The federal Environmental Protection Agency will remove soil contaminated with arsenic and lead from 10 residential yards on Capen Street next spring, officials announced this week.
Only two yards had levels of the metals that exceeded safety standards, according to Joseph Ferson of the state Department of Environmental Protection. But an additional eight spots will be cleaned up “to err on the side of caution,” he said.
The state will remove similarly contaminated soil this winter from a wooded area owned by the Department of Conservation and Recreation along the Neponset River, he said.
“Clearly, [with] any kind of contaminated area you have concerns, so we’re very happy it’s going to be cleaned up,” said Marion McEttrick, chairwoman of the Board of Selectmen. “This is being resolved in a very positive way for everyone in the neighborhood.”
The state was looking for PCBs when it tested soil along the Neponset River last summer and, instead, found high concentrations of lead and arsenic, Ferson said. The state then tested 14 properties on nearby Capen Street, he said.
Two Capen Street yards tested above residential safety standards for the heavy elements; eight had amounts within the safety standards but enough that warranted removal, Ferson said.
The residential safety standard for arsenic is 20 parts per million; one property tested 21.7, he said. That property also had an unsafe level of lead; the standard is 300 parts per million, and it tested 349.
The second property with safety problems didn’t exceed the arsenic standard, but tested at 560 parts per million for lead, he said.
It was unclear where the contamination originated.
The original thought was that it came from soil dropped along the banks of the Neponset River when it was dredged in the early 1960s, but a more likely theory blames pesticide and herbicide spraying in the area, Ferson said.
“We may never know the actual source,” he said.
Ferson said the federal government would pay for the cleanup, which involves removing about a foot of soil in the contaminated spots and replacing it with clean topsoil. He said only portions of the yards were affected. That work will start in the spring and should be in about a month, he said.
The work on the DCR property will start this winter, and also entails removing contaminated spots and replacing them with clean soil. McEttrick said the town was assured that only small machinery would be used and all precautions taken to keep dust down.
“There is a small area where people walk their dogs that probably will be used as a staging area, so there will be some inconvenience,” she said.
State and federal officials outlined the plan at a meeting this week in Milton that McEttrick and about 40 Capen Street residents attended.
“I didn’t hear any complaints from anyone,” she said. “In fact, I heard thank you’s.”
Johanna Seltz can be reached at firstname.lastname@example.org.