A conceptual framework for US EPA’s national exposure research laboratory
The challenges of environmental protection range from understanding the potential risk associated with exposure of humans and ecosystems to a newly manufactured chemical, to minimizing human exposure to pathogens at public beaches, to linking human activities on the landscape to physical alterations of ecosystems. In the United States, there are more than 75,000 industrial chemicals that are currently tracked by the U.S. EPA, with an estimated 2,200 new chemicals manufactured or imported each year. Since 2001, the list of environmental chemicals reported in the Centers for Disease Control and Prevention’s First, Second, and Third National Report on Human Exposure to Environmental Chemicals has grown from 27 to 148 (NRC 2006), evidence of both the need and ability to monitor the public for exposure to contaminants of concern.
The popular media routinely reports concerns about contaminants in drinking water supplies, at public beaches, and in the Nation’s surface waters. A June 2007 Newsweek article highlighted a growing public awareness of potential risks associated with “emerging contaminants,” including pharmaceuticals, cosmetics, and antibacterial soaps. Cited in the article was a 2002 survey by the U.S. Geological Survey which detected a number of these compounds in 80 percent of the 139 streams it examined. While each of the compounds was generally present in small quantities, the overarching question remains, “What happens when a person is exposed to a whole cocktail of them?” (Underwood 2007). For ecosystems, environmental protection goes beyond minimizing exposures to chemical contaminants and includes the restoration and maintenance of the physical and biological integrity of ecosystems.
Understanding the relationships between land use, such as urban development and agricultural activities, and how these activities can physically alter ecosystems is a critical component of environmental protection. In the U.S. EPA ‘s 2006 report on the condition of wadeable streams of the US, stream bed sediments and riparian disturbance were identified as two of the most widespread stressors which are degrading stream condition for fish and other aquatic life. Both of these stressors represent physical alteration of stream systems and are typically associated with human activity alongside streams.
Fulfilling the U.S. EPA mission to protect human health and the environment carries with it the challenge of understanding exposures for tens of thousands of chemical contaminants, a wide range of biological stressors, and many physical stressors. The U.S. EPA’s National Exposure Research Laboratory (NERL) is uniquely positioned to address the Nation’s most challenging environmental exposure questions. Exposure science provides the Agency with the fundamental research necessary to assess potential exposures and risks to emerging environmental threats and to mitigate exposures to known contaminants and stressors. NERL’s combined expertise in modeling, chemistry, microbiology, ecology, molecular biology, geographic information systems, and remote sensing enables the Laboratory to bring cutting edge research and technology to the field of exposure science.