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PRELIMINARY PUBLIC HEALTH ASSESSMENT

SUSSEX COUNTY LANDFILL #5
LAUREL, SUSSEX COUNTY, DELAWARE


SUMMARY

Sussex County Landfill No. 5 is an inactive 35.26-acre landfilllocated in Laurel, Sussex County, Delaware, which was placed onthe National Priorities List (NPL) by the U.S. EnvironmentalProtection Agency (EPA) in October 1989. Sussex County operateda landfill at this location from May 1970 through August 1979. Mixed industrial and municipal wastes, reported to containvarious organic wastes, were disposed at the site. In 1976, thesite received 1,000 pounds of asbestos waste. Only limitedsampling has been done on-site. One monitoring well just northof the site was found to be contaminated with several organicchemicals. Three other monitoring wells had limited organiccontamination. Sixteen of 18 residential wells tested north ofthe site had nitrate/nitrite levels above 10 mg/l. Ingestion ofnitrate/nitrite contaminated water with levels above 10 mg/lwould be a health hazard for infants under 1 year old and adultswith less acidic stomachs than normal. The Sussex CountyLandfill No. 5 does not appear to be a source of thenitrate/nitrite contamination. Based on information reviewed,the Agency for Toxic Substances and Disease Registry (ATSDR) hasconcluded that the Sussex County Landfill No. 5 NPL site is anindeterminate public health hazard. This conclusion is based ona lack of the data required to evaluate the potential for and/orthe amount of off-site contamination of air, soil, surface water,sediment, and the food chain. All the private drinking water andirrigation wells in the three groundwater management zones at theLaurel Landfill should be sampled. Analysis should be done forthe priority pollutants and the standard water qualityparameters. A more complete evaluation should be made of theamount of or potential for movement of contaminants off-site. Samples should be collected as required to assess the potentialfor migration of the asbestos on-site.

The Sussex County Landfill No. 5, Laurel, Sussex County, Delawaresite has been evaluated for appropriate follow-up with respect tohealth effects studies by the ATSDR Health ActivitiesRecommendation Panel (HARP). This site is not being consideredfor follow-up health activities at this time because no exposureto site-related contaminants was identified. ATSDR willreevaluate this site for any indicated follow-up, if data becomeavailable suggesting that exposure of humans to site-relatedcontaminants at levels of health concern did or is occurring.


BACKGROUND

A. SITE DESCRIPTION AND HISTORY

The Sussex County Landfill No. 5 is an inactive 35.26-acrelandfill located in Laurel, Sussex County, Delaware (Figure 1)which EPA placed on the NPL in October 1989. Sussex Countypurchased the property on January 5, 1970, and operated alandfill on it from May 1970 through August 1979. The site iscurrently used as a transfer station. Mixed industrial andmunicipal wastes, reported to contain various organic wastes,were disposed at the site. In 1976, the site received 1,000pounds of asbestos waste from the DuPont Seaford Plant. OnDecember 19, 1984, the NUS Corporation, which was the Region IIIField Investigation Team Contractor for the EPA, conducted a sitesampling inspection of the site.

The Remedial Investigation/Feasibility Study (RI/FS) Work Planfor the Sussex County Landfill was finalized in August 1991. TheATSDR provided comments on this work plan to the EPA. TheRemedial Investigation of this site will begin in spring 1992 andis scheduled for completion in April 1993.

B. SITE VISIT

Two separate site visits have been made relating to this site. Ms. Lisa Hayes and Lynn Wilder of ATSDR made a site visit onMarch 9, 1989.1 Along with staff from the Delaware Division ofPublic Health (DDPH) and Department of Natural Resources andEnvironmental Control (DNREC), they toured the site andsurrounding area and met with the Sussex County EngineeringDepartment. Dr. John Crellin of ATSDR made a site visit on June19-21, 1991.2 He collected community health concerns on June 19-20 through participation in a community survey with two EPARegion III staff. Along with Bucky Walters of ATSDR and the twoEPA staff, he made a tour of the site on June 20, 1991. Theinformation gathered during these site visits is included in theappropriate sections of this public health assessment.

