OLD BRIDGE, MIDDLESEX COUNTY, NEW JERSEY
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
In conducting an ATSDR public health assessment, the health assessors identify and review all available environmental contamination data for a site. The on- and off-site portions of this section describe the sampling that has been done and identify contaminants of concern. The quality of the environmental data is discussed in the Quality Assurance and Quality Control subsection. Physical and other hazards not related to toxic substances, if any, are described in the Physical and Other Hazards subsection. This introductory portion discusses the process for selecting contaminants of concern, Toxic Chemical Release Inventory (TRI) data, and the relevance of the environmental sampling to evaluating the possible health impact of this site.
Selection of Contaminants of Concern
ATSDR selects contaminants for further evaluation based upon the following factors (8):
|1)||comparison of concentrations of contaminants on- and off-site with values for noncarcinogenic and carcinogenic endpoints,|
|2)||sampling plan and field and laboratory data quality, and|
|3)||community health concerns.|
Identification of a contaminant of concern in the On-Site and Off-Site Contamination subsections does not mean that exposure will result in adverse health effects, only that additional evaluation is necessary. The public health significance, if any, of exposure to the contaminants of concern is evaluated in subsequent sections of the public health assessment. If a specific contaminant is clearly not site-related, that will be identified. For the protection of public health, the possible health impact of those non-site related contaminants will be evaluated. Once a contaminant has been identified in one environmental media (e.g., ground water), the contaminant's concentration in other environmental media is evaluated for possible combined exposures above a comparison value. If there are potential combined exposures that exceed a comparison value, that will be reported and evaluated further.
Comparison values for public health assessment are contaminant concentrations in specific media that are used to select contaminants for further evaluation. These values include Environmental Media Evaluation Guides (EMEGs), Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines. CREGs are estimated contaminant concentrations based on a one excess cancer in a million persons exposed over a lifetime. CREGs are calculated from EPA's cancer slope factors. Proposed Maximum Contaminant Levels (PMCLs) represent contaminant concentrations that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters water per day. Lifetime drinking water health advisories (LTHA) are similar to MCLs, but consider only protection of health. EPA's Reference Doses (RfD) are estimates of the daily exposure to a contaminant that is unlikely to cause adverse health effects.
Review of Toxic Chemical Release Inventory (TRI) Data
To identify possible facilities that could contribute to the groundwater, surface water, and air contamination near the Global Landfill NPL site, ATSDR searched the 1987-1990 files of the Toxic Chemical Release Inventory (TRI) databases for zip code (08857) where the site is (9). TRI was developed by the U.S. Environmental Protection Agency from chemical release (air, water, and soil) information provided by certain industries.
Several limitations of TRI data should be noted. The air release data in TRI may be estimates or actual measurements. Many of the reported data are estimates based on conservative (overestimated) scenarios. Consequently, the levels of emissions recorded in TRI are often biased on the high side. Another limitation of the TRI database is that only certain industries employing more than a minimum number of workers are required to report releases. In addition, reporting is restricted to specific chemicals that are used or released above specified amounts. Finally, it is believed that there have been and still are industries that do not report releases. Smaller industries may not be aware that report requirements exist or that they are responsible for such reports.
The search of TRI indicates that there are four facilities in the 08857 zip code that report toxic chemical releases. The reported releases to the air ranged from 27,000 pounds in 1987 and 1990 to 42,000 in 1989. None of the chemicals of concern identified in this public health assessment are among those reported released in the 08857 zip code.
Relevance of Environmental Sampling
The sampling data described in this section are adequate for determining appropriate remediation of the site. However, those data are not adequate for fully evaluating the possible health impact of the site. The information on contaminant levels in on-site soil is limited to five grab samples which is insufficient for evaluating health impact. There were no useable data on contaminants in off-site soil. To properly evaluate health impact of soil contaminants, a systematic sampling program, employing both composite and grab samples, needs to be conducted. Because multiple locations were sampled several times, data are adequate for ground water, surface water, and leachate.
There has been no monitoring for specific contaminants in the ambient air, either on- or off-site. The use of an air dispersion model to predict airborne concentrations from landfill gas emissions does not replace the need for ambient air monitoring. This is because the samples of landfill gas were taken on only two occasions in one month which could result in an over or under prediction of actual emission rate.
A. On-Site Contamination
Sampling data come from the 1991 Remedial Investigation (RI) and an investigation by Killam Associates Consulting Engineering (1,3). Tables 1-2 list the contaminants of concern identified at Global Landfill for those exposure pathways considered complete. The contaminants of concern in the eliminated exposure pathways will not be discussed, but the relevant sampling done will be described. The reasons why a pathway was identified as complete, potential, or eliminated are described in the Pathways Analyses section.
