PROPOSED REMEDIAL ACTION PLAN Sag Harbor MGP final.pdf · PROPOSED REMEDIAL ACTION PLAN PAGE 2 The...

PROPOSED REMEDIAL ACTION PLANSag Harbor MGP

Sag Harbor (V), Suffolk County, New YorkSite No. 1-52-159

January 2006

Prepared by:

Division of Environmental RemediationNew York State Department of Environmental Conservation

Sag Harbor MGP 1-52-159 January 2006PROPOSED REMEDIAL ACTION PLAN PAGE 1

PROPOSED REMEDIAL ACTION PLAN

Sag Harbor MGPSag Harbor (V), Suffolk County, New York

Site No. 1-52-159January 2006

SECTION 1: SUMMARY AND PURPOSE OFTHE PROPOSED PLAN

The New York State Department of EnvironmentalConservation (NYSDEC), in consultation with theNew York State Department of Health (NYSDOH),is proposing a remedy for the Sag HarborManufactured Gas Plant. The presence of hazardouswaste has created significant threats to human healthand/or the environment that are addressed by thisproposed remedy. As more fully described inSections 3 and 5 of this document, the use of the siteas a manufactured gas plant has resulted in thedisposal of hazardous wastes, including benzene,toluene, ethylbenzene, and xylene (BTEX) andpolycylic aromatic hydrocarbons (PAHs). Thesewastes have contaminated the surface soil, subsurfacesoil, soil vapor and groundwater at the site, and haveresulted in:

• a significant threat to human healthassociated with potential exposure to surfacesoil, subsurface soil, soil vapor andgroundwater.

• a significant environmental threat associatedwith the impacts of contaminants to surfacesoil, subsurface soil, and groundwater.

To eliminate or mitigate these threats, the NYSDECproposes the following remedy:

• A remedial design program to provide thedetails necessary to implement the remedialprogram.

• Installation of an excavation support system;removal of the commercial building to thenorth of the property; excavation and off-sitedisposal of the top ten feet of contaminatedsoil; and backfilling of the excavated areawith clean fill from an off-site source whichhas been approved by NYSDEC.

• Covering all vegetated areas with clean soiland all non-vegetated areas with eitherconcrete or a paving system.

• Installation of several passive NAPLrecovery wells.

• Development of a site management plan toaddress residual contamination, evaluatebuildings for soil vapor impacts, address anyuse restrictions, and provide for theoperation, maintenance, and monitoring ofcomponents of the remedy.

• Imposition of an institutional control in theform of an environmental easement.

• Periodic certification of the institutional andengineering controls.


The proposed remedy, discussed in detail in Section8, is intended to attain the remediation goals identifiedfor this site in Section 6. The remedy must conformwith officially promulgated standards and criteria thatare directly applicable, or that are relevant andappropriate. The selection of a remedy must alsotake into consideration guidance, as appropriate.Standards, criteria and guidance are hereafter calledSCGs.

This Proposed Remedial Action Plan (PRAP)identifies the preferred remedy, summarizes the otheralternatives considered, and discusses the reasons forthis preference. The NYSDEC will select a finalremedy for the site only after careful consideration ofall comments received during the public commentperiod.

The NYSDEC has issued this PRAP as a componentof the Citizen Participation Plan developed pursuantto the New York State Environmental ConservationLaw and Title 6 of the Official Compilation of Codes,Rules and Regulations of the State of New York (6NYCRR) Part 375. This document is a summary ofthe information that can be found in greater detail inthe June, 2002 Remedial Investigation (RI) Report,the December, 2003 Final RI report, the September2005 Feasibility Study (FS), and other relevantdocuments. The public is encouraged to review theproject documents, which are available at thefollowing repositories:

John Jermain Public LibraryMain St, corner of Jermain StSag Harbor, NY Kevin Verbesey, Director(631) 725-0049Hours: Mon. - Sat. 10-5, Thurs. 10-9

NYSDEC Region 1 HeadquartersSUNY-Stony BrookStony Brook, NY 11790Contact: Mr. Walter Parish

Regional Hazardous Waste Engineer(631) 444-0241Hours: Mon.-Fri. 9-5 (by appointment)

Douglas MacNealNYSDEC- 11th Floor625 BroadwayAlbany, NY 12233-7014(518) 402-9564Hours: Mon.-Fri. 8-4 (by appointment)

The NYSDEC seeks input from the community on allPRAPs. A public comment period has been set fromJanuary 13 to February 17, 2006 to provide anopportunity for public participation in the remedyselection process. A public availability session isscheduled for January 25 from 6 until 9 at the PiersonMiddle-High School. A public meeting is alsoscheduled for February 6 at the Pierson Middle-HighSchool beginning at 7.

At the meeting, the results of the RI/FS will bepresented along with a summary of the proposedremedy. After the presentation, a question-and-answer period will be held, during which verbal orwritten comments may be submitted on the PRAP.Written comments may also be sent to Mr. MacNealat the above address through February 17.

The NYSDEC may modify the proposed remedy orselect another of the alternatives presented in thisPRAP, based on new information or publiccomments. Therefore, the public is encouraged toreview and comment on all of the alternativesidentified here.

Comments will be summarized and addressed in theresponsiveness summary section of the Record ofDecision (ROD). The ROD is the NYSDEC’s finalselection of the remedy for this site.


SECTION 2: SITE LOCATION ANDDESCRIPTION

The site occupies roughly 0.76 acres in thedowntown section of the Village of Sag Harbor inSuffolk County. The site is adjacent to theintersection of Bridge Street and Long Island Avenueand is roughly 200 feet to the south of Sag HarborCove. The site’s location is noted on Figure 1.

SECTION 3: SITE HISTORY

3.1: Operational/Disposal History

From 1859 to 1930 the site was operated as amanufactured gas plant. The plant originallyproduced gas from coal or wood rosin and wasswitched to a water gas process in 1892. The by-products of gas production that either spilled, leaked,or were disposed on the site are the source of thecontamination.

3.2: Remedial History

In 1997 a preliminary site assessment was performedon the MGP site and, as a result, the NYSDEC listedthe site as a Class 2 site in the Registry of InactiveHazardous Waste Disposal Sites in New York in1998. A Class 2 site is a site where hazardous wastepresents a significant threat to the public health or theenvironment and action is required. Following thatlisting, an Interim Remedial Measure (IRM) wasperformed to remove and cap historic piping that waspresent at the site to prevent migration of MGP by-products through these pipes.

Originally the site was part of the Sag Harbor BridgeStreet Site (Site Number 1-52-126) which was listedas a Class 2 site in the Registry of Inactive HazardousWaste Disposal Sites in New York in 1987. Thisoccurred after an incident when Suffolk CountyWater Authority workers were exposed to tar during

an excavation on Bridge Street. It was then delistedin 1995 because investigations had failed to findhazardous wastes on the Bridge Street Site as definedby the contemporary edition of 6 NYCRR Part 375.

