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HEALTH CONSULTATION

FRESH KILLS LANDFILL
STATEN ISLAND, RICHMOND COUNTY, NEW YORK


3.0 METHODS

ATSDR assesses a site by evaluating the level of exposure in potential or completed exposure pathways. An exposure pathway is the way chemicals may enter a person's body to cause a health effect. It includes all the steps between the release of a chemical and the population exposed: (1) a chemical release source, (2) chemical movement, (3) a place where people can come into contact with the chemical, (4) a route of human exposure, and (5) a population that could be exposed. In this consultation, ATSDR evaluates the pathway of air that people living in nearby neighborhoods inhale (the route), which might cause a chemical exposure to compounds from the landfill.

Data evaluators use comparison values (CVs), which are screening tools used to evaluate environmental data that is relevant to the exposure pathways. Comparison values are concentrations of contaminants that are considered to be safe levels of exposure. Comparison values used in this document include ATSDR's environmental media evaluation guide (EMEG) and cancer risk evaluation guide (CREG), and New York State Department of Environmental Conservation's annual guideline concentration (AGC). Comparison values are derived from available health guidelines, such as ATSDR's minimal risk levels and EPA's cancer slope factor.

The derivation of a comparison value uses conservative exposure assumptions, resulting in values that are much lower than exposure concentrations observed to cause adverse health effects; thus, insuring the comparison values are protective of public health in essentially all exposure situations. That is, if the concentrations in the exposure medium are less than the CV, the exposures are not of health concern and no further analysis of the pathway is required. However, while concentrations below the comparison value are not expected to lead to any observable health effect, it should not be inferred that a concentration greater than the comparison value will necessarily lead to adverse effects. Depending on site-specific environmental exposure factors (for example, duration of exposure) and activities of people that result in exposure (time spent in area of contamination), exposure to levels above the comparison value may or may not lead to a health effect. Therefore, ATSDR's comparison values are not used to predict the occurrence of adverse health effects.

The comparison values used in this evaluation are defined as follows: The CREG is a concentration at which excess cancer risk is not likely to exceed one case of cancer in a million persons exposed over a lifetime [13]. The CREG is a very conservative CV that is used to estimate cancer risk. Exposure to a concentration equal to or less than the CREG is defined as an insignificant risk and is an acceptable level of exposure over a lifetime [14]. The risk from exposure is not considered as a significant risk unless the exposure concentration is approximately 10 times the CREG and exposure occurs over several years. The EMEG is a concentration at which daily exposure for a lifetime is unlikely to result in adverse noncancerous effects [13]. New York's guideline, the AGC [15], is similar to either ATSDR's CREG or EMEG. If the AGC is based on potential cancer risk, it represents estimates of air concentrations associated with an excess cancer risk of one-in-a-million from lifetime exposures. If the AGC is based on noncarcinogenic risk, it corresponds to the EMEG. New York sets the AGC at the most conservative of the two concentrations.

Table A: Contaminants Selected for Additional Data Review

1,1,2- Trichloroethane**
1,2- Dichloroethane
Acetaldehyde
Acrolein
Benzene
Carbon tetrachloride
Chloroform
Formaldehyde
Methylene chloride**
Propionaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl chloride**
PM10: total, arsenic, cadmium, chromium, nickel

** Contaminants not selected as contaminants of concern

Selecting the Contaminants of Concern

Contaminants of concern (COCs) are the site-specific chemical substances that the health assessor selects for further evaluation of potential health effects. Identifying contaminants of concern is a process that requires the assessor to examine contaminant concentrations at the site, the quality of environmental sampling data, and the potential for human exposure [13]. A thorough review of each of these issues is required to accurately select COCs in the site-specific exposure pathway. The following text describes the selection process.

In the first step of the COC selection process, the maximum contaminant concentrations in Appendix A-Table 1 were compared directly to health comparison values. ATSDR considers site-specific exposure factors to ensure selection of appropriate health comparison values. If the maximum concentration reported for a chemical was less than the health comparison value, ATSDR concluded that exposure to that chemical was not of public health concern; therefore, no further data review was required for that chemical. However, if the maximum concentration was greater than the health comparison value, the chemical was selected for additional data review. In addition, any chemicals detected that did not have relevant health comparison values were also selected for additional data review. Table A shows chemicals that were selected in this step.

Comparison values have not been developed for some contaminants, and, based on new scientific information other comparison values may be determined to be inappropriate for the specific type of exposure. In those cases, the contaminants are included as contaminants of concern if current scientific information indicates exposure to those contaminants may be of public health concern.

The next step of the process requires a more in-depth review of data for each of the contaminants selected. Appendix A presents a summary table for each monitoring station. Those tables (Tables 2 through 13 in Appendix A) were used to determine the chemicals that would require further data review and analysis to determine whether ambient levels were of public health significance. ATSDR reviewed data for each monitoring station. Factors used in the selection of the COCs included the number of samples with detections above the minimum detection limit, the number of samples with detections above an acute or chronic health comparison value, and the potential for exposure at the monitoring location.

At the completion of the data review and analysis, ATSDR selected the following chemicals as contaminants of concern (COCs): 1,2-dichloroethane; carbon tetrachloride; chloroform; tetrachloroethylene; trichloroethylene; PM10; benzene; and aldehydes, including acetaldehyde, acrolein, formaldehyde, and propionaldehyde. Additional environmental and toxicological evaluation was required for each of these chemicals. Methylene chloride, 1,1,2-trichloroethane, and vinyl chloride were not selected as COCs.

