Lab Matters Winter 2019 - Page 7

FEATURE Beginning in the late 20 th Century, PTFE also began turning up in human blood, with the most heavily exposed populations located on or near industrial sites, such as chemical manufacturing plants, and the hundreds of airports, military facilities and fire departments that store and use PFAS-containing firefighting foams. Collectively known as per- and polyfluoroalkyl substances, or PFAS, these compounds now pervade almost every aspect of modern life. “The type of LC/MS/MS instrumentation for this analysis costs between $250-300K and a further $140K for the automated 96-well plate technologies for SPE for serum testing, and a further $40K for the automated SPE for water testing.” Polytetrafluoroethylene (PTFE), the first in this huge family of compounds, was the basis for Teflon ® non-stick coatings. Other PFAS repel water, oil and stains in umbrellas, tents, Gore-Tex ® outerwear, carpets and upholstery. They repel grease and moisture in pizza boxes, fast food wrappers, microwave popcorn bags and pet food bags. And they have been incorporated into everything from cell phones to fabric softeners to Oral-B ® Glide dental floss. Beginning in the late 20 th Century, they also began turning up in human blood, with the most heavily exposed populations located on or near industrial sites, such as chemical manufacturing plants, and the hundreds of airports, military facilities and fire departments that store and use PFAS-containing firefighting foams. “People are scared,” said Doug Farquhar, JD, who analyzes environmental health legislation for the National Conference of State Legislators. “That’s putting a lot of pressure on [government] agencies to come up with some sort of response.” PublicHealthLabs @APHL A second problem is contamination from PFAS already in the laboratory. Thus, sample introduction systems have to be stripped of Teflon ® degassers, Teflon ® SPE cartridges, PTFE vial caps and all other PFAS-containing components. Blood specimens are collected during community clinic visits or at local patient service centers. Serum is harvested and transferred into bar-coded blue top tubes for transport to the Wadsworth Center for PFAS analysis. Photo: Wadsworth Center According to the US Centers for Disease Control and Prevention (CDC), in 2000, the average US resident had a blood perfluoroctane sulfonic acid (PFOS) level of 30 µg/L; 3M workers had roughly 500 µg/L. Human exposure, in turn, has been associated with a long list of health problems, notably including kidney and testicular cancers, thyroid disease, pre-eclampsia, asthma diagnoses and decreased antibody response to vaccines, especially in children. Older LC/MS/MS systems may be incapable of detecting PFAS at the low levels required, on the order of parts per trillion (ppt). And that, in turn, has created a growing—as yet, unmet—demand for laboratory testing to detect and measure the chemicals in people and in the environment. PFAS testing: costly, complex But laboratory testing for PFAS isn’t cheap. Or easy. Patrick Parsons, PhD, head of environmental health sciences at New York’s Wadsworth Center—the state public health laboratory—explained the hurdles. First is cost. “Testing for PFAS in aqueous samples involves an extraction of the analytes using solid phase extraction (SPE) techniques and determination using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS),” he said. APHL.org Of course, laboratories must also have staff experienced in mass spectrometry and assure additional, specialized training in trace analysis of the compounds. And because there are few standardized test methods for these unregulated chemicals—and literally thousands of possible analytical targets in a variety of test matrices—scientists must often develop and validate their own testing protocols. After all these tasks have been accomplished, laboratories still need approval from the Centers for Medicare & Medicaid Services before clinical test results can be reported to patients. “This requires a substantial amount of work to document the validation studies performed and to develop the protocols that meet clinical quality standards,” said Parsons. Analyzing drinking water for PFAS, he said, “also requires a substantial effort to document validation and to develop the detailed protocols that meet environmental quality standards.” Winter 2019 LAB MATTERS 5