SECTION 4: ENFORCEMENT STATUS

Potentially Responsible Parties (PRPs) are those whomay be legally liable for contamination at a site. Thismay include past or present owners and operators,waste generators, and haulers. The NYSDEC and KeySpan Corporation enteredinto a Consent Order on March 31, 1999. TheOrder obligates the responsible parties to implementa full remedial program.

SECTION 5: SITE CONTAMINATION

A remedial investigation/feasibility study (RI/FS) hasbeen conducted to evaluate the alternatives foraddressing the significant threats to human health andthe environment.

5.1: Summary of the Remedial Investigation

The purpose of the RI was to define the nature andextent of any contamination resulting from previousactivities at the site. The RI was conducted betweenApril 2000 and May 2004. The field activities andfindings of the investigation are described in the RIreport.

The following activities were conducted during the RI:

• Research of historical information;

• A survey of public and private water supplywells in the area around the site;


• Installation of 46 soil borings and 30monitoring wells for analysis of soils andgroundwater as well as physical properties ofsoil and hydrogeologic conditions;

• Multiple rounds of sampling of 32 new andexisting monitoring wells;

• Collection of 29 surface soil samples forchemical analysis;

• Collection of 134 discrete groundwatersamples using a direct push technique;

• Collection of 16 surface water samples;

• Collection of 18 aquatic sediment samples;

• Collection of 8 sediment pore water samples;

• Collection of 3 tap water samples;

• Collection of 4 storm water runoff samples;

• Collection of 13 soil vapor samples, 45indoor air samples, and 27 outdoor airsamples.

To determine whether the soil, groundwater, surfacewater, soil vapor, air and sediment containcontamination at levels of concern, data from theinvestigation were compared to the following SCGs:

• Groundwater, drinking water, and surfacewater SCGs are based on NYSDEC“Ambient Water Quality Standards andGuidance Values” and Part 5 of the NewYork State Sanitary Code.

• Soil SCGs are based on the NYSDEC“Technical and Administrative GuidanceM e m o r a n d u m ( T A G M ) 4 0 4 6 ;

Determination of Soil Cleanup Objectivesand Cleanup Levels".

• Sediment SCGs are based on the NYSDEC“Technical Guidance for ScreeningContaminated Sediments.”

• Indoor air SCGs are based on the NewYork State Department of Health Databasesummary of indoor and outdoor air sampleresults in control homes collected andanalyzed by NYSDOH from 1989 through1996.

Based on the RI results, in comparison to the SCGsand potential public health and environmentalexposure routes, certain media and areas of the siterequire remediation. These are summarized below.More complete information can be found in the RIreport. 5.1.1: Site Geology and Hydrogeology

The site is located in an area that was a marinewetland before being filled in the 1800s. Today, theground surface stands a few feet above sea level, withthe uppermost soil layer made up of material (sandysoils, brick fragments, ash, etc.) used to fill theoriginal wetland. The peat, silt and clay depositswhich formed the original wetland bottom are stillpresent at depths of 8 to 12 feet below the groundsurface. Below these lie several hundred feet ofunconsolidated sands.

The peat, silt, and clay layers are important becausethey are far less permeable than the predominantlysandy soils above and below. Groundwater andother liquids do not readily move through the peat,sand, and clay. In most areas, this has had the effectof limiting the degree to which MGP tar can movedownward through the subsurface. However, thesedeposits are absent in some portions of the site, and


MGP tar has moved downward into the underlyingsands in these areas.

The water table at the site is very shallow. Thedepth to groundwater varies from about 6 inches toabout 18 inches below grade. This high groundwaterlevel leads to localized ponding during heavy rains.The groundwater is tidally influenced, but consistentlyflows in a northerly or northwesterly direction. Thegroundwater is brackish and discharges to SagHarbor Cove.

5.1.2: Nature of Contamination As described in the RI report, many soil,groundwater, ambient and indoor air, and sedimentsamples were collected to characterize the nature andextent of contamination. As summarized in Table 1,the main categories of contaminants that exceed theirSCGs are volatile organic compounds (VOCs) andsemi-volatile organic compounds (SVOCs).

The principal human health and environmental risksposed by this site relate to the widespread distributionof MGP (coal) tar throughout the site and surroundingarea. Understanding the physical and chemicalbehavior of coal tar is essential to propercharacterization and clean up. The tar at this sitedoes not have the sticky, viscous consistency of othermaterials commonly labeled as “tar.” Instead, thecoal tar found at this site has the consistency of motoroil, and is consequently able to move about as a liquidthrough the subsurface.

MGP tar belongs to a group of organic contaminantsknown as dense non-aqueous phase liquids,commonly abbreviated as DNAPLs. DNAPLs donot readily dissolve in water and tend to sink to thebottom of water bodies and aquifers. When releasedinto the subsurface, these liquids can spread out incomplex directions that may or may not be the samedirection as groundwater flow. MGP tar is anunusual DNAPL, in that its density is only slightly

greater than water. Although MGP tar does tend tosink, the relatively slight difference in density betweentar and water makes this sinking effect somewhatunpredictable. Two classes of chemical compounds contained in thetar are of concern:

Benzene, toluene, ethylbenzene, and xylenes(collectively known as the BTEX compounds) arevolatile organic compounds, which are alsocommonly found in unleaded gasoline, paint thinnersand other solvents. They are somewhat soluble inwater; consequently, groundwater which comes intocontact with MGP tar often becomes contaminatedwith these compounds. This contaminatedgroundwater is then free to move away from the sitealong with the ordinary groundwater flow through thesubsurface.

The second class of compounds are known aspolycyclic aromatic hydrocarbons, commonlyabbreviated as PAH. This is a large group of semi-volatile organic compounds, with several hundreddifferent individuals known to exist. They are far lesssoluble than the BTEX compounds, and consequentlyare far less likely to cause groundwatercontamination. They are also far less likely to bedigested by soil bacteria, and thus are very persistentin the environment. The United States EnvironmentalProtection Agency has identified 17 of the PAHs ashazardous materials, and these are the ones used todefine the extent of PAH contamination at this site.

An inorganic contaminant of concern is cyanide.Cyanide, bound to iron to form ferric-ferro- cyanide,is a component of some MGP tars. While it is notdangerous in its bound form, certain conditions canrelease free cyanide, causing an exposure risk bothfor humans and the environment.


5.1.3: Extent of Contamination

This section describes the findings of the investigationfor all environmental media that were investigated.

Chemical concentrations are reported in parts perbillion (ppb) for water, parts per million (ppm) forwaste, soil, and sediment, and micrograms per cubicmeter (:g/m3) for air samples. For comparisonpurposes, where applicable, SCGs are provided foreach medium.

