PETITIONED PUBLIC HEALTH ASSESSMENT
FRESH KILLS LANDFILL
STATEN ISLAND, RICHMOND COUNTY, NEW YORK
The Agency for Toxic Substances and Disease Registry (ATSDR) uses a conservative approach to determine whether levels of environmental contamination indicate a past, present, or future health hazard. The following discussion briefly describes ATSDR's public health assessment methodology, and then explains how the methodology was applied to evaluate levels of environmental contamination at the Fresh Kills Landfill. This section presents an overview of how ATSDR evaluated environmental sampling data. Relevant data summaries are presented in the appendices of this report. As noted earlier, this report includes very detailed analyses on potential inhalation exposures to air contaminants, since the community health concerns focus on this exposure pathway.
A. Assessment Methodology
ATSDR used established methodologies for determining how people might come into contact with (or be exposed to) contaminants from the Fresh Kills Landfill and what harmful effects, if any, might result from such exposure. This section describes the following chemical exposure pathways, or routes of physical contact with chemicals: ingestion, inhalation, and skin contact.
When evaluating a site, ATSDR determines if exposure to chemicals was or is possible. If ATSDR identifies potential or completed exposure pathways, ATSDR then considers whether chemicals were or are present at levels that might be harmful to people. ATSDR does this by first screening the concentrations of contaminants detected in the environment against health-based comparison values (CVs). CVs are derived using very conservative assumptions and often have large safety factors built into them to be protective of human health. Some CVs might be hundreds or thousands of times lower than exposure levels shown to produce effects in either humans or laboratory animals. While concentrations at or below the relevant CV might be considered safe, it does not necessarily follow that any concentration that exceeds a CV would be expected to produce adverse health effects in the community. Chemicals that are detected above CVs simply require a more detailed evaluation of site-specific exposure conditions. ATSDR also emphasizes that regardless of the level of contamination, a public health hazard exists only if people come into contact with, or are otherwise exposed to, harmful levels of contaminated media.
For a more detailed discussion of ATSDR's public health assessment methodology which includes quality assurance considerations, human exposure pathway analyses, ATSDR's health comparison values, and the methods of selecting contaminants of concern, refer to Appendix C. A summary of exposure pathways for the Fresh Kills Landfill is provided in Table 1.
B. Main Exposure Pathway--Inhaling Contaminated Air
Given the Staten Island residents' concerns regarding the air quality in their neighborhoods, ATSDR extensively reviewed data characterizing the chemicals released by the Fresh Kills Landfill and the chemicals found in the ambient air that local residents breathe. The following five questions and answers review ATSDR's findings regarding air quality in the neighborhoods surrounding the Fresh Kills Landfill. Each question is followed by a brief summary statement, and then by detailed discussions of air quality issues. Additional evaluations of air quality data are presented in appendices, as noted below.
Yes. In 1995, an extensive emissions study confirmed that the Fresh Kills Landfill releases more than 100 organic chemicals to the air. Some operations at the landfill also release dusts that contain metals and other toxic chemicals. The Fresh Kills Landfill will release organic chemicals, metals, and other pollutants to the air for years to come, but the amounts released are expected to decrease as dumping ceases and emission controls continue to be installed at the site.
Chemicals in waste received by the Fresh Kills Landfill enter the air by various processes. For example, volatile chemicals evaporate into the air from municipal solid waste, regardless of whether the waste is in barges, on trucks, or buried in the landfill. Furthermore, metals can enter the air with dusts or particulate matter, which are released as trucks drive on the landfill surface and as winds blow over it. These emission sources, except for releases from barges, are found at virtually every municipal solid waste landfill in the United States.
In 1995, the Environmental Protection Agency (EPA) conducted an extensive field sampling study to estimate how much chemicals the Fresh Kills Landfill releases to the air in a year (USEPA, 1995). Because measuring emissions at every location on the landfill surface would have been prohibitively expensive, the field study instead measured emissions at selected locations on the four landfill sections. Data analysts then used the limited measurements to estimate the chemical emissions for the landfill as a whole. Table 2 lists the 20 chemicals (or pairs of chemicals) that the 1995 EPA study reported as having the highest emission rates from the Fresh Kills Landfill. It is important to note that the emissions data in the table are emissions estimates, and these estimates might be considerably higher or lower than actual emission rates. Despite this uncertainty, ATSDR used the results of the emissions study to identify chemicals that need to be evaluated further.
Not shown in Table 2 is the fact that the 1995 EPA study estimated that the Fresh Kills Landfill emitted 380 pounds of mercury and that the landfill's gas collection system processed 2,000 pounds of mercury (USEPA, 1995). After the emissions report was released, some concern was expressed about these seemingly elevated releases of mercury (ARI, 1996). Also concerned about this finding, EPA conducted a follow-up study in 1997 on the mercury emissions from the landfill. The follow-up study reported that mercury releases were much lower than previously reported and provided evidence that the mercury sampling device used in the 1995 study might not have been functioning properly (ERG, 1997).
Though these previous studies offer useful insight into the types and amounts of chemicals released from the Fresh Kills Landfill, the levels of emissions measured in the past might not be representative of current conditions. As New York City Department of Sanitation (NYCDOS) continues to implement emissions controls (e.g., flaring, capping, and collecting and treating landfill gas), and as the amount of waste disposed of at the Fresh Kills Landfill continues to decrease, the levels of emissions from the landfill will almost certainly decrease.
Yes. The prevailing winds at Staten Island blow some emissions from the Fresh Kills Landfill into nearby neighborhoods. Ambient air monitoring studies in these residential neighborhoods have detected chemicals identified in previous landfill emissions tests. Based on these monitoring studies, ATSDR has identified 25 air contaminants of concern for this site.
Once released to the air, chemicals from the Fresh Kills Landfill mix with other air pollutants and gradually disperse. The emissions from the landfill, at one time or another, have blown to all of the nearby neighborhoods. Though wind directions vary from one day to the next, the most common wind directions observed near the Fresh Kills Landfill are from the southwest, from the west, from the northwest, and from the north (ERG, 1999; NYSDEC, 1995a) (see Figure 3). Since winds in this area rarely blow from east to west, the landfill's emissions are expected to have a greater impact on air quality in Staten Island than on air quality in New Jersey.
To evaluate the extent to which emissions from the Fresh Kills Landfill affect local air quality, several ambient air monitoring (or air sampling) efforts have been conducted at Staten Island over the last 10 years. ATSDR has focused its public health evaluation on three of these studies, since they were particularly extensive and examined air quality on and near the Fresh Kills Landfill. The following discussion reviews these studies; the next section of this report comments on the public health implications of inhaling the levels of contaminants that were measured.
Studies on Air Monitoring
New York State Department of Environmental Conservation (NYSDEC) Air Monitoring
From 1990 to the present, NYSDEC has operated 13 monitoring stations on Staten Island, 12 of which were either on the Fresh Kills Landfill or in the neighborhoods that surround it (see Figure 4). Some of these stations operated throughout the entire 10-year time frame, but most operated from 1994 through 1997. When they were operating, all stations collected 24-hour average ambient air samples, which were later analyzed for concentrations of either volatile organic compounds (VOCs), particulate matter, metals, or some combination of these pollutants.
