EPA Proposes Interim Cleanup Plan for Groundwater at the Davis Liquid Waste Superfund Site, Smithfield, R.I.
BOSTON – The U.S. Environmental Protection Agency (EPA) has released a Proposed Plan for an interim remedy for the cleanup of groundwater at the Davis Liquid Waste Superfund Site located on Tarkiln Road in Smithfield, Rhode Island. EPA is accepting public comments on the proposed plan until July 15, 2020. EPA is also holding a virtual public hearing on the proposal on June 24, 2020.
EPA has considered several alternative methods to address groundwater contamination at the Site and is seeking public comments on the preferred remedy. After the public has had an opportunity to review and provide comment, EPA will formalize selection of the interim remedy in a "Record of Decision (ROD) Amendment 2 (Interim Remedy)" expected in September 2020. This decision document will amend the groundwater remedy selected in the 1987 ROD and amended in the 2010 ROD Amendment.
EPA's preferred alternative for the interim remedy in the Proposed Plan is designed to prevent current and future human health and ecological exposure to, and risk from, hazardous materials until a final remedy is selected for groundwater at the Site. The proposed plan includes:
- In-situ treatment of groundwater contaminants, which will be evaluated at regular intervals to determine efficacy.
- Filling an existing man-made ditch to maintain groundwater flow in the overburden aquifer.
- Monitoring of the dissolved groundwater contaminant plume.
- Institutional Controls to prevent contact with contaminated groundwater and exposure to vapor intrusion from contaminated groundwater into structures.
- Continued monitoring and assessment as well as Five-Year Reviews to assess the performance of the interim remedy and ensure the Site remains protective of human health and the environment.
The interim action that EPA proposes defers the selection of a final groundwater remedy for the Site pending an evaluation of the effectiveness of in situ treatment to reduce the presence of "dense non-aqueous phase liquid" (DNAPL). During the first Five-Year Review of the Site's remediation, EPA will assess the need for changes to the interim remedy. During the second Five-Year Review, EPA will evaluate progress in reducing the DNAPL mass and attaining cleanup levels in groundwater.
The estimated total present value of this proposed cleanup approach, including construction, operation and maintenance, and long-term monitoring is approximately $6.7 million.
During the mid-1970s, local officials received complaints from nearby residents about chemical odors in their private water supply. The drinking water wells were found to have been contaminated by a variety of chemicals. The major contaminants of concern in the overburden and bedrock groundwater that exceed federal and state standards are: volatile organic compounds (VOCs), such as tetrachloroethene, trichloroethene, vinyl chloride and benzene; semi-volatile organic compounds (SVOCs), including bis(2-chloroethyl) ether; pesticides, such as aldrin and dieldrin; and metals, including arsenic and manganese.
Exposure risks to residents from contaminated groundwater has already been minimized by prior cleanup activities at the Site, including the following:
- Extension of the municipal waterline.
- Approximately 100,000 cubic yards of contaminated soil and debris were excavated and either disposed off-site or treated and backfilled at the Site.
- Removal of buried hazardous waste drums.
- Removal of over 6 million discarded tires.
More information and Public Comment Opportunity:
Copies of the detailed Proposed Plan, as well as historical information about EPA's efforts at the Davis Liquid Waste Superfund Site may be viewed on EPA's website at: www.epa.gov/superfund/davisliquid, or if local conditions allow, may also be reviewed at the Site information repository at the Greenville Public Library, 573 Putnam Pike Greenville, R.I. 02828.
EPA is accepting comments on the proposed interim plan. Comments must be submitted no later than July 15, 2020, and can be submitted either in writing or orally during the virtual public hearing or via voicemail.
On Wednesday, June 24, 2020, at 7:00 p.m., EPA will hold a virtual informational meeting, immediately followed by a formal public hearing at which people can submit oral comments, which will be included in the official record. Both events will be held virtually so people can participate online or by telephone. Detailed Instructions are available at EPA's website at: www.epa.gov/superfund/davisliquid.
Comments may also be submitted in writing during the 30-day public comment period, which may be submitted via email, fax or mail to:
Darryl Luce, Remedial Project Manager
US EPA New England
5 Post Office Square
Boston, MA 02109
EPA has established a dedicated voice mailbox at 617-918-1820 to receive oral comments during the 30-day comment period. Please note that there is a five-minute limit to voicemail messages.