Table 1 summarizes the degree of contamination forthe contaminants of concern in surface soil,subsurface soil, groundwater, indoor air, surfacewater, soil vapor, and sediment and compares thedata with the SCGs for the site. The locations of allthe samples are noted on Figure 2. The following arethe media which were investigated and a summary ofthe findings of the investigation.

Waste Materials

The waste material associated with this site is coaltar. Coal tar has migrated to a depth of roughly 8-10feet below the ground surface. At this level, itencountered a layer of peat, silt and clay which itcould not readily penetrate, and spread laterally ontop of this layer beneath the MGP site. It has alsospread beyond the site boundaries, roughly 50 feet tothe south and 80 feet to the north, where it is nowfound beneath a row of retail stores.

Near the center of the MGP site, the peat, silt andclay layer is absent, and the MGP tar has spreaddownward much further, to a total depth of roughly90 feet. No deep penetration of tar has been foundbeyond the limits of the MGP site.

The tar now appears to be in a steady state, in whichthe overall limits of the tar migration should notchange unless site conditions change significantly.However, within the area of tar contamination, some

pockets of pooled, mobile tar may exist. This pooledtar can enter wells which are drilled nearby and couldenter future excavations as well. The extent of theMGP tar contamination is shown on Figures 3 and 4.This material requires remediation, as it acts as asource for soil and groundwater contamination.

Surface Soil

Surface soil samples were collected from the upper0-2 or 0-6 inches across the site, as well as off-site.All samples were analyzed for SVOCs, metals andcyanide. The off-site samples were also analyzed forVOCs.

Contaminated surface soil represents a potentialexposure route through ingestion, dermal contact, orthe breathing of dust or vapors coming from thesurface soil. Although BTEX was detected in the off-site samples, all of the detections were below theNew York State Recommended Soil CleanupObjectives from Technical Administrative GuidanceMemorandum 4046 (TAGM 4046).

PAHs were found in the majority of the surface soilsamples across the site and in some off-site areas.The maximum detections of PAHs were, in themajority of samples, above the individual SCGs. Thehighest total PAHs in surface soil was 950 ppm andwas found in the historic location of the southeasterngas holder.

Cyanide was identified in both on-site and off-sitesamples, with the maximum concentration foundonsite in the location of the former gas holders. Thecyanide is not above guidance levels and is, mostlikely, a constituent of the coal tar.

Subsurface Soil

PAH and BTEX contamination of subsurface soilswas detected in several areas, with the highestcontaminant concentrations found in areas where


visible tar contamination was present. Thus, thehighest levels of soil contamination are found in theshallow subsurface soils (generally less than 8 feetbelow the ground surface) in the eastern portion ofthe MGP site. Outside of the zones of tarcontamination, PAH and BTEX concentrationsdecrease rapidly. Individual BTEX concentrationsranged from not detectable to 500 ppm, and PAHconcentrations ranged from not detectable to 1,700ppm.

Cyanide was detected in only a few subsurfacesamples, at low levels. The highest value, 4.8 ppm,was found in an area of shallow visible tarcontamination, which also contained high levels ofPAH and BTEX.

The contaminants in the subsurface are anenvironmental concern as they are a potential sourceof groundwater contamination.

Groundwater

Both PAH and BTEX compounds are found in on-site and off-site groundwater, with the highestcontaminant levels found at shallow depths, in closeproximity to the MGP tar. Groundwater flowdirection is north toward Sag Harbor Cove.

BTEX compounds were found in the majority of thegroundwater samples, both on site and off site.Benzene was the individual compound detected mostfrequently, and at the highest concentration, withvalues ranging from non detect to 8,700 ppb. PAH compounds are less soluble than BTEX, butdue to the extensive distribution of MGP tar, theywere detected in most groundwater samples as well.Naphthalene is the PAH compound detected mostfrequently, and at the highest concentration, withvalues ranging from non-detect to 79,000 ppb.

The extent of groundwater contamination is shown onFigure 5.

Surface Water

Surface water and groundwater seep samples werecollected. The only site-related contaminant detectedwas xylene at a concentration of 1 ppb in one of the31 surface water samples, which is far below theSCG for xylene of 19 ppb.

Sediments

The sediments in Sag Harbor Cove were sampled forBTEX and PAHs. None of the samples indicate animpact from the MGP. The low levels of BTEX andPAH which were detected were distributed randomlyacross the survey area, which suggests that theyrepresent general background conditions in the areaand are not the result of MGP contamination.

Soil Vapor

Soil vapor samples were collected and analyzed forBTEX compounds and naphthalene. Naphthaleneand other PAHs were not detected in any of thesamples. BTEX was detected in samples collectedabove areas of MGP tars.

Indoor and Ambient Air

Indoor and ambient air samples were collected duringtwo rounds of sampling from buildings surroundingthe site. The samples were analyzed for VOCs,which included BTEX and naphthalene. Althoughsome VOCs were detected in several samples, theNYSDOH has determined that these detections donot appear to be related to the MGP site. Furthermonitoring of soil vapor and air samples will berequired to monitor for potential indoor air exposures.

5.2: Interim Remedial Measures

An interim remedial measure (IRM) is conducted ata site when a source of contamination or exposure


pathway can be effectively addressed beforecompletion of the RI/FS. There were no IRMsperformed at this site during the RI/FS.

5.3: Summary of Human Exposure Pathways:

This section describes the types of human exposuresthat may present added health risks to persons at oraround the site. A more detailed discussion of thehuman exposure pathways can be found in AppendixG and E of the June 2002 and December 2003 RIreports, respectively.

An exposure pathway describes the means by whichan individual may be exposed to contaminantsoriginating from a site. An exposure pathway has fiveelements: [1] a contaminant source, [2] contaminantrelease and transport mechanisms, [3] a point ofexposure, [4] a route of exposure, and [5] a receptorpopulation. The source of contamination is the location wherecontaminants were released to the environment (anywaste disposal area or point of discharge).Contaminant release and transport mechanisms carrycontaminants from the source to a point where peoplemay be exposed. The exposure point is a locationwhere actual or potential human contact with acontaminated medium may occur. The route ofexposure is the manner in which a contaminantactually enters or contacts the body (e.g., ingestion,inhalation, or direct contact). The receptorpopulation is the people who are, or may be,exposed to contaminants at a point of exposure.

An exposure pathway is complete when all fiveelements of an exposure pathway exist. An exposurepathway is considered a potential pathway when oneor more of the elements currently does not exist, butcould in the future.

Potential exposure pathways at the Sag Harbor MGPsite include the following:

• Direct contact with, incidental ingestion orinhalation of contaminated soil

• Direct contact with, or inhalation of vapors fromcontaminated groundwater

• Direct contact with or incidental ingestion ofNAPL

• Inhalation of vapors in indoor air related tosubsurface vapor intrusion

None of these pathways has been found to becomplete at this site. The contamination(contaminated soil, groundwater, and NAPL) isbelow the ground surface, which minimizes thelikelihood of incidental exposure. Two private watersupply wells were identified in the area surroundingthe site. Both were sampled, and neither containedsite-related contamination. The rest of the area usesa public water supply, which is routinely tested toensure that it meets drinking water standards formany chemicals, including the contaminants found atthe Sag Harbor MGP site. KeySpan collected tworounds of indoor air samples from many of thebuildings immediately surrounding the site, and theNYSDOH has determined that contamination fromthe site was not affecting the indoor air quality in thebuildings.