Methylene chloride was not selected as a COC because it was detected at levels above the comparison value in only 1 of 317 samples collected at monitoring stations associated with residential areas. In addition, that one sample was collected at Port Richmond, the background station. 1,1,2-trichloroethane was not selected as a COC because it was detected infrequently and, although slightly greater than the CREG, exposure to the maximum concentration detected is not a health concern. Vinyl chloride was not selected as a COC because it was detected in only 1 of 618 samples above the minimum detection limit (MDL). The MDL for vinyl chloride in the NYSDEC monitoring program was 0.08 ppb. The MDL was greater than the ATSDR comparison value. However, ATSDR reviewed the scientific literature and determined adverse health effects are unlikely from exposure to concentrations similar to the MDL [16]. Since the concentration that people were exposed to was less than the MDL, ATSDR did not select vinyl chloride as a COC.


4.0 PUBLIC HEALTH EVALUATION

Using the available health guidelines and scientific information, ATSDR determines the likelihood that an adverse health effect may occur as a result of exposure to the COCs. The following sections of this consultation include: 1) ATSDR's conclusion concerning the risk of adverse health effects from exposure to the concentrations of the COCs detected in the NYSDEC monitoring program, and 2) a summary of the review and analysis of ambient air data for each COC (information on which the conclusion is based).

When evaluating the health implications from long-term inhalation exposures (more than 365 days), ATSDR estimates the average concentrations to which people are being exposed. To estimate the concentrations that people living or working in the vicinity of Fresh Kills Landfill were exposed to, ATSDR calculated geometric and arithmetic means for each of the COCs (see Tables 14-21 in Appendix A). The geometric mean is a statistical tool used to represent the central tendency of lognormal distributions and is the most appropriate measure of central tendency when evaluating long-term ambient air exposures [17]. As a best estimate of actual concentration, this analysis assigned all nondetect observations a concentration equal to one-half the estimated detection limit. This approach has been used by many previous monitoring studies and is a recommended approach for assessments involving environmental monitoring data [18]. Many ambient air monitoring efforts and health standards are reported as arithmetic means as indicators of annual averages. Therefore, the arithmetic mean is included in this evaluation to allow comparisons of this data with those sources of information.

The following sections provide public health evaluations for each of the chemicals selected as a COC.

Halogenated Volatile Organic Compounds

Halogenated volatile organic compounds (VOCs) selected as COCs include 1,2-dichloroethane, carbon tetrachloride, chloroform, tetrachloroethylene, and trichloroethylene. Tables 14 through 18 in Appendix A present a summary of statistical data for each of these chemicals. The data tables include the following information: monitoring station identification; number of valid ambient air samples; number of nondetect ambient air samples; concentration ranges; concentrations at the 25th, 50th, and 75th percentiles; and estimates of the annual average concentrations (arithmetic and geometric means with the standard deviation). The discussion section for each COC contains a graphical presentation of the relevant statistical data.

1,2-dichloroethane (1,2-DCA)

Exposure to concentrations of 1,2-dichloroethane (1,2-DCA) detected in the NYSDEC monitoring program are not expected to result in adverse health effects. Maximum levels detected ranged from 0.12 - 0.6 ppb. The maximum level (0.6 ppb) was detected at Port Richmond, the background station.

1,2-dichloroethane is currently used in the manufacturing process of other chemicals and as a solvent. Direct emissions to the air comprise the largest component of all releases of 1,2-DCA to the environment. The Toxic Chemical Release Inventory (TRI) reported that approximately 99.1% of the total environmental release in the United States in 1991 was discharged to the air from manufacturing and processing; less than 1% of the environmental release in the United States was discharged to the land [19]. ATSDR recognizes that the TRI is not a complete list of all facilities that potentially emit 1,2-DCA. However, the database does indicate that direct air emissions may be a primary source of 1,2-DCA in the ambient air in urban areas.

The range of the geometric means for 1,2-DCA for all of the monitoring stations in the NYSDEC program was 0.007-0.012 ppb (see Figure 2 and Appendix A-Table 14). This range is representative of average concentrations that the population in the vicinity of Fresh Kills Landfill is expected to be exposed to on a long-term basis. The geometric means for all of the monitoring locations are less than or similar to the cancer risk evaluation guide (CREG) and the NYSDEC annual guideline concentration (AGC) of 0.01 ppb. The EMEG (200 ppb), the guideline for noncancerous effects, is approximately 20,000 times the geometric means. Therefore, ATSDR concluded adverse health effects are unlikely from chronic exposure to 1,2-DCA at the levels detected in this monitoring program.

Maximum levels detected at the monitoring stations are shown in Figure 3. The maximum level of 1,2-DCA (0.6 ppb) was detected at Port Richmond, the background station. Similar maximum levels of 1,2-DCA were detected at the District 2 Garage ( 0.57 ppb) and Unloading Zone 2 (0.5 ppb), stations associated with the landfill and residential areas. The maximum concentrations detected at the other nine monitoring stations ranged from 0.12-0.25 ppb. The acute inhalation MRL is 200 ppb. Because the acute MRL is approximately 300 times the maximum levels detected, ATSDR concludes that adverse acute health effects are unlikely from exposures to the maximum levels of 1,2-DCA detected.

The levels of 1,2-DCA detected in the NYSDEC monitoring program are similar to levels detected in other urban sites and reported in the Environmental Protection Agency's (EPA) database. EPA compiled a database of median daily atmospheric concentrations from a review of approximately 950 papers on VOCs in air published from 1970 to 1987 [20]. The median daily atmospheric concentrations of 1,2-DCA were 0.012 ppb (1,214 samples) in urban sites and 0.26 ppb (182 samples) for source-dominated samples [21]. The 50th percentiles for all of the monitoring stations were less than the median levels reported in EPA's database. The 75th percentiles at District 2 Garage, Unloading Zone 2, and Meteorology Tower are slightly greater than levels reported for urban areas but are one-tenth levels reported for source dominated areas. Therefore, ATSDR concluded that the concentrations detected in the monitoring program are similar to levels reported in the EPA database for urban areas.