In March 1988, a limited excavation was conducted to determine whether drums were buried within the 6.5-acre extension area (1). The excavation activities included a total of eight test trenches and seven pits. A total of 63 drums were discovered during the excavation. Eighteen drums were removed, sampled, and overpacked during the excavation work. The drum contents varied from powder and other solids to sludge and liquids.
The focus of the 1991 RI was to determine the nature, extent, and source(s) of the contamination at Global Landfill (3). Samples were taken of surface and subsurface soil, leachate, surface and ground water, sediment, and soil and landfill gas. An electromagnetic survey was done to identify the presence of containerized waste. Soil gas sampling was also conducted for this purpose. The results of the landfill gas and groundwater sampling were input into appropriate models and the output used to predict possible exposure levels. This will be discussed further in the Pathways Analyses section.
Subsurface soil samples were taken by borings at five locations on the landfill mound, one at the edge of the mound, ten northwest of the mound, and one "background" location (3). Detected in the samples were over 35 organics including seven volatiles, 24 semi-volatiles, and seven pesticides; and 20 metals including chromium, lead, and zinc. Concentrations of organics ranged up to 61,000 ppb and metals up to 9,580 ppm. As will be discussed in the Pathways section, subsurface soil is considered an eliminated exposure pathway so the contaminants of concern will not be described.
Five surface soil samples were taken at locations on the north and west of the landfill where contact with the soil by local residents appeared most likely (3). Those samples were grab samples taken from 0-6 inches in the soil. The analytes detected included five volatiles, 10 semi-volatiles, four pesticides, three polychlorinated biphenyls (PCBs), and 21 metals. The contaminants of concern identified in the surface soil samples are indicated in Table 1.
Samples from several leachate seeps were taken in October 1986, quarterly from October 1987 through April 1990, and in June 1991 (1,3). Results of the sampling revealed six volatiles, 20 semi-volatiles, and nine pesticides. The contaminants of concern identified in the leachate samples are indicated in Table 2.
Fifteen monitoring wells are located around the landfill (see Appendix A, Figure II). Results of the samples taken in the water-table aquifer (upper aquifer) indicated similar contaminants to those found in the leachate. Analysis of groundwater-monitoring samples from the Old Bridge Sand aquifer (lower aquifer) revealed some site-related contaminants. The concentrations of several contaminants did exceed comparison values and thus are considered contaminants of concern. As will be discussed in the Pathways Analyses section, ground water is considered an eliminated exposure pathway, so the contaminants of concern will not be described here.
Surface water was taken from ten locations at the edge of the landfill on several occasions in 1986 and 1987 and from ten different locations, some further from the landfill, in 1991 (1, 3). Ten organic compounds and several metals were detected. None of the concentrations met ATSDR's guidance for a contaminant of concern.
Sediment samples were obtained from ten locations in the vicinity of Global Landfill (3). Five volatiles, 20 semivolatiles, ten pesticides, one PCB, and 21 metals were detected. One of the volatiles, 11 of the semivolatiles, and 18 of the metals were also detected in a background sediment sample.
Fecal coliform bacteria, a microorganism normally used as an indicator of microbiological contamination, have been detected in the leachate, upper-aquifer groundwater, and in surface water on-site (upwards of 24,000 colonies per 100 milliliters) (1, 3). Although fecal coliform bacteria are not classified as a toxic substance, the concentration of bacteria detected exceeds public health standards (e.g., NJDEPE Surface Water Quality Standards).
Some samples of air were obtained during the site investigations (1). Measurements taken with non-compound-specific instruments revealed relatively high concentrations of combustible gases (thought to be methane) in the fissures of the soil cover. A soil-gas survey conducted northwest of the landfill using a combustible-gas indicator revealed that methane is migrating towards the northwest. The measurements indicate that the methane had not reached the northern residential areas at the time of the survey.
Chemical specific analysis of landfill gas from eight locations on the landfill mound was done on two occasions in July 1991 as part of the RI (3). Samples were obtained using a flux chamber which allowed measurement of emission rates. Seventeen volatile organic compounds (VOCs), and several inorganic compounds including methane and hydrogen sulfide were detected. The VOCs were detected in all the samples with the highest concentrations being 50,000 ppb of xylenes, 23,000 ppb of ethylbenzene, and 17,000 of toluene. The results of the landfill gas sampling was used in an air model to calculate possible exposure levels on and off-site. This will be discussed further in the Pathways Analyses section. Landfill-gas data are not appropriate for determining health impact because they do not measure exposure levels at the breathing zone. Possible health impact can be determined by sampling the ambient air, rather than the emission point in the landfill.
