PUBLIC HEALTH ASSESSMENT
PORT WASHINGTON LANDFILL
NORTH HEMPSTEAD, NASSAU COUNTY, NEW YORK
The Port Washington Landfill is on the eastern portion of Manhasset Neck which bordersHempstead Harbor, Nassau County, New York. The community of Port Washington is west ofthe site. On-site and off-site contamination of groundwater and soil gas has been attributed to asection of this municipal landfill called L4. Principal contaminants are volatile organic compounds(gasoline components, dry-cleaning fluids, solvents) from industrial waste disposal at the site. Aresidential area is 100 feet west of the landfill. In the past, landfill soil gas had migrated westwardinto this residential neighborhood. People can be exposed to contaminated soil gas from thelandfill, either through sub-surface migration into homes or through ambient air. The landfill soilgas plume may have migrated to as many as 20 homes and several minor explosions have beendocumented. The area is served by a public water supply system using groundwater wells. Theclosest public water supply well is 1,300 feet west of the landfill and was taken out of service afterlow levels of volatile organic compounds (VOCs) were detected in the water.
During the fall of 1990 operational problems at the then active disposal cell, called the L5 Field 3,led to the production of large amounts of hydrogen sulfide gas which migrated off-site. People inthe community complained of odors and were concerned about short-term health effects. InMarch 1991 the Agency for Toxic Substances and Disease Registry (ATSDR) completed a healthconsultation in response to citizen concerns over the hydrogen sulfide emissions from the L5portion of the Port Washington Landfill. The ATSDR concluded that the concentrations ofhydrogen sulfide which were measured on- and off-site posed a potential health threat to on-siteworkers and sensitive individuals living next to the landfill. The ATSDR recommendations in the health consultation reiterated the need for the actions which have since been taken.
Based on the information reviewed, the Port Washington Landfill represented a public healthhazard (see Appendix E for additional information) because of past exposures to site-relatedcontamination in soil gas, groundwater and ambient air. The town installed active and passive gasventing systems to control the off-site migration of soil gas. The Nassau County Department ofHealth (NC DOH), the New York State Department of Health (NYS DOH) and the New YorkState Department of Environmental Conservation (NYS DEC) directed the Town of NorthHempstead to perform remedial measures to reduce or eliminate hydrogen sulfide emissions. TheTown of North Hempstead performed these measures by February 1991 and greatly reduced theemissions. The site currently poses a no apparent public health hazard.
The NYS DOH has made further recommendations to (1) control and monitor landfill gasemissions, (2) address the landfill's role as an on-going source of groundwater contamination and treat existing groundwater contamination, and (3) conduct additional health studies.
The data and information developed in the public health assessment for the Port WashingtonLandfill, North Hempstead, New York, have been reviewed by the ATSDR's Health ActivitiesRecommendation Panel for appropriate follow-up with respect to health activities. The panelagreed that fact sheets and public meetings should continue to be used by county, state andfederal agencies to provide health information. The panel also determined that a review of healthstatistics and education of local health professionals are needed. In addition, the panel determinedthat the site be considered by the NYS DOH for inclusion in the state VOC registry.
Public health actions have been taken and/or are planned. (1) The NYS DOH evaluated thecancer incidence in census tracts north and west of the Port Washington Landfill for the years1978-1984. The 1987 study showed a significant excess of brain cancer among males in a smallportion of the study area. (2) As a follow-up, the NYS DOH is conducting a study of cancerincidence near a number of landfills in New York State which are known to be generating landfillgases, including the Port Washington Landfill. (3) The NYS DOH and the NC DOH haveprovided, and will continue to provide information in response to residents' health concerns. (4)Landfill closure measures will be taken which will prevent on-site contact with contaminatedmedia and reduce human exposure due to the migration of contaminants from the site. (5) Theconstruction of a groundwater treatment facility is planned. (6) An operation and maintenanceplan for the landfill gas withdrawal system will be developed. (7) The selected clean-up remedyfor the site will include a long-term monitoring plan to determine the effectiveness of the remedy.
The Port Washington Landfill is in the northwestern portion of Nassau County, New York, in theTown of North Hempstead (Figure 1). It is on the eastern portion of Manhasset Neck and isbordered to the east by Hempstead Harbor, to the south by the Seaview Industrial Park, to thewest by the North Hempstead Country Club and a residential area which is part of the PortWashington community, and to the north by a gravel mine. The landfill is on a 139 acre lot,owned and operated by the Town of North Hempstead. The parcel contains two landfilled areas;L4 is a 53 acre inactive section and L5 consists of four 15- acre sections, three of which were closed and the other one was never used.
