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News Releases from Region 01

Comments Sought on Revised Cleanup Plan for Nyanza Chemical Waste Dump Site, OU4 (Sudbury River)

Contact Information: 
Jim Murphy (murphy.jim@epa.gov)

BOSTON – This summer, EPA will be gathering public input on plans to modify the existing remedy for the Sudbury River component of the Nyanza Chemical Waste Dump Superfund Site in Ashland, MA.. The proposed modification entails replacing the Enhanced Natural Recovery (ENR) component of the 2010 remedy (also known as "thin-layer sand capping") with a monitoring only approach (referred to as Monitored Natural Recovery or MNR). Public input will be accepted until September 9, 2016.

If modified as proposed, all affected sections of the Sudbury River would be under the same continued MNR approach and institutional controls. MNR had been selected as the preferred remedy for the majority of the river concurrently with institutional controls such as posting and maintaining fish consumption advisories. The proposed modification for the Sudbury River component is based on reductions of mercury in fish tissue which are larger than were expected.

In 2014, EPA collected fish from that portion of the river (i.e., Framingham Reservoir No. 2) where thin-layer sand capping had been selected. The fish were collected and analyzed for total mercury. The same species, number, and size of fish were caught so as to compare the present-day risks from the consumption of fish to the levels of mercury (and risk) as calculated in 2003. The results of this study revealed a 21% decrease in mercury concentration and corresponding risk. Further, the risk to an adult fish consumer (as opposed to a child) are now below the level of adverse health effects for all river reaches.

In 2015, as part of the selected remedy specifying MNR in other river reaches, EPA collected additional fish from Reach No. 2, 4, 6, 8, 9, and 10. Like the 2014 collection effort in Reach 3 (described above), the same species, number, and size of fish were collected so as to allow the results to be compared with previous risk estimates. The newly calculated risk of adverse health effects from the consumption of these fish in these reaches decreased between 10% and 37%.

From August 10, 2016 to September 9, 2016, EPA will be seeking public input on recommended modifications to the site’s remedy for the Sudbury River.

Comments can be sent to Daniel Keefe at Keefe.Daniel@epa.gov or mailed in writing to

Daniel Keefe
U.S. Environmental Protection Agency
5 Post Office Sq.
Suite 100, mail code 07-01
Boston MA 02109

The details of EPA's recommendation are presented in a document called an "Explanation of Significant Differences" (ESD), which describes the actions and modification that the EPA believes are warranted. The draft Explanation of Significant Differences can be found on EPA's website at https://semspub.epa.gov/src/document/01/591246

More information:

All EPA documents and background on Nyanza Chemical Waste Dump Superfund Site (www.epa.gov/superfund/nyanza)

The draft ESD and additional EPA technical reports and documents are available for public review in the site information repositories located in both the Framingham and Ashland Public Libraries. The public may also review information about the site at the EPA Region 1 Records Center, 5 Post Office Square, Boston, MA, 617-918-1440.