5.4: Summary of Environmental Impacts

This section summarizes the existing and potentialfuture environmental impacts presented by the site.Environmental impacts include existing and potentialfuture exposure pathways to fish and wildlifereceptors, as well as damage to natural resourcessuch as aquifers and wetlands.

The Fish and Wildlife Impact Analysis, which isincluded in the RI report, presents a detaileddiscussion of the existing and potential impacts fromthe site to fish and wildlife receptors. The followingenvironmental exposure pathways and ecologicalrisks have been identified: Site contamination has


impacted the groundwater resource in the upperglacial aquifer.

At this time, sediment sampling has not indicated anyimpacts to Sag Harbor Cove. However,contamination from the migration of DNAPL andgroundwater from the site could potentially enter SagHarbor Cove.

Sag Harbor Cove is an environmentally sensitive areawhich includes many species of flora and fauna. It isalso a valuable recreational resource to thesurrounding community. The potential for futurecontamination of the cove with MGP by-productscould lead to a decrease in the cove’s ability tosupport wildlife and could potentially lead to itsdevaluation as a recreational asset.

SECTION 6: SUMMARY OF THEREMEDIATION GOALS

Goals for the remedial program have beenestablished through the remedy selection processstated in 6 NYCRR Part 375-1.10. At a minimum,the remedy selected must eliminate or mitigate allsignificant threats to public health and/or theenvironment presented by the hazardous wastedisposed at the site through the proper application ofscientific and engineering principles.

The remediation goals for this site are to eliminate orreduce to the extent practicable:

• exposures of persons at or around the site toVOCs, SVOCs, and cyanide in surface soil,subsurface soil, groundwater and soil vapor;

• environmental exposures of flora or fauna toVOCs, SVOCs, and cyanide in surface soil,subsurface soil, and groundwater;

• the release of contaminants from soil intogroundwater that may create exceedances ofgroundwater quality standards; and

• the release of contaminants from surface soil,subsurface soil, groundwater, sediment, andsoil vapor into ambient air, indoor air,sediment, and surface water throughdesorption, storm water erosion,vaporization, wind borne dust anddissolution.

Further, the remediation goals for the site includeattaining to the extent practicable:

• ambient groundwater quality standards and

• recommended soil cleanup values for surfacesoils.

SECTION 7: S U M M A R Y O F T H EEVALUATION OF ALTERNATIVES

The selected remedy must be protective of humanhealth and the environment, be cost-effective, complywith other statutory requirements, and utilizepermanent solutions, alternative technologies orresource recovery technologies to the maximumextent practicable. Potential remedial alternatives forthe Sag Harbor Manufactured Gas Plant Site wereidentified, screened and evaluated in the FS reportwhich is available at the document repositoriesidentified in Section 1.

A summary of the remedial alternatives that wereconsidered for this site are discussed below. Thepresent worth represents the amount of moneyinvested in the current year that would be sufficient tocover all present and future costs associated with thealternative. This enables the costs of remedialalternatives to be compared on a common basis. Asa convention, a time frame of 30 years is used to


evaluate present worth costs for alternatives with anindefinite duration. This does not imply thatoperation, maintenance, or monitoring would ceaseafter 30 years if remediation goals are not achieved.

7.1: Description of Remedial Alternatives

The following potential remedies were considered toaddress the contaminated surface soil, subsurfacesoil, groundwater, and soil vapor at the site.

Alternative 1: No Action

Present Worth: . . . . . . . . . . . . . . . . . $2,000,000Capital Cost: . . . . . . . . . . . . . . . . . . . . . . . . . $0Annual OM&M: . . . . . . . . . . . . . . . . . $180,000

The No Action Alternative is evaluated as aprocedural requirement and as a basis forcomparison. It requires continued monitoring only,allowing the site to remain in an unremediated state.This alternative would leave the site in its presentcondition and would not provide any additionalprotection to human health or the environment.

Alternative 2A: Off-site excavation to a 10 footdepth, NAPL recovery, Engineered cap, On-sitecontainment cells, Institutional controls,Groundwater and indoor air monitoring

Present Worth: . . . . . . . . . . . . . . . . . $6,100,000Capital Cost: . . . . . . . . . . . . . . . . . . $3,200,000Annual OM&M: . . . . . . . . . . . . . . . . . $120,000

This alternative would involve containment of the tarwhich remains on the MGP site, combined withlimited excavation of neighboring properties where tarhas spread. The overall approach would be toremove the tar which has already left the MGP site,and to immobilize the tar which remains on theKeyspan property (MGP site). The remedy isillustrated in Figure 6.

Subsurface barrier walls would be installed aroundthe perimeter of the MGP site to prevent contaminantmigration off-site. An impermeable engineered capwould be installed within the limits of the subsurfacebarrier walls to prevent rainwater infiltration throughthe contaminated soil and to prevent any directexposures to contaminants. The barrier wall wouldextend downward far enough to reach the peat, silt,and clay unit beneath the site, thus reducing theimpact of the tar as a groundwater contaminationsource. It should also be noted that some tar hasbeen found below the peat, silt, and clay unit (whichis absent in the central portion of the MGP site), andthat the containment wall would not isolate thisdeeper contamination.

There would be two areas of off site excavation in theparking lots to the north and the south of the site.Excavation would proceed to a depth ofapproximately 10 feet, which should effectivelyremove all tar-impacted soil in these areas. Thecontamination underneath the retail stores adjacent tothe north site boundary would not be addressed bythis alternative.

NAPL collection wells would be installed in at leastthree locations within the limits of the barrier wall.The objective would be to reduce the volume of tarin the soil and to reduce the mobility of the tar thatremains. These wells will collect tar passively(without pumping); however, provisions would bemade to pump some or all of the wells at low flowrates if it appears that this would improve tar removal.The number of wells could be increased, if collectionfrom the initial wells proves successful.

An institutional control, in the form of anenvironmental easement on the MGP property, wouldbe established to protect the integrity of thecontainment system. Groundwater and indoor airquality would be monitored.


Construction of the remedy would requireapproximately 1 season (October through April).These time restrictions reflect a long-standingagreement between Keyspan and the Village of SagHarbor.

