FRESH KILLS LANDFILL
STATEN ISLAND, RICHMOND COUNTY, NEW YORK
In conjunction with her constituents, former U.S. Congresswoman Susan Molinari petitioned the Agency for Toxic Substances and Disease Registry (ATSDR) to perform a public health assessment (PHA) of the Fresh Kills Landfill. A PHA is an evaluation of pertinent environmental data, health outcome data, and community concerns related to a waste site. Aware of community concerns about air emissions from the landfill, ATSDR has decided to produce individual health consultations on air quality data as soon as possible after the data are available to ATSDR. A health consultation primarily responds to a specific question. The consultations will become components of the future PHA, and any comments or additional data received in response to this consultation will be addressed in subsequent reports.
ATSDR has released two previous health consultations for this area. A consultation released in May of 1993 used the available data from the Staten Island/New Jersey Urban Air Toxics Assessment Project , and consultation released in March 1996 used the first six months of available data from the New York State Department of Environmental Conservation (NYSDEC) monitoring network on Staten Island . Future documents about soil and water pathways and health evaluations will be prepared, and the set of documents developed regarding this site will be combined to complete the PHA.
SUMMARY OF FINDINGS
As explained in detail in the text below, ATSDR has evaluated approximately one year of air quality data from the files of the NYSDEC. ATSDR has found no landfill-related contaminants at levels of public health concern in the data. ATSDR has also reviewed data collected on behalf of the Environmental Protection Agency (EPA) in a study of landfill gas emissions and found that a number of compounds detected in the emissions study are not considered in the ambient air monitoring conducted by the NYSDEC. ATSDR considers this a data gap and recommends appropriate follow-up action for those compounds significant to evaluation of public health. ATSDR classifies the air pathway from Fresh Kills Landfill as an Indeterminate Public Health Hazard pending review of forthcoming data.
PURPOSE OF THIS CONSULTATION
There have been numerous concerns and complaints associated with the odor of the Fresh Kills complex. Respiratory illnesses, reproductive difficulties, and perceived rates of cancer are all concerns of the citizens in the area . This health consultation will evaluate ambient air quality data from monitoring stations operated by the NYSDEC to determine if there are issues of public health significance indicated by the data.
In addition, this consultation will review data from a 1995 EPA sampling effort to evaluate emission rates from the surface of the landfill  and a follow-up EPA project performed in 1996 . Where appropriate, this consultation will also make use of data collected at a network of air monitoring stations operated by the New York City Department of Environmental Protection (NYCDEP) .
FRESH KILLS LANDFILL SITE HISTORY
The Fresh Kills Complex is one of the largest landfills in the United States. Established in 1948, the site covers over 2,200 acres on the western shore of Staten Island. The site is surrounded on the north, east, and south by areas of mixed residential and commercial use (see Figure 1), and approximately 40,000 people live in the adjacent census tracts . Landfill operations are currently being conducted on approximately 775 acres of the landfill with approximately 13,000 tons of solid waste received daily .
Since 1987, various local and state organizations have assessed and evaluated
the landfill and the surrounding area. The New York City Department of Health
completed a study of cancer incidence rates on Staten Island in 1996 
and the New York State Department of Health has completed a health study of
sanitation workers . ATSDR will review and comment on these studies
in greater detail in the forthcoming PHA for the Fresh Kills site.
Figure 1. Fresh Kills Municipal Landfill Air Monitoring Locations
New York State Department of Environmental Conservation Data
A summary of New York State Department of Environmental Conservation (NYSDEC) air quality data collected October 1, 1994, through December 31, 1995 is in Appendix A.
The NYSDEC has been collecting quantitative air samples in the Fresh Kills area since the fourth quarter of 1994. Staff members collecting the samples used carbon-based adsorbents, which trap the contaminants within them during ambient air sampling. They sent the adsorbents to a laboratory for analysis of volatile organic compounds (VOCs). In addition, several NYSDEC sampling stations also collected particulate metals samples on filter media, which were then digested in the lab and analyzed to provide results for metal particulates in the air. The NYSDEC provides two types of particulate metals data: total suspended particulates (TSP) and particulate material smaller than 10 microns (PM10). The NYSDEC reports also include information on a number of organic compounds in the air belonging to the chemical classes of aldehydes and ketones. The Public Health Evaluation section of this consultation contains a discussion of the public health implications of the NYSDEC data.
