DESIGNING A BIOLOGICAL MONITORING PROGRAM TO ASSESS COMMUNITY EXPOSURE TO CHROMIUM - CONCLUSIONS OF AN EXPERT PANEL

The possible benefits of biological monitoring of large groups of peop le potentially exposed to environmental contaminants has become an are a of much interest in recent years. Because chromite-ore processing re sidue has been found in some soils in northern New Jersey, urinary chr omium monitoring of people in the community was evaluated as a potenti ally useful tool. In an attempt to identify those who could be exposed and to quantify the magnitude of exposure to the chromium in these so ils, the New Jersey Department of Health (NJDOH) initiated a public he alth screening project. In 1992, the NJDOH proposed to evaluate over 4 000 people who lived or worked near these sites. Volunteers were admin istered a questionnaire and were given a limited physical examination, and a single spot urine sample was collected. Because of the difficul ties in using urinary chromium to assess low-level exposure and the po tential implications of any regulatory decisions that could be based o n the results of this project, a panel of experts was convened to eval uate the protocol. The panel consisted of five scientists and physicia ns with expertise in toxicology, dermatology, epidemiology, biological monitoring, and analytical chemistry. Like a World Health Organizatio n group, the panel concluded that although urine biomonitoring can be useful in evaluating high levels of exposure to chromium, it is not re liable for assessing low-level exposure similar to that which may have occurred in northern New Jersey. The panel also noted that when urina ry biomonitoring is to be used to assess the public's possible exposur e, a large number of precautions must be taken to ensure the accuracy and usefulness of the results. The single most important recommendatio n was to collect a second, and perhaps a third, spot urine (or 24-h ur ine) sample before concluding that a person may be routinely overexpos ed. These suggestions are applicable to designing a biomonitoring prog ram for nearly any environmental contaminant to which a community may be exposed. A review of scientific literature associated with biologic al monitoring of chromium is provided.