|TABLE 1 - CONTAMINANTS OF CONCERN IN ON-SITE SOIL AT GLOBAL LANDFILL|
|CONTAMINANT||CONCENTRATION RANGE IN ppb||COMPARISON VALUE (CV) FOR INGESTION||FREQ >CV|
|benzo(a)anthracene||<DL - 770j||car*||2/51|
|chrysene||<DL - 910j||car*||3/51|
|benzo(b)fluoranthene||<DL - 1100j||car*||1/51|
|benzo(k)fluoranthene||<DL - 340j||car*||1/51|
|benzo(a)pyrene||<DL - 1100j||100||CREG2||1/5|
|indeno(1,2,3-cd)pyrene||<DL - 1400j||car*||1/51|
|dibenz(a,h)anthracene||<DL - 300j||car*||2/51|
|Aroclor-1248(PCB)||<DL - 480j||90||CREG||1/5|
|Aroclor-1254(PCB)||<DL - 190j||90||CREG||1/5|
|Aroclor-1260(PCB)||<DL - 180||90||CREG||1/5|
|arsenic||1,300j - 7,300||400||CREG||5/5|
|beryllium||340j - 21,000||200||CREG||5/5|
|cadmium||260j - 1,200||400||EMEG4||3/5|
|j- the associated numerical value is an estimated quantity because quality control criteria were not met. However, presence of the material is reliable.
* This chemical does not have a comparison value, however, because it is considered a carcinogen, it is ATSDR policy that it be evaluated further in this public health assessment.
1 Number is frequency above detection limit (DL).
Source for Data - (3)
|TABLE 2 - CONTAMINANTS OF CONCERN IN ON-SITE LEACHATE AT GLOBAL LANDFILL|
|CONTAMINANT||CONCENTRATION RANGE IN ppb||COMPARISON VALUE FOR WATER||FREQ >C.V.1|
|benzene||<DL - 71j||1.0||CREG2||4/5|
|chlorobenzene||<DL - 4,600||200||RMEG3||1/5|
|1,4-dichlorobenzene||<DL - 27j||car*||4/54|
|naphthalene||2j - 48j||20||LTHA5||3/5|
|trichloroethene||<DL - 110||3.0||CREG||NA6|
|tetrachloroethene||<DL - 15||0.7||CREG||NA6|
|trans-1,2-dichloroethene||<DL - 1,200||200||RMEG||NA6|
|vinyl chloride||<DL - 140||0.2||EMEG7||NA6|
|carbon tetrachloride||<DL - 5||0.3||CREG||NA6|
|bis(2-ethylhexyl)phthalate||<DL - 67||3.0||CREG||NA6|
|benzo(b)fluoranthene||<DL - 28||0.2||PMCL8||NA6|
|benzo(a)pyrene||<DL - 20||0.2||PMCL||NA6|
|indeno(1,2,3-cd)pyrene||<DL - 16||0.4||PMCL||NA6|
|Aroclor 1260 (PCB)||<DL - 5||0.005||CREG||NA6|
|aldrin||<DL - 0.32j||0.002||CREG||3/5|
|heptachlor||<DL - 0.041j||0.008||CREG||1/5|
|heptachlor epoxide||<DL - 0.028j||0.004||CREG||1/5|
|chlordane||<DL - 0.127||0.03||CREG||2/5|
|arsenic||13.5 - 34.7||0.02||CREG||5/5|
|cadmium||<DL - 210||2.0||EMEG||4/5|
|lead||<DL - 5,530||15||AL9||4/5|
|manganese||53.5 - 387j||50||RMEG||5/5|
|nickel||66.9 - 134||car*||5/54|
|vanadium||16.7j - 89.4j||20||LTHA||3/5|
|nitrate as nitrogen||<DL - 404,000||16,000||RMEG||NA6|
EXPLANATION OF TABLE 2
j- the associated numerical value is an estimated quantity because quality control criteria were not met. However, presence of the material is reliable.
* This chemical does not have a comparison value, however, because it is considered a carcinogen, it is ATSDR policy that it be evaluated further in this public health assessment.
1 Unless otherwise indicated, the number is frequency above CV for RI data.
2 CREG - ATSDR's cancer risk evaluation guide
3 RMEG - An EMEG calculated using an EPA reference dose (RfD)
4 Number is frequency above detection limit (DL).
5 LTHA is EPA's lifetime health advisory for drinking water.
6 The only levels above the DL were from the site investigation data for which there was information only on range, not individual values.
7 EMEG - ATSDR's environmental media evaluation guide
8 PMCL - EPA's proposed maximum contaminant level
9 AL - EPA's action level for lead in drinking water
B. Off-Site Contamination
Limited sampling of off-site soil, soil gas, surface water, and biota has been conducted at the Global Landfill NPL site. No groundwater, sediment, or air monitoring has been conducted.
In 1984, the New Jersey Division of Fish, Game, and Wildlife sampled some of the local aquatic biota (e.g., mussel, crab, and white perch) (1). No metal or organic compounds were detected in the biota samples above comparison values.
Surface-water samples were taken when on-site samples from the marsh and creek surrounding Global were taken. Analyses did not indicate any compounds above background levels (2).
