Role of chelating agents for prevention, intervention, and treatment of exposures to toxic metals.

ence was prompted by emerging evidence that low-level exposures to metals may result in toxic effects not previously recog? nized. For example, the recent interest in use of chelation as an intervention strategy to reduce blood lead levels followed the awareness that exposure to lead in infants and young children resulting in blood lead levels as low as 10-15 ug/dl may impair cognitive and behavioral development (1). The question increasingly asked is to what degree, if any, does increased excretion of a toxic metal reverse established toxicity? For example, does reduction in blood lead levels reverse the impairment of cognitive and behavioral development in children? Does the process of chelation cause potentially dangerous redistribution of lead to suscepti? ble organs from those less susceptible to lead toxicity? While intervention for toxici? ty from any metal includes removal from exposure, what are the indications for using chelating agents that enhance excretion of metals? Complete answers to these questions may not be currently available, but discus? sion of benefits and problems related to chelation therapy should help identify areas needing further study. The conference par? ticipants were asked to share current data and to identify gaps in data necessary to obtain a better understanding of the proper place of chelating agents in the manage? ment of metals exposure and toxicity.