An Assessment of Adult Risks of Paresthesia Due to Mercury from Coal Combustion

Abstract

This paper presents a probabilistic assessment of the risks of transient adult paresthesia (tingling of the extremities) resulting from ingestion of methylmercury (MeHg) in fish and shellfish. Two scenarios are evaluated: the “baseline,” in which the MeHg dose results from the combined effects of eating canned tuna fish, various marine seafoods, and freshwater sportfish, and an “impact” scenario in which the Hg content of the freshwater sportfish is increased due to local deposition from a hypothetical 1000 MWe coal-fired power plant. Measurements from the literature are used to establish the parameters of the baseline, including atmospheric rates of Hg deposition and the distributions of MeHg in fish. The Hg intake for the impact scenario is then based on linear scaling of the additional annual Hg deposition as estimated from a Gaussian plume dispersion model. Human health responses are based on a logistic fit to the frequencies of paresthesia observed during a grain poisoning incident in Iraq, 1971–2. Based on a background prevalence rate of 2.2% for adult paresthesia, the assessment predicts a 5% chance that the increase in paresthesia prevalence due to either baseline or incremental Mg doses might approach about 1% of the background prevalence rate.