Overall, ATSDR evaluated nearly 70,000 ambient air concentrations that were measured in NYSDEC's ambient air monitoring network. This monitoring effort accounts for many factors that ATSDR believes are central to evaluating public health concerns regarding air pollution:
- A long duration of monitoring. The data that NYSDEC has provided spans almost 10 years. More importantly, the data characterize air quality conditions during different phases of the landfill's operation. Some data were collected in the early 1990s, when the Fresh Kills Landfill was receiving nearly 15,000 tons of waste a day, 6 days a week (USEPA, 1995). Other data were collected in recent years, after waste disposal rates have declined considerably and several emissions controls have been installed. In short, the ambient air monitoring data provide a reasonable metric for both past and current inhalation exposures.
- Selection of representative monitoring locations. As Figure 4 shows, NYSDEC has measured air quality both on the Fresh Kills Landfill and at selected locations in residential neighborhoods north, east, and south of the landfill. In fact, more than 90 percent of NYSDEC's toxic air sampling at Staten Island has occurred at locations within 1 mile of the Fresh Kills Landfill. Due to this selection of monitoring locations, ATSDR has data on potential inhalation exposures that are representative of most of the Staten Island. neighborhoods nearest the Fresh Kills Landfill.
- Adequate selection of pollutants to be monitored. The concentrations characterize air quality trends for 58 pollutants (see Tables 3a, 3b, and 3c); most of which either have been detected in emissions from the landfill (USEPA, 1995) or are otherwise believed to be emitted by the landfill. Some pollutants (e.g., VOCs and particulate matter) have been regularly monitored at Staten Island for 10 years, but other pollutants (e.g., carbonyls) have only 2 years of monitoring data available.
For the reasons listed above, ATSDR believes the NYSDEC air monitoring data provide an adequate basis for evaluating the Staten Island residents' concerns regarding emissions from the Fresh Kills Landfill.
Tables 3a, 3b, and 3c summarize the 10 years of ambient air monitoring data collected by NYSDEC for particulate matter, VOCs, and polar compounds, respectively. The data are 24-hour average concentrations for the days that NYSDEC collected samples. The tables compare the highest concentrations measured by NYSDEC to conservative health-based comparison values. Readers should note that this initial comparison was done only to identify contaminants of concern and that the data in Tables 3a, 3b, and 3c do not evaluate public health implications for this site. As the tables show, 24 of the 58 pollutants measured by NYSDEC exceeded their corresponding most conservative health-based comparison values at least once in the last 10 years. The public health implications of these chemicals, including site-specific data trends, are reviewed in the following section of this report.
In addition, Tables 3a, 3b, and 3c indicate that every ambient air concentration of 29 of the pollutants that NYSDEC sampled were lower than the corresponding most conservative health-based comparison value. Thus, the monitoring data suggest that concentrations of these pollutants have not reached "unsafe" or "unhealthy" levels in the vicinity of the Fresh Kills Landfill. Accordingly, toxicological evaluations of these pollutants are not provided in this health consultation.
Finally, Tables 3a, 3b, and 3c indicate that neither ATSDR, EPA, or NYSDEC have published health-based comparison values for the remaining 5 pollutants detected in the Staten Island ambient air. For sake of thoroughness, ATSDR has selected these pollutants--sulfate, n-butyraldehyde, hexanal, methacrolein, and m-tolualdehyde--as contaminants of concern. The toxicological evaluations presented later in this report put the monitoring data for these pollutants into perspective.
York City Department of Environmental Protection (NYCDEP) Air Monitoring Network.
For additional insight into air quality at Staten Island, ATSDR obtained and reviewed a subset of the ambient air monitoring data that NYCDEP collected at five locations during its "Staten Island Air Toxics Monitoring Program." As the map of monitoring locations indicates (see Figure 4), NYCDEP focused its sampling efforts on locations along the perimeter of Staten Island that are at least 1 mile away from the Fresh Kills Landfill. NYSDEC, in contrast, focused its sampling on the immediate surroundings of the Fresh Kills Landfill.
The distinct geographic areas considered by these two monitoring programs are an important consideration for interpreting the data. If air emissions from the Fresh Kills Landfill are the predominant source of air pollutants at Staten Island, then one would expect ambient air concentrations measured at the NYSDEC monitors (which are located in close proximity to the Fresh Kills Landfill) to be considerably and consistently higher than those measured at the NYCDEP monitors (which are located further from the Fresh Kills Landfill).
If, on the other hand, emissions from sources throughout the Staten Island area and beyond (e.g., mobile sources) are the predominant source of air pollution on Staten Island, then one would expect the ambient air monitoring data from the NYCDEP and NYSDEC networks to be somewhat similar.
Several different statistical approaches are available for comparing trends among different sets of ambient air monitoring data. In this case, ATSDR focused on descriptive summary statistics (e.g., concentration ranges, average concentrations) when comparing the NYCDEP and NYSDEC data sets. Table 4 presents an example of such an analysis, by comparing the frequency with which ambient air concentrations measured in 1995 exceeded health-based comparison values for both the NYCDEP and NYSDEC networks. As the table shows, neither sampling network yielded a consistent pattern of poor air quality. The frequency of concentrations exceeding a comparison value was greater at the NYCDEP sites for some contaminants, at the NYSDEC sites for others, and nearly equal for many contaminants.
The absence of considerable spatial variations in air quality at Staten Island, as indicated by the data in Table 4 and results of other statistical analyses, suggests, but does not prove, that air quality in the neighborhoods that surround the Fresh Kills Landfill is not dramatically different from the air quality in some Staten Island neighborhoods located much further from the landfill, at least in terms of the contaminants used for this comparison. This finding, in turn, implies that emissions sources other than the Fresh Kills Landfill likely account for a considerable portion of the airborne contaminants throughout Staten island. Though these generalizations do not characterize public health implications of the levels of air pollution near the landfill, they provide perspective for understanding the extent to which the Fresh Kills Landfill affects local air quality.
Fresh Kills Air Monitoring Program (FKAMP).
As part of its 1997 health investigation at Staten Island, ATSDR organized a 2-month intensive air sampling program in the residential neighborhoods east of the Fresh Kills Landfill, during which sampling devices continuously measured air concentrations of ozone, hydrogen sulfide, PM10, and PM2.5 (ERG, 1999). More than 140,000 observations of ambient air quality were collected at 16 locations on Staten Island during this program. Figure 4 indicates these monitoring locations.
Of particular note is the FKAMP's monitoring of hydrogen sulfide, an odorous chemical that the landfill emits but was not considered in previous NYCDEP and NYSDEC sampling efforts. In fact, the 1995 emissions study estimated that the Fresh Kills Landfill released 16 tons of hydrogen sulfide to the air each year (ERG, 1999). Though the landfill clearly emits large quantities of the chemical, hydrogen sulfide was measured at detectable levels in only about half of the samples, and the measured concentrations ranged from 2 ppb (the detection limit of the sampling devices used) to 33 ppb. Though these concentrations did not exceed any health-based comparison values, ATSDR selected hydrogen sulfide as a contaminant of concern since the chemical is believed to contribute to landfill-related odors--a subject of many community concerns. The public health implications of hydrogen sulfide in the Staten Island air are reviewed in the following section.
As noted above, the FKAMP also measured concentrations of three pollutants that are common to most urban areas: ozone, PM10, and PM2.5. All of the measured concentrations for these pollutants were lower than EPA's current health-based standards, though 8-hour average ozone levels did exceed a health-based standard that EPA has proposed, but has not been able to implement due to a court decision. More information on ozone in Staten Island is provided later in this report.
of ambient air monitoring studies and data gaps.
