ABSTRACT

Complex Carcinogenic Mixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 496

There is no area of occupational or environmental health that is more daunting to practitioners than estimating the exposure and effects of carcinogens. Factors such as multiple routes of potential exposure, the severity of the disease, the lag time between initial exposure and manifest effects, and multiplicity of mechanisms contribute to the problem. In addition, regulatory agencies have yet to provide substantial guidance to help practitioners estimate carcinogen exposures and place them into perspective. The United States Environmental Protection Agency (USEPA) does not have a formal policy on carcinogen exposure assessment, although carcinogen risk assessment is an important part of their efforts [1]. The USEPA home page does not list “carcinogens” or specific carcinogenic compounds [1]. The National Institute for Occupational Safety and Health (NIOSH) that “has not identified thresholds for carcinogens that will protect 100% of the population . . . , recommends that occupational exposures to carcinogens be limited to the lowest feasible concentration” (emphasis in original) [2]. NIOSH goes on to describe appropriate respiratory protection without mentioning dermal exposure potential. The Occupational Safety and Health Administration (OSHA) lists 45 compounds or mixtures as known human carcinogens, but neither does it detail specific guidelines or tools for estimating exposure, nor provide an overall carcinogen exposure assessment philosophy [3]. Proscribing exposure across the board does not help the occupational health professional in the absence of specific tools for assessing exposure and dose. Estimating exposure to carcinogens is where “the rubber meets the road” for intervention in the carcinogenic process and cancer prevention. The focus of this chapter is to provide a brief overview of air monitoring methods for carcinogens. This is followed by a detailed description of methods of carcinogen biomonitoring and biomarkers, particularly for polycyclic aromatic hydrocarbons (PAHs) and aromatic amines.