The London Terrace and Parkwood Village apartment complexes, which are in the immediate vicinity of Global and Sommers Brothers Landfills, were evaluated for possible sources of environmental contamination (5). Soil gas was sampled at 34 locations in the two complexes, a vacant lot, and two control locations (Appendix A, Figure III). Organic vapors were detected at six locations in London Terrace, one in the vacant lot, and one control location. Six of the eight locations were not near the two landfills.
Soil borings of 20-24 feet were made at six locations identified through the soil gas sampling and soil samples obtained (5). Results of the soil samples did not indicate that contaminants were above comparison values. However, the soil samples arrived at the laboratory at temperatures significantly above the required 4 degrees celsius (C). Therefore, the results of the analyses are probably lower than the actual levels due the loss of VOCs because of the elevated soil temperature. This evaluation will be discussed further in the Pathways Analyses.
C. Quality Assurance and Quality Control
ATSDR was not provided with quality assurance and quality control (QA/QC) information concerning all analytical data discussed above. In preparing this public health assessment, ATSDR relied on the information provided in the referenced documents and assumed that adequate quality assurance and quality control measures were taken in regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analysis and conclusions of this public health assessment depend upon the completeness and reliability of the referenced information.
D. Physical and Other Hazards
As discussed in the Background section, erosion of the cover soil caused waste material to be exposed. In addition, the side slopes of the landfill are not stable and have collapsed at least once. Such conditions present physical dangers (cuts, punctures and falling hazards) to anyone walking on-site.
An additional concern is the potential migration of methane generated by Global Landfill. It is estimated that Global Landfill generates up to three million cubic feet of methane per day (1,2). The methane may migrate into nearby structures and buildup to explosive levels. Because all of the nearby residences are physically separated from the landfill by a valley and the nearest residence is 500-feet north of the landfill, the potential for methane to migrate into a nearby structure at explosive levels is significantly diminished. The potential for methane migration should be further reduced once the proposed methane collection system is operational (operable unit 1).
In this section of the public health assessment, the possible exposure pathways are evaluated to help determine whether persons have, are, or will be exposed to contaminants associated with the site. Pathway analysis consists of five elements (8):
- identifying contaminants of concern possibly related to the site,
- determining that contaminants have/are/will be transported through an environmental medium,
- identifying a point of exposure (i.e., a place or situation where humans might be exposed to the contaminated media),
- determining that there is a plausible route of human exposure (i.e., can the contaminant enter the body?), and
- identifying an exposed population (i.e., how many people, if any, are at the point of exposure).
An exposure pathway is considered complete when there is good evidence that all five elements exist. The presence of a completed pathway indicates that human exposure to contaminants has occurred in the past, is occurring, or will occur in the future. When one or more of the five elements of an exposure pathway are missing, that pathway is considered potential. The presence of a potential exposure pathway indicates that human exposure to contaminants could have occurred in the past, could be occurring, or could occur in the future. An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present. If there is uncertainty about the site-relatedness of the contaminants of concern in an exposure pathway, the pathway will be evaluated as if the contaminants were site-related.
The completed exposure pathways are on-site soil and leachate. The potential human exposure pathways are on-and off-site ambient air, on- and off-site surface water, biota, and off-site surface soil. The eliminated exposure pathways are subsurface soil and groundwater. Those human exposure pathways are explained below. The completed and potential exposure pathways and estimates of the number of exposed individuals for the Global Landfill site are presented in Tables 6 - 8, Appendix C.
At Global Landfill, there is a large amount of contaminant material and many opportunities for those contaminants to be transported (1-3). Those contaminant materials contain varying types and concentrations of toxic chemicals. Because Global Landfill does not have any engineering controls to prevent rainwater infiltration or landfill gas migration, the toxic compounds in the landfill will be transported from the landfill into the surrounding environments (e.g., soil, surface water, groundwater, and air).
A. Completed Human Exposure Pathways
Besides the following discussion, the completed human exposure pathways are depicted in Table 6, Appendix C.
On-site soil is considered a completed human exposure pathway because the five elements described previously are present. Humans have or are probably ingesting, inhaling, or having dermal contact with surface soil contaminated with a variety of compounds during recreational activities on-site (e.g., motorcycle riding). During ATSDR's site visit and the RI, teenagers and adults were observed walking around the site (3,6). Individuals were also seen riding all terrain vehicles (ATV) across the landfill (3).
Some leachate contaminants will adhere to the soils through which the leachate migrates, thereby contaminating the soils at Global. Surface soils are likely to be contaminated wherever leachate seeps out of the landfill, so there could be widespread contamination of surface soil. However, only limited (five samples) surface-soil sampling has been conducted (3). In addition, those samples were taken from 0-6 inches. ATSDR considers samples from 0-3 inches to be more appropriate for evaluating health impact (8). Additional surface-soil sampling is needed to properly characterize this environmental pathway.
