HARLEM’S NORTH RIVER WASTEWATER TREATMENT PLANT:

SANCTUARY OR SEPULCHER?

A growing body of studies clearly show that communities of

color bear a disproportionate burden of pollution problems

in the United States. Communities of color are adversely

affected by industrial toxins, dirty air and drinking water,

and the location of municipal landfills, incinerators, and

hazardous waste treatment, disposal, and storage facilities.

Robert Bullard[1]

Introduction

People in communities all over the world are engaged in a perpetual battle for environmental survival. The war against pollution at the community level spans the globe. In North Carolina, Warren County residents fought, and continue to fight, against contamination by polychlorinated biphenyls (PCBs).[2] In Nigeria, the Ogoni people fought, and continue to fight, against devastating oil spills by Shell Oil Company and other oil companies.[3] Controversy began in 1914 over where to build a new wastewater treatment plant in New York City. Almost 50 years of debate and controversy over the siting issue “officially ended” in 1962 when the New York City Planning Commission approved a 28-acre site in Harlem (on the Hudson River, west of the West Side Highway from 137th Street to 145th Street). The North River Wastewater Treatment Plant (NRTP) began full operation in April 1991.[4] Community protests and complaints against the NRTP continued from 1962 to the present and various community-based environmental organizations continue to monitor the NRTP for compliance with applicable environmental laws and court orders. [5] Many community residents and environmental groups contend that opposition to the NRTP was quelled by the City and State government’s agreement to build the multi-million dollar state park on the roof of the NRTP.[6] The Riverbank State Park has become one of the Harlem community’s most treasured recreational sanctuaries.[7] However, in the middle of Riverbank State Park there are several 100-foot ventilation stacks that emit carbon monoxide (CO), hydrogen sulfide (H2S), particulate, metals, and volatile organic compounds (VOCs). The sewage treatment process in NRTP beneath the park emits these substances.[8] Should community residents and visitors be concerned about the emissions from the plant? Of course they should be concerned. The judicially mandated requirements set forth in the North River Odor, Flow, and Emissions Control Order (dated July 1, 1992)[9] was imposed on the government to address legitimate and critical community health concerns. Is the NRTP a sanctuary or a hidden sepulcher? This is a complex question. This evaluation of two of the monitored VOCs will provide a methodology and information for non-scientist laypersons, judges, or juries. This paper will evaluate scientific data in recent environmental compliance reports from the NRTP.[10] The evaluation will focus on the New York Department of Environmental Protection (DEP) North River Air Quality Monitoring Program data on carbon tetrachloride (CCl4)[11] and benzene (C6H6).[12]

Both carbon tetrachloride (CCl4) and benzene (C6H6) are VOCs, which means they are “organic carbon compounds that exist in the gaseous state in ambient air.”[13] The strong, sweet smell of carbon tetrachloride (CCl4) is similar to chloroform or ether (See Appendix A: CCl4 stereo chemical image). This very dangerous chemical poses a triple threat to humans and animals. It is a carcinogen, mutagen, and a neurotoxin. It can cause cancer, cause genes to mutate (or change), and can destroy the nervous system. Carbon tetrachloride (CCl4) is poisonous and has earned the distinction of being listed on the Community Right-to-Know List.[14] Benzene (C6H6) is also extremely dangerous to humans when it is released into the air. Benzene has a sweet odor, similar to carbon tetrachloride (See Appendix B: C6H6 stereo chemical image). The potential danger to community residents is obvious and this danger is more insidious because the absence of odor does not mean you are not being exposed. Despite this fact, “[t]o improve the control of odors from [NRTP], New York City has recently spent an additional $55 million beyond the cost of construction of the original odor control facilities. North River’s odor control facilities are among the most elaborate in the [United States].” Dispite the tremendous expense of the odor control members of the Environmental Justice Advisory Group (EJAG) remain vigilant about the toxic emissions from NRTP. Ms. Peggy Shepard, Executive Director of West Harlem Environmental Action (WHEACT), is one of several members of EJAG.[15] According to Ms. Shepard one of WHEACTs missions is to evaluate the compliance reports from NRTP and other sites in Harlem that pose an environmental threat to the health of community residents and New Yorkers generally. Where does carbon tetrachloride (CCl4) and benzene (C6H6) come from during wastewater treatment process at NRTP and how much is being released into the air?