Alternative 2B: Off-site stabilization to a 10 footdepth, NAPL recovery, Engineered cap, On-sitecontainment cells, Institutional controls, Sub-slab depressurization system, Groundwater andindoor air monitoring

Present Worth: . . . . . . . . . . . . . . . . . $7,500,000Capital Cost: . . . . . . . . . . . . . . . . . . $5,500,000Annual OM&M: . . . . . . . . . . . . . . . . . $180,000

This alternative would include the features ofAlternative 2A, with the off-site excavation in thenorthern parking lot replaced by in-situ stabilization.Stabilization is a form of containment which involvesthe in-situ mixing of contaminants with a stabilizingagent such as cement. The overall approach is tomake a large, solid mass of low-strength concretewhose low permeability would reduce contact withgroundwater and thus reduce the amount ofgroundwater contamination being generated.

In addition, a sub-slab depressurization system wouldbe installed beneath the block of retail stores to thenorth of the site, to provide an increased level ofprotection against potential vapor intrusion. Thisalternative is also illustrated on Figure 6.

Construction of the remedy would requireapproximately 1 season.

Alternative 3A: Excavation of on-site and off-site source material to a 10 foot depth, NAPLrecovery, Institutional controls, Groundwaterand indoor air monitoring

Present Worth: . . . . . . . . . . . . . . . . $10,700,000Capital Cost: . . . . . . . . . . . . . . . . . . $9,100,000

Annual OM&M: . . . . . . . . . . . . . . . . . $100,000

This alternative would include the excavation of tar-impacted soil up to a depth of 10 feet over the entiresite as well as on the parcels to the north and south ofthe site. This would require the removal of theexisting commercial buildings on the north parcel. Asshown on Figure 7, the excavation limits would reachto Long Island Avenue on the north, into Bridgestreet on the west, east to the Post Office, and intothe parking area for the commercial building to thesouth

This alternative would remove the majority of tar inthe subsurface both on-site and off. The area of deeptar penetration in the center of the MGP site wouldbe the only appreciable location of contamination toremain.

The NAPL recovery, institutional controls,groundwater monitoring, and indoor air monitoringwould be similar to alternative 2A.

Construction of this remedy would require from1 to2 seasons.

Alternative 3B: On-site and off-site excavationto a 10 foot depth, On-site and off-sitestabilization to a 36 foot depth), NAPL recovery,Sub-slab depressurization system, Institutionalcontrols, Groundwater and indoor air monitoring

Present Worth: . . . . . . . . . . . . . . . . $12,300,000Capital Cost: . . . . . . . . . . . . . . . . . $10,400,000Annual OM&M: . . . . . . . . . . . . . . . . . $160,000

The excavation proposed in this remedy wouldinclude most of the site as well as the parking lot areato the south to a depth of ten feet. The stabilizationwould occur in three areas both on and off-site, to adepth of 36 feet, to contain the remaining deeperDNAPL in these areas. This alternative, including


the areas selected for excavation and deeperstabilization, is illustrated in Figure 6.

The sub-slab depressurization system would beinstalled beneath the retail building north of the site.The institutional controls and groundwater and indoorair monitoring aspects of the remedy would be similarto remedy 2A. The construction of the remedywould require from1 to 2 seasons.

Alternative 4: Excavation of on-site and off-sitesource material to a 10 foot depth, On-sitestabilization to a 60 foot depth, Institutionalcontrols, Sub-slab depressurization,Groundwater monitoring

Present Worth: . . . . . . . . . . . . . . . . $33,300,000Capital Cost: . . . . . . . . . . . . . . . . . $31,600,000Annual OM&M: . . . . . . . . . . . . . . . . . $160,000

This remedy would entail excavation of contaminantsfrom the top ten feet of soil both on the site and offthe site in the parking lot to the north and in theparking area for the commercial building south of thesite. Following this, stabilization would beperformed on the remaining contamination on-site toa depth of sixty feet below grade. The remedy isillustrated in Figure 6.

The sub-slab depressurization system would beinstalled beneath the retail store building north of thesite. The institutional controls and groundwater andindoor air monitoring aspects of the remedy would besimilar to remedy 2A. Construction would require from 1 to 2 seasons.

Alternative 5: Excavation of the site tounrestricted levels

Present Worth: . . . . . . . . . . . . . . . . $69,000,000Capital Cost: . . . . . . . . . . . . . . . . . $69,000,000Annual OM&M: . . . . . . . . . . . . . . . . . . . . . . . $0

This alternative would excavate the entire mass ofcontaminated soil, regardless of depth, to provide themaximum extent of groundwater protection and directexposure protection. Due to the great depth to whichtars have penetrated in areas where the peat, silt, andclay layer is absent, the excavation would be quitedeep and very expensive. With all contaminated soilremoved, there would be no need for ongoingoperation, monitoring, and maintenance.

Construction would require from 3 to 8 seasons.

7.2 Evaluation of Remedial Alternatives

The criteria to which potential remedial alternativesare compared are defined in 6 NYCRR Part 375,which governs the remediation of inactive hazardouswaste disposal sites in New York State. A detaileddiscussion of the evaluation criteria and comparativeanalysis is included in the FS report.

The first two evaluation criteria are termed “thresholdcriteria” and must be satisfied in order for analternative to be considered for selection.

1. Protection of Human Health and the Environment.This criterion is an overall evaluation of eachalternative’s ability to protect public health and theenvironment.

2. Compliance with New York State Standards,Criteria, and Guidance (SCGs). Compliance withSCGs addresses whether a remedy will meetenvironmental laws, regulations, and other standardsand criteria. In addition, this criterion includes theconsideration of guidance which the NYSDEC hasdetermined to be applicable on a case-specific basis.

The next five “primary balancing criteria” are used tocompare the positive and negative aspects of each ofthe remedial strategies.


3. Short-term Effectiveness. The potential short-term adverse impacts of the remedial action upon thecommunity, the workers, and the environment duringthe construction and/or implementation are evaluated.The length of time needed to achieve the remedialobjectives is also estimated and compared against theother alternatives.

4. Long-term Effectiveness and Permanence. Thiscriterion evaluates the long-term effectiveness of theremedial alternatives after implementation. If wastesor treated residuals remain on-site after the selectedremedy has been implemented, the following itemsare evaluated: 1) the magnitude of the remaining risks,2) the adequacy of the engineering and/or institutionalcontrols intended to limit the risk, and 3) the reliabilityof these controls.

5. Reduction of Toxicity, Mobility or Volume.Preference is given to alternatives that permanentlyand significantly reduce the toxicity, mobility orvolume of the wastes at the site.

6. Implementability. The technical and administrativefeasibility of implementing each alternative areevaluated. Technical feasibility includes the difficultiesassociated with the construction of the remedy andthe ability to monitor its effectiveness. Foradministrative feasibility, the availability of thenecessary personnel and materials is evaluated alongwith potential difficulties in obtaining specificoperating approvals, access for construction,institutional controls, and so forth.

7. Cost-Effectivness. Capital costs and operation,maintenance, and monitoring costs are estimated foreach alternative and compared on a present worthbasis. Although cost-effectiveness is the lastbalancing criterion evaluated, where two or morealternatives have met the requirements of the othercriteria, it can be used as the basis for the finaldecision. The costs for each alternative arepresented in Table 2.