NJDEPE is planning to place a modified hazardous waste cap on the landfill, collect and treat the leachate, fence the site, conduct storm-water management, and conduct soil-erosion control measures (operable unit 1). When those corrective actions are completed, it is likely that the on-site surface soil exposure pathway would be eliminated, provided operable unit 1 is appropriately designed and maintained.
Leachate is considered a completed human exposure pathway because the five elements described previously are present. Humans have or are probably ingesting, inhaling, or having dermal contact with leachate contaminated with a variety of compounds during recreational activities on-site (e.g., motorcycle riding). During the RI, teenagers and adults were observed riding ATVs through the leachate (3).
Leachate is generated when rain water infiltrates through waste material and when liquids (e.g. sludge) in the landfill migrate. The toxic chemicals in the landfill may dissolve in the water as the water moves through the waste. Analysis of leachate samples reveal organic and inorganic contaminants above comparison values (see Table 2). The Global Landfill leachate migrates into the groundwater beneath the landfill, the surface water next to the landfill, or onto the soil on or adjacent to the landfill as leachate seeps.
NJDEPE is planning to place a modified hazardous waste cap on the landfill, collect and treat the leachate, fence the site, conduct storm-water management, and conduct soil-erosion control measures (operable unit 1). When those corrective actions are completed, it is likely that the leachate exposure pathway would be eliminated, provided operable unit 1 is appropriately designed and maintained.
B. Potential Human Exposure Pathways
Besides the following discussion, the potential human exposure pathways are depicted in Table 7, Appendix C.
Ambient air is considered a potential human exposure pathway because there is no evidence of exposure occurring. There are good data that Global Landfill is generating several VOCs and methane. In addition to VOCs, surface-soil contamination can be transported as airborne particulates through wind erosion. Humans wandering onto or near the NPL site could inhale the VOCs or airborne particulates. As mentioned earlier, individuals have been observed on-site (3,6). The VOCs, methane, and particulates could also be blown into the residential areas. Air monitoring needs to be done before this human exposure pathway can be evaluated further.
The results of the landfill gas sampling were input into an air dispersion model which was used to predict VOC concentrations at five points off-site including the nearest apartment complex. No levels of health concern were identified. As discussed in the introduction to the Environmental Contamination and Other Hazards section, the air modelling does not replace the need for monitoring of ambient air off-site.
While exposure to methane or VOCs off-site may be occurring due to airborne migration from the site, exposure in the residential areas is not occurring due to dumping in those areas (5). The data from the community soil monitoring program indicates that the neighboring apartment complexes were not built on a landfill (5).
Surface water is considered a potential human exposure pathway because, while there does not appear to be exposure above comparison values, the other elements of a pathway are present. A variety of contaminants have been identified in surface water samples. Individuals are known to use the larger surface waters for fishing and boating, but not for swimming or as drinking water.
Off-site Surface Soil
Off-site surface soil is considered a potential human exposure pathway because, while there is no evidence of exposure occurring (i.e., no valid off-site sampling of soil has been done), there is a good opportunity for off-site movement. On-site surface-soil contamination can be transported as airborne particulates into the residential areas through wind erosion. Sampling of off-site surface soil needs to be done before this human exposure pathway can be evaluated further.
Biota are considered a potential human exposure pathway because, while there is no evidence of exposure occurring, the other elements of a pathway are present. A variety of organic compounds and heavy metals have been detected in the leachate, sediment, groundwater. Some of those compounds accumulate and concentrate in aquatic biota (e.g., fish and mussel). Observations during the RI indicate that biota are being exposed and that area waters are being utilized for fishing (3). However, limited biota sampling by the New Jersey Division of Fish, Game, and Wildlife did not detect any metal or organic compounds at levels of public health concern. Additional aquatic biota sampling is needed to confirm the initial findings.
C. Eliminated Human Exposure Pathways
On-site subsurface soil is considered an eliminated exposure pathway because it is very unlikely that anyone has, is, or will be exposed to this media. Sampling does indicate that the subsurface soil on Global Landfill is contaminated with a variety of chemicals at several locations (3). However, there appears to be no access to the subsurface soil (e.g., no one digs in the soil or removes it) now or in the future (2,3). The planned capping and fencing of the landfill will make accessing the subsurface soil even more difficult.
Ground water is considered an eliminated exposure pathway because the ground water around and downgradient from Global Landfill is not used as drinking water, nor will it in the future (2,3). The groundwater exposure pathway is complex and is described in this portion of the public health assessment.
The Global Landfill area is considered to have three aquifers - water-table (upper aquifer), Old Bridge (lower aquifer), and Farrington Sand (deep aquifer). No evaluation of the deep aquifer was done in the RI or other documents available to ATSDR. On-site investigations indicate that the Global Landfill NPL site rests on top of a meadow mat (0- to 10-feet thick) (1,3). The meadow mat (thatch) is part of the local wetlands and contains a water-table aquifer. Groundwater-monitoring data have demonstrated that contaminants from the landfill have migrated into the local water-table aquifer (3). The contaminated groundwater within the water-table aquifer flows south-southeast and is very likely discharging into the wetlands surrounding the landfill.
