Getting the lead out: important exposure science contributions

Exposure to lead has long been known to exert toxic effects on the nervous system as a key target, with the greatest concern typically being for unborn fetuses, infants, and young children. It is now recognized, however, that people of all ages can be affected (including geriatric populations) and that lead impacts virtually all organ systems. Since the 1960s, as research revealed adverse effects of lead at lower and lower exposure levels, views regarding “unacceptable” lead concentrations have been repeatedly revised downward to prevent or reduce human lead exposures. This has led to remarkable progress in reducing exposures, as well illustrated by the graph above showing decreased percentages of blood lead levels in US children. These dramatic decreases in lead exposure are attributable mostly to the phase-out of the use of leaded gasoline in the United States. The ongoing decline also reflects success in reducing other major lead sources (e.g., house paint, soil, house dust, drinking water from leaded pipes, and food). Exposure science has been essential to showing the need for reducing lead exposure, pathways of exposure, and the success of implementing laws aimed at exposure reduction, e.g., the Lead Contamination Control Act of 1988. As sources of lead are further elucidated, exposure science will continue to play a crucial role in enabling protection of public health. Lead is a highly useful metal, but it has long been feared because of the risks it poses to human health. The characterization of human lead-exposure pathways and internal lead burdens is an important exposure science advance that has contributed to an impressive public health success story that is not yet finished. Getting the lead out: important exposure science contributions