Significant exposure to lead in paints and gasoline can lead to nervous disorders. Organic toxic wastes can lead to liver and kidney inflammation. Others, such as PCBs, are suspected of causing birth defects. Some organic materials, such as benzene, are known to cause cancer in laboratory animals and are listed as possible cancer-producing agents in humans. Moderately high levels of copper, silver, and other heavy metals are detrimental to the growth of algae.
Some toxic wastes cause ecological imbalances.
It destroyed the birds' ability to develop a sufficiently strong egg shell to assure hatching. Other laws required the reduction of lead in gasoline and the termination of PCB production. DDT is still used in developing countries for its effectiveness against the malaria-carrying mosquito. Treatment and Disposal Depending on the type of waste, toxic wastes can be treated chemically, biologically, or by combustion. An acid spill, for example, may be treated with lime or bicarbonate to neutralize the acid.