The water-table aquifer is generally separated from the larger Old Bridge Sand aquifer by a clay confining layer (1-35 feet thick) (1,3). However, the clay confining layer does not appear to be continuous throughout the landfill site, especially in the northwest portion of the site (3). Groundwater sampling data and the results of groundwater flow modelling indicate that site contaminants are and can move down into the Old Bridge Sand aquifer (3). Groundwater-monitoring and modelling data indicate the local water-table aquifer and Old Bridge aquifer generally flow in a southeasterly direction (1,3). However, the water-table aquifer appears to flow in the reverse direction, northwesterly, in the northwest part of the landfill (3). It is also this area where it is mostly likely that contaminants from the water-table aquifer move into the Old Bridge aquifer.
All residents of the Global Landfill area reportedly utilize municipal water supplies for drinking water (1,3). Those supplies have groundwater as their source. The municipal supply wells draw from the lower (Upper Bridge) and deep (Farrington Sand) aquifers. Those wells are upgradient from the landfill and thus are not at risk for contamination from the landfill.
Based on well surveys, there appears to be only one well southeast (downgradient) of the landfill (2,3). This well is about a mile southeast of the site. It is used only to replenish Hooks Creek Lake in Cheesequake State Park, and not for drinking water.
PUBLIC HEALTH IMPLICATIONS
As discussed in the Pathways Analyses section, on-site surface soil and leachate represent completed exposure pathways. The contaminants of concern in the surface soil pathway (Table 1) include seven polycyclic aromatic hydrocarbons (PAHs), three PCBs, and six metals. The contaminants of concern in the leachate exposure pathway include eight VOCs, two semi-volatiles, three PAHs, one PCB, four pesticides, six metals, and nitrates.
The Toxicological Evaluation portion of this section will discuss the possible health hazard from exposure to the contaminants of concern in the completed exposure pathways. Community health concerns will be addressed in Community Health Concerns Evaluation section and health outcome data in the Health Outcome Data Evaluation section.
A. Toxicological Evaluation
The toxicological evaluation in a public health assessment is a comparison of the exposure dose for those people in an exposure pathway to ATSDR's Minimal Risk Levels (MRLs) or EPA's Reference Doses (RfD). The exposure dose is the maximum amount per day, based on the available sampling data, that one might take into their body. The MRLs and RfDs are estimates of daily human exposure to a contaminant below which noncarcinogenic adverse health effects are unlikely to occur (10). That means that any exposure dose below the appropriate MRL or RfD does not represent a hazard to human health. However, for exposure doses above a MRL or Rfd, there is a wide zone of uncertainty above the MRL or Rfd whether adverse health effects will occur. Therefore, a review of the toxicological literature is done to determine whether the specific exposure situation represents a hazard to public health. The methodology for calculating the exposure doses is described in Appendix C.
Available information on the Global Landfill site indicates that children less than five years old do not have regular access to the site (3). Because of this, exposure doses for pica children were not calculated. Pica is the habit of ingesting significant amounts of soil each day (5 grams/day).
The risk of carcinogenic health effects is also evaluated in this section. The limitations and methodology for the carcinogenic evaluation are described in Appendix C.
Health guidelines for comparing to exposure doses were not available for benzene, 1,4 dichlorobenzene, naphthalene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, dibenz(a,h)anthracene, indeno(1,2,3-cd)pyrene, lead, nickel, and vanadium. Cancer slope factors for calculating cancer risk were not available for 1,4-dichlorobenzene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(b)fluoranthene, indeno(1,2,3-cd)pyrene, dibenz(a,h)anthracene, lead, and nickel.
Except for lead, the limited environmental data and gaps in knowledge about the toxicity of the chemicals without health guidelines or cancer slope factors preclude any additional evaluation of possible adverse health effects. A short discussion of the toxicology of lead is included at the end of this section for the reader's information.
The Results of Exposure Dose and Cancer Risk Calculations
The results of the comparisons of exposure doses to health guidelines are in Table 9, Appendix C. None of the exposure doses for the contaminants of concern exceeded the health guideline for the contaminant, so adverse health effects are unlikely to occur at those locations sampled. However, as discussed in the Environmental Contamination and Other Hazards section, the data for soil are not appropriate for determining the possible health impact of the entire site.