The Wastewater Treatment Process

Wastewater treatment is generally divided into three stages: preliminary, secondary, and advance wastewater treatment.[16] The NRTP uses a variation of all three of these treatment stages, “…wastewater goes through five major steps: preliminary treatment, primary treatment, secondary treatment, disinfection and finally sludge treatment.”[17] The primary and secondary processes take about seven hours to remove 85% to 90% of the pollutants from the wastewater. Even after primary and secondary treatment the treated water still contains disease-causing organisms that are removed by a chlorine-contact to disinfect the water before it is released into the Hudson River.[18] Carbon tetrachloride (CCl4) and Benzene (C6H6) enter the NRTP daily from specific locations or point sources (industries that use these chemicals for manufacturing or as solvents) within New York City. However, it is generally accepted that these chemicals primarily enter the NRTP from thousands of unknown locations or “non-point sources.”[19] Carbon tetrachloride (CCl4) and benzene (C6H6) are accumulated and emitted during wastewater operations. Figure 1 illustrates the various points during the wastewater process where these VOCs are emitted. As you can see these chemicals escape into the air at every stage of the wastewater treatment process.

Equipment Leaks

Product transfer

Figure 1. Emission points from wastewater treatment process. The black arrows ( ) indicate the various points in the treatment process where toxic fumes escape into the air. [20]

The Monitoring Report: Carbon tetrachloride (CCl4) and Benzene (C6H6)

The City of New York, Department of Environmental Protection (DEP) contract with Environmental Monitoring Instruments, Inc. (EMI) to monitor ambient air pollutants as part of the North River Air Quality Monitoring Program. The January 2000 report (JY2K report) on particulate, metals, volatile and semi-volatile organic compounds is the focus of this paper. These reports are required monthly and cover a wide range of chemicals that are emitted and potentially emitted into the air and released into the Hudson River. The NRTPs air quality monitoring system uses three air quality monitoring stations (AQMS)[21] that are located in the adjacent residential Harlem community. The following data was collected from AQMS #6 which is located at 626 Riverside Drive (149th Street and Riverside Drive). The air samples

are collected using the latest EPA methodology.[22] The samples are analyzed using a gas chromatograph/mass spectrometer (GS/MS). The GS/MS determines the type and quantity of specific VOCs in parts per billion units of air (ppb v/v). According to the JY2K report there were four days during January 2000 that the amounts of both Benzene (C6H6) and carbon tetrachloride exceeded the minimum detection limit (M.D.L.) at AQMS #6. The chart below is a summary of the JY2K data including the specific collection dates, results and M.D.L. for benzene (C6H6) and carbon tetrachloride (CCl4).[23] The M.D.L. for these chemicals is critical because although both benzene (C6H6) and carbon tetrachloride (CCl4) are hazardous to humans and animals indoors and in ambient air, there are no specific legal reporting limits (RL) for the emission of these chemicals. The MDL is used to determine the RL. Currently the EPA has set RLs for carbon tetrachloride (CCl4) in drinking water and releases into wastewater, and minimum concentration limits for workplaces have been set by the Occupational Safety and Health Administration (OSHA).[24] However, the New York State Department of Environmental Conservation (NYSDEC) and the EPA want to determine a RL for releases into outside air and possibly set a standard for these chemicals. Even if the NYSDEC does set a RL or other standards, establishing a connection between the emission of these harmful chemicals into the outside air and impact on community health is extremely difficult. Community health risk assessment will be discussed in the next section. Both the EPA and NYSDEC have not set a RL or standard for benzene (C6H6) releases into outdoor air. According to The Agency for Toxic Substances and Disease Registry (ATSDR) “[o]utdoor air contains low levels of benzene (C6H6) from tobacco smoke, automobile service stations, exhaust from motor vehicles, and industry emissions.”[25] The outdoor air near wastewater treatment plants contain higher levels of benzene (C6H6).[26] Human exposure to benzene (C6H6) can be determined, but like carbon tetrachloride (CCl4), health impacts are difficult to determine. The NYSDEC has developed the Toxic Air Monitoring System (TAMS) that monitors VOCs statewide.[27] The data reports from this program include the actual or proposed annual guideline concentration (AGC). Unfortunately the AGC is not helpful in determining whether the community is safe fro these and other chemicals. The “AGCs are guideline values only, developed for screening and toxicity ranking, and are not standards or absolute limits of acceptable risk.”[28]

The compliance data from NRTP is complex and has no real meaning unless a connection is established between the chemicals reported and people. The one method for making practical use of environmental compliance data (ECD) is the “young scientific discipline of ‘chemometrics.’”[29] This new discipline offers tremendous possibilities for understanding and using ECD. The sheer amount of ECD from NRTP is overwhelming and the amount environmental information is expected to increase exponentially. This is the situation at any location that is being monitored by the government at any level. The rapid development of chemometrics. . .

