Chemical Pollution Problems

In the old days, human waste created the biggest pollution problems. Now there are more than 80,000 chemicals in use, and most have not been tested for environmental or health impacts. Only 1,400 have been tested and found harmful.

Microtoxicity

• Chemical pollution is associated with ecosystem disruptions, cancers, birth defects and learning disabilities. Routes of exposure have increased exponentially because of the problem of general microtoxicity, that is, the diffusion of many chemicals in small quantities throughout the air, water and soil.

After the Big War

• Chemical pollution became a global problem after World War II, when two major chemicals went into general use: polychlorinated biphenyls (PCBs) and dichlorodiphenyl trichloroethane (DDT). Both were later discovered to be highly carcinogenic and non-biodegradable, but by then they had been dispersed in enormous quantities into the environment, where they could circulate and re-circulate. Even with these two historic cautionary tales, new chemicals have been relentlessly produced and used.

The Plastic Fantastic Ocean

• Aside from local exposures of chemical pollution, there is one kind of chemical pollution that figures to have many and unpredictable consequences for the entire biosphere: oceanic pollution. The Deepwater Horizon catastrophe brought this problem into bold relief, when the chemicals in the gushing oil created one problem, then the toxic dispersants used to "break down" the oil compounded the problem. But until that disaster, only 12 percent of oceanic chemical pollution was from oil spills. The new concern is that plastics, accounting for uncounted millions of tons of trash in the oceans, dissolve into various chemicals after sustained contact with the ocean water, specifically styrene trimer and bisphenol A (BPA). BPA affects mammalian reproductive systems, and styrene is carcinogenic.