In the gas emission survey of the landfill, the Radian Corporation reported 1,2-DCA was emitted from the landfill. ATSDR used a dispersion model to estimate a 1-hour peak concentration of 1,2-DCA that might be expected in the nearby community as a result of the emissions from the landfill. The estimated 1-hour peak concentration was 0.02 ppb. This estimated peak concentration is approximately 3% of the maximum 24-hour concentration (0.6 ppb) reported in the NYSDEC ambient air quality data. Based on this information, it appears the landfill may not significantly contribute to the levels of 1,2-DCA detected on Staten Island.

Carbon Tetrachloride

ATSDR concluded adverse health effects are not expected from exposures to the levels of carbon tetrachloride detected in the NYSDEC monitoring program. The concentrations of carbon tetrachloride detected at the 12 monitoring stations in the NYSDEC monitoring program ranged from less than 0.02-0.16 ppb. Levels detected at all of the monitoring stations, including the background station (Port Richmond), are very similar. Both the actual levels detected and the arithmetic and geometric means are similar to average levels reported for cities in the U.S. All levels detected in the monitoring program were less than the level reported for a typical home.

All monitoring stations had concentrations reported above the CREG for carbon tetrachloride (0.01 ppb). The sample with the maximum concentration reported (0.16 ppb) in the ambient air monitoring program was collected at Port Richmond, the background station. The arithmetic means range from 0.029-0.040 ppb and the geometric means range from 0.020-0.029 ppb (see Figure 4 and Appendix A-Table 15). The geometric means for all stations are approximately 2 to 3 times the CREG, the screening value used to select carbon tetrachloride as a COC. EPA's risk-based concentration for carbon tetrachloride in ambient air is 0.77 ppb [22]. The geometric and arithmetic means are less than this guideline. In addition, all actual concentrations of carbon tetrachloride detected at the 12 monitoring stations are less than this risk-based concentration. Based on these comparisons, adverse effects are not expected to occur as a result of exposure to the levels of carbon tetrachloride detected in the NYSDEC monitoring program.

Carbon tetrachloride is ubiquitous in ambient air. The average concentration reported in the National Ambient Volatile Organic Compounds Database (NAVOCDB) updated in 1988 was 0.168 ppb [23]. Average values reported in four U.S cities ranged from 0.144-0.291 ppb [24]. Average concentrations reported from five coastal monitoring stations around the world were 0.1-0.13 ppb. Similar concentrations of carbon tetrachloride were also reported in air at five hazardous waste sites and one landfill in New Jersey. Average values ranged from 0.02-0.12 ppb. Carbon tetrachloride is also commonly detected in indoor air. Based on 2,120 indoor air samples in the United States, the average concentration was 0.4 ppb. A typical level in homes in several U.S. cities was 0.16 ppb [23].

TRI data reported levels of carbon tetrachloride released into the ambient air were substantially reduced in 1990 [25]. Levels reported in the NYSDEC monitoring program indicate that the concentrations in this area are lower than the levels reported in the NAVOCDB. The 50th percentile concentrations of carbon tetrachloride in the NYSDEC data range from 0.01-0.04 ppb, approximately 4 to 10 times less than the reported average level in the NAVOCDB. The 75th percentiles are also less than the average levels reported in the NAVOCDB.

In the gas emission survey of the landfill, the Radian Corporation reported carbon tetrachloride was emitted from the landfill. ATSDR used a dispersion model to estimate a 1-hour peak concentration that might be expected in the nearby community as a result of the emissions from the landfill. The estimated 1-hour peak concentration was 0.008 ppb. This estimated peak concentration is approximately 5% of the maximum 24-hour concentration (0.16 ppb) reported in the NYSDEC ambient air quality data. Based on this information, it appears the landfill may not significantly contribute to the levels of 1,2-DCA detected on Staten Island.

Chloroform

Based on available ambient air monitoring data for chloroform, health scientists do not expect adverse health effects in the exposed population in the vicinity of Fresh Kills Landfill. Concentrations reported for all monitoring stations were similar. In addition, all concentrations detected in the monitoring program were similar to average concentrations reported for urban areas.

Concentrations reported for all monitoring stations are very similar (see Figure 5 and Appendix A-Table 16). The ranges are 0.011-0.013 ppb and 0.01-0.015 ppb for the geometric and arithmetic means, respectively. The maximum level detected in the ambient air monitoring program was 0.1 ppb. The MRL for chronic inhalation exposure to chloroform is 20 ppb, 200 times the maximum concentration detected. In addition, more than one-half of the samples were reported as nondetects. Therefore, noncancerous health effects are unlikely from exposures to chloroform.

All monitoring stations had levels reported above the comparison value for cancerous effects. The CREG for chloroform is 0.008 ppb. The geometric means for all stations range from approximately equal to the CREG to 1.5 times the CREG. Therefore, concentrations that people are potentially exposed to are expected to be very similar to the CREG, an exposure considered safe. Cancer risk calculations show these exposures to be no apparent increased risk. Therefore, ATSDR concludes that adverse cancerous health effects are unlikely from exposures to these concentrations.

Typical median indoor air concentrations range from approximately 0.2-4 ppb. One of the most significant indoor sources of chloroform is chlorinated tap water. Chloroform concentration ratios of indoor air to outdoor air range from less than 1 to 25 [26]. The maximum and background levels found in seven U.S. cities between 1980 and 1981 were 5 ppb and 0.02 ppb, respectively. The median reported in the 1987 update of the NAVOCDB was 0.06 ppb [26]. All of these levels are higher than levels detected in the NYSDEC monitoring program.