The "L4" section of the Port Washington Landfill was placed on the United States EnvironmentalProtection Agency (US EPA) National Priorities List (NPL) in December 1982 because ofcontamination in the area. Planning for a remedial investigation/feasibility study (RI/FS) wasstarted in 1984. The RI/FS report was completed in June of 1989. The Remedial Investigation is carried out to determine the nature and extent of contamination at the site. Remedialinvestigations follow preliminary site investigations conducted by Town, County, State and/orFederal agencies that verify hazardous wastes are present and that the wastes pose a significantthreat to public health and the environment. The FS uses RI information to develop alternativeremedial actions that will reduce or eliminate the threat to public health or the environment posed by the site.
Prior to the Town's purchase of the property, the site was a sand and gravel mining operationwhich began in the 1880's when sea water was used for washing the sand and gravel from steepbanks. After the mining operation stopped, the All American Sand and Gravel Company used thesite as a construction and demolition debris landfill. The land was purchased by the Town for a municipal landfill in 1973.
The initial design of the landfill called for placing a clay liner between the refuse and the nativesoil. In January 1974, a 20 mil polyvinyl chloride (PVC) liner was installed which covered only 4acres. Landfilling at L4 began in March 1974. About 260,000 tons per year of waste materialwere disposed at the L4 landfill. The fill consisted of residential, commercial, industrial,construction and demolition debris, and incinerator residue. Oil and gasoline saturated soil andasbestos were also disposed under New York State permit. Nearby residents have stated thatdrummed liquid waste were disposed at the site.
During 1975, leachate overflowed the liner and numerous odor complaints were made byresidents in the surrounding communities. Leachate seeps occurred in areas of the landfill notprotected by the liner. In March of 1976 a leachate treatment system was constructed consistingof a collection system, a receiving lagoon, and mechanical aerators. The effluent was chlorinatedand then returned back to the L4 section through a series of sprinkler heads on the surface. Continuing problems with leachate due to the incomplete liner resulted in inorganic and organiccontamination of on-site groundwater monitoring wells in 1977. In September 1977, the leachatecollection system was connected to the Port Washington sewer system.
Expansion of the L4 section started in 1979 and eventually the liner covered a total of 29 acres. In addition to the PVC bottom liner, clay material was placed between waste material and thesand and gravel banks on the west side of the site.
During the winters of 1979, 1980 and 1981, small furnace area explosions occurred in homes100-500 feet west of the landfill. In 1981, the NC DOH did extensive monitoring of the ambient,indoor, and soil gas and found methane levels that exceeded the lower explosive limits insideseveral homes. Volatile organic compounds (VOCs) in several of the affected homes ranged from10.9 micrograms per cubic meter (mcg/m3) for 1,1,2-trichloroethane to 612 mcg/m3 for vinylchloride. Soil gas sampling showed methane along the western boundary of L4 as well asextending onto the North Hempstead Country Club property to the southwest and to the SeaviewIndustrial Park to the south. As a result of the off-site methane migration, the Town installed, inseveral phases, active and inactive gas venting systems. Between July and October 1982, the USEPA monitored emissions from the passive vents at the landfill. Methane and other gases (vinylchloride, toluene, tetrachloroethene, trans-1,2-dichloroethene, 1,1,1-trichloroethane andethylbenzene) were being emitted from the landfill vents. Given the close proximity of residential areas to the site, the contaminants could migrate via ambient air into these areas west of the site.
In September 1980, VOCs (1,2-dichloropropane, 1,1,1-trichloroethane and tetrachloroethene)were detected in the Port Washington Water District's (PWWD) Southport Well, about 1,300 feetwest of the L4 landfill. The initial finding of 107 micrograms per liter (mcg/L) for1,2-dichloropropane was not confirmed by subsequent analysis in early March 1981. Samplescollected in September 1981 showed 1,1,1-trichloroethane and tetrachloroethene at levels of 5and 2 mcg/L, respectively, not exceeding NYS DOH or US EPA drinking water standards. Thewell was taken out of service in June 1981 on the basis of the detection of 33 mcg/L and 47mcg/L of vinyl chloride in consecutive analyses. These results were later retracted by thereporting laboratory because improper instrumentation was used in the analyses. Additionalsamples collected in June and July 1981 and tested by two independent laboratories ruled out the presence of vinyl chloride; however, the follow-up samples were collected after the well pump was shut down.
Disposal operations ceased at the L4 landfill in July 1983. Since then, disposal activities werecarried out at the adjacent L5 portion of the Town landfill. The current cell within the L5 landfillbegan operation in December 1989. This cell (Field 3) received baled municipal wastes, rawsewage sludge, uncompacted commercial and municipal wastes and processed construction anddemolition debris (containing gypsum products) until the cell was closed by order of the NassauCounty Board of Health in January 1991.
