Superfund Report - 11/24/2014
California Exploring Detection Of Wide List Of PFASs At Low Levels
Posted: November 21, 2014
California's Department of Toxic Substances Control (DTSC) is developing a method to detect in groundwater low
levels of about two dozen chemicals known for their persistent, non-stick qualities, signaling the regulatory agency's
concern about ongoing, low-level exposure to a broad array of compounds within the class, including precursors to
chemicals with known effects.
DTSC's Environmental Chemistry Laboratory is developing a detection method for low level occurrences in
groundwater of at least two dozen poly- and perfluoroalkyl substances -- both known as PFASs -- investigating more
compounds than most current methods have and at lower detection limits, according to minutes from an EPA
regional Technical Support Project Ground Water Forum teleconference held Sept. 4. DTSC researchers presented
information about the work during the teleconference, according to the minutes.
The DTSC lab "is developing this method because there are many military bases, refineries, and industries in
California that are suspected to be significant sources of PFASs," the minutes say. "High-level contamination in
groundwater may pose an acute threat to human health, but DTSC is also concerned about low-level, ongoing
exposure to these chemicals, particularly in regions of California that use groundwater for their drinking water
supply."
PFASs are emerging contaminants that are largely unregulated. Regulators' focus has primarily been on the two
most prevalent compounds -- perfluoroalkyl chemicals known as perfluorooctanoic acid (PFOA) and
perfluorooctane sulfonate (PFOS). These are ubiquitous in the environment, after being used to manufacture a wide
range of consumer products, such as non-stick materials like Teflon, and have had widespread applications in
chemical manufacturing, metal plating, aircraft production processes, fire control equipment and some electronic
products.
EPA's water office is preparing risk estimates of PFOA and PFOS as replacements for interim health advisories that
the agency issued in 2009 following concerns about occurrences of PFOA in Ohio groundwater near a former
DuPont PFOA factory. The work is currently in peer review (Superfund Report, Sept. 1). Eventually, regulators will
use the finalized numbers to craft health advisory levels and cleanup requirements at sites contaminated with the two
substances, which are now being eliminated through agreements between EPA's toxics office and industry.
Perfluorochemicals -- a term which is being phased out and which generally refers to perfluoroalkyl substances -are considered "extremely persistent in the environment" and resist typical environmental degradation methods,
EPA says in a March 2013 fact sheet. "As a result, they are widely distributed across the higher trophic levels and
are found in soil, air, and groundwater at sites across the United States," it says. Recent studies have suggested a
range of possible adverse health effects from PFOA, including testicular and kidney cancers, as well as ulcerative
colitis, thyroid disease, pregnancy-induced hypertension and medically diagnosed high cholesterol.
But DTSC is developing a detection method that will applied to a wide variety of compounds, beyond PFOA and
PFOS, capturing substances that are being used in current manufacturing processes, as well as the historically
important chemicals -- PFOA and PFOS -- according to a DTSC researcher.
"Many of the compounds in the DTSC method are known to be precursors to the highly stable perfluorinated acids,
which include [PFOS, PFOA], and their shorter-chained analogs," the teleconference minutes say.
DTSC particularly wants information on polyfluorinated compounds, the DTSC researcher says, noting that the
researchers do not expect them to be found at levels as high as PFOA and PFOS. The polyfluoroalkyl compounds
might be precursors to perfluoroalkyl compounds, the source says. Chemical or biological reactions in the
environment can convert polyfluoroalkyl substances into perfluoroalkyl substances, according to another researcher
outside of DTSC.
The second researcher believes the most significant aspect of the effort by California is that it is looking at a wide
variety of compounds, some of which are precursors, in its creation of a standard method of detection. Broadly
speaking, the effort is important because California is starting to look at this issue in depth, the source says, noting
the state's traditional role as a leader among states on environmental regulatory issues and toxicology.
California's work was prompted in part by Air Force findings of PFASs at 100 percent of sites it sampled, and
separate findings of some of the highest levels of PFASs in the world found in marine mammals in San Francisco
Bay, according to DTSC staff. The state has a number of closed Air Force bases, the first researcher notes. Of
particular interest are locations where aqueous fire fighting foam, which contains PFASs, has been used in fire
fighting training, such as on military bases. DTSC suspects other potential locations are refineries and airports,
where the foam was used. Historically, PFOS was a component in the foam, although modern versions of the foam
have replaced that chemical with polyfluorinated compounds, according to the first researcher.
The DTSC lab is looking to reach a detection level of one nanogram/liter for the chemicals in groundwater, much
lower than the reporting threshold of 20-40 nanograms/liter for several PFASs called for under EPA's rule for
monitoring currently unregulated contaminants in drinking water.
The regulatory agency wants to be able to make low detections so it can determine the rate and extent of the
contaminants, and get a sense of the problem, a second DTSC researcher says.
DTSC's Environmental Chemistry Laboratory provides sample analysis and other support to the department for
cleanup and enforcement efforts, and studies issues of emerging concern that could lead to new regulations, a DTSC
spokesman says in a written response to questions. The lab had already been monitoring 12 PFASs in Californians'
blood through biomonitoring work, and has now expanded the method to include more PFASs in blood and
groundwater.
DTSC researchers during the teleconference solicited from EPA regional staff groundwater samples collected near
refineries, industrial complexes, landfills, airports and military and municipal firefighting training areas to help the
department validate the method and determine the range of PFAS concentrations found in groundwater from
different sources, the minutes say.
DTSC was able to test groundwater samples from within California to validate measuring PFASs, and is awaiting
samples from outside the state, according to the spokesman's written response. "Many analytes have been detected in
California groundwater samples," including PFOS, PFOA, perfluorohexane sulfonate, perfluorobutanoate,
perfluoroohexanoate, and 6:2 and 8:2 fluorotelomer sulfonate, he says."Other analytes capable of measurement have
not been detected in any samples," he adds.
The expanded detection method in groundwater is in the final stage of validation, according to DTSC researchers.
The second DTSC researcher says it is premature to know whether the state will develop policy or standards as a
result of the development of the new detection method and its use.
"Whether results of California's effort will drive interest [in] regulations will likely depend upon the frequency and
concentrations found," another researcher, who does not work for DTSC, says of the work.
Meanwhile, a spokesman for California's Office of Environmental Health Hazard Assessment says a governorappointed panel of scientific experts on biomonitoring will consider next year expanding biomonitoring work to
include a broader range of PFASs.
Superfund Report - 11/24/2014 , Vol. 28, No. 24
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