AIR TOXICS REGULATORY ISSUES FACING URBAN SETTINGS

Biomarker research does not exist in isolation. Its usefulness can onl y be realized when it is translated into prevention strategies to prot ect public health. In the context of air toxics, these prevention stra tegies begin with the development of regulatory standards derived from risk assessment schemes. The Clean Air Act Amendments of 1990 list 18 9 air toxics, including many volatile organics, metals, and pesticides . The National Institute of Environmental Health Sciences (NIEHS), thr ough its affiliation with the National Toxicology Program, has generat ed toxicity and carcinogenicity data on more than 100 of these air tox ics. The NIEHS extramural and intramural research portfolios support a variety of projects that develop and validate biomarkers for use in e nvironmental health science and risk assessment. Biomarkers have a tre mendous potential in the areas of regulating air toxics and protecting public health. Risk assessors need data provided by biomarkers of exp osure, biomarkers of dose/pharmacokinetics, biomarkers of susceptibili ty or individual variability, and biomarkers of effects. The greatest benefit would be realized if biomarkers could be employed in four area s of primary and secondary prevention. The first is the use of biomark ers to enhance extrapolation of animal data to human exposure situatio ns in establishing risk standards. The second is the use of biomarkers that assess noncancer. as well as cancer, end points. Important healt h end points include pulmonary dysfunction, immunotoxicity, and neurot oxicity. Third, biomarkers that serve as early warning signs to detect intermediate effects would enhance our ability to design timely and c ost-effective intervention strategies. Finally, biomarkers used to eva luate the effectiveness of intervention strategies, both in clinical a nd regulatory settings, would enable us to ensure that programs design ed to protect public health do, in fact, achieve the desired outcome.