine compounds are known to maintain their solubility in the aquatic environment for long period.

The fishes trapped from river Rapti and Gandak the residues level of α-HCH, ß-HCH, y- HCH. A-HCH and DDT estimated in tissue of all the species of fishes are summarized in tables 3 and 4 respectively. The determination of residues of HCH and DDT indifferent organs of fishes collected from Rapti river showed that comparatively higher level of residues of a- HCH was found in all types of fishes as compared to other residues. The accumulation of ß-HCH was found to be highest magnitude in the brain tissue of Channa punctatus as compared to other tissues. These observations were more significant during post-monsoon period.

The great affinity of chlorinated pesticide residues for the tissues of aquatic animals and rapid bio-accumulation is primarily due their lipophilic nature and alkalinity. The chlorinated pesticide residue reaches to the river through agricultural run-off. Chlorinated pesticides and toxicants of similar nature found their way quickly their body as evidenced by the universal presence of the chlorinated pesticide residue in various species of fish analyses in the present investigation.

Periodic surveys and monitoring of toxic substances in fishes would enable to take remedial measures as and when required. Such measures are also useful to identify the possible sources of pollutants in the food chain which maintain the predator’s relationship in the aquatic system. This pesticide might significantly affect human body. The minimart disease in Japan and the silent spring stray are the well known episodes of fish poisoning.

The continuous use of agrochemicals might pose a threat to fresh water fish’s population and the aquatic fauna. The pesticide pollution of river water has gained a considerable importance in Eastern Uttar Pradesh. There is a great need for systematic monitoring together more quantitative data on organ chlorine pesticides water and accumulation in fish organs.

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