A toxicity-based analysis of Canada's National Pollutant Release Inventory (NPRI): a case study in Nova Scotia

After the success of the Toxics Release Inventory (TRI) in the United States (US), Canada created the National Pollutant Release Inventory (NPRI). Both NPRI and TRI focus on public opinion to coerce facilities to reduce quantities of emissions, through market pressure, although early reductions in Canada may be attributed to traditional command-and-control mechanisms. NPRI uses a quantity-based approach to report atmospheric and effluent releases of pollutants to air and water, but does not account for relative toxicity of releases, which could lead to harmful chemicals being overlooked. A toxicity-based approach using characterization factors from the USEtox® environmental impact assessment tool was used for this study. Releases of organic and inorganic pollutants to both air and water in Nova Scotia for 2015 were analyzed. Using an ecotoxicity analysis found that the highest priority chemicals identified using the NPRI's quantity-based approach differed markedly from those identified using the toxicity-based approach. Many of the high-priority chemicals identified using toxicity-based analysis are detrimental to ecosystem health and warrant regulatory attention. The Office of the Auditor General of Canada recently suggested that the Canadian federal government needs to improve control risks of toxic substances. Using a toxicity-based approach may help decision makers in the Canadian federal government effectively control risks of toxic substances and help to inform decision makers, regulators, and Canadians about those risks.