C. DEMOGRAPHICS, LAND USE, AND NATURAL RESOURCE USE

Information in the recently approved RI/FS Work Plan for SussexCounty Landfill No. 5 indicates that there are only 29 domesticwells potentially at risk for contamination from the landfill.3 These 29 wells lie within the groundwater management zonesestablished in an agreement between Sussex County and the DNREC. The groundwater management zone was developed to control andrestrict groundwater usage around the landfill. Assuming thatthere are 3.5 persons per household, there are about 100 peopleconsuming water from the wells in these management zones. Thereare no public water wells in or near the groundwater managementzones.

D. STATE AND LOCAL HEALTH OUTCOME DATA

The DDPH was consulted about available health outcome databases. The Delaware Tumor Registry is the 3rd oldest in the UnitedStates and has population-based coverage of the state. The tumorregistry data can be analyzed for specific zip codes and cities. The Delaware Birth Defects Registry was started in 1989. Standard mortality and morbidity data are available for SussexCounty by zip code and city since 1986.

These databases were not searched since the population with thepotential for exposure (about 100) is much smaller than thepopulation in a zip code. This disparity would make it veryunlikely that any health effects due to the site could bedetected.


COMMUNITY HEALTH CONCERNS

Community health concerns were identified through participationin a community survey conducted by EPA and contact with LaurelCity and Sussex County officials and the DDPH.2 The communitysurvey included a explanation of the role and responsibilities ofEPA and ATSDR at NPL sites, and solicitation of health concerns.

The following health concerns were expressed by those surveyed:

(1) What are the health effects of nitrates and othercontaminants found in private wells, especially for children,elderly, and chronically ill? (All the residents interviewedwere aware that the nitrate contamination was a county-wideproblem and probably not site-related.)

(2) Do safe levels for chemicals (i.e., Maximum ContaminantLevels [MCLs] or other permissible exposure levels)identified in sampling results protect sensitive individuals?

(3) Could the migraine headaches being experienced by somearea residents be site-related?

(4) Could there be contaminants in the spray from the nearbyirrigation sprinklers and could the use of those sprinklersinfluence the groundwater flow so that residential wellsbecome contaminated?

(5) Is the latex polymer that Dupont reportedly disposed inthe landfill potentially hazardous?


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

The tables in this section list contaminants which have beenfound in sampling around the site. We evaluate thesecontaminants in the subsequent sections of the public healthassessment and determine whether exposure to them has publichealth significance. ATSDR selects and discusses thesecontaminants based upon the following factors:

  1. Concentrations of contaminants on and off the site.

  2. Field data quality, laboratory data quality, and sample design.

  3. Comparison of on-site and off-site concentrations with comparison values for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints.

  4. Community health concerns.

Environmental sampling around the Sussex County Landfill No. 5were recently reviewed in the RI/FS work plan for the site.3

The data tables include the following acronyms:

  • CREG = Cancer Risk Evaluation Guide

  • EMEG = Environmental Media Evaluation Guide

  • MCL = Maximum Contaminant Level

  • ug/l = micrograms of contaminant per liter of water

  • mg/l = milligrams of contaminant per liter of water

  • ug/kg = micrograms of contaminant per kilogram of soil

Comparison values are the contaminant concentrations in specificmedia that are used to select contaminants for furtherevaluation. These values include Environmental Media EvaluationGuides (EMEGs), Cancer Risk Evaluation Guides (CREGs), and otherrelevant guidelines. CREGs are estimated contaminantconcentrations based on a maximum of one excess cancer in onemillion persons exposed for 70 years. CREGs are calculated fromEPA's cancer slope factors. EPA's Maximum Contaminant Levels(MCLs) represent contaminant concentrations that EPA deemsprotective of public health (considering the availability andeconomics of water treatment technology) over a lifetime (70years) at an exposure rate of 2 liters water per day.