Cancer risk was calculated for aldrin, Aroclor/PCB, arsenic, benzene, benzo(a)pyrene, beryllium, bis(2-ethylhexyl)phthalate, carbon tetrachloride, chlordane, heptachlor, heptachlor epoxide, trichloroethene, and tetrachloroethene. See Appendix C for a description of how the cancer risk was calculated. The calculated maximum risk from regular ingestion of soil or dermal contact contaminated with the maximum concentrations of those chemicals does not represent an apparent increased risk of cancer. There was no apparent increased risk of cancer for exposure to arsenic, benzo(a)pyrene, and PCB through a combination of soil ingestion and dermal contact with leachate. As for the exposure doses, the results of the cancer risk calculations are applicable only to the specific locations where soil was sampled, and not for the whole site.
Toxicology of Lead
This discussion of the toxicology of lead is provided for the information of the reader. The pediatric evaluation of 175 children from the area around the site included blood lead analyses (5). Thirty-nine had levels above 10 µg/dL, but none of those were considered site-related (5).
Exposure to lead causes a wide range of effects (11). Young children and fetuses are especially sensitive to the toxic properties of lead (11,12). Factors accounting for the enhanced susceptibility in children include (1) the immaturity of the blood brain barrier that allows entry of lead into the immature nervous system; (2) hand-to-mouth behavior and pica, which leads to consumption of lead contaminated media; and (3) the enhanced gastrointestinal absorption of lead (affected by the nutritional condition of the child). The fetus is at risk since lead is readily transferred across the placental barrier.
The Centers for Disease Control has recently revaluated its guidelines on acceptable blood lead levels based on recent scientific information and studies (12). New data indicate that significant adverse health effects of lead exposure can occur in children at blood lead levels previously believed to be safe. Some health effects have been documented at blood lead levels as low as 10 µg/dl.
Blood lead concentrations of 10 µg/dl are associated with neuro-behavioral deficits, hearing impairments, and inhibition of hemoglobin synthesis in children (12). Blood lead levels between 10-20 µg/dl in children have been shown to result in a four- to five-point decrease in the Intelligence Quotient (I.Q.), and in electrophysiological changes in brain activity. Blood lead concentrations greater than 33 µg/dl in children produce neurotoxic effects as well as a depression in plasma levels of Vitamin D. Neurotoxic effects of lead in children are of primary concern since those effects can be irreversible, even after blood lead levels return to a normal range (11).
Since lead readily crosses the placenta, exposure of women to lead during pregnancy results in uptake by the fetus. Prenatal exposure to lead (8-14 µg/dl umbilical cord blood lead level) is associated with premature delivery, decreased birth weight, impaired postnatal neuro-behavioral development, and decreased postnatal growth rate (11).
Increases in blood pressure, and decreased nerve conduction velocity in peripheral nerves are noted in adults with blood lead levels greater than 30 µg/dl (11). Infertility in males (decreased sperm production) was observed at this concentration. Data on adverse reproductive effects in women at documented blood lead concentrations are inconclusive. Lead concentrations of 50-100 µg/dl in adults result in anemia and encephalopathy (11).
Lead is considered a possible human carcinogen based on studies in experimental animals (11). Investigations of an association between lead exposure and cancer in workers are contradictory, with some indicating a relationship and others not.
Lead enters the blood much easier through inhalation and ingestion than through skin contact (11). Lead is eliminated from the body slowly, with much of it being stored in the bones. Because lead remains in the body, the amount needed to cause health effects decreases as length of exposure increases.
Mixtures of Contaminants
The preceding paragraphs evaluated the possible health consequences from exposure to each of the contaminants of concern in soil and leachate. Many of those contaminants are simultaneously present in soil and leachate, so exposure includes a mixture rather than individual chemicals. Currently, there is no accepted method for determining possible health effects of chemical mixtures.
B. Health Outcome Data Evaluation
In this section, data on pediatric health evaluations, cancer incidence, and health outcomes reported by the clients of the petitioner are evaluated.
Pediatric Health Evaluation
Residents of Old Bridge and Sayreville, New Jersey, raised concerns about possible health effects of exposure to the materials in Global Landfill (5). The Global Task Group, in cooperation with NJDOH, responded by evaluating the current health status of children living in the Global area. The evaluation was not designed as a study to determine a link between exposure and symptoms.
The assessment targeted children under 18 and was conducted by staff of the Division of General Pediatrics of the University of Medicine and Dentistry of New Jersey (5). Participants were selected mostly on proximity of residence to the landfill by a subcommittee of the Global Task Group from children proposed by their parents.
The assessment included a questionnaire, physical exam, and laboratory analyses (5). The questionnaire collected information on demographic characteristics, potential routes of exposure, perceived symptoms, and if the perceived symptoms has been evaluated by a physician. The physical exam focused on physical signs of adverse health effects. Laboratory analyses conducted included a complete blood count, urinalysis, erythrocyte protoporphyrin, lead level, and serum chemistries. The analysis of the data from those assessments emphasized the potential relationships between the possible effect and the proximity of residence and play areas to the landfill.