The NYSDEC monitoring network consists of 12 stations (Figure 1). Data on wind direction are collected at the Susan Wagner High School and Meteorology Tower locations and indicate general wind directions in the vicinity of the landfill. The stations are individually designed to collect samples for various parameters; therefore, some of the stations do not report data provided for other stations (for example, only a few stations have data on PM10 particulate material). The data from the stations include results for 18 VOCs often found in urban air, selected aldehydes and ketones (a different group of VOCs), and suspended particulates (metals) during calendar year 1995. Other NYSDEC data made available to ATSDR after development of this report will be evaluated in subsequent documents prepared as part of the PHA for the site.
The sampling for VOCs was conducted on a routine schedule; a sample was to be collected every six days. Some samples were apparently either not collected or analyzed, leaving uncertainty as to the air quality on those sampling dates. These omissions are data gaps. Data gaps which have a significant bearing upon ATSDR's ability to evaluate the health impacts of a site are identified in the Conclusions and Recommendations sections of this report.
New York City Department of Environmental Protection Data
The New York City Department of Environmental Protection (NYCDEP) operates its own system of air quality monitoring devices throughout the city. On Staten Island, the NYCDEP operates four full-time stations, however these stations are not in close proximity to the landfill . Data from these stations regarding selected VOCs and particulate materials have been collected and made available to ATSDR for the period March 1994 to February 1995. ATSDR has referred to these data in relation to NYSDEC data where appropriate in discussing compounds which are typically found in air in urban areas.
Environmental Protection Agency Data
The Environmental Protection Agency (EPA) also had intensive landfill gas source sampling conducted at Fresh Kills Landfill during the summer of 1995. EPA contracted with a private consulting firm for source sampling and estimation of contaminant emission rates from the surface of the landfill. Sampling was conducted during the summer of 1995, and a report of the results was released in the spring of 1996 . The EPA contract report describes sampling from gas vent pipes on the surface of portions of the landfill and gas samples collected from a gas collection system installed within a portion of the landfill. Many of the results provided in the EPA report are given in terms of fluxes, which is the amount of a chemical per unit time per unit area, rather than chemical concentrations (amount per unit volume of air, the units of air quality standards and ATSDR comparison values). However, because the EPA samples directly measure emissions from the landfill, the report can provide useful information concerning landfill-specific emissions to the air.
Emission rates (mass of compound emitted per unit of time per unit area of landfill) must be analyzed in conjunction with air dispersion rates to develop units of chemical concentration that are needed for a health evaluation of the emissions. Although development of an air dispersion model for a site as large as the Fresh Kills Landfill is beyond the scope of this health consultation, the general data from the survey of emission rates allow consideration of specific compounds emitted from the landfill, and a screening modeling effort has been performed to aid in understanding selected community concerns (such as approximate off-site levels of some specific compounds based on the EPA emissions data).
Of the more than 150 compounds sampled, two are noteworthy because of community concerns expressed by local residents. One of these compounds, hydrogen sulfide, is noteworthy because of its strong odor and the community concerns about odors from the landfill. The other compound, mercury, is noteworthy because of its toxicity and the level of community concerns expressed about its possible presence in landfill emissions.
ATSDR could locate no data regarding ambient air concentrations for hydrogen sulfide, although it is one of the most abundant gases generated within the landfill (number 8 on the list of more than 150 compounds). ATSDR considers that the irritant odor of this compound and the significant presence of this compound in gases generated within the landfill warrant further examination. The lack of ambient air data for this compound is a notable data gap in ATSDR's ability to evaluate the public health effects of the landfill.