The Toxic Chemical Release Inventory (TRI) database was developedunder Section 313 of Title III of the Superfund Amendments andReauthorization Act (SARA) of 1986. TRI contains self-reportedinformation on chemical releases from manufacturing facilities. ATSDR reviewed available TRI data for 1988 to determine whattypes of contaminants have been released into the environment inSussex County and whether any of those releases occur near thesite. A total of twelve industries reported releases of 181,999pounds to the air and 11,327 pounds to the water in 1988. Thechemicals being released included biphenyl, chloride,formaldehyde, phosphoric acid, sodium hydroxide, sulfuric acid,propylene, ammonia, acetone, styrene, nitric acid, dibenzofuran,friable asbestos, zinc, and manganese. None of these releasesoccurred near Sussex County Landfill No. 5 site.

A. ON-SITE CONTAMINATION

The location of sampling points and monitoring wells is indicatedon Figures 2 and 3. Sampling of groundwater, especially fororganic compounds has been concentrated on the wells north of thelandfill. Two of these, LD-1 and LS-4 are located just north ofthe boundary of the site. Because the groundwater flow appearsto be northward, ATSDR considers LD-1 and LS-4 to be adequateindicators of on-site contamination. The monitoring results forthese wells are described in the Off-Site Contamination sectionand Table 1 (Appendix One).

Water and leachate were collected in two 10 foot wide, six inchdeep depressions or ponds at two areas on-site (Figure 2).4 Water samples collected from these ponds contained chromium (8.2ug/l), mercury (2.3 ug/l), nickel (18 ug/l), and silver (13ug/l). Sediments from these on-site ponds contained4-methylphenol (1,880 ug/kg) and toluene (940 ug/kg). Aphotoionization detector revealed levels of organic chemicals inthe air at casings and sink holes just above a detection limit of1 ppm, but nothing six feet above the casings and sink holes. Soil sampling data and information on the disposal of theasbestos waste were not identified in ATSDR's review.

B. OFF-SITE CONTAMINATION

There are 11 monitoring wells north of the site (Figure 3). Samples have been collected from some or all of these wells on anumber of occasions.3 As indicated in Table 1 (Appendix One),the well labeled LD-1 was found to be contaminated with a numberof organic chemicals in 6/6 samples. A single chemical wasdetected in wells LS-7, 10, and 12 on one occasion. Twochemicals have been found in LS-13 on separate samplings.

The locations of the domestic wells north of the landfill aredepicted in Figure 3. These wells were sampled in August 1989,and April and October 1990 for volatile organic compounds,nitrate/nitrite, and several water quality indicators. The welllabeled number 2 in Figure 3 has been found to have low levels ofseveral organic compounds (Table 2, Appendix One).

Five of the 11 monitoring wells and 16 of 18 residential wellshave nitrate/nitrite levels which exceed EPA's maximumcontaminant level (MCL) of 10 mg/l. Nitrate/nitrite levels inall 11 of the monitoring and 17 of 18 residential wells wereabove the detection limit of 1 mg/l. The highest level found was23 mg/l.

Sampling of residential wells in 1984 found four wells withlevels of cadmium and mercury above the EPA MCL for thesemetals.4 However, these results were considered to be ofquestionable validity based upon the quality assurance review ofthe data.4 The results were not confirmed in later samplings. These four wells are located to the north, south, east, and westof the site. Three of the four are not in the path of thegroundwater flowing north from the landfill (Figure 4).

Off-site surface water samples were not collected. Contaminantconcentrations present in upstream and downstream sedimentsamples are presented in Table 3 (Appendix One).

Sampling of soil, air, and other media off-site have not beendone.

C. QUALITY ASSURANCE AND QUALITY CONTROL

Data qualifiers were assigned to many of the reported contaminantconcentration values.4 The reliability of these data will affectthe validity of the conclusions and recommendations of thispreliminary public health assessment.