was initiated by advances in intelligent instruments and laboratory automation as well as by the possibility of using powerful computers and user-friendly software. [C]hemometrics became a tool of analytical chemistry. . . . mankind has also become increasingly aware of problems resulting from environmental pollution. The pathways and effects of pollutants in environmental compartments and on human beings are very complex and often largely unknown. The need to obtain more and deeper knowledge on environmental pollutant loading led to the active development of environmental analytical methods.. . . [However], the enormous flood of data and [the fact that] environmental data [is] characterized by [its] extremely varying character …and the complexity of the objects under investigation urgently require the application of chemometric methods, particularly in the field of environmental research.”[30]

Using chemometrics involves all of the “E buzz words,” referred to by many environmental experts, “earth, ecology, environment, energy, education, economics, ethics, equity, emotion, education, experiment, empowerment, and aesthetics.”[31] According to Dr. Rahni the integration of information from all relevant sources has a synergistic affect.[32] Scientific methods like chemometrics are ideally suited to evaluate both individual and synergistic affects on the environment and humans because the method uses all available resources to arrive at useful conclusions and is interdisciplinary.[33] “Some scientists also use the term ‘environmetrics’ for the application of chemometric methods in the field of environmental science.”[34] Before any of these methods can be used effectively possible gross errors or systematic errors can be detected by using general statistics. Basic statistical analysis can determine the precision and accuracy of data. The data collected from the NRTP using AQMS #6 must be evaluated to determine its precision and accuracy. Prior to using any of the scientific methods discussed above a basic statistical review requires: determination of the rank series, median, range, arithmetic mean (mean), variance, and standard deviation of the collected data.

The data was collected in January 2000 at NRTP/AQMS#6 on both benzene and carbon tetrachloride. The calculations below indicate that the data values fall within a normal range in relation to the mean. In other words, as a rule of thumb: approximately 68% of the data values should fall within one standard deviation of the mean; approximately 95% of the data values should fall within two standard deviations of the mean; and all the data values should fall within three standard deviations of the mean. The mean of the benzene data values is .58 and the standard deviation is .1761. (See Appendix C: example of calculations for benzene.) The results of the calculations are summarized below and on the graph at Appendix D.

Benzene (C6H6)

Rank Series: .35, .39, .40, .52, .57, .60, .60, .61, .83, .88

Median: .59

Range: .53

Arithmetic Mean: .58

Variance: .0310

Standard Deviation: .1761

Carbon Tetrachloride (CCl4)

Rank Series: .10, .10, .10, .12

Median: .10

Range: .02

Arithmetic Mean: .11

Variance: .0001

Standard Deviation: .01

Before any decisions or conclusions can be drawn from the NRTP data it is critical to evaluate the accuracy and precision of the data.[35] Calculating the variance and standard deviation of the data allows a determination about whether there is a normal distribution of data.

V.O.C. / Collection Date / Result / Unit / M.D.L.
Benzene (C6H6) / 1/5/00 / 0.39 / ppb v/v / 0.1201
Benzene (C6H6) / 1/7/00 / 0.52 / ppb v/v / 0.1201
Benzene (C6H6) / 1/11/00 / 0.61 / ppb v/v / 0.1201
Benzene (C6H6) / 1/21/00 / 0.60 / ppb v/v / 0.1201
Carbon tetrachloride (CCl4) / 1/5/00 / 0.10 / ppb v/v / 0.0922
Carbon tetrachloride (CCl4) / 1/7/00 / 0.10 / ppb v/v / 0.0922
Carbon tetrachloride (CCl4) / 1/11/00 / 0.61 / ppb v/v / 0.0922
Carbon tetrachloride (CCl4) / 1/21/00 / 0.12 / ppb v/v / 0.0922

Table 1: Selected Data from AQMS #6 on Benzene (C6H6) and Carbon tetrachloride (CCl4)

