BIOMAGNIFICATION: REDUCING THE USE OF CHEMICALS ON FARMLAND
Poisonous substances, such as persistent insecticides, miss out on a natural way of living in the same way that energy and supplements do. In general, these chemicals will collect in the tissues of plants and animals that store and swallow them. As a result, the higher a creature's position on the natural world, the greater the risk of harm it may encounter in its food.
Following years of widespread use of the potent and long-lasting pesticide DDT (dichloro-diphenyl-trichloroethane), ecologists identified this phenomena, called biological magnification, in the 1950s and 1960s. DDT, like other chemicals that are biologically magnified, does not simply degrade into simpler, less-harmful substances. In other words, it is not biodegradable and instead accumulates, unmodified, in the fatty tissues of animals exposed to it. Ecologists tracked the path of DDT sprayed at a low dosage on particular ponds and lakes to control mosquitoes in one instance.
In addition to pesticides that are intentionally sprayed, long-lasting chemicals like dioxins and PCBs wind up in the environment as byproducts of different manufacturing processes. Chemicals can cause birth defects and difficulties with immune function and reproduction at high concentrations found at the top of the food chain. Many environmental organizations have made cleanup a high priority.
