Environmental copper: Its dynamics and human exposure issues

This article provides an overview of the environmental patterns and dynamics of copper from the perspective of issues that affect our ability to examine current human exposures. It presents selected summary information on the levels of copper found in various media and exposure pathways from a variety of information sources, and discusses the breadth and the limitations of this information. The analysis presented focuses on the ability to provide quantitative values for both external metrics of exposures (microenvironmental levels) and internal biological markers of exposure. The status of the current information on environmental copper is placed within a conceptual framework that can be used to identify data gaps, assess the utility of current biological markers of exposure, and examine the need for systematic and consistent data-gathering studies to improve our ability to complete exposure assessments. A primary concern is the exposure to copper through potable water supplies; this is considered within a framework that examines copper levels and distribution in food, soil, air and sediments, as well as the levels found in biological media such as urine, blood, and hair. An existing water consumption model for copper and associated exposure factors is briefly discussed. This type of model will eventually be valuable within a total exposure analysis modeling framework that can consider and prioritize exposures from multiple routes and differentiate levels of concern for both excesses and deficiencies in exposure, an important issue, since copper is an essential nutrient. Finally, this review attempts to examine the needs for better information using as a basis the concerns briefly mentioned in the recent NRC report "Copper in Drinking Water" (National Research Council, 2000).