Environmental pollution and human health.

Contacts of humans with chemicals from the environment occur via air, water or food. In the past most attention was paid to the contamination of water. Well developed and stringent legislation exists in most countries, although health impairments never occurred from environmental chemicals in drinking water. Xenobiotics in water mainly have a marker function for the general pollution of the environment. Therefore measures to detect and eliminate the sources of contamination are often inappropriately taken. For some persistent and (usually) lipophilic xenobiotics in food, especially from animal origin, acts as carrier. The lipophilic persistent chlorinated compounds, such as DDT, PCBs and dioxins and the heavy metals lead, cadmium and mercury are accumulated in livestock and are there leading to much higher concentrations than in the environment. So far these compounds have not yet reached concentrations which are representing a health risk. A range of environmental chemicals coming from the air act directly on the site of first contact through their cytotoxic property. For many of them the margin of safety is low or even non-existent. Inorganic acid anhydrides, such as SO2, SO3 or NOx often occur in industrialized areas at levels affecting the pulmonary function of susceptible people, such as asthmatics or patients with chronic bronchitis. Ozone and photochemical smog represent another group of important environmental irritants. The intake of airborne lead has diminished in the last 20 years by a factor of 2-3 as a consequence of the most remarkable decrease in the use of leaded gasoline.(ABSTRACT TRUNCATED AT 250 WORDS)