In the gas emission survey of the landfill, the Radian Corporation reported chloroform was emitted from the landfill. ATSDR used a dispersion model to estimate a 1-hour peak concentration of chloroform that might be expected in the nearby community as a result of the emissions from the landfill. The estimated 1-hour peak concentration was 0.028 ppb. This estimated peak concentration is approximately 28% of the maximum 24-hour concentration (0.1 ppb) reported in the NYSDEC ambient air quality data. Based on this information, it appears the landfill may be a limited contributor to the levels of chloroform on Staten Island.

Tetrachloroethylene

Based on available NYSDEC ambient air monitoring data for tetrachloroethylene, health scientists do not expect adverse health effects in the exposed population in the vicinity of Fresh Kills Landfill.

Several comparison values are available for tetrachloroethylene. The chronic MRL, a noncarcinogenic guideline, is 40 ppb. The CREG (0.3 ppb), NYSDEC annual guideline concentration (0.17 ppb), and EPA's risk-based concentration (3.1 µ/m3 or 0.47 ppb) are all carcinogenic guidelines.

All monitoring stations in the NYSDEC monitoring program reported maximum concentrations of tetrachloroethylene above CVs. However, none of the geometric means (range 0.048-0.157 ppb), the average concentration that people would be exposed to, were above these guidelines (see Figure 6 and Appendix A-Table 17). Therefore, neither cancerous nor noncancerous adverse health effects are expected as a result of exposures to the levels detected in the monitoring program. The New York City Department of Environmental Protection (NYCDEP) monitoring program detected similar levels of tetrachloroethylene on Staten Island. Annual averages reported in the NYCDEP data ranged from 0.03-0.14 ppb [27].

In the gas emission survey of the landfill, the Radian Corporation reported tetrachloroethylene was emitted from the landfill. ATSDR used a dispersion model to estimate a 1-hour peak concentration of tetrachloroethylene that might be expected in the nearby community as a result of the emissions from the landfill. The estimated 1-hour peak concentration was 1.1 ppb. The model showed the peak occurred 50 meters from Section 1/9 of the landfill. The estimated peak concentration was approximately 87% of the maximum 24-hour concentration (1.27 ppb) reported in the NYSDEC ambient air quality data. Maximum concentrations of tetrachlorethylene reported in the NYSDEC data were detected at Unloading Zone 2 (1.27 ppb) and Section 1/9 (0.73 ppb). These concentrations were 243% and 140% greater, respectively, than concentrations detected at Port Richmond (0.523 ppb), the background station. Based on this information, it appears the landfill may contribute to the levels of tetrachloroethylene detected on Staten Island.

Trichloroethylene

Based on available ambient air monitoring data for trichloroethylene, health scientists do not expect adverse health effects in the exposed population in the vicinity of Fresh Kills Landfill. The average concentrations that people would be exposed to are less than levels expected to cause adverse health effects.

Several comparison values are available for trichloroethylene. The intermediate MRL is 100 ppb. The EPA's risk-based concentration is 0.18 ppb. The CREG is 0.1 ppb. The NYSDEC annual guideline concentration is 0.08 ppb.

Trichloroethylene was detected at all monitoring stations slightly above comparison values (Figure 7 and Appendix A-Table 18). However, concentrations in more than 75% of the samples were below comparison values. The geometric means ranged from 0.019-0.033 ppb, with the maximum at District 2 Garage. The geometric means (an estimate of annual average concentrations and the concentration used to determine the level of exposure) for all monitoring stations were less than the comparison values. In addition, the maximum concentration detected (0.33 ppb) was approximately 300 times less than the intermediate MRL, a guideline for exposures up to one year. Therefore, all exposures to trichloroethylene, both long-term and short-term, were less than the health comparison values. ATSDR concluded that neither cancerous nor noncancerous adverse health effects are expected as a result of exposure to the concentrations of trichloroethylene detected in the monitoring program.

In the gas emission survey of the landfill, the Radian Corporation reported trichloroethylene was emitted from the landfill. ATSDR used a dispersion model to estimate a 1-hour peak concentration of trichloroethylene that might be expected in the community as a result of the emissions from the landfill. The estimated 1-hour peak concentration was 0.6 ppb. The estimated peak concentration was approximately 182% of the maximum 24-hour concentration (0.33 ppb) reported in the NYSDEC ambient air quality data. The maximum concentration of trichlrorethylene reported in the NYSDEC data was detected at District 2 Garage (0.33 ppb). The maximum geometric means occurred at District 2 Garage (0.033 ppb) and Unloading Zone 2 (0032 ppb). Based on this information, it appears the landfill may contribute to the levels of tetrachloroethylene detected on Staten Island.

Benzene

Because benzene is released to the air during many everyday activities, concentrations in most urban areas are elevated. The levels of benzene reported in the NYSDEC data are similar to levels detected in most urban areas. Because the levels are similar to those detected in most urban areas and the levels are much less than those known to cause adverse health effects, long-term exposure to these levels of benzene on Staten Island is not expected to result in increased adverse health effects.

Benzene is widely distributed in the environment. Benzene is released from manmade and natural sources. Natural sources include crude oil seeps, forest fires, and volatile compounds released from vegetation. Sources from human activities include automobile exhaust, automobile refueling activities, cigarette smoke, and industrial emissions. The most significant source for release of benzene to the environment is from combustion of gasoline [28].

The NYSDEC reported concentrations of benzene ranging from <0.04-2.58 ppb (see Figure 8 and Appendix A-Table 19). Long-term exposures are expected to be similar to the median or mean (approximately 0.5 ppb), about one-fifth the maximum levels reported in the NYSDEC database. These exposure levels are 17 and 13 times greater than the CREG (0.03 ppb) and AGC (0.04 ppb), respectively.