Combined, the three aforementioned ambient air monitoring studies provide an extensive account of air quality at the Fresh Kills Landfill site. These monitoring studies clearly have not measured ambient levels of every chemical the landfill emits, but such a monitoring effort would be prohibitively expensive. Noting that the past and planned future monitoring efforts at Staten Island have measured, or will measure, ambient air concentrations of more than half of the most toxic VOCs that the Fresh Kills Landfill emits (i.e., VOCs with health-based comparison values lower than 10 ppb), ATSDR believes the sampling data provide an acceptable basis for evaluating public health implications of potential exposures to landfill emissions.
Based on the data summarized above, ATSDR has identified the following contaminants of concern for this site:
|Air Contaminants of Concern|
Particulate matter (PM2.5, PM10, TSP)
Most of the contaminants of concern listed above (i.e., those without asterisks) were selected because at least one ambient air concentration exceeded the most conservative health-based comparison value. As emphasized earlier in this report, such a scenario does not imply that adverse health effects result from the levels of contamination. Rather, it simply implies that the levels of contamination need to be investigated further to characterize their public health implications. The contaminants of concern marked with asterisks are chemicals that were detected in the ambient air at Staten Island for which there are no published health-based comparison values ATSDR designated these as contaminants of concern because no health-based comparison values or other convenient tool were readily available as an initial screen of the chemicals' toxicities. The following section reviews the public health implications of all 25 contaminants of concern, regardless of why they were selected.
Does exposure to the site-related air contaminants present a health hazard? Of the chemicals measured in the various monitoring efforts, none were found at levels that are known to be associated with causing adverse health effects. Based on the extensive sampling that has occurred over the last 10 years, therefore, ATSDR finds that the chemicals released from the Fresh Kills Landfill pose no apparent public health hazard. Uncertainties in reaching this conclusion are described below.
To evaluate the public health implications of air emissions from the Fresh Kills Landfill, ATSDR carefully compared the measured ambient air concentrations of the 25 contaminants of concern to results of scientific studies that have examined potential links between exposure to air pollution and adverse health effects. This evaluation was extensive and considered a broad spectrum of issues, ranging from the possibility that the landfill emissions might be associated with less serious health effects (e.g., irritation of eyes) to the possibility that the landfill emissions might be associated with more serious health effects (e.g., cancer). Further, ATSDR examined various exposure scenarios, such as acute exposures to contaminants during "air pollution episodes," and lifelong exposures to current levels of contamination.
Appendix D documents the specific toxicologic evaluations that ATSDR performed for the 25 contaminants of concern. As Appendix D describes in detail, ATSDR found no evidence that any of the contaminants of concern, whether released from the Fresh Kills Landfill or from other sources, have reached levels at Staten Island that are believed to be associated with adverse health effects. This conclusion is based primarily on the air quality trends reported by NYSDEC's air monitoring network. Though this network has not continuously measured levels of air pollution in all neighborhoods at Staten Island, ATSDR emphasizes that this network has characterized air quality at locations north, east, and south of the Fresh Kills Landfill for nearly 10 years. Further, this network has (or will soon) measure ambient air concentrations of a majority of the most toxic chemicals that have been measured in the landfill's emissions.
When evaluating the public health implications of the air exposure pathway, ATSDR not only considered trends among the ambient air monitoring data, but also considered an extremely wide range of peer-reviewed studies on pollution-related adverse health effects, including both epidemiologic and toxicologic studies. The evaluations in Appendix D cite relevant studies for the contaminants of concern.
As the appendix notes, relating low-dose inhalation exposure to adverse health effects is difficult and somewhat uncertain. As an example, this health assessment does not consider potential interactive effects associated with exposures to multiple contaminants--an issue that the science of toxicology has only begun to investigate. Despite the inherent uncertainty in this process, ATSDR believes the toxicologic evaluations represent the current state of the science because of the fact that the main finding of the toxicologic evaluations (i.e., that chemicals emitted from the Fresh Kills Landfill are not at levels of concern) is generally consistent with trends among the limited health outcome data for this site (described later in this health assessment). Additional assurance that no site-related health hazards associated with inhalation exposure have been overlooked will be emphasized
the odors from the Fresh Kills Landfill harmful?
The odors from the Fresh Kills Landfill, which can often be smelled in many neighborhoods on Staten Island, are clearly unpleasant and a nuisance, but it is unclear whether these bad odors cause adverse health effects. Results of ATSDR's recent health study at Staten Island suggest that some residents with asthma were more likely to wheeze and cough on days with bad odor. In addition, study participants were more likely to experience a decrease in peak expiratory flow rate (a measure of lung capacity) from the morning to the evening on the days when they reported these bad odors. More details on ATSDR's study, and its public health implications, follow.
The garbage that is dumped at the Fresh Kills Landfill and its decomposition products contain many malodorous compounds. Residents who live near the landfill have complained for years about the odors that emanate from the site. As evidence of this, every annual report published by the Interstate Sanitation Commission since 1983 indicates that Staten Island residents (particularly those on the western shore of Staten Island) file more odor complaints to this agency than do any other group of residents in the Newark-New York City metropolitan area (ISC, 1997). Moreover, residents have complained about odors from the Fresh Kills Landfill at almost every community meeting that ATSDR has attended. Finally, several ATSDR employees have noticed strong, disagreeable odors when working near the Fresh Kills Landfill.
Though few question the presence of odors near the Fresh Kills Landfill, the public health implications of these odors are unclear for several reasons. First, a wide range of chemicals and chemical mixtures can generate similar odors, and these chemicals and mixtures can have a wide range of toxicities. Therefore, the presence of an odor could result from exposure to many different chemicals, some may be toxic and others are essentially benign. Second, since many chemicals can be smelled by humans at levels much lower than levels of health concern, the presence of an odor does not necessarily mean unhealthy exposures occur. Finally, odor perception varies greatly from one person to the next. An odor that one person finds objectionable might not be noticed by another person. This varying sensitivity complicates efforts to study how odors from a given source might impact exposed populations. ATSDR's health investigation at Staten Island in 1997 found a slight correlation between the perception of odor and an increase in respiratory morbidity among people with asthma (ATSDR, 1999c).
However, the full public health implications of this correlation and a full understanding of the connection between self-reported odor and respiratory morbidity remains unknown (ATSDR, 1999c). As a precautionary measure, however, ATSDR recommends that ongoing and future monitoring efforts near the Fresh Kills Landfill be expanded to include air pollutants that have not been measured extensively at Staten Island, including selected Volatile Organic Compounds (VOCs), methane, hydrogen sulfide, nitrogen and sulfur oxides, fungi and mold spores. ATSDR has been communicating these recommendations to NYSDEC, as that agency releases its plans for future ambient air monitoring at Staten Island.
general air quality throughout Staten Island unhealthy?
At times, yes. Almost every summer since the early 1970s, and possibly earlier, ambient air concentrations of ozone--the primary component of urban "smog"--have reached potentially unhealthy levels throughout the New York City metropolitan area. Exposure to elevated ozone levels can cause various respiratory problems, some of which are consistent with the health problems that Staten Island residents have communicated to ATSDR. These respiratory problems are expected to be most prevalent among people with respiratory conditions, children, the elderly, and outdoor laborers. Emissions from motor vehicles, industrial sources, and natural sources all contribute to the elevated ozone levels in the New York City metropolitan area.
