Risk Assessment as a Decision-Making Tool for Treatment of Emissions at a New Aluminum Smelter in Iceland: 3. Ecological Assessment

Abstract

ABSTRACT Predictive ecological risk assessment was used to determine whether any risk-reduction benefit would result from the installation and operation of wet scrubbers at an aluminum smelter in East Iceland. Sulfur dioxide and hydrogen fluoride exposure will not result in any appreciable risk to mosses, lichens, lodgepole pine, and heather/heath grassland communities beyond the dilution zone without scrubbers. With scrubbers, exceedances of plant criteria may occur beyond the dilution zone. Critical concentrations of polycyclic aromatic hydrocarbons (PAHs) and hydrogen fluoride (HF) in terrestrial wildlife food items were converted to critical air concentrations, which were then compared to modeled air concentrations. Terrestrial wildlife species are not expected to be exposed to PAH concentrations that result in appreciable risk. If wildlife species are assumed to consume only grasses, predicted HF exposures will not result in exceedance of toxicity thresholds. However, if wildlife species are assumed to consume only heather, thresholds are exceeded at some locations for the rock ptarmigan and wood mouse. Results of population modeling indicate no potential for population impacts to rock ptarmigan outside the facility boundary. Impacts to wood mouse carrying capacity are expected to extend beyond the dilution zone with scrubbers, but not without.