D. PHYSICAL AND OTHER HAZARDS

The site is only partially fenced, thus access is not restricted. There has been some unauthorized dumping (empty drums and oldappliances) of wastes that might pose physical injury hazards.1,2,5 During the site visit in 1991, evidence of unauthorized entrysuch as cutting of Christmas trees and target practice wereidentified.2


PATHWAYS ANALYSES

A. ENVIRONMENTAL PATHWAYS (FATE AND TRANSPORT)

The waste buried in the landfill is estimated to be 12 feetthick. Waste material is in contact with the ground water andsampling data for the monitoring wells generally indicate thatleachate from the waste has penetrated into the aquifer to adepth of at least 50 feet (the depth of LD-1) with limitedmovement down to 90-95 feet. A leachate plume extends anestimated 400 to 500 feet down-gradient (north) of the landfill. Groundwater flow does appear to be northward from the site(Figure 4) at an estimated rate of 311 feet/year. Availablemonitoring data indicate that the flow is predominantlyhorizontal/lateral.

The site is underlain by the Columbia Formation, which is acoarse sand and gravel formation, with segregation of pebblesinto bands. The Columbia Formation is underlain by the ManokinAquifer, which is a medium coarse sand that frequently containssmall gravel. These units are hydraulically connected andapparently are unconfined. Within a 3-mile radius of the site,there are 703 domestic wells and 3 municipal wells which utilizewater from either the Columbia Formation or the Manokin Aquifer.

All wastes disposed during landfilling operations have received afinal cover of 2 feet of soil. Some unauthorized dumping ofnonhazardous solid waste has apparently occurred since the sitewas closed.

Two small, shallow on-site ponds or depressions receiveprecipitation runoff and contaminated leachate. Surface waterrunoff and sediments from the site enter Culver Ditch, whichdrains into Broad Creek, which in turn enters into the NanticokeRiver (Figure 1).3 Broad Creek is used for fishing and swimming. The Nanticoke River is used for sport fishing. Although CulverDitch is dry most of the time, surface water and sedimententrained contaminants may migrate off-site via this pathway. Asediment sample collected upstream of the point where runoff fromthe site enters Culver Ditch indicates that agriculturalactivities in the area may be responsible for some sedimentcontamination. However, samples collected downstream of the site(see Table 3) indicate that some sediment contamination may beattributable to the site. Additional sampling is necessary toaddress this issue.

Many of the contaminants found at the site are volatile organiccompounds and they have been detected around well casings and insink areas at the site, but not six feet above the ground.4 Thus, it is unlikely that appreciable concentrations of thesecontaminants will leave the site. However, off-site airmonitoring is needed to confirm this.

Contaminants leaving the site via ground water, surface water,sediments, and air may be taken up by food chain entities presenton and around the site. Ground water containing contaminants maybe used for irrigating crops or watering livestock, contaminantsdissolved or suspended in surface water may be translocated alongwith contaminants adsorbed to sediments to areas where fish orother consumable aquatic animals live, and contaminants mayvolatilize from soil or be resuspended in air and carried fromthe site where they are deposited on plants or inhaled byanimals.

B. HUMAN EXPOSURE PATHWAYS

On-Site

There is no known on-site exposure to the contaminated groundwater under the site. Remedial workers could receive inhalationand dermal contact exposures to contaminants in the water, ifground water is pumped from the ground and treated. However,the concentrations of the contamination are low and exposureswould be infrequent and of short duration. Therefore, they areunlikely to be of public health concern.

Available data indicate that the material used for final cover ofthe wastes was not checked for contamination. Therefore,localized areas of contamination may exist. Soil sampling willbe necessary to address this issue. The only uncovered wasteremaining on-site is believed to be nonhazardous solid waste(empty drums and old appliances).

Access is not restricted, because the site is only partiallyfenced. Trespassers entering the site and wading in thedepressions may receive inhalation, ingestion, and dermal contactexposures to contaminants present in them. Contaminantconcentrations in water and sediment in the ponds or depressionsare low and contact with the contaminants should be infrequentand of short duration. The two small, shallow ponds ordepressions that accumulate leachate and precipitation do notpose a potential drowning hazard. Thus, the leachate collectionponds do not pose a physical or health hazard.

No evaluation of the food chain pathway could be made, because ofthe lack of data on contaminants in animals and plants on-site.

Off-Site

The individuals using residential well 2 (Figure 3) are beingexposed to low levels of 1,1 dichloroethane, trans-1,2-dichloroethene, 1,2-dichloropropane, trichloroethene, andbenzene. The users of 16 wells north of the site are beingexposed to nitrate/nitrite levels above EPA's MCL of 10 mg/l.

