New York State Department of Environmental Conservation ...

1 Joe Martens Commissioner New york State Department of Environmental Conservation Division of Environmental Remediation Office of the Director, 12th Floor 625 Broadway, Albany, New york 12233-7011 Phone: (518) 402-9706 Fax: (518) 402-9020 Website: Sent Via Email Only September 26, 2013 Walter Mugdan Director Emergency & Remedial Response Division United States Environmental Protection Agency 290 Broadway, 19th Floor, E38 New york , New york 10007-1866 Re: Gowanus Canal Site Site No.: 224133 Dear Mr. Mugdan: The New york State Department of Environmental Conservation (DEC), in consultation with the New york State Department of Health, has reviewed the Record of Decision prepared by the United States Environmental Protection Agency (EPA) for the Gowanus Canal Superfund Site in Brooklyn, New york city , NY.

2 The components of the remedy include: Dredging of the entire column of hazardous substance-contaminated sediments which have accumulated above the native sediments in the upper and mid-reaches of the canal (referred to as soft sediments ). In-situ stabilization (ISS) of those native sediments in select areas in the upper and mid-reaches of the canal contaminated with high levels of nonaqueous phase liquid (NAPL). Construction of a multilayered cap in the upper and mid-reaches of the canal to isolate and prevent the migration of polycyclic aromatic hydrocarbons (PAHs) and residual NAPL from native sediments.

3 Dredging of the entire soft sediment column in the lower reach of the canal. Construction of a multilayer cap to isolate and prevent the migration of PAHs from native sediments in the lower reach of the canal. Off-Site treatment of the NAPL-impacted sediments dredged from the upper and mid-reaches of the canal with thermal desorption, followed by beneficial reuse off-site ( , landfill daily cover) if possible. Off-Site stabilization of the less contaminated sediments dredged from the lower reach of the canal and the sediments in the other reaches not impacted by NAPL, followed by beneficial reuse off-site.

4 Excavation and restoration of approximately 475 feet of the filled-in former 1st Street turning basin. Excavation and restoration of the portion of the 5th Street turning basin beginning underneath the 3rd Avenue bridge and extending approximately 25 feet to the east and the installation of a barrier or interception system at the eastern boundary of the excavation. In areas where significant NAPL has infiltrated into the canal bank from the canal and is present at depths that may re-contaminate the remediated sediments, bulkhead replacement in conjunction with subsurface barrier walls as necessary to ensure the long-term effectiveness of the remedy.

5 Implementation of institutional controls incorporating the existing fish consumption advisories (modified, as needed), as well as other controls to protect the integrity of the cap. Periodic maintenance of the cap and long-term monitoring to insure that the remedy continues to function effectively. Combined sewer overflow (CSO) controls as discussed below. We look forward to coordinating our efforts in the remediation of upland sites bordering the Canal with the EPA s efforts in the Canal itself. The former Manufactured Gas Plant facilities (MGPs) will continue to be addressed by National Grid under the direction of DEC.

6 The remedial actions selected by DEC will prevent the migration of MGP contamination into the Canal, and the cleanup of the MGP facilities will be completed in accordance with schedules coordinated with the EPA. DEC recognizes that additional controls on contaminated suspended solids delivered to the Canal by Combined Sewer Overflows (CSOs) will be required to protect the integrity of the sediment remedy. Although DEC anticipates that reductions in CSO solids deposition throughout the canal will result as the current round of CSO upgrades is completed, the degree of reduction in contaminant loading is difficult to predict.

7 Monitoring of the effectiveness of these improvements will provide data to inform future decisions on the need for further improvements in CSO infrastructure. The city of New york s Long Term Control Plan (LTCP) will be required both to comply with DEC s Order on Consent pursuant to the Clean Water Act and to provide for contaminated CSO solids reductions sufficient to ensure the long-term effectiveness of the CERCLA remedy. The EPA s CERCLA remedial design will be informed and refined by the results of additional sampling and modeling, as well as by coordination with DEC and the NYC Department of Environmental Protection as they incorporate Post-Construction Monitoring (PCM) data developed to address CWA compliance through the LTCP implementation.

8 With this understanding, we concur with the selected remedy for the Gowanus Canal Site. Please contact me at (518) 402-9706 if you wish to discuss these issues. Sincerely, Robert W. Schick, , Director Division of Environmental Remediation Enclosure ec: John LaPadula, EPA Doug Garbarini, EPA Christos Tsiamis, EPA Krista Anders, DOH Joe Crua, DOH Michael Ryan, DEC September 23, 2013 Mr. Robert Schick, Director Division of Environmental Remediation NYS Dept. of Environmental Conservation 625 Broadway Albany, New york 12233 RE: Record of Decision Gowanus Canal Site Site #224133 Brooklyn/Kings County Dear Mr.

9 Schick: Per your Department 's request, staff reviewed the September 2013 Record of Decision for the referenced site to determine whether the selected remedy will be protective of public health. Human exposures to contamination in the canal will be addressed by the remedy as follows: Upper and Middle Reaches: Contaminated sediments above the native sediments will be removed and treated prior to disposing properly off site. In select areas, native sediments contaminated with non aqueous phase liquid (NAPL) will be stabilized in place. A multilayered cap will also be installed to isolate and prevent the migration of polycyclic aromatic hydrocarbons and residual NAPL from native sediments.

10 Lower Reach: The entire soft sediment column will be removed and disposed properly off site. A multilayered cap will also be installed to isolate and prevent the migration of polycyclic aromatic hydrocarbons from native sediments. Other: Approximately 475 feet of the filled in former 1st Street turning basin will be removed and restored. Contamination will be removed from the portion of the 5th Street turning basin beginning underneath the 3rd Avenue bridge and extending approximately 25 feet to the east, a barrier or interception system at the eastern boundary of the removal area will be installed, and the area will be restored.