This final criterion is considered a “modifyingcriterion” and is taken into account after evaluatingthose above. It is evaluated after public commentson the Proposed Remedial Action Plan have beenreceived.

8. Community Acceptance - Concerns of thecommunity regarding the RI/FS reports and thePRAP are evaluated. A responsiveness summary willbe prepared that describes public comments receivedand the manner in which the NYSDEC will addressthe concerns raised. If the selected remedy differssignificantly from the proposed remedy, notices to thepublic will be issued describing the differences andreasons for the changes.

SECTION 8: SUMMARY OF THEPROPOSED REMEDY

The NYSDEC is proposing Alternative 3A:Excavation of on-site and off-site source material toa depth of 10 feet, NAPL recovery, Institutionalcontrols, Sub-slab depressurization system,groundwater and indoor air monitoring as the remedyfor this site. The elements of this remedy aredescribed at the end of this section and are shown onFigure 7.

The proposed remedy is based on the results of theRI and the evaluation of alternatives presented in theFS.

Alternative 3A is being proposed because, asdescribed below, it satisfies the threshold criteria andprovides the best balance of the primary balancingcriteria described in Section 7.2. It would achievethe remediation goals for the site by removing soils ator near the surface which would are the most likely toexpose human and wildlife receptors to PAHs,BTEX, and cyanide. This removal would alsoprevent the contamination of shallow groundwaterand production of contaminated soil gas.


The proposed alternative is not expected to fullyachieve groundwater SCGs on site. Tar haspenetrated to depths beyond the limits that thisAlternative will reach. This deeper tar will continueto remain in contact with groundwater movingbeneath the site, and will continue to act as a sourceof groundwater contamination. However, with all ofthe shallow soil contamination removed, the shallowgroundwater contaminant levels are expected todecline significantly. Transfer of volatile contaminantsinto soil gas is also expected to diminish greatly as thecontaminant concentrations decline.

Alternative 1 was rejected because it did not meeteither of the threshold criteria. Remedial Alternatives2A, 2B, 3A, 3B, 4, and 5 all would meet the twothreshold criteria, so the choice between thesealternatives rests upon the remaining five balancingcriteria.

Alternative 2B would require the least construction,with the shortest construction time, and wouldtherefore have the fewest short-term impacts.Alternative 5, with its extended schedule and massivescale of construction, would present the most shortterm impacts, which would include increased noiseand truck traffic for the entire duration of theconstruction. Alternatives 2A, 3A, 3B, and 4 wouldall have similar short-term impacts, since they involvesimilar shallow excavation and installation of similarremedial components. Of these, Alternatives 3A, 3B,and 4 would have the longest construction schedulesat one to two years. These are still significantly lessthan the time required for Alternative 5.

Alternative 5 would have the greatest long-termeffectiveness, since it would permanently remove allor nearly all of the source material. The long-termeffectiveness of Alternatives 2A and 2B would relyheavily on institutional controls, which could be lesscertain in the long term. Alternatives 3A and 3Bwould offer proven long-term effectiveness due to theextent of the source removal and NAPL collection.

Only routine ongoing maintenance procedures wouldbe required. The containment remedies do notreduce the volume of waste, so their long-termeffectiveness would depend on maintaining theintegrity of the barrier wall and cap throughinstitutional controls. Although the cap would divertrainwater away from the contamination, this does notprevent the tar from contacting the groundwaterpassing underneath the site. Thus, the tar wouldcontinue to act as a source of groundwatercontamination.

Evaluating the long-term effectiveness of in-situstabilization, called for in alternatives 2B, 3B, and 4would require treatability testing during the remedialdesign phase of the project. The behavior of thestabilized cement/soil mixture when exposed toseasonal freeze/thaw cycles near the ground surfacehas not yet been established.

Alternative 5 would offer the greatest reduction oftoxicity, mobility or volume, although the actualincreased protection offered over the proposedAlternative is not significant. Alternative 2B wouldoffer minimal reduction in mobility and no reductionin toxicity or volume. Alternatives 2A and 3B wouldprovide more reduction in volume, with somereduction in mobility. The remaining activeAlternatives (3A and 4) would have similar levels ofreduction due to the source removal and NAPLcollection. However, of those six alternatives, 3Awould represent the most feasible and implementableoverall reduction in mobility and volume due to theextent of the source removal combined with NAPLcollection.

Alternative 2B would be the most easily implemented,since the limited off-site work would present fewaccess issues. Alternatives 2A, 3A, 3B, and 4 wouldhave comparable implementability, as the excavationin those options extends to the same level. However,Alternatives 3B and 4 both call for extensive in-situstabilization, which would have more implementation


issues to resolve than 2A and 3A. Alternative 5would be extraordinarily difficult to implement, due tothe depth of the required excavation. Extensiveexcavation support would be required to excavate to90 or more feet. Moreover, the highly permeablesubsurface soils would make dewatering of theexcavation extremely difficult. Sea water would beexpected to flow in from the adjacent Sag HarborCove at a very high rate.

Cost-effectiveness would vary greatly between thealternatives. Alternative 5 would be more than twiceas costly than the next highest alternative, while notproviding any appreciable increase in the level ofprotection from exposures. Alternative 2A would bethe least costly, but would also provide the lowestlevel of protection from exposure. Alternatives 2B,3B, and 4 would provide less protection, and withgreater uncertainty in long-term effectiveness than3A, at similar or greater cost. Alternative 3A,through source removal, NAPL collection,institutional controls, and long-term monitoring wouldaddress all of the readily accessible source materialat this site and would be in the middle of the costrange.

The estimated present worth cost to implement theremedy is $10,700,000. The cost to construct theremedy is estimated to be $9,100,000 and theestimated average annual operation, maintenance,and monitoring costs for 30 years is $100,000.

The elements of the proposed remedy are as follows:

1. A remedial design program would beimplemented to provide the details necessaryfor the construction, operation, maintenance,and monitoring of the remedial program.

2. An excavation support system to allow forshallow subsurface soil removal would beinstalled. The commercial building to thenorth would be removed. The top ten feet of

contaminated soil would then be excavated.Soils would be dewatered and transportedoff-site for proper treatment and disposal.The excavated areas would be backfilledwith clean soil materials from an off-sitelocation. Demolished building materialsdetermined to be free of contamination maybe used to backfill the lower portion of theexcavated areas.

3. All vegetated areas would be covered withone foot of clean soil and all non-vegetatedareas with either concrete or a pavingsystem.

4. Several passive NAPL recovery wells wouldbe installed to collect NAPL remaining in thesubsurface. The wells will collect tarpassively (without pumping) at first.Additional wells will be installed if additionalareas of mobile tar are identified. Low-flowpumping may be implemented if early resultsindicate that this would increase tar recovery.