In Staten Island, air pollution is affected not only by the Fresh Kills Landfill, but also by numerous other sources, particularly motor vehicles and industrial facilities. As emissions from these various sources mix and react with each other in air, they sometimes form other toxic chemicals, like ozone. Because ozone forms in the presence of sunlight, the highest ozone levels at Staten Island, and throughout the United States, occur during the summer, when the days are longest. Certain meteorological conditions, like calm winds and a stable atmosphere, can cause ozone to reach very high levels.
Ozone is a highly-reactive chemical that has been linked with various respiratory health effects. Recognizing this, EPA has regulated ambient air concentrations of ozone for more than 20 years. Currently, EPA's health-based national ambient air quality standard (NAAQS) for ozone is a 1-hour average concentration of 0.120 ppm. When levels of ozone exceed this standard, some people might suffer from respiratory problems, like coughing, wheezing, aggravated asthma conditions, and reduced lung function.
As Figure 4 shows, ambient air concentrations of ozone measured at Susan Wagner High School on Staten Island have exceeded EPA's health-based standard in 13 of the 17 years from 1982 - 1998. Exceedances of these standards is a trend that has been observed in many other major metropolitan areas in the United States. The figure also shows that potentially unhealthy levels of ozone occur less frequently at Staten Island now, as compared to during the 1980s. The ozone levels observed at Staten Island are not unusually higher or lower than those observed in the other boroughs of New York City.
According to recent studies, when concentrations of ozone exceed EPA's health-based standard, exposed persons might develop acute respiratory problems, such as aggravated asthma conditions and inflamed lung tissues (USEPA, 1997a). Therefore, it is possible that the petitioners' concerns regarding respiratory problems among Staten Island residents might be due, at least in part, to exposure to ozone. However, since ozone levels do not vary considerably throughout the New York City area, one would expect to see adverse health effects associated with exposure to ozone throughout this metropolitan area, and not limited specifically to the neighborhoods surrounding the Fresh Kills Landfill.
Both acute and chronic health effects have been linked to inhalation exposure to ozone. The acute, or short term, effects include shortness of breath, coughing, throat irritation, and chest pains; the chronic, or long term, effects include permanent damage to the lungs, reduced lung capacity, and worsening of pre-existing respiratory conditions (USEPA, 1997b). These effects do not occur in every person who is exposed to high levels of ozone. Rather, the effects are generally most prevalent among sensitive populations, such as people with respiratory conditions. Moreover, children who play outdoors and people who engage in strenuous physical activity on days with elevated ozone levels are also at greater risk for having respiratory problems than people who stay indoors. Although these effects are likely to be most prevalent among particular populations, even healthy persons might experience difficulty breathing on "smoggy" days.
Given the dangers associated with inhaling ozone, and the likelihood that high levels of ozone will occur in this area in the future, all Staten Island residents, like the residents of the rest of the metropolitan area, especially children and those with existing respiratory conditions, are encouraged to remain indoors and to avoid moderate levels of exercise on days when ozone levels are expected to be high. During the summer, when ozone levels are their highest, NYSDEC issues daily "ozone forecasts" for the New York City metropolitan area and Long Island. These forecasts can be found at NYSDEC's Web site and are usually broadcast by the local media. Residents are encouraged to follow all warnings issued on days when ozone levels are expected to be high.
In addition to measuring ozone concentrations, NYSDEC also measures ambient levels of other pollutants commonly found in urban environments, such as particulate matter, nitrogen oxides, and carbon monoxide. All such measurements at Staten Island have been safely below EPA's health-based standards, but some measurements of particulate matter and carbon monoxide near heavily-traveled roadways and skyscrapers in Manhattan have exceeded the standards. These measurements, however, are likely not representative of air quality at Staten Island. Therefore, ATSDR has reason to believe that ambient air concentrations of these pollutants are not at levels of concern at Staten Island.
C. Other Exposure Pathways
In addition to evaluating air emissions from the Fresh Kills Landfill, ATSDR researched levels of contamination in groundwater, surface water, sediment, and biota (primarily fish and shellfish) in Staten Island and nearby areas. The following sections comment on the extent of contamination in these media, the likelihood of exposure to contamination, and the public health implications of such exposure, if any. Each section begins with a summary statement, followed by more detailed discussions of the exposure pathways.
Groundwater. The groundwater beneath the Fresh Kills Landfill is contaminated with trace levels of pollutants that originate from various sources, including the landfill itself. However, the likelihood that residents have come into contact or will come into contact with these contaminants is extremely low, because groundwater on Staten Island has not been used for drinking water since 1970 and because future use of groundwater is expected to be restricted. Exposures from the very limited use of groundwater for non-drinking purposes are not at levels of concern. Accordingly, ATSDR finds that the contaminated groundwater beneath the Fresh Kills Landfill poses no apparent public health hazard.
Although landfills are designed to contain wastes in confined areas, chemicals in landfills can contaminate groundwater through a process called "leaching." By this process, chemicals in waste gradually dissolve into the rain water and snow melt that flows through landfills. The resulting contaminated water, commonly referred to as "leachate," can then enter local surface waters and groundwater. Like most landfills constructed in the 1940s, the Fresh Kills Landfill was not designed with a liner or any other form of leachate control. Thus, for many years, untreated leachate from the landfill flowed directly into local surface waters and groundwater.
A leachate treatment plant at the Fresh Kills Landfill currently treats most of the leachate generated on site and is capable of treating more than 1,000,000 gallons of leachate a day (Nabovi, 1999). Before this treatment plant operated, a study estimated that at least 85 % of the leachate generated in the landfill eventually discharged into local surface waters and less than 15 % of the leachate leaked into deeper groundwater layers (IT, 1993b).
Several sampling studies have confirmed the presence of contaminants from the Fresh Kills Landfill (i.e., evidence of leachate migration) in the groundwater at Staten Island (IT, 1995a; IT, 1995b; IT, 1996a; IT, 1996b). Most studies reported observing the highest levels of contamination in shallow wells, with little or no evidence of leachate contamination in deeper wells. The most extensive sampling study to date involved quarterly monitoring of groundwater contamination at more than 200 wells on the Fresh Kills Landfill. Data summaries in Tables 5 through 7 show this quarterly monitoring has identified numerous chemicals at levels greater than their health-based comparison values. Some of these chemicals are believed to have originated in the Fresh Kills Landfill, but others are suspected to be influenced by other sources, like seawater intrusion (IT, 1993b).
Overall, concentrations of only seven chemicals (arsenic, barium, benzene, boron, manganese, total ammonia, and zinc) exceeded their corresponding comparison values in more than 50 percent of the valid samples.
Although chemicals from the Fresh Kills Landfill have clearly contaminated some groundwater resources, the restricted use of groundwater at Staten Island has prevented residents from coming into contact with this contamination. Currently, the New York City water supply system serves all of Staten Island and provides drinking water from reservoirs in the Catskills region of New York. Further, NYCDOH prohibits the installation or use of groundwater wells for drinking water anywhere on Staten Island (Weston, 1996a). Assuming NYCDOH will continue to enforce this restriction, Staten Island residents do not, and will not in the future, drink contaminated groundwater from local wells.
