No abstract

Kolleru Lake is the largest natural freshwater lake of Andhra Pradesh in India. It is situated between latitudes 16 degrees 32' and 16 degrees 47'N and longitudes 81 degrees 05' and 81 degrees 27'E. The use of pesticides for agricultural purposes is widespread in the Kolleru Lake region. The biological indicators like fish help in the studies of aquatic pollution by pesticides. Fish species Channa striata and Catla catla and water samples were collected from Kolleru Lake in each of three seasons over a period of three years. Fish samples were analyzed according to a modified method which is proposed for the gas chromatographic determination for the pesticides viz., alpha-BHC, gamma-BHC, malathion, chloirpyrifos, isodrin, endosulfan, dieldrin, and p,p-DDT. Water samples were analyzed for selected physico-chemical parameters. The extraction efficiency for the selected pesticides is between 82.8% and 91.2%. The maximum concentrations of pesticide residues in Kolleru Lake fish on wet weight basis are 123.8 micrograms/g for alpha-BHC, 98.7 micrograms/g for gamma-BHC, 2.5 micrograms/g for malathion, 88.6 micrograms/g for chlorpyrifos, 0.91 microgram/g for isodrin, 76.5 micrograms/g for endosulfan, 1.98 micrograms/g for dieldrin, and 157.4 micrograms/g for p,p'-DDT. These analyses were used to evaluate the baseline data and the pesticide pollution in the lake's ecosystem.

Kolleru Lake is the largest natural freshwater lake of Andhra Pradesh in India. It is situated between latitudes 16 degrees 32' and 16 degrees 47'N and longitudes 81 degrees 05' and 81 degrees 27'E. The use of pesticides for agricultural purposes is widespread in the Kolleru Lake region. The biological indicators like fish help in the studies of aquatic pollution by pesticides. Fish species Channa striata and Catla catla and water samples were collected from Kolleru Lake in each of three seasons over a period of three years. Fish samples were analyzed according to a modified method which is proposed for the gas chromatographic determination for the pesticides viz., alpha-BHC, gamma-BHC, malathion, chloirpyrifos, isodrin, endosulfan, dieldrin, and p,p-DDT. Water samples were analyzed for selected physico-chemical parameters. The extraction efficiency for the selected pesticides is between 82.8% and 91.2%. The maximum concentrations of pesticide residues in Kolleru Lake fish on wet weight basis are 123.8 micrograms/g for alpha-BHC, 98.7 micrograms/g for gamma-BHC, 2.5 micrograms/g for malathion, 88.6 micrograms/g for chlorpyrifos, 0.91 microgram/g for isodrin, 76.5 micrograms/g for endosulfan, 1.98 micrograms/g for dieldrin, and 157.4 micrograms/g for p,p'-DDT. These analyses were used to evaluate the baseline data and the pesticide pollution in the lake's ecosystem.

Kolleru Lake is a freshwater lake in south-eastern India with a high potential for aquaculture. It is located between 61°32' and 61°47'N latitude and 81°15' and 81°27'E longitude. Various chemicals such as pesticides are used to control diseases and ectoparasites in intensive aquaculture farms in India. The main aim of this paper was to determine selected pesticides in water, sediment and ®sh from 12 ®sh farms located in Kolleru Lake in order to assess the quality of ®sh for human consumption and to improve the further risk assessment and management of such chemicals in aquaculture and also to evaluate the impact of aquaculture chemicals on the Kolleru Lake environment. The chemicals used in intensive aquaculture farms were documented. Water, sediment and ®sh samples were collected from the ®sh farms during the production period and analysed for the pesticides a-BHC, g-BHC, malathion, chloropyrifos, isodrin, endosulfan, dieldrin and p,p'-DDT using gas chromatography.