Issues in the assessment of congenital health risks from mercury in coal

摘要

This paper describes a probabilistic assessment of congenital neurological risks associated with consumption of fish and shellfish containing MeHg and the effects that local coal combustion might have on those risks. Two scenarios were considered with this model: the ''baseline'' scenario (MeHg from fish consumption without local impacts), and the ''impact'' scenario (baseline plus local power-plant impact on freshwater fish). In this paper, we describe the framework and application of the model, including parameters and statistical linkages, the distributions used to represent the parameters, and the statistical methods used to characterize the inherent variability in each individual's diet and the distribution of individuals within a hypothetical population. These factors define the baseline, which is then compared to observations of MeHg in hair in order to demonstrate the model's validity. The incremental effect of local coal combustion is represented by augmenting the distribution of Hg in local freshwater fish by a prescribed amount, which we refer to as the ''impact factor.'' Conventional air pollution dispersion modeling is then used to relate this factor to an appropriate range of powerplant characteristics.