The 175 children (90 boys, 85 girls) evaluated between August 1989 and February 1990 were from one to 18 years old (5). They had a racial and ethnic distribution reflective of the community around Global Landfill. The vast majority of the physical exams and laboratory exams were within normal parameters, and there was no association with proximity to the site for those that were not. Once controlled for confounding factors such as age and living with smokers, the only reported symptom associated with proximity to the landfill was pounding headaches. This association was only for play areas, not for residence.
The analyses for lead identified 39 children with blood lead levels above 10 µg/dL. Thirty-five were 11-15 µg/dL, three 16-20 µg/dL, and one 23 µg/dL (5). There was no significant correlation with exposure to the landfill in the children studied (5). There is a discussion of lead in the Toxicological Evaluation sub-section.
The Global Task Group identified several factors which could have affected the results of the pediatric health evaluation (5). The first was that proximity to the site was used as surrogate for actual exposure to site contaminants. This was done because no exposure to site-related contaminants has been documented. However, proximity may not equate with actual exposure, resulting in the mixing of exposed and non-exposed individuals. The finding of no relationship between an effect and proximity could be due to this mixing.
Other factors that could have affected the results are exposures to contaminants at work or other locations, genetic predisposition for disease, and socioeconomic factors (5). Additionally, there is a strong selection bias. The group of individuals from the which the final study participants were selected, were proposed by their parents, rather than selection on a random basis. The Global Task Group purposely selected individuals who lived closest to the site. Both these selection biases could have resulted in the inclusion of many individuals that are significantly different than the average child in the Global area. This could result in false conclusions being made.
ATSDR's review of the Global Task Group pediatric health evaluation revealed no indication of site-related health effects. However, as described previously, the evaluation's design does not allow any firm conclusions to be made.
Cancer Incidence Data
In response to community concerns, NJDOH evaluated the incidence of cancer in the area around Global Landfill (5). The area studied needed to include a large enough population to provide meaningful statistics, yet restrictive enough to include only those individuals residing relatively near the landfill. Seven census tracts from around the landfill with a total population of about 32,000 comprised the study area. The incidence of colon, pancreatic, lung, bladder, leukemia, lymphoma, brain and central nervous system, rectal, stomach, kidney, female breast, and prostate cancer were evaluated by sex and age for the period 1979-1987. The exposure to site-contaminants was not a variable in the analysis. As discussed in the Environmental Contamination and Other Hazards and Pathways Analyses sections, some exposure has occurred, but not at levels of concern to health.
The analysis of those cancer types indicates that the incidence of all the cancer types combined was significantly lower than that what was expected from state incidence rates (5). The incidence rates for each of the cancer types evaluated and by sex were not significantly different from those expected from state rates.
These results indicate that the incidence of cancer in the area around Global Landfill is not greater than expected as believed by some residents (5). Because actual exposure to site contaminants was not a variable in the analysis, it is not possible to discuss the association or lack of association between site contaminants and cancer.
Several steps are necessary to determine whether a particular disease or condition is caused by chemicals in the environment. The first step is to compare the occurrence of a disease or condition to what is considered normal or average. If the occurrence of disease is greater than expected, the next step is to identify possible reasons. Reasons can include specific personal habits, such as smoking and genetic predisposition, and exposure to chemicals. Suitable comparison populations were available for some of the health outcomes reported by the petitioner.
The health outcomes reported to ATSDR by the petitioner include allergies, asthma, bronchitis, diabetes, heart murmurs, miscarriages, rashes, thyroid problems, and several types of cancer. An appropriate comparison population was available for the first five outcomes listed above.
Appendix B compares the prevalence by age group of those five health outcomes (Table 4) to prevalence numbers from the 1988 National Health Interview Survey (Table 5). A statistical comparison of the two groups revealed no significant differences except for diabetes, where the petitioner group had fewer cases than expected from the national figures.
There is a possible problem in comparing the petitioner's information to the 1988 National Health Interview Survey. First, the National Health Interview Survey is a random sample, while the petitioner group is not. The petitioner's group consists of 374 individuals from the approximate 12,000 living near Global Landfill who either approached or were approached by the petitioner. The National Health Interview Survey consists of about 110,000 individuals randomly chosen from the United States population as a whole (13). The lack of randomness in a survey can result in either under- or over-reporting a health outcome.
Appropriate comparison populations could not be identified for the other reported health outcomes - miscarriages, rashes, thyroid problems, and several types of cancer. Therefore, it is not possible to evaluate those outcomes.
C. Community Health Concerns Evaluation
The community expressed concern about the occurrence of cancer and other specific health
outcomes. As described in the preceding section, NJDOH analyzed data on cancer incidence and
ATSDR evaluated the petitioner provided data. The overall rate of cancer is actually lower than
expected from the state rates. For the petitioner data, none of the outcomes for which
comparison populations were available were statistically elevated.