Draft guidance addresses screening and remediation goals

In February 2019, the EPA issued its Action Plan for per- and polyfluoroalkyl substances (PFAS). The Plan listed five priority actions and four short-term actions to address “key PFAS-related challenges.” One of the priority actions is to provide guidance for groundwater cleanup at sites contaminated with the two PFAS that have prompted the most concern—perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). The Agency recently released a draft of this guidance for public comment. 

The draft provides interim recommendations for addressing groundwater contaminated with PFOA and/or PFOS at sites being evaluated and addressed under federal cleanup programs, including the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) and corrective action under the Resource Conservation and Recovery Act (RCRA). The EPA makes it clear that those two statutes afford the Agency considerable latitude in setting the specifics of those recommendations.

“In addressing PFOA and PFOS contamination, EPA’s statutory and regulatory authorities provide the Agency with flexibility in how it ensures protectiveness of human health and the environment,” states the EPA.

While the draft groundwater guidance is only five pages, it represents an important federal response to the risk PFAS-contaminated groundwater poses to public health. Reactions to the draft were strong from stakeholders who believe the recommended levels provide an inadequate response trigger and level of protection. One environmental group noted that seven states are developing standards, including groundwater standards, for PFOA, PFOS, and other PFAS, which are considerably lower than those in the EPA’s draft.

Unique substances

PFAS are human-made substances that were introduced for commercial and industrial applications in the 1950s; the chemical group comprises over 3,000 substances. PFAS have unique surfactant properties that repel water, grease, and soil and have been used extensively as protectants for paper and cardboard packaging products, carpets, leather products, and textiles and in firefighting foams. PFOA and other PFAS have also been used as processing aids in the manufacture of fluoropolymers, such as nonstick coatings on cookware.

From the manufacturing and product development perspectives, part of the strong appeal of PFAS is that they are very stable. In the environment this means they are resistant to biodegradation, photooxidation, direct photolysis, and hydrolysis. (PFAS have been detected in the oceans and the Arctic, indicating they can migrate intact over long distances.) It also means that once they enter people through drinking water, food consumption, and inhalation, they stay in the body for years.

The Centers for Disease Control and Prevention (CDC) reports that both PFOA and PFOS are present in the blood of 95 percent of the general population. According to the Agency for Toxic Substances and Disease Registry (ATSDR), research “suggests” that high levels of PFAS “may” have health impacts that include high cholesterol levels, resistance to vaccines, increased risk of thyroid disease, decreased fertility in women, increased risk of high blood pressure in pregnant women, and lower infant birth rates. Studies have shown that PFAS causes cancer in animals; a link between PFAS and cancer in people has been neither conclusively established nor disproven.

As a result of voluntary phaseouts undertaken by chemical companies, certain PFAS are no longer manufactured in the United States. However, PFOA and PFOS are still produced internationally and can be imported into the United States in consumer goods. In the United States, there are also legacy stocks of PFOA and PFOS.

DOD’s firefighting foams

The highest levels of PFAS have been found in people who had occupational exposures to the substances and in those living near manufacturing facilities. There is also significant concern about the impact of PFAS—primarily PFOS and, to a lesser extent, PFOA—the Department of Defense (DOD) has used in in firefighting foams. In March 2019, Rep. Brian Fitzpatrick (R-PA) told the House Subcommittee on Environment that some of the highest concentrations of PFAS in drinking water have been found in his district. “This water contamination is primarily associated with the decades-long use of Aqueous Film Forming Foam—or AFFF—on and around military bases in my district,” said Fitzpatrick.

Also at the hearing, a DOD official pointed out that the Interstate Technology and Regulatory Council determined that only 3 percent to 6 percent of PFOA and PFOS were used as firefighting foam. 

“Of this percentage, DOD is only one of many users of AFFF, which also includes commercial airports, the oil and gas industry, and local fire departments,” said Deputy Assistant Secretary of Defense for Environment Maureen Sullivan. Sullivan added that the DOD is engaged in several activities to address PFAS in the environment. For example, in 2016, the DOD issued a policy requiring the military departments to prevent uncontrolled, land-based AFFF releases during maintenance, testing, and training. The policy also requires the military departments to remove and properly dispose of local warehouse supplies of AFFF containing PFOS (other than for shipboard use), where practical. Each military department is taking actions to remove this AFFF containing PFOS from its inventory, said Sullivan. Also, beginning in 2009, the DOD’s Strategic Environmental Research and Development Program initiated research into the fate, transport, and remediation of PFOS and PFOA.

“These efforts have matured from the small scale to field demonstrations that began under [the Environmental Security Technology Certification Program] in 2017 and have continued into 2019 as new technologies mature and are ready for field demonstration,” said Sullivan.

She noted that the DOD will follow the CERCLA process to fully investigate releases and determine appropriate cleanup actions based on risk. Whenever these actions address groundwater, documents such as the EPA’s groundwater guidance will play a critical role in determining the actions that will be taken and minimum cleanup goals that will be established, said Sullivan.

