Environmentalists are urging EPA to add homegrown food ingestion pathways into screening levels for cleanups of chemical constituents at waste sites, arguing their absence represents a “major gap” in protecting the public when previously contaminated sites are re-used and disproportionately affects vulnerable communities.
“The commitments by current EPA leadership to good science and to environmental justice [(EJ)] reinforce the need to commence a scientifically high-quality program to incorporate the food ingestion pathways into EPA’s Regional Screening Levels [(RSL)] for toxic chemicals, paralleling what is already done for radionuclides in EPA’s Preliminary Remediation Goals,” a coalition of 40 environmental and public health groups say in a March 15 letter to EPA Deputy Assistant Administrator Carlton Waterhouse. “Such an initiative would be particularly important in protecting vulnerable communities.”
In particular, they ask that EPA should add “consumption of homegrown foodstuffs in the resident scenario and a farmer scenario” in the RSL calculator.
An EPA spokesperson did not respond by press time to a request for comment on the letter but in the past officials have acknowledged scientific challenges in addressing such requests.
The government watchdog group Public Employees for Environmental Responsibility (PEER) led the letter, which was also signed by Natural Resources Defense Council, California Communities Against Toxics, and Committee to Bridge the Gap (CBG), among others. CBG previously raised the issue several years ago.
The groups argue EPA should close a major gap in making cleanups at Superfund, brownfields and other toxic sites more protective by ensuring remediated sites are safe enough to grow fruits and vegetables.
“Because of EPA’s failure to take into account risks from consuming food grown in chemically contaminated soil, hundreds of toxic sites around the country are not being cleaned up to levels that protect residents,” Jeff Ruch, Pacific director for PEER, says in a March 15 press release.
The groups are calling on the agency’s waste office “to fix this problem by instituting a project to include the food pathway in chemical cleanups as is done with radioactively contaminated sites.”
The request comes as supporters of brownfields cleanups and a key Democratic lawmaker are urging the agency to rethink its long-running practice of requiring cleanup only to levels required to meet future land use needs, saying a new approach is needed to prevent polluting facilities from locating on remediated sites near EJ communities.
Rep. Dan Kildee (D-MI), who represents Flint, MI, urged EPA late last year to emphasize EJ considerations when deciding where to allocate Superfund and brownfields grants it received under the bipartisan infrastructure law while also pushing aside its long-standing policy that calls for cleanup at brownfields sites only to levels needed to satisfy future site reuse.
That would “get the cart and the horse in the proper order here,” he said. First do cleanup -- that way the property can be developed in a way that is not required to reuse it for another polluting-related project, he said. That is the problem with brownfields, he argued, in that stakeholders look for a use of the property that reinforces the past use because it already is a “dirty site” and “the cleanup requirements are fairly minimal to continue with another dirty use.”
Regional Screening Levels Calculator
In the letter, the groups explain they would like to see EPA incorporate garden and farm pathways into the agency’s RSL calculator for chemicals, just like the agency has already incorporated such pathways into its Preliminary Remediation Goal (PRG) calculator for radionuclides.
Contaminated sites being cleaned up under the Superfund law or Resource Conservation & Recovery Act (RCRA) “are supposed to be cleaned up to remediation levels that take into account these food ingestion pathways when future land use (e.g., as set forth in local zoning) would allow them,” the groups write.
“However, because there is no RSL Calculator that can be used to assist in setting those levels, and therefore Remedial Project Managers would need to come up with separate levels for every individual site, it appears that the great majority of contaminated sites where such food ingestion pathways are relevant nonetheless do not consider them.”
They say that on a practical level, “this means that remediation levels at many sites may be very much less protective than they should be.”
Therefore, they ask EPA to add food ingestion pathways into the RSL calculator, parallel to the inclusion of such a pathway for radionuclides in the PRG calculator. They also contend that a “garden pathway” would be easily understood by lay people, gaining communities’ understanding of the protectiveness of the soil cleanup.
“While the task is not trivial, EPA already has a solid base of data on which such an effort can be based,” they say, referring, for example, to PRG calculator consumption rates for many types of homegrown fruits and vegetables drawn from the agency’s exposure factors handbook.
EPA's RSLs and PRGs are used at cleanup sites around the country to provide initial guidance as to what levels contaminants present on sites must be remediated. Sometimes these initial screens guide the eventual cleanup though additional sampling at the site often is taken to craft site-specific cleanup standards.
“The recommended approach for developing remediation goals is to identify screening levels at scoping, modify them as needed at the end of the [remedial investigation] or during the [feasibility study] based on site-specific information from the baseline risk assessment, and ultimately select remediation levels in the [record of decision],” EPA says on its website describing RSLs.
EPA offers the RSL calculator, default tables and users' guide on its website. The calculator allows anyone to plug chemicals into the calculator and craft screening level cleanup numbers.
“The RSL tables provide comparison values for residential and commercial/industrial exposures to soil, air, and tapwater (drinking water). The unified use of the RSLs, to screen chemicals at Superfund sites, promotes national consistency,” EPA says on its website.
One long-time environmentalist raised the issue of including a homegrown food ingestion pathway into the RSL calculator several years ago. Dan Hirsch, president of CBG and one of the signatories to the March 15 letter, in 2016 argued for the addition. If EPA does not include the garden vegetable pathway in its RSL calculator and tables, that source of exposure may be left out if site managers do not know they need to add it in, Hirsch said at the time, adding that it is perplexing the agency includes this pathway for the PRG calculator and not the RSL calculator.
Hirsch noted that some states, such as California, include the garden pathway in their cleanups for chemicals and pointed to one example, cleanup of the Santa Susana Field Laboratory Superfund Site near Los Angeles where California regulators are overseeing remediation. Differences between cancer risk estimates based on vegetable garden exposures versus soil contact exposures for scores of chemicals at this site suggest that leaving out the vegetable gardening exposure pathway generally reduces risk estimates by 10 times to 100 times, Hirsch said.
National Default Level
While EPA’s spokesperson did not respond to a request for comment on the 2022 letter, in 2016, EPA officials acknowledged the exposure pathway was missing from the RSL, but said that was due, in part, to difficulty in determining what a national default level should be.
"We've had trouble coming to a resolution on what would be a reasonable national default for garden soil," Michael Scozzafava, then the chief of the science policy branch within EPA's Office of Superfund Remediation & Technology Innovation (OSRTI), said in a 2016 interview with Inside EPA. Additionally, he said, "Currently we just don't have a lot of chemical-specific information."
But EPA's regional offices can consider the garden exposure pathway on a site-specific basis, Scozzafava said, adding that one of the things regional cleanup officials ask a community when planning a cleanup is whether people in the community garden.
Michelle Burgess, an OSRTI toxicologist, said during the same interview that plants' uptake of chemicals is "very geographically dependent." She noted that EPA's brownfields program "has put out a great deal of information because of the boom of urban gardening." She pointed to advice on EPA's brownfields website, such as the 2011 Interim Guidelines for Safe Gardening Practices at brownfield sites.
Environmentalists have cited concerns over the lack of a homegrown food pathway given the boost in urban gardening in recent years. But Burgess disagreed that excluding the garden exposure pathway from the RSL calculator means that sites are not sufficiently remediated. "I wouldn't say it would be left out," she said. "We look at risk if we didn't do anything and [compare to] future and potential uses. It's part of why the brownfields program has really improved on [its gardening guidance] because that's become so popular." -- Suzanne Yohannan (syohannan@iwpnews.com)