Several accounts suggest that past use of wells for drinking water at Staten Island was extremely limited. For instance, according to two studies, groundwater at Staten Island has not been used for public water supply since September 1970 (Soren, 1988; Weston, 1996a). Moreover, in the years between 1953 and 1970, groundwater at Staten Island was used only to supplement the reservoir supply of drinking water and was reportedly used in relatively small quantities (less than 5,000,000 gallons per day) (Soren, 1988; Weston, 1996a). According to these accounts, therefore, only long-term residents of Staten Island might have drank water from local groundwater sources, but such consumption is believed to be extremely limited and occurred during a time before extensive groundwater monitoring data had been collected. Overall, past exposure to contaminated groundwater via the ingestion pathway is believed to be minimal.
Although Staten Island residents clearly do not drink contaminated groundwater, a small number of residents who live near the Fresh Kills Landfill might come into contact with site-related contaminants through the use of groundwater for non-drinking purposes. According to a recent private well survey, only five private wells within 1 mile of the Fresh Kills Landfill property boundary appeared to be viable sources of non-potable groundwater (IT, 1991a).(5) For three of these wells, prolonged exposure to the groundwater appears to be unlikely. One well (actually, a system of wells) is used to fill a pond at the South Shore Country Club, another well is used to wash trucks at the Fresh Kills Landfill, and the owner of the other well cannot be located.
For two private wells, non-drinking use of groundwater seems possible, but usage data for these wells are either limited or conflicting. First, the Great Kills Swim Club, located southeast of the Fresh Kills Landfill and the Brookfield Avenue Landfill, has a groundwater well. One study reported the well had been abandoned (IT, 1991a), but another study reported the well was being used to fill a pool (NYCDEP, 1998). Second, a private well at a residence near the Great Kills Swim Club is reportedly used for irrigation purposes, but the frequency of well use is not known. An environmental consulting company recently sampled both of these wells. As detailed in the Public Health Assessment (PHA) for the Brookfield Avenue Landfill (ATSDR, 1999a), a small number of contaminants were found in both wells, but not at levels that would pose health hazards for non-drinking purposes.
In summary, several extensive environmental sampling efforts have confirmed that the groundwater beneath the Fresh Kills Landfill is contaminated with chemicals that originate from various sources. However, due to the tightly restricted use of groundwater on Staten Island, the likelihood that residents have come into contact with the chemicals is highly unlikely. Levels of contamination in the few wells used for non-drinking purposes are well below the levels found to be associated with adverse health effects. Therefore, ATSDR concludes that the contaminated groundwater in the vicinity of the Fresh Kills Landfill poses no apparent public health hazard. Due to the levels of contamination in the groundwater, ATSDR recommends that health departments carefully evaluate groundwater monitoring data before relaxing or lifting the current restrictions on groundwater use at Staten Island.
Surface water and sediment. Many contaminants have been found in Arthur Kill, Fresh Kills, and parts of Main Creek and Richmond Creek. Contaminants have also been found in these water ways' sediments. However, prolonged direct contact with these contaminants is not likely to occur since recreational use of these surface waters is extremely limited. Given that Staten Island residents have minimal exposure to surface waters and sediments near the Fresh Kills Landfill, the levels of contamination in these media pose no apparent public health hazard.
Leachate migration (which was defined in the previous section) and stormwater runoff can cause chemicals from landfills to flow into local surface waters. Some of these chemicals, once in surface waters, have a tendency to accumulate in sediments. Over the last 50 years, both leachate migration and stormwater runoff have undoubtedly caused some chemicals from the Fresh Kills Landfill to enter the water and sediments of Arthur Kill, Fresh Kills, Main Creek, and Richmond Creek. (Figure 1 indicates the locations of these surface waters.) Though ongoing releases to surface waters still occur, operation of the leachate treatment plant at the landfill has greatly reduced the impacts of leachate on surface water quality.
Numerous sampling studies have measured, and continue to measure, concentrations of chemicals in the water and sediment of Arthur Kill, Fresh Kills, Main Creek, and Richmond Creek--the surface waters that flow in closest proximity to the Fresh Kills Landfill (NYSDEC, 1991; NYCDEP, 1991; IT, 1991b; IT, 1993c). Most of these studies have reported that high and low tides greatly affect surface water flow in this area, thus causing chemicals released from the landfill to mix with those released from other sources. This mixing has complicated efforts to attribute contaminants in surface waters and sediment near Staten Island to any specific source.
A common finding among the various monitoring efforts is that many pollutants have elevated concentrations in the surface waters and sediment near the Fresh Kills Landfill. Not surprisingly, levels of contamination in surface waters that receive waste from numerous sources (e.g., Arthur Kill) are generally higher than levels of contamination in surface waters beyond the influence of the Fresh Kills Landfill (e.g., the fresh water portion of Richmond Creek). For a sense of the levels of contamination, Tables 8 and 9 summarize the results of a recent sampling study of surface waters and sediments, respectively. According to the tables, surface waters and sediment near the Fresh Kills Landfill are contaminated with elevated levels of inorganics (e.g., ammonia and sulfates) and numerous metals (e.g., arsenic, barium, cadmium, chromium, lead, and nickel).
Even though certain stretches of local surface waters and sediments clearly contain elevated levels of contamination, residents rarely, if ever, come into contact with these contaminants. According to site documents and site personnel, recreational use of onsite surface waters (i.e., Fresh Kills and the sections of Main Creek and Richmond Creek within the landfill property boundary) is prohibited (Nabovi, 1999; NYCDOS, 1995). The fences that surround most of the landfill's property help ensure that residents do not come into contact with onsite surface water or sediment.
Use of offsite surface waters is also extremely limited. For instance, the state of New York has indicated that the water in Arthur Kill does not meet minimum requirements for recreational use (IT, 1996c), and no public beaches are located along this water way. Although no restrictions currently prohibit residents from swimming or wading in the parts of Main Creek and Richmond Creek that are immediately upstream from the Fresh Kills Landfill, ATSDR has found no accounts of regular recreational use of these creeks, most likely because extensive mud flats surround them.
Even if some residents periodically swim or wade in Main Creek or Richmond Creek near the Fresh Kills Landfill, they almost certainly would not swallow large quantities of the surface water or sediment. Accidental ingestion or contact with the chemicals in these surface waters is either minimal or might not occur at all. Trace amounts of contaminants in the creeks and their sediments would be of public health concern only if people routinely ingested them, which seems unlikely. Accordingly, ATSDR classifies the levels of contamination in surface waters and sediments near the Fresh Kills Landfill as no apparent public health hazard.
Based on the levels of contamination in the surface waters and sediment near the Fresh Kills Landfill, ATSDR recommends that health departments carefully evaluate relevant sampling data before entertaining any proposal that would increase residents' likelihood to contact the sediment or water in Arthur Kill, Fresh Kills, or in the portions of Main Creek and Richmond Creek that are immediately upstream of the Fresh Kills Landfill.
Fish and shellfish. According to recent studies, some species of fish and shellfish in Arthur Kill have elevated levels of selected metals and organic compounds. Evidence from other studies suggests that certain species in Richmond Creek might contain toxins as well. Very few Staten Island residents are likely to eat contaminated fish and shellfish, however, due to commercial fishing restrictions and sport fishing advisories. Provided fishers and residents abide by these measures, the contaminants in the fish and shellfish near the Fresh Kills Landfill pose no apparent public health hazard.