Screening sites

According to the draft guidance, screening generally refers to the process of identifying and defining areas, contaminants, and conditions at a particular site that may warrant further attention. Under CERCLA, RCRA, and other regulatory programs, at sites where contaminant concentrations are below risk-based screening levels, no further action or study is generally warranted. Screening levels are not the same as cleanup levels. A decision to take remedial cleanup action typically is based on the results of a baseline risk assessment performed following the recommendations provided in existing EPA guidance, which typically considers the risks posed by all contaminants at a site.

For noncancer effects, the Superfund program typically uses a hazard quotient (HQ) of 1.0 for screening when there is a single contaminant and 0.1 when more than one contaminant is present. The draft recommends an HQ of 0.1 for screening PFOA and/or PFOS for several reasons, including (1) the specific and limited purpose of a screening level; (2) the additive toxicity of PFOA and PFOS; and (3) the possibility that other PFAS compounds, which may be toxic but for which toxicity values may not currently be available, may be colocated with PFOA and/or PFOS.

For carcinogenic effects, the Superfund program generally uses a one-in-one-million excess cancer risk as the screening level. In the case of PFOS, the Agency states that the existing evidence does not support a strong correlation between tumor incidence and dose to justify a quantitative assessment. Also, the EPA says its analysis showed that the equivalent drinking water concentration derived from the reference dose (RfD) (a daily oral exposure that is not likely to have a deleterious effect over a lifetime) for noncancer effects of PFOA is lower than the concentration associated with a one-in-one-million risk, indicating that a screening value derived from the developmental endpoint for the RfD will be protective for the cancer endpoint as well. The EPA’s RfDs, which were used to derive the Agency’s 2016 health advisories (HAs) for PFOA and PFOS when put into Superfund risk equations for an HQ of 0.1, yield a recommended screening value of 40 parts per trillion (ppt) for each chemical.

PRGs

Preliminary remediation goals (PRGs) are initial targets for cleanup, which can be adjusted on a site-specific basis as more information becomes available during the remedial investigation/feasibility study process. Groundwater cleanup levels under CERCLA and similar programs are often established based on chemical-specific promulgated standards (e.g., federal or state drinking water maximum contaminant levels or other applicable or relevant and appropriate requirements (ARARs). Where ARARs are not available or are not sufficiently protective, the EPA generally establishes site-specific, risk-based cleanup levels for carcinogens and noncarcinogens.

In circumstances where a groundwater cleanup program is addressing PFOA- and/or PFOS-contaminated groundwater and where no state or tribal laws or regulations qualify as ARARs, the Agency recommends using the value of 70 ppt for the combined concentration of PFOA and PFOS as the PRG or equivalent preliminary cleanup goal for other programs. (That value was included in the Agency’s 2016 Drinking Water Health Advisory for PFOA.) Where state or tribal laws or regulations qualify as ARARs for PFOA or PFOS, those standards should be used to develop PRGs.

At Superfund sites, final remediation goals and remedy selection decisions should be consistent with CERCLA, the National Contingency Plan, and existing EPA guidance, says the Agency.

Carper says draft is inadequate

The draft contained little to please Senator Tom Carper (D-DE), the ranking member of the Environment and Public Works Committee. “After languishing in interagency review for months, the draft guidance finally released by EPA fails to adequately protect public health from this emerging crisis,” Carper said. 

According to Carper:

• The guidance does not include an emergency removal level for PFAS that will trigger provision of bottled water or other urgent measures to protect the public; this means that people drinking water contaminated at levels in excess of 70 ppt may not be entitled to safe drinking water during the months or years cleanup could take to complete. It also means there is no assurance that the EPA will step in in cases where no responsible party exists to address emergency levels of contamination.
• The guidance fails to clarify that the DOD has agreed to take action to clean up sites that are contaminated at levels between 70 and 380 ppt, a commitment the DOD had previously objected to making. 
• While the second paragraph of the guidance says it applies to “groundwater that is a current or potential source of drinking water,” the second page states that, “In situations where groundwater is being used for drinking water, EPA expects that responsible parties will address levels of PFOA and/or PFOS over 70 ppt.”  This indicates that it is possible that polluters will not be required to clean up groundwater that states have designated as a future source of drinking water.

Also, in an initial comment on the draft guidance, the Natural Resources Defense Council (NRDC) said the screening levels and PRGs were the same as those included in the 2016 HAs. “However, several states and federal agencies have since determined that the 2016 Health Advisory is not health-protective and have proposed stricter standards or guidelines for drinking water and groundwater,” said the NRDC.

The NRDC also pointed out that the ATSDR released a report in 2018 that proposed health thresholds for PFOA and PFOS approximately 10 times lower than the health threshold the EPA used to generate its HA for drinking water.

Based on its own research, the NRDC recommends a drinking water and groundwater standard of 2 ppt for PFOA, PFOS, and other PFAS and a treatment technique of reverse osmosis or the equivalent for total PFAS.