Because of poor operation and an inadequate or inoperative leachate collection system, severalmillion gallons of leachate accumulated within Field 3 and beginning in late summer and fall of1990, Field 3 began emitting high levels of hydrogen sulfide, methane and, to a lesser extent,VOCs. Hydrogen sulfide air levels measured off-site exceeded 1 part per million (ppm) on severaloccasions. Under several consent orders and a summary abatement order with New York State,the Town installed a gas containment system which used the horizontal combustion unit operatingat the L4 landfill. Hydrogen sulfide levels on and adjacent to Field 3 were significantly reduced bymid-February 1991. In March 1991 the ATSDR completed a Health Consultation in response tocitizen concerns over the hydrogen sulfide emissions from the L5 portion of the landfill. TheATSDR concluded that the concentrations of hydrogen sulfide which were measured on- andoff-site posed a potential health threat to on-site workers and sensitive individuals living next to the landfill. The ATSDR recommended the following actions which have since been taken:
- continued maintenance and operation of gas and leachate collection systems,
- continued air monitoring until gas and leachate collection systems are operating,
- periodic air monitoring to determine effectiveness of collection systems once they are operating,
- continued access restrictions to the landfill,
- continued area health advisory as determined by air monitoring results,
- referral of persons with preexisting respiratory problems and sulfur allergies to their personal physician.
The Record of Decision (ROD) presents the remedial action for an inactive hazardous waste siteand documents the information and rationale used to arrive at the decision. A ROD was signed inSeptember 1989 and includes the construction of a permanent landfill cap on the L4 section,extension of the existing gas venting system around the perimeter of the L4 section, up-gradingthe existing active gas venting system and pumping and treatment of contaminated groundwater. The US EPA and the Town of North Hempstead negotiated a Consent Decree for the RemedialDesign, which was signed in September 1991. A significant portion of the project costs will bepaid by the New York State 1986 Environmental Quality Bond Act which will reimburse theTown for three quarters of allowable expenses for investigations, design and construction. Current projections for the completion of the remedial construction is 1998.
In 1987, the NYS DOH evaluated the cancer incidence in census tracts north and west of the PortWashington Landfill for the years 1978-1984. The study showed a significant excess of braincancer among males in a small portion of the study area. As a follow-up, the NYS DOH isconducting a study of cancer incidence near a number of landfills in New York State which areknown to be generating landfill gases, including the Port Washington Landfill. The NYS DOHand the NC DOH have provided, and will continue to provide information in response toresidents' health concerns. The NYS DOH assisted the NC DOH by reviewing hydrogen sulfideair monitoring data and providing technical assistance.
Staff of the NYS DOH and the NC DOH visited the site during February 1985 to collectinformation for the NYS DOH Human Exposure Potential Ranking Model. At that time, strongodors were noted. There appeared to be minimal disturbance of the L4 section. Additional visitswere made to the site during 1989, 1990, 1991 and 1993, for evaluation of the L4 section, as wellas the L5 Field 3. Air emissions from the site have the potential to impact residential areas to thewest and north of the landfill, as well as the Seaview industrial/office park along the southernperimeter of the landfill. Prevailing winds are either from the northwest or southwest. Northwestwinds tend to funnel emissions from the landfill to the south into the Roslyn Harbor area. Thereare several children's camps/day schools several thousand feet to the south of the site. During the1991 visit, the Town had not yet constructed a gas containment system to control hydrogensulfide emissions from the L5 Field 3 cell. Mr. Lloyd Wilson of the NYS DOH and NYS DECstaff visited the site in June 1993. During the 1993 site visit, the L5 field 3 cell gas containmentsystem was operating and no odors were detected either on-site or off-site. Also, no odors werepresent at the L4 section. Construction and monitoring activities associated with furtherremediation of the L4 section were observed during the 1993 site visit. Land use patterns areunchanged. There is an inactive gravel mine located directly to the north. To the east andnortheast are public areas consisting of a bathing beach and Hempstead Harbor. Access to thelandfill is controlled by a manned gate located on West Shore Road. The landfill is completelyfenced.
Land use in the areas surrounding the Port Washington landfill (L4) is varied (Figure 1). Northwest of the site, single family homes predominate. A residential development is located 50feet from the western edge of the landfill. The closest residence to the west is about 100 feetfrom the site perimeter. The South Salem Elementary School is about 700 feet northwest of thelandfill. An industrial park/commercial office development, the Seaview properties, is along thesouthern boundary of the landfill. To the north is a gravel mine. East of the site is the active L5section of the landfill and further east is Hempstead Harbor. Directly west and southwest is theNorth Hempstead Country Club (golf course). The golf course has several wells used for lawnirrigation. Bar Beach, a public beach, is about one mile north of the eastern edge of the site onHempstead Harbor. In addition to swimming, Hempstead Harbor is used for fishing and boating. It is not known to what extent shellfish are harvested from Hempstead Harbor. Residential areasare further to the south and along Shore Road. To the east, across Hempstead Harbor, are theresidential communities of Roslyn Harbor and Glenwood Landing.
