Kidney damage, decalcification of the skeleton, and emphysema are the serious chronic effects of high cadmium exposure, but these are encountered only in some occupational settings. Cadmium is a byproduct in the pyrometallurgical production of zinc, which is the leading anthropogenic source of cadmium to the environment. Cadmium is also a byproduct in the production of lead. Other major sources include fossil fuel combustion and waste incineration, and the manufacture of alloys, pigments, metal coatings, batteries, and electronics. Cadmium is also a contaminant in chemical fertilizer, manure, compost, and sewage sludge.
Cigarette smoking is another major cause of cadmium accumulation in humans.
Lead in the environment is readily absorbed by sediments and soil particles, and is therefore largely unavailable to plants and animals. Leaded gasoline, however, has been and, outside of the United States and Canada, continues to be a major source of lead emissions to the environment on the continental scale. Lead is also emitted from the mining and metallurgic industries, ammunition manufacture and use, and municipal waste incineration. Over the past two years, the Board has reviewed current efforts in the United States and Canada to address the issue of PTSs in the environment, including efforts underway to implement the Great Lakes Binational Toxics Strategy signed by both countries in April 1997. The Board recommends that the Commission closely track implementation of the Great Lakes Binational Toxics Strategy at regular intervals and review the progress in completing specific elements of the strategy as identified by the Board under the strategy.