Lab Matters Winter 2019 - Page 9

FEATURE a Safe Drinking Water Act maximum contaminant level for PFOA and PFOS, a final determination and enforceable regulation are likely years away. advise clinical response, because there’s so little known about PFAS clinically. We don’t know what a level in the blood may mean in terms of past exposure, current risks or future health outcomes.” NHANES data are, however, critical for establishing national background levels—against which local test data can be compared to identify cases of elevated exposure—and for monitoring exposure trends. For example, after manufacturers began voluntarily phasing out use of PFOS around 2000, average US blood concentrations fell by more than 80% over the next 14 years. Yet CDC tracks only a small handful of the thousands of PFAS compounds in existence. The California Department of Public Health (CDPH)—the first state to begin population-wide PFAS biomonitoring— noted in an e-mail the challenges associated with this broad class of chemicals: “Developing methods to identify and measure new compounds is difficult and time consuming, all the more so because we usually do not know what compounds are being used commercially. There are also many analytical complications. Analytical standards (needed for method development) are not readily available. Some of the newer replacement PFAS, such as shorter chain and ether-based compounds, require specialized analytical methods to detect, and there isn’t a consensus yet about how to interpret and report results. These issues are difficult to resolve, and new chemicals are being used in products and released into the environment every day.” The environmental side of the issue is similarly fraught. In 2016, EPA lowered its drinking water health advisory limit for PFOS and perfluorooctanoic acid (PFOA)—two of the best studied PFAS legacy compounds—from 200 ppt PFOS and 400 ppt PFOA down to 70 ppt for both chemicals combined. But this is a nonbinding limit. (A draft CDC toxicology report released last June suggests a much lower lifetime exposure limit for the same compounds.) While the agency is evaluating the need for PublicHealthLabs @APHL In the meantime, EPA is also developing draft toxicity values for the PFOS/PFOA replacement chemicals GenX (HFPO dimer acid) and perfluorobutane sulfonic acid. In the absence of stronger federal action, states have begun their own PFAS monitoring and interventions. Last June, for example, the North Carolina Department of Environmental Quality filed a court order requiring Chemours Company—a DuPont spinoff—to drastically reduce its release of GenX and other PFAS into the air and into the Cape Fear River watershed, where they had contaminated drinking water supplies and alarmed residents. Local communities blame GenX for a cluster of unexplained pediatric cancer cases there. NCSL’s Farquhar said, “People are very, very concerned. They want a solution. North Carolina is not known as a very environmentally rigorous state, which is probably part of the reason [Chemours] built there. Now [the issue has] come back to the state. The public is just up in arms.” Last February, 3M agreed to pay the state of Minnesota $850 million to settle a lawsuit related to PFAS drinking water contamination in the area surrounding the company’s Cottage Grove manufacturing plant, just ten miles south of St. Paul. A notable feature of the policy environment, said Farquhar, is that PFAS are a “very bipartisan” issue, as “reflective of public opinion.” He said, “The state legislatures are not waiting for the federal government. It’s not that they don’t trust the government, they’re just moving ahead.” During 2017-2018, at least ten states (CA, MI, MN, NC, NH, NY, PA, RI, VT, WA) enacted PFAS-related laws. Washington, for example, passed legislation banning the use of certain PFAS-containing food packaging and severely restricting the sale and use of PFAS-containing firefighting foam, beginning in 2022 and 2020, respectively. A 96-well extraction plate showing serum extraction (before and after). Proteins and fats are removed leaving a cleaner sample extract (upper panel) for analysis using high through-put instrumentation. Photo: Wadsworth Center Other states have instituted drinking water standards more stringent than EPA’s 70 ppt health advisory level for PFOS and PFOA. For example, California requires public drinking water systems to notify residents when PFOA exceeds 14 ppt or PFOS exceeds 13 ppt. Vermont allows no more than 20 ppt for the sum of five PFAS, including PFOS and PFOA. New Jersey has a 13 ppt limit for perfluorononanoic acid, a particularly toxic PFAS discharged into the southern Delaware River area by a specialty polymers plant. “Everyone carries a body burden of these persistent chemicals” Michigan began detecting PFAS in sites around the state as early as 2012, beginning with the area around the Wurtsmith Air Force Base (WAFB) in Oscoda and the Army & Air National Guard Training Center at Camp Grayling. “We learned the military, right about that time, had begun to test their bases for PFAS, because firefighting foams carry these ‘forever’ chemicals, and they have to do a lot of training and put out a lot of fires,” said Wells. “After that, we had citizen concerns.” Winter 2019 LAB MATTERS 7