Roundtables Held on Decision Process for Peconic River Cleanup
Following the December 2000 workshop to explore alternative technologies for the Peconic River sediment cleanup, BNL held a series of roundtable meetings in October 2001 to allow for an exchange of information between project staff and stakeholders. A two-hour meeting was held on October 1 for BNL employees and meetings were held on October 3, 4, and 9 for the public.
Two of the public meetings took place at BNL, while the third was held at Cornell Cooperative Extension in Riverhead. The sessions were advertised in Newsday and Suffolk Life, a mailing was sent out to nearly 3,000 residents, and posters were placed at several locations in Riverhead. The roundtables were well attended; 18 employees attended the October 1 meeting and 89 stakeholders participated in the three public roundtables.
The objective of the roundtables was to deliver a progress report and to outline the process by which cleanup technologies would be considered for use when developing a new cleanup plan for the mercury, PCBs, and other contaminants in Peconic River sediment.
Roundtable participants were generally supportive of the plan to move forward with pilot studies and demonstrations of alternative technologies. Their comments mainly focused on the cleanup technologies, their cost, and the timeframes needed to achieve cleanup objectives.
In January 2002, a factsheet, Roadmap to Peconic River Cleanup, was drafted and mailed out to stakeholders. The factsheet identified four technologies other than excavation that showed promise - native species phytoremediation, electrochemical remediation, constructed wetlands, and vacuum dredging, and defined the process to be used to determine their suitability.
During the months that followed, the selected alternative technologies were reviewed. Electrochemical remediation, which uses an electric current to mobilize contaminants in the soil and cause them to migrate toward electrodes placed in the sediment, was initially considered as a way to remove the contaminants without disturbing the river vegetation. However, as more questions were asked, the CAC, the Peconic River Working Group, DOE, and BNL agreed that too many serious concerns remained and it was omitted from consideration. Native plant phytoextraction also initially appeared promising, but additional data showed that contaminant uptake by native Peconic River wetland plants would be extremely slow.
Pilot studies were conducted for vacuum dredging and sediment removal/wetland reconstruction based on input from the New York State Department of Environment Conservation. These were technologies that had already been demonstrated to be successful in other areas of the state.
While the pilot studies were taking place, BNL also reassessed the risk to human health. Following the completion of the Remedial Investigation/Risk Assessment in 1998 additional radionuclide data was collected during the Plutonium Contamination Characterization Report and the Supplemental Sediment Sampling Program. Community members also came forward and reported that people did fish in the river downstream of the Laboratory and that those fish caught were consumed. Thus the fish previously believed to be a threat to only to wildlife, might now pose a hazard to human health.
BNL's new risk assessment, Baseline Human Health Risk Assessment dated March 2003, evaluated the potential risk to human health for defined populations that may now, or in the future, be exposed to various contaminants that were identified in the upstream areas of the Peconic River. The assessment conclusion was that a potential risk that exceeded the criteria established by the EPA existed and remedial action objectives to address the possible risk needed to be established and implemented in a timely manner.
The new risk assessment information and the data from the successful pilot study (excavation and re-vegetation) were used to develop a new plan for cleanup of the Peconic River. The plan for the on-site portion of the river was released in September 2003. The plan called for removing mercury-contaminated sediment from defined areas, disposing of it off-site, and then restoring the river banks. In order to begin cleanup as quickly as possible, an Action Memorandum was issued in January 2004 for the on-site work where the highest concentrations of contaminants were located. In May 2004, a Proposed Remedial Action Plan was released that covered both the on- and off-site portions of the river. This time, the community supported the proposed plan. While awaiting finalization of a Record of Decision for the Peconic River, an Action Memorandum was issued in September 2004 for the off-site work. On-site work was completed in late 2004 and off-site remediation between the Laboratory boundary and just east of Wading River-Manorville Road, was completed in April 2005.
Following several years of monitoring, with exceptions at two sampling locations, one on-site and one off, contaminants in the water column, sediment, and in the fish, are trending downward. In 2010/2011, BNL went back into the river to cleanup two areas (approximately a third of an acre) showing residual mercury contamination.
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