Certain chemicals, when found in surface waters and sediments, are known to accumulate in many species of fish and shellfish. These chemicals, in turn, can accumulate in humans who regularly eat fish and shellfish caught in contaminated waters. The hazardous chemicals most often found in fish and shellfish include, but are not limited to, metals, polychlorinated biphenyls (PCBs), dioxins, furans, pesticides, and polycyclic aromatic hydrocarbons (PAHs). Many of these chemicals have been detected in the surface water and sediment in the vicinity of the Fresh Kills Landfill.
NYSDEC has published numerous studies in recent years documenting levels of contaminants in fish and shellfish in water ways throughout the state of New York, including those near the Fresh Kills Landfill (NYSDEC, 1995b; 1996; 1997a; 1997b; 1997c). Table 10 summarizes some of NYSDEC's recent sampling results of fish and shellfish in Arthur Kill, Kill Van Kull, and Newark Bay. According to the table, levels of cadmium, lead, dioxins, furans, PCBs, DDT, and chlordane in some species of fish and shellfish caught in these water ways exceeded health-based guidelines or action levels. The contaminants in these fish undoubtedly originated from numerous sources throughout the Newark-New York City metropolitan area.
Levels of contamination in fish and shellfish in Fresh Kills, Main Creek, and Richmond Creek are not documented and apparently have never been measured. However, a laboratory study has reported that certain species of mollusks and worms accumulate PAHs and metals after being exposed for 28 days to sediments collected from Richmond Creek (ATSDR, 1999a). This laboratory study provides evidence that fish and shellfish in the surface waters near the Fresh Kills Landfill might be contaminated with chemicals found in the sediments, but the extent of contamination in individual fish and shellfish species found in the creek has not been measured.
The above data reviewed indicated that people who eat fish and shellfish from waters in the vicinity of the Fresh Kills Landfill might be exposed to various contaminants, but the likelihood that Staten Island residents have eaten large quantities--or even small quantities--of fish from these waters is extremely low for the following reasons:
- The State of New York's Official Compilation of Codes, Rules, and Regulations indicate that "all shellfish lands in Westchester, Bronx, Kings, New York, Richmond [Staten Island] and Queens Counties are in such sanitary condition that the shellfish thereon shall not be taken for use as food and such are designated as uncertified areas" for shellfishing (OCCR, 1998). Exceptions to this rule are granted in very few circumstances.
- According to NYSDEC, the state agency that issues fishing permits, commercial fishing does not occur in Arthur Kill, Fresh Kills, Main Creek, or Richmond Creek (Payne, 1999) Further, NYSDOH has issued extensive advisories to limit residents' consumption of potentially contaminated sportfish (NYSDOH, 1999). Table 11 reviews the advisories that apply to fish caught in the vicinity of the Fresh Kills Landfill.
- Signs posted along Richmond Creek indicate that all fishing and shellfishing are prohibited in the vicinity of the Brookfield Avenue Landfill (ATSDR, 1999a).
- Public access to the various surface waters around the Fresh Kills Landfill is extremely limited. Arthur Kill has no publicly accessible boat ramps or fishing piers; NYCDOS prohibits public use of surface waters within the Fresh Kills Landfill property for any reason; and extensive mud flats surround the tidal portions of Main Creek and Richmond Creek.
Based on these reasons, ATSDR believes it is highly unlikely that Staten Island residents have consumed large quantities of fish or shellfish from the waters near the Fresh Kills Landfill. Thus, few, if any residents are likely to have come into contact with unhealthy amounts of the chemicals via this exposure pathway. As a result, the contaminants in the fish and shellfish in the waters near the Fresh Kills Landfill pose no apparent public health hazard. Nonetheless, as a prudent public health measure, ATSDR recommends that residents abide by the fishing and shellfishing restrictions and advisories and that NYSDOH collect and carefully review fish and shellfish samples before relaxing or lifting the current restrictions and advisories.
D. Other Site-Related Hazards
In addition to concerns regarding chemicals in the ambient environment, near some landfills landfill gases (the gases that form as wastes decompose) have been known to migrate through soil and into homes. Landfill gas migration can pose serious hazards, especially if gases accumulate in confined spaces and build up to explosive levels.
Large quantities of landfill gas, which is primarily composed of methane, are generated within the Fresh Kills Landfill daily, but several measures prevent this gas from migrating to offsite locations. First, a series of extraction wells currently removes approximately 5 million cubic feet of gas from within the Fresh Kills Landfill daily (Shrivastaza, 1999). This gas, which otherwise could have been released to the air or migrated off site, is instead treated on site and sold to a local utility. Second, roughly 15,000 cubic feet of landfill gas vents every minute from the Fresh Kills Landfill to an onsite flaring system (Shrivastaza, 1999), thus removing additional gases that might otherwise have migrated off site. Finally, NYCDOS has constructed gas venting trenches around the perimeter of the landfill sections (NYCDOS, 1995). These trenches serve as a last defense to prevent offsite migration of landfill gases. They allow any gases that migrate away from the draw of the extraction wells and passive vents to pass directly into the atmosphere, rather than to continue migrating to offsite locations.
In addition to the controls installed to prevent landfill gas migration, NYCDOS has installed a network of 84 gas monitoring wells around the four landfill sections to detect offsite migration of landfill gases and continuous methane sensors in all trailers and buildings on landfill property to detect dangerous buildup of landfill gases. Quarterly reports of landfill gas monitoring are available from 1993 to the present. The most recent reports indicate that the extent of landfill gas migration is minimal (Weston, 1997). These monitoring results suggest that landfill gas migration does not pose a public health hazard, and ongoing monitoring will likely prevent any future hazards associated with landfill gas migration.
The fence that surrounds the Fresh Kills Landfill greatly reduces the possibility that local residents will encounter physical hazards on site. However, due to the steep terrain of certain landfill sections and the presence of flares and other potentially dangerous equipment on site, ATSDR recommends that NYCDOS routinely verify that access to the Fresh Kills Landfill continues to be restricted.
Contaminants from the Fresh Kills Landfill have been found in trace amounts in the air, groundwater, surface water, sediments, fish and shellfish. The public health implications of this contamination depends on where the site-related chemicals are found. In the case of contaminants in groundwater, surface water, sediments, fish and shellfish, restrictions and advisories likely prevent most Staten Island residents from ever coming into contact with the chemicals in these media. Therefore, the contaminants in these media do not pose a health hazard, provided residents abide by the restrictions and advisories.
In the case of contaminants in the air, Staten Island residents have inhaled, are inhaling, and will continue to inhale some of the chemicals that the Fresh Kills Landfill releases. All indications from the many air sampling studies that have been conducted in the nearby residential neighborhoods in the past decade, however, suggest that the site-related chemicals do not reach levels that have been associated with causing adverse health effects--a finding that is based on a detailed review of one of the most extensive ambient air monitoring data sets that ATSDR has evaluated for a municipal solid waste landfill. However, due to the absence of past air monitoring data, ATSDR is unable to evaluate the public health implications of air contamination at this site in the past. ATSDR acknowledges that its evaluation does not fully consider the public health implications of inhaling the complex mixture of chemicals in the air at Staten Island, but very limited information is available in the toxicological literature on this topic.
