Division of Hazardous Waste Remediation Croton Point Landfill1 Site Number 360001 Westchester County, New York Record of Decision March 1993 Funded Under Title 3 of the 1986 Environmental Q~alityBond Act New York State Department of Environmental Condewation . MARIO M. CUOMO, Governor THOMAS C. JORLING. ~ornrnissioner, RECORD 01 DECISION CROTON POI= SANITARY LWDFILG WESTCEESTER COmOrm, NEW YORK ID NUMBER 360001 PREPARED BY NEW YORX STATE DEPARTUENT OF ENVIRONMENTAL CONSERVATION DIVISION OF HAZARDOUS WASTE REHEDIATION NARCE 1993 DECLARATION FOR TEE RECORD OF DECISION SITE N M AND LOCATION Croton Point Sanitary Landfill Croton Point Peninsula Village of Croton-on-Hudson, Town of Cortlandt Westchester,County, New York Site Code: 360001 Funding Source: 1986 Environmental Quality Bond Act OF BASIS AND PURPOSE ST- This decision document presents the selected remedial actiqn for the Croton Point Sanitary Landfill Site, which was chosen in accord nce with the New York State Environmental Conservation Law (ECL), and is con istent with the Comprehensive Environmental Response, Compensation, and Li ility Act of 1980 (CERCLA), 42 USC Section 9601, et., aeq., as amended by thei Superfund Amendments and Reauthorization Act of 1986 (SARA). Exhibit A iclentifies the documents that comprise the Administrative Record for the site. The documents in the Administrative Record are the primary basis for the proposed remedial action. 4 ASSESSMENT OF THE SITE Actual or threatened releases of hazardous substances from this site, if not addressed by implementing the response action selected in this Record of Decision (ROD), present a current or potential threat to pubzic health, welfare, and the environment. DESCRIPTION OF TEE SELECTED REMEDY The major elements of the selected remedy include: o 3 Design and construction of an engineered capping syst to isolate the landfilled wastes from rainfall and human c cap system will extend over both the original fill area an Ballfield cell. A stonnwater diversion system will be incl hydraulically control precipitation induced runoff and to permitted discharge to the Hudson River and Croton Bay. tact. the This Design and construction of an active landfill gas coll ction system to prevent exposure to landfill emissions. This sys& will include active removal of landfill gases with a gas flare tp destroy the volatile components of the gas. 0 o Design and construction of a leachate seepage collectilon system. This system will enclose the landfill perimeter at the toe bf the cap. This system will collect and convey leachate seepage to a s ries of r system. pumping stations for permitted discharge to the sanitary s The system will have sufficient storage capacity to avoid dlischarging leachate to the sanitary sewer system during periods of hi& flow to the sewers (storm events). 4 o Environmental monitoring to determine the remedial. uroaram. Groundwater. surface waters. gases, storm;ater discharges and marsh sediments will all subjected to a periodic monitoring program designed to detect any ch gas in the effectiveness of the remedial program. Groundwater and su face water parameters monitoring parameters will include 6 NYCRR Part 360 baseli annually and routine parameters quarterly at a minimum for he first five years. Subsequent monitoring may vary based on those results. 5: t The County must prepare and submit for NYSDOH and NYSDEq acceptance a complete plan for the operational, maintainance and monworing activities, as well as long-term land after construction. Monitoring of leachate quality monthly for the first several years to quality which may impact the sewage treatment it. Should the leachate monitoring indicate quality or the sewage treatment plant's that the leachate would exceed those pretreatment limits, pretreatment of the ,?eachate will be implemented. Deed restrictions to prevent future uses of the si+ interfere with the effectiveness of the remedy. o that would The estimated net present worth of the preferred altern&ive described above is $33,370,000. This estimate includes $28,700,000 in lcapital costs and $4,670,000 in present worth of costs for the 30 year post closure based upon a combination of actual pr~jected annual operational costs. DECLARATION The selected remedv is ~rotectiveof human health and thk environment. complies with State and-fedekal requirements that are legally applicable o; relevant and a ~ ~ r o ~ r i ato t ethe remedial action to the extent ~racticable. and is cost-ef?actbe. Waiverp are justified for applicable 02 relevant hnd appropriate requirements that will not be met. This remedy ukilizes permanent solutions and alternative treatment or resource recpvery technologies, to the maximum extent practicable. However, beFaUSe treatment of the principal threats of the site was not found to be practicable, this remedy does not satisfy the preference for treatment as a pribcipal element. Because this remedy will not allow for unlimited use and unrestricted exposure to wastes, within five years after completion of rembdial action, a five year review will be conducted. This evaluation will be /conducted within five years after the completion of remedial action to iensure that