Emerging Contaminants Summit
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Emerging Contaminants Summit
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John Newsted John Newsted
Technical Manager
Ramboll

Dr. John Newsted holds a PhD from the Michigan State University. He has over 20 years of experience in aquatic ecology, environmental toxicology and ecological risk assessment. He has studied the effects of endocrine disruptors at the molecular, biochemical, organismal and population level in aquatic species. Currently his work has centered on emerging chemicals of concern, specifically per- and polyfluoroalkyl substances (PFAS). Much of this work concern understanding the fate, transport and ecotoxicological effects of perfluorooctane sulfonate (PFOS) in aquatic and terrestrial ecosystems. Dr. Newsted has published over 90 peer reviewed articles and numerous reports and abstracts.



PLATFORM PRESENTATION

An evaluation of PFAS -based fish consumption advisories in the Laurentian Great Lakes

Per- and polyfluoroalkyl substances (PFAS) are synthetic compounds are persistent and resistant to degradation in the environment and have received considerable attention with respect to their occurrence and fate in the aquatic environment and biota. Two PFAS, perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), have been identified as “Chemicals of Mutual Concern” pursuant to the 2012 Great Lakes Water Quality Agreement. One of the issues identified in this agreement concerns the risk posed by human consumption of fish containing contaminants, including several PFAS. Fish consumption advisories (FCAs) for PFOS have been issued by Canada and several U.S. states within the Great Lakes basin. To date, USEPA has not derived an FCA applicable to the Great Lakes. As such, the FCA values derived by the different federal and state regulatory agencies vary due to differences in methodology, assumptions (e.g., fish consumption rates), as well as toxicity data used to derive reference doses (RfD). PFAS fish tissue data from multiple states (primarily MI, MN, and WI) and USEPA’s Great Lakes Human Health Fish Tissue Study were evaluated in conjunction with available FCA guidance documentation. Several U.S. states and Ontario, Canada have derived PFOS-based FCA screening values (e.g., PFOS concentration at which a 1 meal/month FCA is issued), with screening values ranging substantially. In the Great Lakes region, most states without a published PFOS-based FCA screening value reported they would follow the protocol in the Uniform Great Lakes Sport Fish Consumption Advisory (1993) if they were to develop a PFOS FCA screening value. Case studies of locations with significant PFAS fish tissue data will be presented and factors such as water body type (lentic versus lotic), were evaluated. PFAS concentrations across fish species, and species-specific bioaccumulation are also examined. Results from this analysis showed that: (1) PFOS was the predominant PFAS detected, exceeding the most conservative FCA screening value (3.9 ppb, wet weight) in greater than 75% of samples, regardless of species and collection location; (2) on average, PFOS concentrations were greatest in species from the family Centrarchidae (bass and sunfishes); (3) “Do Not Eat” FCA screening values were exceeded in less than 5% of samples but FCA screening values vary considerably by regulatory agency; (4) PFOS-based FCA screening values are trending lower (more conservative) in recent years; (5) the downward trend may continue if the assumed fish consumption rate (grams per day)rises and/or if regulatory agencies assume an additive toxicity approach and sum PFAS fish tissue concentrations (i.e., “total PFAS” versus PFOS only); and, (6) decreasing FCA screening values may result in additional water bodies being listed as impaired (USEPA 303[d] listing) due to the changes in the assumed fish consumption rates. PFOS-based FCAs are compared to that of legacy compounds such as mercury and PCBs to assess if PFOS-based FCAs are greater or less restrictive in areas where these compounds have been quantified.


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