ADVERSE HEALTH-EFFECTS DUE TO SOIL AND WATER ACIDIFICATION - A SWEDISH RESEARCH-PROGRAM

Environmental acidification is a global problem, especially in areas w ith a combination of high fallout of acid precipitation and a low buff ering capacity of water and soil. In light of the considerable effects caused by acid precipitation in soil and water, it is important to id entify and quantify the possible adverse effects on human health. The Swedish Environmental Protection Agency initiated a five year research program, starting in 1991, on the effects of acid precipitation on hu man health. The program focused on the indirect effects of acid precip itation, effects due mainly to changes in the mobility of trace elemen ts, giving in most cases an increase, but sometimes a decrease in meta l levels. Through the food-chain, the intake of toxic as well as essen tial elements may be altered in man. The objective of the program is t o elucidate i) to what extent acidification will change human exposure to elements, either the total levels or the chemical form; and ii) wh at this means for human health. The aim is to detect effects as early as possible, in order to be able to prevent harmful effects in humans. Although there are several indications that the exposure to toxic ele ments, e.g. cadmium, methylmercury and lead, as well as the intake of essential elements, e.g. selenium, may be affected by acid precipitati on, there is at present no firm evidence of adverse health effects in man. However, the present data clearly indicate that the safety margin s are small and efforts should be made to keep all sources of exposure to toxic elements as low as possible.