Residential well 2 has low levels of organic contaminants. Thiswell draws water from the same formation as off-site monitoringwell LD-1 which has also consistently been shown to have lowlevels of organic contaminants. Residential well 2 lies directlydown-gradient from LD-1. However, only two of the fourmonitoring (LS 4-7) and one residential well (9) that lie betweenLD-1 and residential well 2 have shown any contamination and thiswas one chemical one time. Therefore, it is not certain that thelandfill is the source of organics contamination in residentialwell 2. Every home around the site has its own on-site sewagedisposal system (septic system) so this would be another possiblesource for contamination of residential wells.

Seventeen of the 18 wells sampled north of the landfill arecontaminated with nitrate/nitrites. Sussex County and DDPHindicated that nitrate/nitrite contamination is common in shallowresidential wells in Sussex County.2 The mostly likely sourcesof the nitrate/nitrites are poultry production and other types ofagriculture.

Sussex County samples the 18 residential wells every six months. Every household in the "no well" area of the groundwatermanagement zones will be given the opportunity to hook up to apublic water system the county will be installing.5

Off-site soil samples were not collected. Thus, it is not knownif persons living, working, or playing in the area immediatelysurrounding the site are receiving ingestion, inhalation, ordermal contact exposures to off-site soil contaminants.

Surface water and sediments leaving the site may contain sitecontaminants, and thus represent a potential source of exposure. There has been no sampling of off-site surface water samples.Off-site sediment sampling data are inadequate to determine ifcontaminants present in off-site sediments are attributable tothe site or to agricultural activities in the area.

Data describing the occurrence of game and non-game food chainentities on and around the site were not identified in ATSDR'sreview. Therefore, the potential for site-related contaminantsto be taken up by off-site food chain entities and subsequentlyingested by humans cannot be addressed.


PUBLIC HEALTH IMPLICATIONS

As discussed in the preceding sections, the data available toATSDR indicate exposure of humans to organic chemicals andnitrate/nitrites is occurring in wells immediately north ofSussex County Landfill No. 5. Low levels of a variety of organiccompounds have been found in one residential well and a singlechemical in another. As indicated in Table 2, only the levels of1,1-dichloroethane and 1,2-dichloropropane exceed the appropriatecomparison values. Seventeen of 18 residential wells haddetectable levels of nitrate/nitrite and in 16 the levels wereabove the EPA MCL of 10 mg/l. The Toxicological Evaluationportion of this section will review the health effects possiblefrom exposures to nitrate/nitrites, 1,1-dichloroethane, and 1,2-dichloropropane. In addition, the community concerns will beaddressed. As discussed in the State and Local Data Section,health outcome data were not obtained.

A. TOXICOLOGICAL EVALUATION

As will be discussed, drinking the nitrate/nitrite contaminatedwater from the 16 wells with levels above 10 mg/l would be ahealth concern for infants less than a year old and adults withless acidic stomachs than normal.6 Exposure to 1,1-dichloroethane and 1,2-dichloropropane at the low levels found inresidential well 2 does not represent a health hazard.

Only one health effect, methemoglobinemia, has been documented inhumans or animals exposed to nitrate.6 Except formethemoglobinemia, extensive studies of rodents found no evidenceof birth or reproductive effects nor any systemic effects, evenat doses over 1100 parts per million (ppm). Severalepidemiological studies of human exposures reveal similarresults.

Methemoglobinemia due to nitrate exposure occurs almostexclusively in infants less than one year old.6 Methemoglobin isa type of hemoglobin and, unlike normal hemoglobin, is unable tocarry oxygen. Too much methemoglobin causes the lips and skin toturn blue and can lead to weakness, rapid pulse, and, eventually,death.