ATSDR did review the NYSDEC data for particulate mercury, and those data were considered in the selection of ATSDR's contaminants of concern. In addition, ATSDR reviewed two projects developed by EPA [5,6] to evaluate mercury emissions from the landfill. ATSDR's evaluation of the EPA mercury data required the development of a screening air dispersion model. This effort is described in the following section, Air Modeling Screening Evaluation.
Air Modeling Screening Evaluation
In an effort to develop better understanding of potential health concerns regarding mercury emissions detected by the EPA study, ATSDR has performed a screening level air modeling effort. A screening level effort is one in which conditions are presumed to be the highest typical exposure scenario (e.g., typical average summer conditions on Staten Island with relatively high temperatures and humidity and little or no wind speed). The screening model (SCREEN3) was used to generate estimated 1-hour peak levels for mercury, hydrogen sulfide, and 11 other chemicals found in both the EPA study  and the NYSDEC database in order to evaluate how conservative the model predictions were.
Although the screening model provided 1-hour peak concentrations for the compounds modeled, it is reasonable to compare these estimates to 24-hour sample data collected in the NYSDEC program. Regulatory guidance indicates that maximum hourly concentration estimates should be applicable for averaging times as long as 24 hours . Although no formal guidance exists for extending the estimated concentrations to longer time periods, previous studies have indicated that annual average concentrations could range from 10 to 40 percent of the maximum hourly estimates . As a conservative approach, ATSDR has estimated that annual average concentrations would be the approximate level of 40 percent of the maximum hourly estimate indicated by the screening model.
The screening model's estimated 1-hour peak results were compared to the maximum levels detected in the 1994- 1995 NYSDEC data for the 11 chemicals found in both studies. The results of the comparison indicate that the screening model is useful in estimating maximum exposures. Of the 11 chemicals compared, 7 showed results where the model estimate was higher than the highest value measured by the NYSDEC. In the other cases, the highest measured value was less than twice the modeled value for all except benzene. The peak level of benzene was measured at the District 2 Garage sample location. Because it is likely that a significant amount of benzene in the District 2 Garage sample came from sources other than the landfill (benzene is a common component of automobile and truck emissions), and because the model only estimates levels of a chemical anticipated in the air resulting from the emissions from the landfill, it is reasonable that the model would underestimate the peak level of benzene at this location. Because the majority of the peak concentrations estimated by the model were conservative when compared with the NYSDEC data, and because the four chemicals that were not overestimated by the model were in reasonably close agreement with expected conditions, ATSDR considers the screening model results to be conservative in predicting the order of magnitude of landfill emissions.
The screening model indicated an estimated 1-hour peak off-site hydrogen sulfide level of approximately 35 parts per billion (ppb). This estimated peak level is above a New York State 1-hour standard of 10 ppb for hydrogen sulfide, which appears to be based on odor perception. ATSDR does not have a health comparison value for hydrogen sulfide. Because hydrogen sulfide may be a potential concern off site and because no actual ambient air data are available to allow proper assessment of the public health implications of hydrogen sulfide releases, sampling of hydrogen sulfide in ambient air is recommended later in this report as an appropriate follow-up public health activity.
For mercury, ATSDR evaluated both the EPA report from 1995  and a follow-up effort performed by EPA in 1996  due to concerns that sampling equipment used in the 1995 work may have malfunctioned. After evaluating the type of equipment used and the data from the two reports [5, 6], ATSDR developed a screening model to provide estimated annual average mercury concentrations based upon mercury content of landfill gas reported in the 1996 work . The screening model indicated an estimated annual average offsite concentration of 0.000013 ppb. ATSDR's current chronic exposure comparison value for mercury is 0.0017 ppb, which is more than 100 times higher than the concentration estimated by the model. Also, ATSDR has recently reviewed the appropriate toxicological literature and proposed a revised chronic comparison value of 0.02 ppb for inhalation exposure to mercury. The revised comparison value is more than one thousand times the annual average concentration estimated from the screening model. Based on indications from the modeling effort and the field data collected to date, ATSDR does not find mercury to be of public health concern.