MIDDLESEX - Decades after a handful of Wilmington families began sounding the alarm over an apparent spike in childhood cancer diagnoses, federal authorities earlier this month unveiled plans to cleanup contaminated soils and subsurface pollution plumes at the Olin Chemical Superfund site by Route 129 and the Woburn line.
In an April 1 announcement, the U.S. Environmental Protection Agency proposed a multi-faceted remediation plan for various pollution sources that dot the landscape of a 53-acre parcel at 51 Eames Street.
The final EPA proposal is a virtual mirror image of a tentative remediation plan that was first pitched to various Wilmington officials and citizens during a virtual public forum in August of 2020.
The vast industrial site off of Eames Street, seated around underground aquifers that were until 2003 relied upon by much of the community for drinking water, is located by Woburn Street and reasonably close to I-93. For nearly a half-century, the site housed a multitude of plastics and rubber chemical manufacturers before being taken over by Olin Chemical in 1980.
Olin shuttered the plant in 1986 and is suspected of only partially contributing to the existing groundwater and soil contamination, but as the current site owner, the firm is being held largely responsible by the EPA for the cleanup.
According to initial projections first released in Aug. of 2020, the federal agency is estimating the cost of the cleanup will be at least $48 million.
"Issuing this final cleanup plan for the Olin Chemical Superfund Site is a major step towards ensuring that contamination at the site will not harm the health of people living near this site, and ultimately could allow for the site's reuse," said EPA New England Acting Regional Administrator Deborah Szaro earlier this month. "EPA is proud to be part of the cleanup solution of this site for the citizens of Wilmington."
It is possible that the final cleanup costs could exceed that figure, as the EPA’s final cleanup plan includes calls to further study the full breadth of subsurface pollutants that have sank to the bottom of a bedrock aquifer by Maple Meadow Brook.
Last fall, the EPA reportedly flew a specialized helicopter equipped with electromagnetic sensors over the wetlands in an attempt “to characterize the bedrock” and “better understand the distribution of contamination in the bedrock”.
The EPA proposal includes plans to remove contaminated wetlands soils and sentiments for off-site disposal, as well as for extraction of the pollutants from the aquifer itself through a a series of a extraction wells. The water would then be treated at a new onsite treatment system.
To ensure that solution is working, the EPA plans to “conduct long-term groundwater and surface water monitoring and periodic five-year reviews to ensure protectiveness of the remedy,” according to the final remediation plan.
Cancer cluster links
The EPA’s announcement about the Olin Chemical Superfund Site cleanup plan coincided closely with the release of a Mass. Department of Pubic Health’s (DPH) report in late March that potentially links the chemical plant contamination to a childhood cancer cluster in the 1990’s.
Specifically, just a week before the EPA unveiled the final remediation proposal, the Mass. Bureau of Environmental Health concluded that Wilmington children exposed to contaminated well water during pregnancy between 1990 and 2000 were more likely to develop leukemia and other childhood cancers than peers with no exposure to the pollutants.
The findings were based off of presumed exposure to two particular chemicals known to be present at the Olin Chemical site: NDMA, a semivolatile chemical commonly used as a lubricant and plastics softener, and an industrial solvent called trichloroethylene or TCE.
Mass. DPH officials conducted the study when Wilmington’s Board of Health, after being approached by a number of area parents, expressed concern about an childhood cancer cluster.
According to local and state authorities, between 1982 and 1989, Wilmington recorded just two instances of childhood cancer. However, between the years of 1990 and 2000, a total of 22 children were diagnosed with cancer, including 11 cases of leukemia and lymphoma-type forms of the disease.
“The most compelling results include statistically significantly higher odds of a leukemia or lymphoma diagnosis among children or adolescents whose mothers lived in homes with the highest estimated n-nitrosodimethylamine (NDMA) concentrations in drinking water compared to children or adolescents whose mothers were estimated to have had no NDMA exposure during the year before their child’s birth,” the study authors ultimately concluded.
“Although this study’s risk estimates were not precise, the associations suggested with past NDMA and/or TCE drinking water exposures offer what we believe is a plausible explanation, supported by valid objective data, for the pattern of elevated cancer observed in areas of Wilmington,” added the DPH epidemiologists.
According to DPH officials, the number of childhood cancer cases in Wilmington returned to a more normalized rate in 2001, when just one case was recorded.
That drop-off beginning at the turn of the century coincides with the town’s decision to shut down nearly half of its well-generated water supply about 18-years-ago.
Specifically, beginning in late 2002, the Town of Wilmington shuttered five of its nine drinking water wells after NDMA was detected in several samples taken from the Maple Meadow Brook aquifer, which sits downhill from the Olin Chemical property.
Today, the community purchases the bulk of its water supply from the Mass. Water Resource Authority (MWRA), the quasi-public entity that provides potable water and sewer services to dozens of Boston area cities and towns.
Olin Chemical officials paid for the costs associated with extending MWRA pipeline infrastructure into the community.
According to the EPA, it will likely take years before its cleanup plan is fully-impelmented, while the entire remediation effort could last untold decades.
Beginning with the introduction of the final plan earlier this month, EPA officials explained they were set to enter into direct negotiations with Olin Chemical to design the proposed on-site construction of a groundwater treatment system.
The design process itself is expected to last roughly nine months, and construction on the plant won’t begin until next year at the earliest.
Besides removing NDMA and TCE contaminates from the groundwater and polluted soils, the EPA also wants to remove plumes of other so-called “dense aqueous-phase liquids (DAPL)” through the extraction wells and cap other contaminated soils.
There are four pools of DAPL, which are dense liquids that quickly sink to the bottom of bodies of water. One extends under the Olin site, and second heads towards Jewel Drive by the former FedEx building.
The largest pool is located under both Jewel drive and Main Street, while smallest DAPL pools is believed to exist near Maple Meadow Brook. There is an estimated 25 million gallons of DAPL around the entire superfund site.
To help sort out the contamination sources, the EPA broke the site down into three “operable units” during a series of environmental impact studies conducted between 2010 and 2015.
Operable Unit 1 dealt with the former 30 acre Olin property itself including soil, sediment, and some surface water tributaries that run across that property. Operable Unit 2 includes all of the areas of surface water and sediment not only that exist on Olin’s property, but to the east of Olin’s property in the “east ditch,” which is the drainage ditch that runs along the MBTA corridor, and then to the west with Maple Meadow Brook and Sawmill Brook and the associated wetland areas.
Operable Unit 3 deals with the groundwater contamination, including the sites of what were once 20 separate private drinking wells in the area.
According to the EPA, the final remedial plan proposes the following:
• Begin cleanup of the aquifer by constructing and operating new groundwater extraction and treatment systems.
• Capture and treat oily waste and contaminated groundwater that flows into surface water by constructing and operating new multi-phase extraction and treatment systems.
• Construct and maintain caps and cover systems on areas of soil contamination, including an impermeable cap over the feature on the Olin property known as the “Containment Area.”
• Excavate contaminated wetland soil and sediment, dispose excavated materials off-site at an appropriate approved facility, and restore impacted wetlands and floodplains.
• Prevent potential exposure to contaminants that pose inhalation risks in future buildings by requiring additional evaluations and/or engineering controls such as vapor barriers or venting systems.
• Implement land use controls (called “Institutional Controls”) to protect the remedy and public health.
• Conduct long-term groundwater and surface water monitoring and periodic five-year reviews to ensure protectiveness of the remedy.