Nitrate is converted to nitrite by certain bacteria in thestomach.6 When nitrite enters the blood it causes the formationof methemoglobin. Only small amounts of nitrate are converted tonitrite in the normal human because the number of those certainbacteria is low. Large numbers of those bacteria occur only whenthe stomach is less acidic than normal. This less acidiccondition is usually found only in infants whose primary sourceof food is milk (usually children under one year old). Rarely,this less acidic condition is found in adults. For infants andadults with less acidic stomachs, the safe level of exposure tonitrates is 10 ppm.6

Significant environmental exposure to nitrates appears to occuronly through drinking water or formula contaminated withnitrates.6

Exposure to the highest levels of 1,1-dichloroethane (2.6 ppb)and 1,2-dichloropropane (1.4 ppb) found in residential well 2does not represent a health hazard to the users of this well. These two chemicals are considered carcinogens based on studiesin animals. They were selected as contaminants of concern usingcomparison values based on an additional risk of cancer of 1 inone million after 70 years of exposure.6 Exposure for thoseusing residential well 2 would be less than 70 years based on theextent of the contaminant plume, the groundwater flow rate, andthe pending connection to a public water supply. This results ina maximum additional risk of cancer less than 1 in one million.

B. EVALUATION OF COMMUNITY HEALTH CONCERNS

The concerns listed in the Community Health Concerns section areevaluated below.

(1) What are the health effects of nitrates and othercontaminants found in private wells, especially for children,elderly, and chronically ill?

The health effects of the nitrates found in residential wellsnorth of the landfill are described in the ToxicologicalEvaluation section. This information was also explained tothe participants in the community survey from which thecommunity concerns were obtained.2 All the residentsinterviewed were aware that nitrate contamination is acounty-wide problem and probably not site-related.

Other contaminants were found in two residential wells. (Seethe Environmental Contamination and Other Hazards section.) The concentrations of those contaminants, which are organiccompounds, were below levels of health concern. Thehousehold using this well, along with the other households inthe "no well" groundwater management zone, will be offeredconnections to a public water supply.5

(2) Do the safe levels identified in sampling results protectsensitive individuals?

Yes, they do. The safe levels used in the sampling resultsare numbers established by EPA. EPA uses a "margin ofsafety" method of setting non-carcinogenic safe levels. Inthis method, the identified safe dose is adjusted by a factorof 10 to 10,000 to account for sensitive individuals, forextrapolating from animal data to humans, where appropriate,and for quality of animal and/or human data.

The nitrate safe level of 10 ppm is not adjusted by anysafety factors because it is based on actual exposures ofsmall infants (the most sensitive individuals). An exampleof a substance where adjustments are made is chloroform,where the safety factor is 1,000. Adjustments are to accountfor sensitive individuals, extrapolation of animal data tohumans, and lack of a observed no effects level.

(3) Could the migraine headaches being experienced by some arearesidents be site-related?

It is unlikely that these migraine headaches are site-related. As described in the Environmental Contamination andOther Hazards section, there is little indication from thelimited sampling done that exposures to site contaminants areoccurring. Samples have been taken of the wells serving thehouseholds of the residents raising this concern.

(4) Could there be contaminants in the spray from the nearbyirrigation sprinklers and could the use of those sprinklersinfluence the groundwater flow so that residential wells becomecontaminated?

Available environmental data indicate that the contaminantplume does not extend out to the wells supplying theirrigation sprinklers. However, it is possible that the useof the irrigation wells could influence the flow anddirection of groundwater and result in contamination of someresidential wells. The work plan for the remedialinvestigation of the Sussex County Landfill No. 5 includes anevaluation of this problem.

(5) Is the latex polymer that Dupont reportedly put in thelandfill potentially hazardous?

ATSDR was unable to identify specific information on what wasplaced in the landfill. Without knowing exactly what wasdisposed of at the site, it is not possible to determinewhether it is a health hazard. However, off-site movement ofany site materials are unlikely if the site is properlycovered to prevent air-borne movement and if sampling of theoff-site monitoring wells continues.


CONCLUSIONS

Based on information reviewed, the ATSDR has concluded that theSussex County Landfill No. 5 NPL site is an indeterminate publichealth hazard. This conclusion is based on a lack of the datarequired to evaluate the potential for and/or the amount of off-site contamination of air, soil, surface water, sediment, and thefood chain.

