How do pesticides harm the environment?
• Some harm living organisms other than the targeted pest • Some travel through the food chain to bioaccumulate in higher organisms. • And some persist in soil, air, surface water and groundwater, continuing to poison for a long time. • What is `bioaccumulation’ of pesticides and why is it a concern? Pesticides can become concentrated, perhaps to toxic levels, via the food chain. Thus, an insect feeding on plant sprayed with pesticides might be eaten by another insect which might then be eaten by a bird. This is especially a problem with pesticides that are fat-soluble and highly persistent, including DDT and other organochlorines. Traces of pesticides too small to kill the targeted pest can accumulate to levels high enough to harm species further on up the food chain. In the early 1970s, hundreds of people in South India – all poor and of low caste ? were afflicted with a mysterious, painfully crippling disease. Investigations finally determined that the condition was caused by eating