Application environmetrics to the selected data from NRTP (Table 1) involves several topics, from recognition of the pollution problem to monitoring the problem for legal enforcement and community health.[36] The amount of benzene and carbon tetrachloride emitted from NRTP are expressed in part per billion (ppb). An example of one ppb would be the equivalent of one drop in 265,000 gallons of water or one pinch of salt in 10 tons of potato chips.[37] It’s tempting to think that such minute amounts of these deadly toxins will have no adverse impact on the health of the community, however “three factors determine how severe the harmful effects of a pollutant are: the nature of the chemical, its concentration, and its persistence (how long the chemical remains in the air after its emission. Of these three factors, the general toxic chemical nature of both benzene (C6H6) and carbon tetrachloride (CCl4) are fairly well known. However the degree of bioaccumulation and biomagnification are still being studied. Despite ongoing studies ATSDR determined that “benzene (C6H6) does not build up in plants or animals.”[38] This conclusion appears to be premature and inaccurate because another ATSDR study recognized that one of the negative consequences of benzene exposure is its harmful effects on bone marrow and that it can lower the red blood cell count in humans. Carbon tetrachloride, unlike benzene, according to ATSDR is “very stable in air and has an estimated lifetime of 30 to 100 years…it doesn’t build up in animals…[but] we do not know if it builds up in plants.”[39] It’s interesting to note that ATSDR is still reluctant to conclude that carbon tetrachloride bioaccumulates even when the science appears to support bioaccumulation. Clearly ATSDR is concerned about crossing the line from science and pseudoscience. Nevertheless, armed with basic understanding of the dangers of these chemicals and general knowledge about ecosystems and life cycles it seems reasonable that at least the precautionary approach should be taken in this area. Further study must be done to determine what impact the accumulation of these chemicals in plants has on animals, humans, and plants. It is often tempting to move into the realm of frontier science, but the essence of accepted science is that it is accepted and generally agreed upon by the scientific community.

Carbon tetrachloride (CCl4) and benzene (C6H6) also contribute to photochemical smog.[40] It appears that photochemical smog is one of several chemical reactions that occurs when carbon tetrachloride (CCl4) and benzene (C6H6) mix with oxygen and sunlight. These VOCs combine with other known pollutants that increase the overall health impact. Two of the chemicals that combine with VOCs to produce a more toxic ambient air cocktail are carbon dioxide and carbon monoxide. Both carbon dioxide and carbon monoxide are well documented as being major types of air pollution with serious health consequences.[41] Additional dangers associated with carbon tetrachloride (CCl4) and benzene (C6H6) exists because they are both primary pollutants (dangerous alone) and secondary pollutants (they react with air, sunlight, and other pollutants to create new health dangers). There are several variables that are used to evaluate the impact that VOCs could have on a community. These variables and other issues related to community health risk assessment will be covered in the next section.

Community Health Risk Assessment and the Pollution Standards

The most important reason for gathering data on VOCs or any other harmful chemical in communities is our desire to assess potential health. The New York State Department of Environmental Conservation (NYSDEC)[42] and the New York State Environmental Quality Review Act (SEQRA) riskThe factors considered when evaluating the effects of VOCs on the community are: levels/concentrations of pollutants, duration of exposure, severity and duration, environmental conditions, and interactions among pollutants (synergistic, additive, potentiative, and antagonistic.) This process is very complicated and requires the analysis of information from numerous sources. The goal of a community health risk assessment is to determine whether the health of a community (people, animals, and plants) are adversely impacted by the specific chemicals, in this case benzene and carbon tetrachloride. Although strict standards exist at both the State and Federal levels for these chemicals as treated effluents, there is no specific standard for the amount of benzene and carbon tetrachloride that can be released into the ambient air (outside air) during the wastewater treatment process. As discussed in the introduction these known toxic chemicals have a tremendous adverse impact on human health. The AQMS system is designed to capture data on the amount of various VOCs that are emitted into the air near NTTP, but merely reporting the M.D.L. has no value without the existence of a scientifically derived standard to evaluate the data. There are standards established for these chemicals to protect people in the workplace.[43] The people in the community surrounding NRTP or any wastewater treatment plant must rely on the data that is provided (MDLs from the AQMSs) and use this data in conjunction with other information from area health care facilities about reported illnesses that may be related to exposure to benzene and carbon tetrachloride. In addition, there are medical test to determine exposure to these chemicals but the existing tests are only effective with short-term exposure.[44] It is well established and fully documented that and many communities, especially those with high concentrations of African-Americans, Hispanics, and economically challenged people, “suffer disproportionately from industrial toxins, dirty air, and drinking water, unsafe work conditions, and the location of noxious facilities such as municipal landfills, incinerators, and toxic-waste dumps,” including wastewater treatment plants.[45] The challenges involved with determining health risk are formidable even in places like Chester, Pennsylvania where the connection between the hazards and community health are obvious. Unfortunately the “common sense” test is not sufficient to overcome legal standards that require scientific proof. Establishing the connection between the emission of benzene/carbon tetrachloride from NRTP to any adverse health problems in the Harlem community is difficult, but not impossible.