Monthly Variations in Perfluorinated Compound Concentrations in Groundwater

Abstract

Large-scale manufacturing of poly- and perfluorinated compounds in the second half of the 20th century has led to their ubiquity in the environment, and their unique structure has made them persistent contaminants. A recent drinking water advisory level issued by the United States Environmental Protection Agency lowered the advisory level concentration of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) from 200 nanograms per liter and 400 nanograms per liter, respectively, to 70 nanograms per liter separately or combined. Small temporal variations in PFOS and PFOA concentrations could be the difference between meeting or exceeding the recommended limit. In this study, newly sampled data from a contaminated military site in Alaska and historical data from former Pease Air Force Base were collected. Data were evaluated to determine if monthly variations within PFOS and PFOA existed. No statistically significant temporal trend was observed in the Alaska data, while the results from Pease, although statistically significant, showed the spread of observed contaminant concentrations around the fitted line is broad (as indicated by the low R2 values), indicating that collection date has little value in predicting contaminant concentrations. Though not currently the subject of a US EPA health advisory, data on perfluorobutanesulfonic acid (PFBS), perfluorohexane sulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA), and perfluorononanoic acid (PFNA) were collected for each site and their average concentrations evaluated.

Determination of organically bound fluorine sum parameters in river water samples—comparison of combustion ion chromatography (CIC) and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS)

“…Substitution of hydrogen with fluorine in organic molecules affects their chemical and physical properties, e.g., increased chemical and thermal stability and/or oleophobic as well as hydrophobic properties [ 1 , 2 ]. These molecules are described according to Buck et al as per- and polyfluorinated alkyl substances (PFASs) [ 3 ].…”

Surface-water/groundwater boundaries affect seasonal PFAS concentrations and PFAA precursor transformations

“…There have been few studies investigating temporal trends of PFAS in groundwater or PFAS transport across surface-water/groundwater boundaries. Steele et al 60 found no statistically signicant temporal trend in groundwater data from a site in Alaska, but did nd (weakly) statistically signicant temporal trends for groundwater at Pease Air Force Base in New Hampshire. Our results indicate stronger seasonal trends, likely owing to the surface-water/groundwater boundary investigated in this work.…”