5. A site management plan would bedeveloped to: (a) address remainingcontaminated soils that may be excavatedduring future redevelopment. The plan wouldnote that soils beneath the remaining peatlayer are considered contaminated; andwould require soil characterization and,where applicable, disposal/reuse inaccordance with NYSDEC regulations; (b)evaluate the potential for vapor intrusion forany buildings on or adjacent to the site,including provision for mitigation of anyimpacts identified; (c) identify any userestrictions; and (d) provide for the operationand maintenance of the components of theremedy.

6. Imposition of an institutional control in theform of an environmental easement that


would (a) require compliance with theapproved site management plan; (b) limit theuse and development of the property tocommercial uses only unless authorized byNYSDEC and NYSDOH; (c) restrict theuse of groundwater as a source of potablewater, without necessary water qualitytreatment as determined by NYSDOH; and(d) require the property owner to completeand submit to the NYSDEC a periodiccertification.

7. The property owner would provide aperiodic certification, prepared and submittedby a professional engineer or such otherexpert acceptable to the NYSDEC, until theNYSDEC notifies the property owner inwriting that this certification is no longerneeded. This submittal would containcertification that the institutional controls andengineering controls, are still in place, allowthe NYSDEC access to the site, and thatnothing has occurred that would impair theability of the control to protect public healthor the environment, or constitute a violationor failure to comply with the site managementplan.


TABLE 1Nature and Extent of Contamination

{April, 2000-May, 2004}

SURFACE SOIL Contaminants ofConcern

ConcentrationRange Detected (ppm)a

SCGb

(ppm)a

Frequency ofExceeding SCG

Volatile Organic Total BTEX NDd to 0.012 10 0 of 15

Compounds (VOCs)

Semivolatile Organic Total PAHs ND-950 500 2 of 29

Compounds (SVOCs)

SUBSURFACE SOIL

Contaminants ofConcern


SCGb

(ppm)a


Volatile Organic Total BTEX ND-1390 10 25 of 129

Compounds (VOCs)

Semivolatile Organic Total PAHs ND-6222 500 24 of 129

Compounds (SVOCs)

SEDIMENTS Contaminants ofConcern


SCGb

(ppm)a

Frequency ofExceeding

SCG

Volatile OrganicCompounds (VOCs)

Total BTEX ND-0.027 NA NA

NA NA

Semivolatile OrganicCompounds (SVOCs)

Total PAHs ND-46.8 ER-Lc= 4 7 of 18

ER-Mc=45 1 of 18

GROUNDWATER Contaminants ofConcern

ConcentrationRange Detected (ppb)a

SCGb

(ppb)a


Volatile Organic Total BTEX ND-23900 NA NA

Compounds (VOCs) Benzene ND-8700 1 109 of 240

Toluene ND-7900 5 41 of 240

Ethylbenzene ND-6900 5 84 of 240

Xylene ND-4600 5 92 of 240

GROUNDWATER Contaminants ofConcern


SCGb

(ppb)a



Semivolatile Organic Total PAHs ND-580200 NA NA

Compounds (SVOCs)

SURFACE WATER Contaminants ofConcern


SCGb

(ppb)a


Volatile Organic Total BTEX ND-1 NA NA

Benzene ND 10 0 of 16

Toluene ND 6000 0 of 16

Ethylbenzene ND 4.5 0 of 16

Compounds (VOCs) Xylene ND-1 19 0 of 16

Semivolatile Organic Total PAHs ND NA NA

Compounds (SVOCs)

SOIL GAS Contaminants ofConcern

ConcentrationRange Detected (:g/m3)a

SCGb

(:g/m3)a


Volatile Organic Benzene ND-52 NA NA

Compounds (VOCs) Toluene 3.8-349 NA NA

Ethylbenzene ND-39 NA NA

Xylene ND-172 NA NA

Semivolatile Organic Naphthalene ND NA NA

Compounds (SVOCs)

INDOOR AND AMBIENTAIR



SCGb

(:g/m3)a

Frequency ofDetection

Volatile Organic Benzene ND-11.4 NA 8 of 63

Compounds (VOCs) Toluene ND-400 NA 39 of 63

Ethylbenzene ND-14 NA 8 of 63

INDOOR AND AMBIENTAIR



SCGb

(:g/m3)a

Frequency ofDetection


Xylene ND-122 NA 25 of 63

Semivolatile Organic Naphthalene ND NA NA

Compounds (SVOCs)a ppb = parts per billion, which is equivalent to micrograms per liter, ug/L, in water; ppm = parts per million, which is equivalent to milligrams per kilogram, mg/kg, in soil; ug/m3 = micrograms per cubic meter

b SCG = standards, criteria, and guidance values; {list SCGs for each medium}

c ER-L = EffectRange - Low and ER-M = Effect Range - Moderate. A sediment is considered to be contaminated if either of these criteria is exceeded. If both criteria are exceeded, the sediment is severely impacted. If only the ER-L is exceeded, the impact is considered to be moderate.

dND = Not Detected

eNA = Not applicable


Table 2 Remedial Alternative Costs

Remedial Alternative Capital Cost Annual OM&M Total Present Worth

Alternative 1: No Action $0 $0 $0

Alternative 2A: Off-siteexcavation (10'), NAPL recovery,

Engineered cap, On-sitecontainment cells, Institutional

controls, Groundwater and indoorair monitoring

$3,200,000 120,000 $6,100,000

Alternative 2B: Off-sitestabilization (10'), NAPL recovery,

Engineered cap, On-sitecontainment cells, Institutional

controls, Sub-slab depressurizationsystem, Groundwater and indoor

air monitoring

$5,500,000 $180,000 $7,500,000

Alternative 3A: Excavation of on-site and off-site source material

(10'), NAPL recovery, Institutional controls, Groundwater

and indoor air monitoring

$9,100,000 $100,000 $10,700,000

Alternative 3B: On-site and off-site excavation (10'), On-site andoff-site stabilization (36'), NAPL

recovery, Sub-slabdepressurization system,

Institutional controls, Groundwaterand indoor air monitoring

$10,400,000 $160,000 $12,300,000

Alternative 4: Excavation of off-site source material (10'), On-site

stabilization (60'), Institutionalcontrols, Sub-slab

depressurization, Groundwatermonitoring

$31,600,000 $160,000 $33,300,000

Alternative 5: Restoration of thesite to pre-release conditions

$69,000,000 $0 $69,000,000

0 300150 Feet

SAG HARBORMGP

SAG HARBOR MANUFACTURED GAS PLANT

Site No. 1-52-159Figure 1

Site Location Map

SAG HARBOR MANUFACTURED GAS PLANT

Not to Scale

Not to Scale

B-09 NO VISUAL ENVIDENCE OF NAPL NOTED

I

Not to Scale

N

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

A

A

A

A A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

AA

A

A

MW-03

MW-04

MW-05

SHGP-05

SHGP-16

SHGP-18

SHGP-21

SHGP-22

SHGP-SHGP-26

SHMW-01S

SHMW-03S

SHMW-04S

SHMW-06S

SHMW-08S

SHGP-25

SHGP-29 (0.00)(0.00)

