资源环境科技发展态势分析平台

BACKGROUND: Billions of dollars are spent on environmental dredging (ED) to remediate contaminated sediments, with one goat being reduced human health risks. However, ED may increase health risks in unanticipated ways, thus potentially reducing net benefits.

OBJECTIVES: To assess the ways that ED may increase health risks in unanticipated ways, thus potentially reducing net benefits, we quantitatively assessed a subset of population health benefits and risks of ED, using the 2009-2015 remediation of the Hudson River Polychlorinated Biphenyls (PCBs) Superfund Site as a case study. Three remediation scenarios were evaluated: No Action (NA), Source Control (SC), and ED.

METHODS: We quantified health benefits for each scenario from reduced PCB levels in Hudson River fish, and health risks from ED operations due to increased inhalation exposures to PCBs and fine particulate matter (PM2.5), using disability-adjusted life years (DALYs) as a common meuic. Occupational health risks were also considered in a separate sensitivity analysis. Estimates of population-level benefits and risks included Monte Carlo simulation-based uncertainty analysis.

RESULTS: Under NA, fish consumption would result in an estimated health burden of 112 DALYs, and ED would lead to a reduction of 15 DALYs in excess of SC. ED operations were estimated to induce a total burden of 33 DALYs, dominated by PM2.5 impacts from rail transport emissions (32 DALYs). Including uncertainty, the net health benefit of ED ranged from -138 to + 1,326 avoided DALYs (90% confidence), with a median of -11 avoided DALYs.

CONCLUSIONS: For the considered impacts, ED in the Hudson River might not have led to an overall net positive human health impact. The benefits and risks of ED, however, have different degrees of uncertainty and involve different populations. Reducing long-distance transport of dredged sediment is a priority. This comparative approach could be used prospectively to better determine trade-offs involved in different remediation scenarios and to improve remediation design to maximize benefits while minimizing risks.