Benzene is a known human carcinogen because high occupational exposures have been consistently associated with an increased incidence of acute myelogenous leukemia [28]. Hematopoietic (blood-forming) and lymphoid tissues are the most sensitive targets; bone marrow depression and aplastic anemia are the major symptoms of chronic low- and high-dose exposure, respectively [28]. Benzene risk assessments are typically based on extrapolations from high-level exposure in workers during more environmentally permissive periods, e.g., the 1940s [29]. Also, occupational exposures in the past that have been associated with leukemia were much higher than previously estimated [29].

A few human studies indicate that chronic exposure to low levels of benzene (10 ppm or less) may be associated with leukemia [30] [31] [32] [33]. However, these studies are not conclusive and cannot rule out other exposure factors. Most studies indicate that carcinogenic effects are the result of exposures to concentrations of benzene greater than 10 ppm [28]. Based on the levels of benzene detected in the current sampling program (see below), exposure of populations near Fresh Kills Landfill are expected to be approximately 2,000 times less than the lowest concentration associated with carcinogenic effects (1 ppm) and 20,000 times less than levels that are considered to be the lowest levels with more definitive evidence of carcinogenic effects (approximately 10 ppm).

Based on conservative cancer risk estimates, long-term exposure to benzene at levels similar to those detected in the NYSDEC monitoring program would result in a low increased risk of developing cancer (about two cancers per 100,000 persons exposed). However, since the concentrations of benzene are similar to most urban areas it is unlikely that an increase in cancer rates would be observable.

The levels (<0.04 to 2.58 ppb) of benzene detected at all stations of the NYSDEC monitoring program were within ranges typically reported for urban areas. The urban/suburban daily median benzene concentrations reported in the Volatile Organic Compound National Ambient Database was 1.8 ppb [28]. The median range in the NYSDEC data was 0.31-0.49 ppb. However, most of the concentrations reported in the monitoring program were above the comparison value of 0.03 ppb (CREG). The arithmetic and geometric means were also above this comparison value. The maximum level detected in the monitoring program was 2.58 ppb at the District 2 Garage and at the Composting Facility. A maximum level of 2.2 ppb was detected at Port Richmond, the background monitoring station, and a maximum of 2.09 ppb was detected at the meteorology tower, the station considered to be upwind of the site. Figure 9 shows the monthly average concentrations of benzene are similar at stations representative of background, upwind of site, and on-site. This data implies that benzene levels are similar across Staten Island.

Although the levels of benzene detected are above health comparison values, the data indicate that the benzene levels detected in the monitoring program may be related to general air quality on Staten Island. Similar levels of benzene have been reported for other urban areas. The New York City monitoring program reported similar concentrations of benzene in the ambient air. In 1995, the actual concentrations detected ranged from 0.018-1.53 ppb with an annual average concentration range of 0.25-0.63 ppb [27] and in 1994, the actual concentrations detected ranged from 0.03-1.95 ppb with an annual average concentration range of 0.42-0.62 ppb [7]. In 1992, ambient air concentrations of benzene in Boston, Massachusetts were reported as 0.69-3.1 ppb with a median of 1.06 ppb [34]. The Staten Island/New Jersey Urban Air Toxics Assessment Project reported benzene concentrations ranging from 0.65-5.60 ppb for samples collected from October 1989 through August 1990 [35]. Mobile sources (autos and trucks), refineries, and gasoline stations were found to be the major contributors to the concentrations of benzene reported.

To determine if mobile sources contributed to the concentrations detected in the NYSDEC program, ATSDR reviewed the ratios of benzene, toluene, and xylenes to ethylbenzene. The ratios for Port Richmond, District 2 Garage, Meteorology Tower, landfill surface emissions, and passive vent emissions were compared with the ratios of a roadside study in Atlanta (see Figure 10). The comparison indicates that levels detected at the Port Richmond monitoring station and the Meteorology Tower are similar to ratios typically observed near busy highways. Ratio comparisons for landfill surface emissions and the passive vent emissions indicate the ratios of levels emitted from the landfill are different from those observed near highways. This analysis indicates that vehicular emissions may be a major contributor to ambient air levels of benzene on Staten Island.

In the gas emission survey of the landfill, the Radian Corporation reported benzene was emitted from the landfill. ATSDR used a dispersion model to estimate a 1-hour peak concentration of benzene that might be expected in the nearby community as a result of the emissions from the landfill. The estimated 1-hour peak concentration was 0.96 ppb. The estimated peak concentration was approximately 37% of the maximum 24-hour concentration ( 2.58 ppb) reported in the NYSDEC ambient air quality data. Maximum concentrations of benzene reported in the NYSDEC data were detected at District 2 Garage (2.58 ppb), Composting Facility (2.58 ppb), and Unloading Zone 2 (2.46 ppb). Concentrations detected at other monitoring stations were similar to the levels predicted by the model. Based on this information, it appears the landfill may contribute marginally to the levels of benzene detected on Staten Island.

Aldehydes

Because the data collection and analysis for aldehydes are limited, a thorough evaluation of potential exposure to aldehydes is not possible. Annual estimates of exposure cannot be calculated from the data because samples have not been collected for a full year, therefore, estimated annual concentrations may not be representative of actual long-term exposures. However, based on the available monitoring data, the estimated average concentrations are potentially greater than the comparison values. NYSDEC has collected additional aldehyde data during 1995 and 1996. Thus, ATSDR recommends a more thorough evaluation of exposures to aldehydes be performed when the data are available for public health evaluation.

Sampling for aldehydes in the NYSDEC monitoring program was limited. Only selected monitoring stations were used in the program, and data were only collected over a period of nine months. Samples were collected at IS75 and Unloading Zone 2 from April to December 1995; and at District 2 Garage, Port Richmond, Arthurkill Road, Meteorology Tower, and the Composting Facility for approximately three months in the last quarter of 1995 (see Figure 16).

