Identification and Quantification of Potential Sources of Per- and Polyfluoroalkyl Substance (PFAS) Contamination in Ontario

Abstract

Per- and polyfluoroalkyl substances (PFAS) are large class of anthropogenic and recalcitrant chemicals that are primarily categorized using their carbon fluorine bonds. First known to have been manufactured in the 1930s, they have since become seemingly ubiquitous across several industrial sectors due to their chemical and physical properties. The widespread implementation of PFAS based innovations in industry has since posed significant questions regarding their environmental fate once they are released. Documented instances of environmental media impacted by PFAS have become commonplace across the globe and present elevated concerns with regards to freshwater resources. Despite the highly documented nature of PFAS use within specific industrial sectors, little is known about the potential number of facilities that may be point sources of PFAS release into their surrounding environment. The objective of this project is to estimate the number of industrial sites acting as potential PFAS point sources in Ontario and what sites may be impacting freshwater resources. In order to reliably estimate the number of sites, an approach consisting of five stages was used. First, industrial sectors of concern for PFAS contamination were identified. Second, the individual sites of each industrial sector were detailed and catalogued. Third, the individual sites were evaluated using a decision-making framework specifically developed for each industrial sector of concern to classify each site with respect to the probability of being a PFAS source. Fourth, using geographical information system (GIS) software, the facilities were plotted across Ontario. Fifth, the distances between the facilities and freshwater resources such as groundwater sources and surface water bodies were quantified using GIS. The following six industrial sectors were identified: pulp and paper, metal fabrication, automotive manufacturing, petroleum product manufacturing and storage, landfills, and wastewater treatment. A data base was then prepared that detailed over 3800 unique sites using information gathered from publicly available information resources such the National Pollutant Release Inventory, small landfill dataset, and municipal treated wastewater effluent. To evaluate the facilities and provide estimates for their likelihood of being a source of PFAS contamination, a series of decision-making frameworks was developed using background knowledge about each industrial sector. Available information about each site was used to assess it using the applicable decision-making framework. Throughout the entire course of the project, information was sourced from a plethora of publicly accessible resources such as governmental reports, scientific publications, technical support documents, company websites, and others. Once evaluated, a unique site could be assigned one of three outcomes in descending likelihood of being a PFAS point source: likely, possible, and unlikely. After classification, the sites were plotted across Ontario using GIS to inform the prospective end user of their likelihood of being a source of contamination, industrial sector, and corresponding decision point. Following the plotting of the individual sites in GIS the distances between the sites and freshwater resources such as surface water bodies and groundwater sources were quantified in the following increments: 10 kilometres, 1 kilometre, 500 metres, and 100 metres. Of the six industrial sectors evaluated, a total number of 3582 individual sites were concluded to be likely sources of PFAS contamination with an additional 273 sites concluded to be possible sources of PFAS contamination. Using the described methodology, no facilities could be classified as being unlikely sources of PFAS contamination. Quantification of the distances from the identified facilities to freshwater resources indicated that there are 322 facilities thought to be probable contamination sources located within 100 meters of surface water bodies, and 2286 within 100 meters of groundwater sources. The implementation of this methodology has revealed the concerns of environmental PFAS contamination resulting from industrial sites to be well founded. Furthermore, the approach would likely be amenable to other jurisdictions and future industrial sectors of concern.