Additional data are needed to determine: the extent of migrationof the ground water contaminant plume; the extent of off-sitesoil contamination; the extent of off-site surface water,sediment, and air contamination; and the potential for food chaincontamination. Data are also needed to evaluate the potentialhealth threats posed by the asbestos disposed of at the site.

Ingestion of nitrite/nitrate contaminated water from 16residential wells north of the site with levels above 10 mg/lwould be a health hazard for infants under 1 year old and adultswith less acidic stomachs than normal. The Sussex CountyLandfill No. 5 does not appear to be a source of thenitrate/nitrite contamination.


RECOMMENDATIONS

  1. All the private drinking water and irrigation wells in thethree groundwater management zones at the Laurel Landfillshould be sampled. Analyses should be done for the prioritypollutants and the standard water quality parameters. Thegroundwater management zones referred to above are indicatedon Figure 3.3 in the site-work plan.3

  2. A more complete evaluation should be made of the amount of orpotential for movement of contaminants off-site. Mediaevaluated should include on- and off-site soil, air, andsurface water; sediment in Culver Ditch, Broad Creek, and theNanticoke River; and food chain entities such as crops,livestock, and game animals.

  3. The potential for migration of the asbestos off-site shouldbe assessed.

  4. All wastes disposed of at the landfill should be covered andaccess to the site should be restricted. The site should bemonitored on a regular basis to ensure the integrity of thecap.

  5. When indicated by public health needs, and as resourcespermit, the evaluation of additional relevant health outcomedata and community health concerns, if available, isrecommended.

The Sussex County Landfill No. 5, Laurel, Sussex County, Delawaresite has been evaluated for appropriate follow-up with respect tohealth effects studies by the ATSDR Health ActivitiesRecommendation Panel (HARP). This site is not being consideredfor follow-up health activities at this time because no exposureto site-related contaminants was identified. ATSDR willreevaluate this site for any indicated follow-up, if data becomeavailable suggesting that exposure of humans to site-relatedcontaminants at levels of health concern did or is occurring.


PUBLIC HEALTH ACTIONS

The following public health actions have been committed to bySussex County in the final work plan for the remedialinvestigation of Sussex County Landfill No. 5.4

1) An evaluation of the potential for movement ofcontaminants off-site will be done by placing new off-sitemonitoring wells to the east, west, and south of the site. These wells along with the existing monitoring wells will beused to better quantify groundwater direction and flow.

2) All the on- and off-site monitoring, two irrigation, and 6residential wells (1, 2, 9, 10, 13, and 15 on Figure 3) willbe sampled for target compounds list (TCL) and target analytelist (TAL) parameters and asbestos. Both filtered andunfiltered samples will be analyzed.

3) The impact of irrigation wells on groundwater flow anddirection will be evaluated by monitoring the water levels inall the monitoring wells as the irrigation wells are used.

4) The potential for movement of asbestos off-site will beevaluated by conducting on-site air monitoring for asbestosand, if any is found in the air, testing will be conducted inoff-site soil for asbestos.

5) An evaluation of the potential for migration ofcontaminants off-site through the surface water pathway willbe done by sampling on-site soil and surface water forTCL/TAL parameters and asbestos. If the results of thistesting indicate that migration may be occurring, then thesediment and surface water from off-site drainageways will betested.


PREPARERS OF REPORT

Environmental and Health Effects Assessors:

Mike Allred, Ph.D.
Environmental Health Scientist
Division of Health Assessment and Consultation

John R. Crellin, Ph.D
Environmental Health Scientist
Division of Health Assessment and Health Consultation


Oak Ridge Associated Universities Summer Intern:

Ahmed E. Gomaa, M.D.,
M.S.P.H.
Tulane University School
of Public Health and Tropical Medicine


ATSDR REGIONAL REPRESENTATIVE

Regional Representative:

Charles J. Walters
Senior Public Health Advisor
ATSDR Region III


REFERENCES

  1. Trip Report: Site Visit of Sussex County Landfill #5 site inLaurel, DE on March 9, 1989. From L Hayes (ATSDR) to BLJohnson (ATSDR), 1989.