Aldehydes detected above comparison values include formaldehyde, acrolein, acetaldehyde, and propionaldehyde. Levels above health comparison values were detected in 141 of 142 formaldehyde samples, 136 of 142 acetaldehyde samples, 23 of 53 acrolein samples, and 141 of 141 propionaldehyde samples. Similar rates of detection were reported in a study of the Bronx area in New York. Acetaldehyde, formaldehyde and propionaldehyde were detected in 99% of the samples collected [36]. Crotonaldehyde and valeraldehyde were detected at levels less than health comparison values. Other aldehydes detected that do not have appropriate CVs include benzaldehyde, hexanal, methacrolein, and n-butylaldehyde.

Aldehydes are potentially irritating toxic compounds which under certain circumstances can sensitize animals and humans. Formaldehyde is the most studied of the aldehydes, but other exposure to other aldehydes has been shown to result in adverse health effects. Aldehydes detected in the monitoring program shown to present irritating, toxic, or immunologic effects in humans include formaldehyde, acetaldehyde, and acrolein [37]. Acrolein and formaldehyde appear to be more toxic than acetaldehyde [36]. These three aldehydes are discussed below.

Because the data collection and analysis for aldehydes are limited, the data may not be representative of long-term exposures. Annual estimates of exposure cannot be calculated from the data. However, estimated annual concentrations, based on the monitoring data, are potentially greater than the comparison values.

Also, concentrations may vary with location of and season when samples were collected; this data set may not represent the maximum levels of aldehydes to which people may be exposed. Therefore, a review of spatial and temporal trends of the data appears below. Because the concentrations of the different aldehydes detected appear to track together in the environmental data, the spatial and temporal discussion covers only formaldehyde.

Formaldehyde

Formaldehyde is ubiquitous in urban ambient air. Many different industries, especially manufacturers of certain resins and plastics, emit formaldehyde as both stack and fugitive emissions. Pressed wood products, such as particle board, plywood, and paneling, made from ureaformaldehyde resins emit formaldehyde vapors for several years after their manufacture. Formaldehyde emissions also result from the incomplete oxidation of hydrocarbon fuels, most significantly ethanol and methanol. Several studies have reported elevated concentrations of formaldehyde in automobile exhaust. Formaldehyde is also a natural decay product of most organic compounds.

Figure 11 and Appendix A-Table 20 present data summaries for formaldehyde. Maximum levels detected were 13.32 ppb and 12.84 ppb at the Unloading Zone 2 and the Intermediate School 75, respectively in April 1995. Samples were not collected at other stations during April 1995. In November and December, when more stations were sampled, the maximum level (7.518 ppb) was detected at Port Richmond, the background station. On that same day levels detected at the stations within the landfill boundaries ranged from 1.063-2.593 ppb. Since the data are limited, ATSDR cannot conclude from these data whether these levels are associated with landfill emissions. However, it should be noted, when elevated concentrations were observed at Port Richmond, the background station, depressed concentrations were observed at the Composting Facility station where decaying products might be expected to produce formaldehyde (see Figure 12).

ATSDR and NYSDEC have established comparison values for formaldehyde of 0.06 ppb and 0.05 ppb, respectively. All but one of the formaldehyde concentrations (141 of 142) reported by NYSDEC exceed both of these comparison values.

Formaldehyde has been shown to be carcinogenic in animals. Repeated inhalation exposure of rats to about 14,000 ppb resulted in cancerous lesions in the nasal cavity. More than 30 epidemiologic studies have been performed to address the potential carcinogenicity of formaldehyde in humans. Some epidemiological studies have indicated an increased risk of nasopharyngeal cancer in humans [38][39][40][41]. However, people in these studies were exposed to concentrations of formaldehyde of 500 ppb or greater, and the evidence was not conclusive. Two of the largest studies were conducted by the National Cancer Institute in the United States and the Medical Research Council in the United Kingdom [42][43]. These studies concluded there is no evidence that formaldehyde caused cancer in humans [44].

The NYSDEC guideline based on carcinogenicity is 0.05 ppb; as with all health guidelines, this is a highly conservative estimate of risk. The average (arithmetic mean) concentrations ranged from 1.01 ppb at the Composting Facility to 3.41 ppb at Unloading Zone 2. Exposures to these average concentrations would result in risk estimates ranging from no apparent increased risk to a low increased risk for developing cancer. Based on these low risk calculations and the lack of evidence for carcinogenicity in humans, it is unlikely that an increased rate of cancer would occur in the exposed population.

Spatial and Temporal Analysis

A cursory review of the data indicates some spatial variation (levels reported are related to the location) in the concentrations of formaldehyde reported in the NYSDEC monitoring program. For example, the maximum levels observed at Port Richmond, Intermediate School 75, and Unloading Zone 2 all exceed 7.0 ppb, but the maximum concentrations reported at District 2 Garage, Arthur Kill Road, Meteorology Tower, and Composting Facility did not exceed 3.0 ppb. A similar trend is reported for the mean and median. A thorough review reveals the spatial variation is related to time frames (dates/season) of the data collection at the different stations. Therefore, because the data are limited and it is unsuitable to make direct comparisons between the monitoring stations because of temporal differences in collection, ATSDR cannot determine whether the maximum levels detected are related to the landfill or general air quality on Staten Island. The time frames for data collection at each station are fundamental to the interpretation of the indicated spatial variations.

Data collected in the NYSDEC monitoring program also indicate some seasonal (temporal) variations in formaldehyde concentrations. However, the time frame of data collection was limited and not all stations were used throughout the program. Samples were collected at IS75 and Unloading Zone 2 from April to December 1995; samples were collected at District 2 Garage, Port Richmond, Arthur Kill Road, Meteorology Tower, and the Composting Facility for approximately three months in the last quarter of 1995.

