Immunotoxicology and Risk Assessment - Present Prospects, Future Directions

This series of articles originates from a platform session at the 26th Annual Aquatic Toxicity Workshop, October 3-6, 1999, Edmonton, Alberta, Canada. That platform session was concerned with recent advances in immunotoxicology. This series of papers, which deals with fish, marine mammals, and humans, builds on those presentations to describe what is possible now and what may be possible in future, focusing on the use of immunotoxicology in risk assessment. The first paper, by Zelikoff et al. (2002), describes the development, application and validation of immune assays, originally developed for rodents, to laboratory fish. They also discuss the utility of these laboratory-developed immunotoxicological assays as biomarkers for predicting both hazard and risk to feral fish populations, including the key issue of extrapolation from the laboratory to the field. Arkoosh and Collier (2002) describe research involving feral salmon in Puget Sound, Washington, USA, exposed to PAHs and PCBs. Effectively, the laboratory model described by Zelikoff et al. (2002) is applied to endangered salmon stocks following an ecological risk assessment (ERA) paradigm. Their findings highlight the role that contaminant-induced immunosuppression may have on salmon survival and suggest the need for similar studies at other sites. Ross (2002) focuses on marine mammals in the context of emerging infectious diseases, related to persistent organic pollutants. He suggests that immunotoxic contaminants may facilitate disease emergence and lead to the creation of susceptible “resevoirs” for new pathogens in contaminated marine mammal populations. His paper describes the effects of chemicals on mammalian immune systems, and the evidence linking such chemicals with disease outbreaks particularly for marine mammals. He concludes with the need for an integrated human and ecological risk assessment framework to address this complex issue. Luebke (2002) focuses on human health, overviewing potential consequences of chemicals (particularly pesticides) on the immune system, and host factors that mitigate or exacerbate immunotoxic effects. He finishes by discussing human studies of pesticide-associated immunotoxicity.