(0.00)(0.00)

(5)(37)

(610)(5,878)

(223)(557)

(3,250)(3,069)

(0)(156)

(75)(44)

SHGP-30 (0.00)(0.00)

(150)(385)

(950)(1,678)

(2,580)(5,126)

(2,068)(3,340)

(228)(610)

(212)(239)

(310)(1,643)

(1,866)(3,207)

(112)(187)

(1,885)(9,357)

(1,990)(17,924)

(1,003)(11,326)

(7,090)(7,261)

(792)(4,726)

(615)(1920)

(346)(5,381)

(6,960)(5,191)

(7,400)(3,910)

(6,860)(5,509)

SHGP-15

SHGP-12

SHGP-08

SHGP-10

MW-02

SHGP-27

SHGP-23

SHGP-28

(66)(32,594)

SHGP-17

SHGP-04

SHGP-01

SHGP-09

SHMW-07S

SHGP-11

SHGP-13

MW-01

SHGP-07

SHGP-02

MW-06

SHGP-06

SHGP-03

SHGP-19

SHMW-05S

SHGP-14

SHMW-09S

SHGP-20

SHGP-56

SHGP-55

SHGP-54

SHGP-53

SHGP-51

SHGP-50

SHGP-49

SHGP-48

SHGP-44

SHGP-45

SHGP-42

SHGP-41

SHGP-40

SHGP-39

SHGP-38

SHGP-37

SHGP-36

SHGP-35SHGP-34

SHGP-33

SHGP-32

SHGP-31

(1)(1)

(0.00)(40)

(1)(85)

(5)(103)

(33)(42)

(2)(102)

(0.00)(4)

(0.00)(228)

(38)(434)(75)

(84)

(148)(801)

(0.00)(12)

(0.00)(10)

(0.00)(170)

(0.00)(0.00)

(0.00)(0.00)

(0.00)(0.00)

(0.00)(0.00)

(0.00)(0.00)

(2,210)(2,860)

(1,827)(6,745)

(0.00)(0.00)

SHMW-12S

SHMW-11S

SHMW-10S

(2)(71)

(59)(60)

(9)(402)

(69)(170)

(0.00)(22)

(10)(0.00)

(874)(2,663)

(3,154)(5,107)

(0.00)(0.00)

(2,463)(4,694)

(1,363)(3,774)

(0.00)(0.00)

(5,840)(10,729)

(91)(258)

(102)(1,160)

(506)(2472)

(1,562)(6,585)

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

A

A

A

A A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

)Î

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

AA

A

A

MW-03

MW-04

MW-05

SHGP-05

SHGP-16

SHGP-18

SHGP-21

SHGP-22

SHGP-SHGP-26

SHMW-01S

SHMW-03S

SHMW-04S

SHMW-06S

SHMW-08S

SHGP-25

SHGP-29 (0.00)(0.00)

(0.00)(0.00)

(5)(37)

(610)(5,878)

(223)(557)

(3,250)(3,069)

(0)(156)

(75)(44)

SHGP-30 (0.00)(0.00)

(150)(385)

(950)(1,678)

(2,580)(5,126)

(2,068)(3,340)

(228)(610)

(212)(239)

(310)(1,643)

(1,866)(3,207)

(112)(187)

(1,885)(9,357)

(1,990)(17,924)

(1,003)(11,326)

(7,090)(7,261)

(792)(4,726)

(615)(1920)

(346)(5,381)

(6,960)(5,191)

(7,400)(3,910)

(6,860)(5,509)

SHGP-15

SHGP-12

SHGP-08

SHGP-10

MW-02

SHGP-27

SHGP-23

SHGP-28

(66)(32,594)

SHGP-17

SHGP-04

SHGP-01

SHGP-09

SHMW-07S

SHGP-11

SHGP-13

MW-01

SHGP-07

SHGP-02

MW-06

SHGP-06

SHGP-03

SHGP-19

SHMW-05S

SHGP-14

SHMW-09S

SHGP-20

SHGP-56

SHGP-55

SHGP-54

SHGP-53

SHGP-51

SHGP-50

SHGP-49

SHGP-48

SHGP-44

SHGP-45

SHGP-42

SHGP-41

SHGP-40

SHGP-39

SHGP-38

SHGP-37

SHGP-36

SHGP-35SHGP-34

SHGP-33

SHGP-32

SHGP-31

(1)(1)

(0.00)(40)

(1)(85)

(5)(103)

(33)(42)

(2)(102)

(0.00)(4)

(0.00)(228)

(38)(434)(75)

(84)

(148)(801)

(0.00)(12)

(0.00)(10)

(0.00)(170)

(0.00)(0.00)

(0.00)(0.00)

(0.00)(0.00)

(0.00)(0.00)

(0.00)(0.00)

(2,210)(2,860)

(1,827)(6,745)

(0.00)(0.00)

SHMW-12S

SHMW-11S

SHMW-10S

(2)(71)

(59)(60)

(9)(402)

(69)(170)

(0.00)(22)

(10)(0.00)

(874)(2,663)

(3,154)(5,107)

(0.00)(0.00)

(2,463)(4,694)

(1,363)(3,774)

(0.00)(0.00)

(5,840)(10,729)

(91)(258)

(102)(1,160)

(506)(2472)

(1,562)(6,585)

SAG HARBOR MANUFACTURED GAS PLANT SAG HARBOR (V), SUFFOLK COUNTY NEW YORK

CONTAMINANT IMPACTS IN SHALLOW GROUNDWATER (0 TO 10 FEET)

FIGURE 5

³

LEGEND:

ð

ÎC

Groundwater Probe Showing Total BTEX (top) and Total PAHs (bottom). All values are ug/l.

Monitoring Well Showing Total BTEX (top)and Total PAHs (bottom). All values are ug/l.

SHGP-15 (233) (557)

SHMW-07S(2011)(7211)

ÎC

Existing Monitoring Well Showing TotalBTEX (top) and Total PAHs (bottom). All values are ug/l.

MW-01(8)(402)

SCALE:

>100 ug/l Total BTEX/PAHs

>1,000 ug/l Total BTEX/PAHs

> 5,000 ug/l Total BTEX/PAHs>10,000 ug/l Total BTEX/PAHs

0 300150Feet

Not to scale

PROPOSED REMEDIAL ACTION PLAN Sag Harbor MGP final.pdf · PROPOSED REMEDIAL ACTION PLAN PAGE 2 The...

Documents

Transcript of PROPOSED REMEDIAL ACTION PLAN Sag Harbor MGP final.pdf · PROPOSED REMEDIAL ACTION PLAN PAGE 2 The...