Part, but not all, of the exposure calculus on what can be done at the LCP Chemicals Superfund site comes down to the fact small children tend to eat more dirt than they should. That’s why the standard of cleanup proposed by the Environmental Protection Agency for upland soils at the site isn’t as stringent as it could be otherwise.
LCP, which is zoned for basic industrial use, would be left to an industrial use standard, as opposed to residential use.
“When we look at a residential scenario, versus a commercial/industrial scenario, you have a lot of differences,” Kevin Koporec, an EPA human health risk assessor, said at the community hearing on LCP cleanup Thursday evening. “For a residential scenario, you have a young child, someone exposed since birth, so they weigh less, they incidentally ingest more soil than older children and adults, and certainly more than a typical worker does. So, they have a higher dose, and that’s the driver for why we would have a higher risk for residential, and therefore lower cleanup goals for residential.
“We also do look at length of exposure, as you mentioned. Especially for things that are carcinogenic, we average those out over a person’s whole lifetime. So, if it’s a person who’s exposed for a worker number of years — we assume 25 years, usually, versus 25-30 yers for a resident. It’s similar, but some of those years are as a child, for the resident, whereas, of course, for a worker, they’re not.”
What’s proposed is no action for the soils, which constitute about 2-5 feet of area above the water table. Pam Scully, one of the remedial project managers, said testing’s determined the soil is not a primary source of pollution for the groundwater. The soil is classified as Operable Unit 3 at the site, while groundwater is Operable Unit 2 and governed under a separate, but related, process.
While otherwise taking no action, the EPA would place into effect institutional controls.
“Institutional controls are administrative tools, they are covenants that are put on property deeds so that those properties cannot be used in a certain way,” Scully said.
For instance, the EPA would have access to the site to continue groundwater remedial actions, among other property rights.
Rachael Thompson of the Glynn Environmental Coalition asked whether the EPA believes workers are still protected, even though small, concentrated areas of chemicals remain on the property.
“Because of the way it’s been used in the past, we used a larger exposure area,” Scully said. “What we would normally do is, whatever our exposure area is, we use a more-conservative assessment of the average. We’re not trying to hide any hot spots — we look at what’s called a 95 percent upper-confidence limit, which means that we’re using a higher average than normal to assess that exposure area.
“We’re required, really, to look at what the future use is going to be, and the way it’s zoned right now, that would be what we would look at — a larger area for exposure. If, for some reason, it was sold off in smaller parcels, we would know about it, because Superfund sites aren’t just sold without EPA being involved.”
Responding to a question by Glynn County Commissioner Allen Booker, Scully said it’s possible for the majority of the site to go into reuse before it clears the Superfund process.
“One of my other sites is an active chemical facility, and we evaluated the risk at that facility, determined what the cleanup would be, and it’s basic industrial,” Scully said. “So, it affects people who are out there every day right now. But those people have access to that whole facility and it’s about 60 acres, and that’s the way we did that risk assessment on an exposure unit of 60 acres.”
Also, public comment on the plan for OU3 was extended, from Oct. 2 as originally stated, to Dec. 2. Those interested can email Scully at email@example.com or mail her at Pam Scully, US EPA-Region 4, 11th Floor, 61 Forsyth St. SW, Atlanta, Ga. 30303.