Odors from the Fresh Kills Landfill are clearly a nuisance and raise quality of life issues among those who must frequently smell them, but the public health implications of these odors are unclear. Without knowing the exact composition of the chemicals that cause the odors, ATSDR cannot determine whether the presence of an odor is due to exposure to potentially unhealthy or benign chemicals. However, air monitoring has been conducted for most of the predominant chemicals that have been identified in the emissions from the landfill.
ATSDR's recent health investigation at Staten Island found that ambient air concentrations of hydrogen sulfide, particulate matter and ozone measured during the study period did not exceed levels known to cause adverse health effects. Results of the investigation showed that on days when participants smelled the odor of rotten eggs or garbage, they were more likely to report the occurrence of wheeze. A small relationship was also observed between the smell of rotten eggs or garbage and evidence of air flow obstruction. These findings varied among subgroups of the study population by variable such as age and duration of asthma.
More than 20 years of air sampling in the New York City metropolitan area have shown that ambient levels of ozone throughout the area has periodically reached potentially unhealthy levels. Though ozone levels in this area have been steadily declining, the infrequent, elevated concentrations of ozone could cause respiratory health problems among some residents. Children, outdoor laborers, the elderly, and people with pre-existing respiratory conditions are most at risk from suffering health problems from inhaling high amounts of ozone. As a precautionary measure, all Staten Island residents are encouraged to follow public health advisories (e.g., staying indoors and avoiding strenuous activity) on days when ozone levels are expected to be high.
Because children often are at greater risk than adults for being exposed to toxic chemicals, and because 11 percent of the population living near the Fresh Kills Landfill is children, age 6 and younger, ATSDR's exposure and public health evaluations for this site explicitly considered children's health issues. In general, children are more likely than adults to suffer from adverse health effects due to environmental exposure for several reasons:
- Children's developing bodies can be particularly sensitive to toxic exposure during certain critical growth stages, especially when children are exposed to chemicals known to cause developmental effects (e.g., lead).
- Children weigh less than adults. Therefore, when children and adults ingest or inhale the same amount of chemicals, children receive a greater dose (on a pound of contaminant per pound of body weight basis) than adults. This higher dose causes a greater likelihood for developing adverse health effects.
- Because children play outside more than adults, they are generally more likely to come into contact with contaminated soils and to inhale greater amounts of airborne pollutants.
ATSDR carefully considered the aforementioned factors to identify any unique health risks or threats to the children who live near the Fresh Kills Landfill. For example, when selecting contaminants of concern, ATSDR used comparison values specifically developed for exposures to children (if available); and, when performing toxicologic evaluations, ATSDR reviewed the most recent scientific literature to determine if children were unusually sensitive to site-related chemicals. Based on these evaluations, ATSDR found no evidence that children who live near the Fresh Kills Landfill are exposed to unique or special site-related hazards.
ATSDR is concerned, however, that children throughout Staten Island have a greater risk of being exposed to elevated levels of ozone than do adults. This concern stems from the fact that ozone levels are generally highest during the afternoon hours on sunny summer days, when most children are not in school and likely to be outdoors playing. Children who have asthma or who engage in moderate to strenuous exercise on such days (e.g., swimming and running) are at particular risk for inhaling unhealthy levels of ozone and possibly having air pollution-related breathing problems. Since children might not understand the meaning of ozone forecasts, parents on Staten Island should encourage their children to play indoors on days when ozone levels are predicted to be unhealthy. As noted earlier, NYSDEC issues these ozone forecasts, and the local media usually broadcast them.
For a complete account of the public health implications of living near the Fresh Kills Landfill, ATSDR obtained and reviewed studies that collected and reported health outcome data for the neighborhoods in the immediate vicinity of the landfill. Health outcome data can come in many forms, but they generally indicate the incidence of selected diseases or adverse health effects among a study population. ATSDR has identified the following studies that have reported health outcome data for the neighborhoods that surround the Fresh Kills Landfill. The significance of these studies is reviewed below:
Staten Island Cancer Incidence Rate Study. To address Staten Island residents' concerns that exposures to chemicals in the Fresh Kills Landfill and Brookfield Avenue Landfill were causing an increased incidence of cancer, NYCDOH conducted a review of cancer incidence rates among Staten Island residents (NYCDOH, 1996). Using the NYSDOH Cancer Registry data, NYCDOH compared the number and incidence rates of new cancer cases reported between 1979 and 1988 for four distinct populations: residents of the 13 census tracts that surround the two landfills (called "the Study Area"); residents of all of Staten Island; residents of areas outside of Staten Island with similar demographics, but not located near a landfill; and residents of the rest of New York City (other than Staten Island). For this last comparison population, NYCDOH selected the Bay Ridge neighborhood in Brooklyn and the Flushing neighborhood in Queens. The study considered 14 different types of cancer.
In general, the NYCDOH study did not find "any consistent evidence of an elevation in cancer incidence in the Study Area" (NYCDOH, 1996). More specifically, the incidence of all types of cancer in men, women, and children who live in the Study Area were not statistically significantly elevated when compared to the population of Staten Island as a whole. However, the incidence of lung, bladder, and colon cancers among men and women on all of Staten Island were found to be between 12 % and 36 % higher than the incidence among men and women in the rest of New York City-these differences were classified as "slight to moderate" and were statistically significant (NYCDOH, 1996).
The study hypothesized that cancer rates on Staten Island might be truly elevated, but no evidence of statistically significant higher cancer rates was observed for the census tracts that surround the Fresh Kills Landfill and the Brookfield Avenue Landfill. The absence of statistically significant trends, however, does not necessarily imply that cancer rates in the Study Area are not elevated. In fact, the Cancer Study reported that the incidence of kidney cancer in men and leukemia and lymphoma in women who live in the Study Area is indeed elevated, but this trend was not statistically significant (NYCDOH, 1996). Because these findings raised questions about certain cancers on Staten Island, a panel of nationally recognized experts recommended that NYCDOH analyze more recent cancer incidence data, evaluate trends in cancer incidence for Staten Island and the Study Area, and explore funding opportunities for an in-depth study of cancer risk factors on Staten Island.
NYCDOH revisited its cancer incidence study now that many more years of data are available from the state's Cancer Registry. In a report released in April 2000, the NYCDOH evaluated cancer incidence data for 1989-1992 for the Study Area and Staten Island as a whole. The report also evaluated if there are overall trends of increasing or decreasing cancer incidence rates in Staten Island and the Study Area over a 15-year period (1978-1992) and if these trends are significantly different from trends elsewhere. This report concluded that the analyses did not indicate consistent evidence of elevated cancer rates specific to the landfill area. For the majority of cancer sites, rates in the Study Area were lower than, or equivalent to, rates in the rest of Staten Island. A moderate elevation was noted for leukemia among children and CNS cancers among men and women during this time period these were attributed in the report to natural variation in rates over time (NYCDOH 2000).
These additional analyses also indicate that cancer incidence for most cancers on Staten Island as a whole was not significantly different than elsewhere in the City. Also, trends in cancer incidence on Staten Island were not significantly different from those elsewhere in the City for most sites. Importantly, children on Staten Island had significantly lower rates of cancer than children in the rest of the City. However, for the time period evaluated in these analyses there continue to be statistically significant elevations for some adult cancer types on Staten Island and several of these cancers also have trends that are statistically significantly different from the comparison areas for the 15 year time period evaluated. In conjunction with the prior study findings, these analyses provide fairly consistent evidence of a continuing moderate elevations in lung and bladder cancer among men and women and breast cancer in women in Staten Island. These analyses also point out other areas of potential concern, primarily pancreatic cancer and to a lesser degree, adult leukemia. Because of the limitations of the study approach it is impossible to rule in or out with 100% certainty the role of environmental, lifestyle or other cancer risk factors (NYCDOH 2000).
