Monte Carlo Analysis of Dioxin Exposures and Risks from Consumption of Fish Caught in Freshwaters of the United States Affected by Bleached Chemical Pulp Mill Effluents, 1992 Environmental Conference Proceedings

Regulatory agencies, the general public and many environmental organizations are increasingly demanding more stringent environmental laws and standards. This demand arises from the perception that existing standards are designed to protect the average individual in the general population. Consequently, a segment of the general population, potentially a large one, is perceived to have a greater exposure to a particular compound and thus to be at greater health risk than assumed by a standard. This perception is wrong. The attempts to revise the standards and make them more conservative are in many cases misguided and unnecessary. This paper examines one such case: the potential for people to be exposed to dioxin* discharged from pulp and paper mills when eating fish caught downstream of bleached chemical pulp mills. This paper presents a Monte Carlo Analysis. The results demonstrate that the potential exposure, and risk from dioxin in such rivers is far lower than perceived by the general public and many regulatory agencies. Further, exposure and toxicity assumptions used in the existing dioxin water quality criteria provide very stringent levels of protection for the general population, because exposure and risk for virtually all members of the population are overestimated. The paper also demonstrates that, contrary to the conclusion reached by the recent U.S. EPA national dioxin risk assessment^1, few if any people, including avid sportfishermen have exposures to, and risks from, dioxin that would be considered unacceptable by regulatory agencies.