Question: Is bioaccumulation a big problem today for farming and wildlife

Becky Thomas answered on 22 Jun 2018:

What a great question! Bioaccumulation is a massive problem for wildlife. The best example of the harm it can cause is with birds of prey. Farmers were using a chemical called DDT, which was used in the 40’s and 50’s to kill insects on crops. This was washed into rivers and started to move up the food chain, by the time it got to birds of prey (because they were eating big fish in rivers) it was very concentrated.

Female peregrine falcons (lovely birds of prey that are very common in cities now) were laying eggs that had very thin shells because of the DDT, and because of this, when they went to sit on them (to keep them warm) they got crushed. Numbers of peregrines declined because of this, and DDT was finally banned in the 1970s. This ban was a big success for conservation, but there are many other harmful chemicals which are still being used on farms today.