How are insecticides harmful for the environment?

Question

How are insecticides harmful for the environment?

2 Answers

Answer Question

Answer 1

Many pesticides have a very persistant nature, they do not break down very quickly. A common example is DDT an insecticide that didn't break down at all (now banned).

Picture this a farmer sprays a field, all the bugs die, each bug has abosrbed 1 unit of DDT, a lod of hungry mice come along that night and eat ten bugs each, they now all contains 10 units of DDT per mouse, then a hungry owl swoops down and eats 10 mice the owl now has 100 units of DDT in its body, and as the DDT doesn't break down the next night (ten more mice) it will be 200 . . .300 . . 400 = dead owl.
Environmental Consultants

Answer 2

Insecticides are supposed to harm only insects. However when sprayed onto soil or onto plants parts such as fruits and vegetables they might get absorbed by the roots and get stored with the starch inside the plant. As a result they get introduced in the food chain. These when consumed my living organisms have a toxic effect on them especially humans as they are at the top of the food chain.

Many of these insecticides are considered carcinogenic. Further when ingested they may also get stored inside the body along with fat (some are fat soluble) and accumulate causing more damage.