SUPFES: ENVIRONMENTAL RISK ASSESSMENT ON SHORT-CHAIN PER- AND POLYFLUOROALKYL SUBSTANCES APPLIED TO LAND IN MUNICIPAL SEWAGE SLUDGE
Conference poster, 2014
In a recent risk assessment of sludge application to Swedish farmlands perfluorooctane sulfonate (PFOS) was identified as a substance contributing to risks to the environment and a regulation of permissible levels in sludge was proposed. This is only one of many actions taken to regulate the so called long-chain per- and polyfluoroalkyl substances (PFAS), a group of substances which include e.g. PFOS, perfluorooctanoic acid (PFOA) and their precursors. These regulations are enforced due to concerns regarding the persistence, bioaccumulation potential and effects for wildlife and human health of the long-chain PFAS. With the regulation and phase out of PFAS products containing long perfluoroalkyl chains, PFAS products containing short-chain perfluoroalkyl chains are seen as viable alternatives by the manufacturing industry, but to date knowledge about these alternative emerging products is limited and risk assessments have not yet been conducted.
In this project, which is a subproject of the Swedish research programme SUPFES (www.supfes.eu), we assess the risks associated with short-chain PFAS in municipal sewage sludge applied to agricultural land in Sweden. Different scenarios are created regarding the loads of PFAS to wastewater treatment plants (WWTP). Further modelling scenarios are undertaken to estimate the loading of PFAS to agricultural land in Sweden as well as the subsequent fate and uptake in agricultural plants and leakage to water. The model predicted concentrations provide a basis for environmental risk assessment. With the long-chain PFAS as a benchmark, the study also aims to assess if the transition from long- to short-chain PFAS is beneficial from an application of sludge to agricultural land perspective. The risk assessment is connected to a life cycle assessment (LCA) on possible sludge handling alternatives which helps to place the problems associated with PFAS risks into a larger LCA perspective. The project results will help to determine if action is needed by water authorities to reduce the diffuse emissions of PFAS to agricultural land by introducing improved treatment technologies to remove PFAS from WWTP. This is thus an important contribution to the overarching goal of the SUPFES project which is to quantify and, if necessary, reduce diffuse emissions of PFAS to the environment.
In the poster preliminary results from the risk assessment will be presented and ideas for further work discussed. Important methodological issues will be highlighted.