The Environmental Protection Agency extended a public comment period on its proposed clean-up plan for the Pike and Mulberry Streets Superfund Site in Martinsville.

The deadline for submitting comments about the site is now Oct. 2.

The EPA has proposed on-site chemical oxidation of the 38-acre groundwater plume, continuing carbon filtration of the municipal drinking water and soil vapor intrusion mitigation in their plan. This proposal would take an estimated 15 years to complete at the earliest, and it addresses the potential pathways the contamination could harm human health.

The agency estimates it will cost around $7.54 million to mitigate vapors from the contaminated soil and an additional $4.27 to clean the groundwater to drinking water standards. The EPA will cover the costs.

Traditionally the proposal would have been presented at a town hall meeting, but due to COVID-19 restrictions, a virtual presentation was released.

The agency is asking for residents’ input on the proposed plan. Community response could change parts of the current plan.

“We hope you will all look at that document and give us any comments you might have. EPA will consider these comments and then select the final clean-up plan in a document called a record of decision,” said Erik Hardin, EPA remedial project manager for the Martinsville Superfund site, in the virtual presentation.

Tetrachloroethylene, or PCE, was first discovered in one of the three Martinsville municipal wells in 2002. The city called the Indiana Department of Environmental Management, which performed a site investigation. IDEM determined that a former industrial dry cleaner, Master Wear, was one of the facilities that contributed to the ground water contamination.

PCE is likely to be carcinogenic to humans and can harm the liver, nervous and reproductive systems, according to the Agency for Toxic Substances and Disease Registry.

Overseen by the EPA, an emergency clean-up action of the contaminated area was conducted from 2005 to 2008, and carbon filters were installed on the city’s well system to clean the drinking water.

During further investigation in 2011, soil vapor contamination was found containing PCE and Trichloroethylene, or TCE.

TCE is also carcinogenic to humans and affects the nervous and developmental systems, according to the toxic substances registry.

Despite clean-up efforts, the plume continued to grow and pose a threat to Martinsville’s drinking water, so in 2013, the site was listed as a Superfund and added to the National Priorities List.

From 2015-2017, the EPA conducted sampling of all potential pathways of exposure in seven phases.

It looked at six different options for groundwater clean-up before deciding on site chemical oxidation. Hardin said the chemical most likely to be chosen for the process is potassium permanganate, which would be brought onsite as a solution in a tanker truck.

The purple solution would be injected into the ground in the plume area at five possible proposed injection sites. Once injected into the ground, it doesn’t pose a risk to human health.

This option also is expected to treat more mass in a shorter amount of time.

One of the six options the EPA evaluated was using a sorptive-reactive material, such as PlumeStop, which it ruled out in the first round of testing and again after the city asked for a second look.

“I went back to our technical experts and asked them to do a deeper dive just to make sure we weren’t missing anything,” Hardin said. “We all still agreed there were still too many unknowns with this option for the EPA to be able to propose it. The issue is there isn’t enough long-term data to show how well it works, and it’s somewhat difficult to monitor. If you just look at the ground water it seems to go away quickly but the contamination is still down there, and monitoring what is happening with it is difficult.”

The agency also evaluated three drinking water treatment options and decided that the carbon filters currently being used by the city are still the best option.

However, Hardin cautions that if a resident has a private drinking water well in the plume area, it needs to be tested.

“We want to make sure no one is drinking from an untreated well that is drawing water from this plume,” he said. “We put effort into identifying private wells, but we can’t say we identified all of them. We were able to test the few private wells we found and they were in the clear, but those wells were located more at the edges or off to the side of the plume. If you have a private well, please let me or the city know so that we can get it tested. And at a minimum, don’t drink from that well until it’s been tested.”

Finally, for vapor intrusion mitigation, the EPA is recommending a three-step approach: pathway sealing, installation of vapor intrusion mitigation systems (VIMS) and soil vapor removal.

Vapor intrusion is the process in which chemicals such as volatile organic compounds (VOCs) in the soil or groundwater turn into vapor and enter buildings or homes through cracks in the foundation or openings for utility lines.

Of the 230 properties the EPA identified for testing, only 50 property owners gave the required written permission to test. Hardin says two homes were found to have issues, but he would like to look at a few more again.

“PCE and TCE vapors have been shown to be harmful to breathe in so, we strongly encourage those property owners to agree to this testing,” he said.

Hardin hopes to send letters asking for permission to test by early next year. In the meantime, property owners interested in testing should contact him directly.

The sampling is free and so is the installation of a vapor intrusion mitigation system if needed. These systems consist of pipes that are installed to carry vapors from below the property and up above the roofline, where they safely dissipate in the air.

“PCE breaks down quickly in the sunlight, and the concentrations we are looking at are so low that these are diluted to safe levels as soon as they are vented outside,” Hardin said.

To comment online about the proposed plan, click here, or to leave a confidential voicemail, call 312-886-6015. Residents can also email Kirstin Safakas, the EPA community involvement coordinator for the Superfund site, at safakas.kirstin@epa.gov.

The comment period now ends on Oct. 2.