They include aldrin, chlordane, DDT, dieldrin, endrin and heptachlor, which have been banned in most countries, along with organophosphates. As pesticides deteriorate, they form by-products, which may be more toxic than the original substance. In addition to pesticides, waste sites contain contaminated sprayers, empty containers and huge quantities of heavily polluted soil. The dumps are often abandoned, unmanaged and in very poor condition. In many cases, pesticides are left in the open or stored in unsubstantial mud and straw structures with earth floors, and numerous containers are corroding.
Local people complain about headaches, nausea and coughs.
The pesticide waste has accumulated over more than 30 years, and products are being added continuously, according to the report. Obsolete pesticides have built up because they were not used or were not removed after being banned for health or environmental reasons. In many African countries, for example, dieldrin was used to control locust outbreaks until the late 1980s. After that time, it was decided not to use dieldrin any further, but existing stocks were not removed or used up. Some formulations are not stable under tropical conditions, causing them to degrade rapidly.