Maximum concentrations in the monitoring program were reported at stations, Unloading Zone 2 and Intermediate School 75. Data was collected at both of these stations over a 9- month period, therefore, ATSDR reviewed the monthly variations for these two stations. Figure 13 shows the monthly variations summary for those two stations. The data indicate that peak levels may occur in the summer months. However, data are insufficient to support a determination of whether seasonal variations of formaldehyde concentrations occur. It would be necessary to secure data from additional stations and from collections throughout the year (seasons) to evaluate seasonal trends in formaldehyde levels.

Acetaldehyde

Acetaldehyde is widely distributed in the environment. It occurs in the air as a consequence of wood combustion and incomplete combustion of fuels and is a major component in the gas phase of tobacco smoke. It is widely used to manufacture plastics, disinfectants, drugs, dyes, rubber accelerators, and varnishes. Automobile emissions contribute to daily acetaldehyde production and release into the environment occurs [36].

Concentrations of acetaldehyde detected in the NYSDEC monitoring program ranged from 0.015-9.93 ppb. As with formaldehyde, the maximum concentration was detected at Unloading Zone 2 (9.93 ppb), and concentrations at Intermediate School 75 (2.98 ppb) and Port Richmond (2.84 ppb) ranked second and third.

The most conservative comparison value for acetaldehyde is the CREG, 0.27 ppb. The environmental data collected by NYSDEC indicate that annual average concentrations of acetaldehyde may slightly exceed this conservative comparison value. The CREG is based on animal studies; one epidemiological study provided inadequate evidence for human carcinogenicity [45].

Occupational standards are much less conservative. The occupational exposure limits for acetaldehyde in different countries vary from 25,000 to 200,000 ppb [36]. The OSHA time weighted average in the U.S. is 200,000 [46]. These standards are based on information showing that concentrations from 50,000 to 200,000 ppb cause eye irritation and upper respiratory discomfort [36]. These concentrations are much greater than concentrations detected in the ambient air in the vicinity of Fresh Kills Landfill. However, because acetaldehyde has been shown to produce tumors in animals, the National Institute for Occupational Safety and Health (NIOSH) recommends that acetaldehyde be considered a potential occupational carcinogen and that consideration be given to reducing exposures to aldehydes [45].

Acrolein

Acrolein is a major component of wood, cotton, polyethylene, and cigarette smoke [36]. It is used in the manufacture of pharmaceuticals, perfumes, food supplements, and resins.

Acrolein was reported at concentrations less than the minimum detection limit of 0.007 ppb to 0.03 ppb in the NYSDEC monitoring program. The maximum concentration (0.03 ppb) was detected at Unloading Zone 2. Similar concentrations were detected at the Composting Facility (maximum concentration 0.027 ppb). Acrolein was also detected in residential areas; the maximum concentrations at Intermediate School 75 and Port Richmond were 0.013 ppb and 0.017 ppb, respectively. The comparison value is 0.009 ppb. As with the other aldehydes, the environmental data collected by NYSDEC indicate that annual average concentrations of acrolein may exceed the comparison value.

Because the highest concentrations detected were above comparison values and in areas that may be more associated with occupational exposures than residential exposures, ATSDR reviewed occupational exposure standards. As a result of exposure factors (healthy worker effect, less than lifetime duration, and adult exposure) considered in the development of occupational standards these standards are often less conservative than comparison values that are developed to protect all segments of a population, including potentially vulnerable populations, such as children, elderly, and pregnant women. The OSHA time-weighted average standard is 100 ppb [45]. No concentrations greater than this occupational health standard were detected. However, acrolein is a suspected carcinogen and NIOSH has recommended that exposure to aldehydes that are potential occupational carcinogens be reduced [45].

PM10

Concentrations of PM10 reported in the NYSDEC ambient air monitoring program were below relevant health standards. Therefore, ATSDR concludes that adverse health effects from exposure to coarse particles (from 2.5 to 10 micrometers in diameter) are unlikely. However, because only PM10 was measured in the NYSDEC monitoring program, no conclusions can be drawn concerning potential health impact from exposure to fine particles, those less than 2.5 micrometers in diameter. In 1997, EPA proposed health standards for PM2.5 based on possible health effects in susceptible population groups. These standards were promulgated by EPA in September 1997. Because PM2.5 sample collection was not required in the 1994 data reviewed by ATSDR and new scientific information has led to the establishment of standards for PM2.5, ATSDR recommends that future monitoring include analysis for PM2.5. When data are available, a health evaluation should be conducted for PM2.5.

PM10 is airborne particulate matter having a cross-sectional diameter less than 10 microns. Appendix A-Table 21 presents the summary of PM10 data statistics. PM10 was monitored at eight of the 12 stations in the NYSDEC monitoring program. All eight monitoring stations had maximum levels detected above the NYSDEC annual guideline concentration of 50 µg/m3 (see Figure 14). However, none of the maximum concentrations were greater than the NYSDEC 24-hour average standard of 150 µg/m3 (this concentration is "not to be exceeded more than once per year"). The arithmetic and geometric means (representative of exposure concentration) for all eight stations were less than the NYSDEC annual guideline concentration. The 75th percentiles for all eight stations were less than the annual guideline concentration, indicating that concentrations in more than 75% of the samples were less than the annual guideline concentration. The NYSDEC guidelines for particulate material are based on the National Ambient Air Quality Standards.