For a complete account of the public health implications of living near the Fresh Kills Landfill, ATSDR obtained and reviewed studies that collected and reported health outcome data for the neighborhoods in the immediate vicinity of the landfill. Health outcome data can come in many forms, but they generally indicate the incidence of selected diseases or adverse health effects among a study population. ATSDR has identified the following studies that have reported health outcome data for the neighborhoods that surround the Fresh Kills Landfill. The significance of these studies is reviewed below:
Health Study of New York State Department of Sanitation (NYCDOS) Landfill Employees. In response to a concern that workers at the Fresh Kills Landfill have higher rates of various illnesses than workers at other NYCDOS locations, NYSDOH conducted a cross-sectional health study to compare the prevalence of selected symptoms and injuries between these two groups (Gelberg, 1997). For the study, NYSDOH conducted telephone interviews with 238 male employees of the Fresh Kills Landfill and 262 male employees at other NYSDOS locations. During these interviews, workers were asked a series of questions, including questions about self-reported symptoms and injuries, and the extent to which these might be job-related. Female employees were not included in the study, since too few of them worked at landfill sites.
The NYSDOH study found that workers at the Fresh Kills Landfill had a higher prevalence of self-reported sore and itching throats and various dermatologic, neurologic, hearing, and respiratory symptoms than the off-site NYSDOH employees considered as the control group (Gelber, 1997). On the other hand, the off-site employees had a higher prevalence of injuries and neuromuscular symptoms. All of these findings were statistically significant, but the many occupational factors and exposures that workers face prevented NYSDOH from attributing the higher prevalence of self-reported symptoms to any agent or agents. This study did not look into cancer.
The NYSDOH study noted some limitations in its health study, most of which are common to cross-sectional studies involving self-reported symptoms. For example, the workers surveyed were asked questions to differentiate work-related symptoms from other symptoms. The authors acknowledged that such a distinction is more easily made for acute outcomes than chronic outcomes and that responses are subjective. Further, the study indicates that examining job tasks and duties might offer greater insight into reported health outcomes than simply considering the job location. As an example of this, NYSDOH found that employees who worked primarily on the active bank of the Fresh Kills Landfill were no more likely to have work-related neurologic or respiratory symptoms than other NYCDOS workers, though the employees who worked on the active bank were more likely to have sore throats and hearing symptoms (Gelberg, 1997). Finally, noting that the employees at the Fresh Kills Landfill might have a heightened awareness of environmental and health problems, the study authors indicated that reporting bias might have affected the results.
When interpreting this study, it is important to remember that landfill workers are exposed to much higher levels of landfill emissions and other pollutants (e.g., exhaust from trucks) than are Staten Island residents. Therefore, the apparent increase in selected self-reported symptoms among workers does not necessarily imply that a similar increase in symptoms would occur in the community.
Overview of health outcome data. Overall, the health outcome data listed above are generally consistent with the findings presented earlier in the document. The NYCDOH Cancer Study did not find the incidence of cancer among residents living near the Fresh Kills Landfill to be statistically significantly elevated when compared with the rest of Staten Island, consistent with the analysis of 10 years of ambient air monitoring data presented earlier. Though the NYSDOH health study found workers at the Fresh Kills Landfill had a higher rate of certain self-reported symptoms than other NYCDOS employees, these workers' exposures to environmental contaminants are considerably different than the residents' exposures. Therefore, the apparent higher rate of certain symptoms among workers is not necessarily replicated among community members, who generally do not breathe in the concentrated emissions observed at the Fresh Kills Landfill surfaces.
Staten Island community members originally petitioned ATSDR to perform a public health assessment to address concerns regarding health effects that might be related to air emissions from the Fresh Kills Landfill. These concerns, and ATSDR's response to these concerns, follow:
- Community members expressed concern about children's health problems, miscarriages, infertility, and cancer among residents who live near both the Fresh Kills Landfill and the Brookfield Avenue Landfill. Concerns specific to the Fresh Kills site focus on a suspected link between air emissions and adverse health effects.
Linking observed health effects with low-level environmental exposures is extremely difficult, especially in cases where relevant data are limited or missing. In the case of the Fresh Kills Landfill, however, levels of air contaminants have been measured in residential areas for the last 10 years, thus providing an extensive basis for evaluating potential health concerns.
ATSDR thoroughly reviewed the large volume of ambient air monitoring data for this site and carefully examined whether short-term or long-term exposures to the air pollutants reach levels of concern. Based on its current evaluations, and the evaluations performed since first receiving a petition in 1991, ATSDR has not found any evidence among the environmental measurements that site-related contaminants could be the likely cause of adverse health effects to people who live near the Fresh Kills Landfill. The levels of site-related contaminants that have been measured in the air over the last 10 years are not believed to be consistent with any of the effects reported by the petitioners, including developmental effects, reproductive effects, and cancer.
ATSDR notes, however, that evaluating the potential effects of environmental contaminants on humans involves some uncertainty. For instance, the health effects that might result from exposure to complex mixtures of chemicals is largely not understood. Moreover, this health assessment does not consider the Staten Island residents' possible risk factors (e.g., smoking, family history of disease, and past exposures) as a possible contributing factor for their reported health concerns. Though these uncertainties undoubtedly exist, ATSDR's approach to evaluating the health implications of chemical exposures is generally conservative, thus accounting for the inherent uncertainties associated with establishing links between exposure and adverse health outcomes.
ATSDR's general finding that ambient air concentrations of chemicals are not of concern is not entirely consistent with the results of ATSDR's 1997 health study, which found that Staten Island residents with asthma are slightly more likely to cough, wheeze, or experience shortness of breath on days with self-reported odors. Several hypotheses might explain this apparent inconsistency, such as the possibility that a reporting bias among the subjects influenced the results and the possibility that environmental agents that (1) are often present on days with bad odor and (2) were not measured during the health study caused the self-reported outcomes. Unfortunately, a full understanding of the connection, if any, between self-reported odors and respiratory health problems remains unknown. As noted below, however, ATSDR recommends future actions to put the issue of potential odor-related health effects into perspective.
2. This framework for examining the two sets of air monitoring data is somewhat simplistic. ATSDR acknowledges that other factors (e.g., differences in sampling methods, analytical methods, and detection limits used by NYCDEP and NYSDEC) might also explain differences and similarities between the two different sets of ambient air monitoring data. Nonetheless, ATSDR believes the similarity of the data trends from the NYCDEP and NYSDEC networks, which focused on different geographic areas on Staten Island, deserves mention.
3. In 1997, EPA proposed a revised national ambient air quality standard for ozone, but the proposed revision has not been implemented due to a court ruling.
4. The NYSDEC Web site currently is: http://www.dec.state.ny.us/website/dar/bts/ozone/oz4cast.html.
5. Note, according to the well survey, several hundred groundwater monitoring wells were found to be located within 1 mile of the Fresh Kills Landfill, but water from these wells is used strictly for groundwater sampling.