Pesticide Contamination in Lake Anasagar of Ajmer, Rajasthan

The lake Anasagar is a perennial, shallow fresh wetland situated in the heart of Ajmer city. It is degraded because of anthropogenic activities including input of detergents, agricultural activities, sewage disposal and human settlement around the lake. It is also a major tourist attraction for boating and recreational activities. Trapa bispinosa is the primary cash crop, comprises about 50% of the periphery. A large area of the catchment is being used for agriculture particularly for vegetable crops such as Cauliflower, Tomato, Cabbage, Brinjal, Okra etc. Such activities lead to input of agrochemicals particularly pesticides. The water quality of the lake was studied for assessing inputs of organo-chlorine (OC) pesticides for selected five sites influenced by different activities such as cloth washing, agriculture and sewage inputs. The organochlorine pesticides recorded in the samples were Heptachlor, Beta HCH, pp DDD, pp DDE, pp DDT and Aldrin in the range of 0.004ppm to 0.068ppm, 0.125ppm to 1.174ppm, 0.0102ppm to 0.0491ppm, 0.006ppm to 0.0361ppm, 0.026ppm to 0.0562ppm and 0.0051ppm to 0.0268ppm, respectively. The study reveals that water of Anasagar is highly contaminated with these synthetic pesticides. Among these agrochemicals the level of beta HCH, Heptachlor and pp DDT were found to be significantly high in the lake. Seasonal fluctuations in the concentration of these pesticides were also observed. The concentration of organochlorine was higher in summers (April to June) than in the rainy season (July to September). Therefore, the research efforts are needed to conserve the wetlands as well as the impacts of agrochemical on Anasagar lake ecosystem.