Concentrations of PM10 detected on Staten Island are similar to concentrations detected at other locations in the NYSDEC ambient air monitoring program [35]. Concentrations reported for six monitoring locations used in a health consultation for South Bronx were all similar to monitoring stations reviewed in this consultation. PM10 concentrations in Midtown (1991-1994) ranged from 5-130 µg/m3 with a mean of 48 µg/m3. The other five stations ranged from 5-93 µg/m3. Similar concentrations were also detected on Staten Island by NYCDEP [7].

EPA recently reviewed the PM10 standards and proposed changes to the particulate material standards [47]. The current health- and welfare-based standards for particulate matter (measured as PM10, particles 10 micrometers in diameter or smaller) were set in 1987. Since then, a number of studies on the health effects of particulate matter have been published. Many of these studies suggest that significant effects, such as premature mortality, hospital admissions, and other respiratory illness, occur at concentrations below the current standards. "EPA believes that the current standards do not adequately protect the public from adverse health effects of particulates...". [48].

Particulate materials in the ambient air include "coarse" particles (from 2.5 to 10 micrometers in diameter) and "fine" particles (smaller than 2.5 micrometers in diameter). Coarse particles come from sources such as windblown dust and dust from vehicle traffic. Fine particles are generally emitted from industrial and residential combustion and vehicle exhaust. Coarse particles deposit in the respiratory system and may contribute to health effects such as asthma. Fine particles are more likely to contribute to health effects such as premature mortality and hospital admissions, primarily among the elderly and individuals with cardiopulmonary disease. [47]

The concluding section of health effects information in EPA's PM Criteria Document provides the following summary of the science with respect to this issue [46]:

"The evidence for PM-related effects from epidemiologic studies is fairly strong, with most studies showing increases in mortality, hospital admissions, respiratory symptoms, and pulmonary function decrements associated with several PM indices. The epidemiologic findings cannot be wholly attributed to inappropriate or incorrect statistical methods, misspecification of concentration-effect models, biases in study design or implementation, measurement errors in health endpoint, pollution exposure, weather, or other variables, nor confounding of PM effects with effects of other factors. While the results of the epidemiology studies should be interpreted cautiously, they nonetheless provide ample reason to be concerned that there are detectable effects attributable to PM at levels below the current National Ambient Air Quality Standards. (Criteria Document, p13-92)"

Because of new scientific information, EPA has proposed to change the current particulate material standards by adding standards for PM2.5 (fine particles). The proposed annual arithmetic mean for PM2.5 is 15 µg/m3 and the 24-hour average is 65 µg/m3. In the proposal, EPA concluded that fine particles are a better surrogate than coarse particles for those components of particulate material linked to mortality and morbidity effects at levels below the current standards. No change was proposed for the annual average for PM10.

As stated above, concentrations of PM10 reported in the NYSDEC monitoring program were below relevant health standards. Therefore, ATSDR concludes that adverse health effects from exposure to coarse particles (from 2.5 to 10 micrometers in diameter) are unlikely. However, because only PM10 was measured in the NYSDEC monitoring program, no conclusions can be drawn concerning potential health impact from exposure to fine particles, those less than 2.5 micrometers in diameter. ATSDR recommends future sampling in the NYSDEC program include analysis for PM2.5.

Spatial and Temporal Analysis of PM10

ATSDR reviewed PM10 data from each of the monitoring stations to determine if any spatial or temporal variations in the data existed. Figures 14 and 15 present this information.

The maximum values for the arithmetic mean (34.43 µg/m3), geometric mean (30.81 µg/m3), and concentration (78 µg/m3) of PM10 were all detected at Section 1/9, a monitoring station located within the landfill boundary. The highest geometric means, arithmetic means, 75th percentiles, and maximum detections occurred at Section 1/9, Composting Facility, and Arthur Kill Road monitoring stations (Section 1/9 greater than Composting Facility greater than Arthur Kill Road). These stations are located within and just south of the boundaries of Fresh Kills Landfill (see Figure 1). Stations north and northeast of the landfill (Port Richmond, Public School 69, and Susan Wagner High) had the lowest arithmetic and geometric means and 75th percentile concentrations. Stations identified with the north-northwest section, Public School 26 and the Meteorology Tower, concentrations were generally less than concentrations reported for stations south of the landfill and greater than concentrations reported for stations north-northeast of the landfill. This data suggests that the highest concentrations may be associated with the landfill.

ATSDR also reviewed monthly arithmetic means to determine if there were temporal variations in the PM10 concentrations detected. This information is presented in Figure 15. As shown in the figure, PM10 concentrations measured at Section 1/9 are consistently higher than those measured at the other monitoring stations. This information is consistent with spatial variations noted above. PM10 concentrations are highest between June and August in both 1994 and 1995. Data also suggest peak concentrations in December 1994. However, because only one year of data was reviewed for this season (October through December), ATSDR cannot determine whether this peak may be seasonal. A peak for benzene concentrations was also observed in December 1994, but was not observed in December 1995.

Sampling times between the monitoring stations were inconsistent. That is, data were not collected at all monitoring stations during the same months. Figure 16 shows the sampling times for each monitoring station for PM10. Note that PM10 data was not collected June through August 1994, at Public School 69 or Arthur Kill Road monitoring stations, and PM10 data was not collected at Meteorology Tower during June and July 1994. Data suggest that maximum concentrations of PM10 may occur during these months. Therefore, the reported geometric and arithmetic means for these stations may be slightly lower than might be expected if sampling period had occurred during this peak. Because samples were collected in 1995 during these peak months, the maximum concentrations reported are expected to be representative of the monitoring location.

This spatial and temporal information may be useful in determining future monitoring for PM10 and PM2.5. Samples should be collected consistently among the monitoring stations so that accurate comparisons of concentrations detected at the various stations is possible. Seasonal variations should be considered when collecting samples. Peak concentrations (worsecase situation) must be evaluated to determine possible impact to public health.


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