The NYS DOH estimated, from the 1990 Census, 7,856 people live within 1 mile of the PortWashington Landfill. The population within 1 mile of the site is 90.4 percent white, 0.8 percentof the African-American and 8.8 percent of other races. The site is within census tract 3014.00,in which 7.3 percent of the population is under 5 years of age, 17.4 percent is 5-19 years of age,61.2 percent is 20-64 years of age and 14.1 percent is 65 years or older. The median householdincome in 1989 for this census tract was $79,901 with 2.4 percent of the families with income below the poverty level.
Beneath the landfill the Upper Glacial aquifer represents the uppermost water-bearing zone. TheMagothy aquifer immediately underlies the Upper Glacial, with the Lloyd aquifer below separatedfrom the Magothy by the Raritan aquitard. The Lloyd aquifer is the assumed bottom of thegroundwater flow system because it overlies the bedrock. To the north, the Magothy, Raritan,and Lloyd have been replaced by the Port Washington Confining Unit and Aquifer. All of theaquifers described above are utilized locally for public water supplies.
The Upper Glacial aquifer, which generally flows from west to east beneath the landfill, carrieswater from the crown of the peninsula to Hempstead Harbor (an extension of Long IslandSound). The Magothy aquifer, which has similar flow characteristics, also discharges intoHempstead Harbor. The Lloyd aquifer is insulated from the local surface water bodies by theRaritan clay so that waters contained in this unit can migrate beneath Hempstead Harbor andManhasset Harbor. According to the United States Geological Survey (USGS) (1987), thewaters in the Lloyd Aquifer flow from east to west beneath the landfill discharging regionally intoManhasset Harbor and Long Island Sound. The Port Washington aquifer also has a regional flowcomponent which allows for some water to flow beneath the water bodies bordering thepeninsula.
The most significant users of groundwater in the area are the Port Washington Water District(PWWD) and the North Hempstead Country Club (NHCC). Several PWWD production wellsare potentially affected by Landfill operations including the Southport, Stonytown, and Hewlettwells, as well as the Bar Beach Road well to the north of the site. Additionally, the NHCC hastwo irrigation wells along Port Washington Boulevard. There are no known private drinkingwater wells in the area.
The Southport well is 1,300 feet due west and hydraulically upgradient from the Port Washingtonlandfill. It was constructed in 1954 and was utilized for public water supplies until June 12, 1981. The PWWD pumping records indicate that the cone of influence which was created when theSouthport Well was pumping, reached eastward towards the landfill and intercepted groundwaterfrom beneath the site. The Stonytown well was constructed 3,000 feet southwest andhydraulically upgradient from the landfill and was brought on line to replace the lost yield causedby the closing of existing district wells. However, the annual pumping rate at this location wasreduced in 1982 to limit its cone of influence as a safeguard against possible contaminationmigrating to the well from the Port Washington landfill. Subsequently, in 1987 a permit from theNYS DEC was issued authorizing increased annual pumpage for the Stonytown well; however,water level and water quality monitoring requirements were also increased as an additionalsafeguard.
Throughout this time period, irrigation pumping has continued on the NHCC grounds. Withdrawals have been estimated to be as high as 1,000 gallons per minute during the summermonths. This groundwater extraction may have significant impacts on the groundwater flow fieldbeneath the landfill, especially given the proximity of the local water supply pumping.
The NYS DOH maintains several health outcome data bases which could be used to generate sitespecific data, if warranted. These data bases include the cancer registry, the congenitalmalformations registry, the heavy metals registry, the occupational lung disease registry, vital records (birth and death certificates) and hospital discharge information.
The NYS DOH conducted a study of cancer incidence in census tracts 3010p and 3014 in PortWashington for the years 1973 to 1984.
The NC DOH has been maintaining odor complaint records related to recent hydrogen sulfideemissions from the L5 Field 3 landfill, as well as odor complaints of a general nature, notspecifically related to the Port Washington Landfill.
Since 1974 the community has expressed concerns that contaminants in the soil vapor andambient air are affecting the health of those residents living near the landfill.
Since 1991, a series of public meetings were held with the community to address their concernsover severe odor problems and air emissions from the L5 section of the landfill and remediation ofthe L4 section. Public concerns over possible health effects from acute and long-term exposure tohydrogen sulfide were raised. In addition, there was concern over the ability of local and stateofficials to deal effectively with the problems. The most recent public meeting was in July 1993.
On May 2, 1994, the NYS DOH sent copies of the public health assessment for the PortWashington Landfill to all known interested parties, requesting concerns and comments on thereport by June 9, 1994. The NYS DOH was alerted to additional community concerns aboutgroundwater contamination posing a threat to the public and environment and about the potentialcontamination of Hempstead Harbor. The responses to public comments are in Appendix D.