  2. Trip Report: Participation in Community Survey and SiteVisit of Sussex County Landfill #5 site in Laurel, DE on June19-21. From JR Crellin (ATSDR) to R Williams (ATSDR), July12, 1991.

  3. NUS Corporation Site Inspection of the Sussex CountyLandfill No. 5. Superfund Division. 1986

  4. Roy F. Weston. RI/FS Work Plan Sussex County Landfill No. 5,Laurel, Delaware; Roy F. Weston, West Chester, PA. November22, 1991.

  5. Personal Communication: Conversation regarding notificationof citizens of results of water well sample analyses andinstallation of public water system. Telephone call betweenM Allred (ATSDR) and M Izzo (Sussex County EngineeringDepartment). May 28, 1991.

  6. National Library of Medicine. Toxicology Information ProgramOnline (Computer) Services. Hazardous Substances Data Bank(HSDB) and Integrated Risk Information Service (IRIS) files. Bethesda, Maryland: National Library of Medicine, 1991.

APPENDIX ONE: TABLES AND FIGURES

Table 1.

ORGANIC CONTAMINANTS IN MONITORING WELLS NORTH OF SUSSEX COUNTY LANDFILL NO. 51
CHEMICALRange in ug/lFound inWells #ComparisonValue-ug/lSource2
benzenend - 8.015.0 MCL
chlorobenzenend - 3.01100DWHA
chloroethanend - 20.01no data  
chloroformnd - 3.212, 135.7CREG
1,4-dichlorobenzenend - 19.011.5CREG
1,1-dichloroethanend - 2.21, 70.4CREG
trans-1,2-DCE3nd - 2.01200EMEG
1,2-dichloropropanend - 5.010.5CREG
ethylbenzenend - 25.01100EMEG
tetrachloroethenend - 1.2125PMCL
toluenend - 5.01, 103,000EMEG
total xylenesnd - 97.0120,000EMEG


Table 2.

ORGANIC CONTAMINANTS IN RESIDENTIAL WELL 2 NEAR SUSSEX COUNTY LANDFILL NO. 51
CHEMICALRange in ug/l Times FoundComparisonValue-ug/lSource2
benzene1.1 - 1.53/35.0MCL
1,1-dichloroethanend - 2.61/30.4CREG
trans-1,2-DCE32.2 - 3.63/3200EMEG
1,2-dichloropropane1.0 - 1.42/30.5CREG
trichloroethenend - 2.41/3 5.0MCL

Explanation of Tables 1 and 2

1 The source of the data in these tables is RI/FS Work Plan Sussex County Landfill No. 5, Laurel, Delaware; Roy F. Weston, West Chester, PA. August 30, 1991.

2 See the introductory paragraphs of the Environmental Contamination and Other Hazards section for an explanation of these abbreviations.

3 DCE is the abbreviation for dichloroethene.


Table 3.

Maximum Contaminant Concentrations Present In Off-Site Sediments of Culver Ditch (ug/kg)
  Location
 
Organic Contaminants Upstream Downstream
4-methyl-2-pentanone ND 2.9
toluene 10 800
toxaphene 545.7 ND
Inorganic Contaminants    
arsenic 3 Q 6.5 Q
chromium 6.9 12
cyanide ND 1.6
lead 59 105
mercury ND 0.12 Q

F - Quantitative approximation based on quality assurance review
J - Approximate value detected below quantification limit
N - Evidence for presence of material is presumptive
P - Results of questionable qualitative significance based on quality assurance review of data
Q - Compound present; value is below required reporting limit
ND - Not detected

SOURCE - NUS Corporation. Site Inspection of the Sussex CountyLandfill No. 5. TDD No. F3-8410-13. 1986. Samples collected in1984

Site Location Map
Figure 1. Site Location Map

Site Layout
Figure 2. Site Layout

Residential, Monitor and Irrigation Well Locations
Figure 3. Residential, Monitor and Irrigation Well Locations

Groundwater Elevation Contours
Figure 4. Groundwater Elevation Contours



Table of Contents

  
 
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