PUBLIC HEALTH ASSESSMENT
BLOOMINGTON PCB SITES
BLOOMINGTON, MONROE COUNTY, INDIANA
SPENCER, OWEN COUNTY, INDIANA
This section describes the incineration facility Westinghouse proposes to build in Bloomington, Indiana, to treat the excavated landfill material (ELM) and other PCB-contaminated sediments and sludges in the Bloomington area; potential stack and fugitive emissions from that facility; and the public health considerations relevant to the proposed facility. Members of the panel of incineration experts that ATSDR convened in Bloomington to discuss the public health implications of incinerating PCB wastes were not aware of any existing facility that burns the proposed combination: municipal solid wastes (MSW); sewage sludge; PCB-contaminated soils, sediments, and sludges; and excavated old MSW/industrial waste landfill materials (ATSDR, 1994).
A. Summary of Proposed Facility
The information in this section comes from the following Westinghouse permit applications: TSCA/RCRA Incinerator Permit Application, Volumes 1 and 2, and Application for an Air Quality Permit. The proposed site for the incinerator facility is in Perry Township, Monroe County, Indiana. The site consists of approximately 15 acres that are 2.5 miles southwest of the city limits of Bloomington. Figures 1 and 2 show the location of the proposed site. The triangular site is surrounded by Indiana State Highway Route 37 on the east, the Illinois Central Railroad right-of-way on the northwest, and the City of Bloomington's Dillman Road Sewage Treatment Plant on the south. See the Demographics subsection (Subsection F of this section) for a discussion of the population near the proposed incinerator site.
Westinghouse proposes to build two identical incinerators at the facility. Figure 3 shows the general layout of each incinerator. Each incinerator will use MSW as the principal fuel in the primary combustion chamber to treat Dillman Road Sewage Treatment Plant sewage sludge and ELM. As discussed in the Waste Characterization section, ELM waste also includes the sewage sludges from the Winston-Thomas Facility and stream sediments that are contaminated with PCBs. ELM waste will be processed to shred or remove any material larger than 2 inches. Processed ELM will be mixed with sewage sludge in the processed ELM tank before being fed to the incinerator. The primary combustion chamber is a rotary combustor Model RC-100 designed by the Westinghouse Electric Corporation (see Figure 4). The combustion chamber is a hollow, water-cooled, cylinder constructed of webbed carbon steel water tubes alternating with fins welded between the tubes. Preheated combustion air blown up through perforations in the webs that connect the combustor water tubes will provide oxygen for combustion.
"Siftings," the solids that sift through the holes in the web, will fall into a water-filled siftings hopper. A drag conveyor will transfer the siftings from the hopper to an isolated siftings container. When the container is full, it will be transferred to the ELM building to be dumped back into the processed ELM pit, or, if the PCB concentration is less than 2 parts per million (ppm), the siftings might be disposed of with the incinerator residue.
The bottom ash and any remaining unburned waste solids will reach at least 1,000F before discharging from the rotary combustor into the refractory-lined dropout chamber. The bottom ash will be quenched before discharging onto the residue collecting conveyor and being conveyed to the residue handling building.
The exhaust gases from the rotary combustor will be approximately 1,400F to 1,650F when they enter the afterburner chamber (ABC). Two natural gas burners in the ABC will heat the gases to 2,012F to 2,372F for at least 2 seconds to ensure combustion of the PCBs and compliance with the Environmental Protection Agency (EPA) PCB regulations.
From the afterburner, the flue gases will be drawn into the boiler for heat recovery and to generate steam. The steam will be sent to a turbine generator to produce electricity. The boiler will have a soot-blowing system to prevent steam impingement from eroding the tubes. Hoppers below the boiler will collect particulates falling from the gas stream and discharge them to the fly-ash collection system conveyor. The exit temperature of the exhaust gases leaving the boiler will be about 350F.
The air pollution control (APC) equipment proposed for the incinerator consists of a spray dryer absorber (SDA) followed by a fabric filter (FF) system. The SDA will use a calcium hydroxide slurry--called lime slurry--injected as a finely atomized spray to neutralize acid gases. Westinghouse proposes the following acid gas stack outlet concentrations and removal efficiencies:
Continuous emission monitors will measure the sulfur dioxide concentration at the SDA inlet and the FF outlet and automatically adjust the lime slurry concentration to assure acid gas removal within the permit limits. A monitor that continuously measures the flue gas temperature at the SDA inlet and outlet will control the dilution water flow to the atomizer automatically.
The FF downstream from the SDA will collect most of the reactant products, unreacted sorbent, and fly ash. However, hoppers at the bottom of the SDA chambers will collect the solids that fall out in the SDA. Double-dump discharge devices will remove solids from the SDA hoppers.
The cooled, scrubbed gases leaving the SDA will go to an FF system designed to meet a total particulate matter (PM) emissions limit of 0.015 grains per dry standard cubic foot (gr/dscf) corrected to 7% O2. The system is also designed to meet opacity limits and the 0.012 gr/dscf corrected to 7% O2 emission limit for particulate matter with an aerodynamic diameter of less than 10 microns (PM-10).
The FF baghouse, commonly called a baghouse or FF system, will have multiple compartments that contain long cylindrical fabric bags to remove PM from the flue gas. Each compartment can be isolated, so maintenance can be performed on one compartment while the unit is on line and still meet the emissions requirements. Each compartment will be off line while the FF system periodically cleans the bags with pulses of compressed air. The FF cleaning cycle will be initiated by a timer or by a signal from the FF pressure drop sensor if the pressure drop should be too great. The filter cake removed from the bags will fall to the bottom of the compartments and exit through double-dump discharge devices into hoppers that are located below the compartments.
The solids removed from the SDA and FF hoppers will discharge onto the enclosed dry drag fly-ash conveyor. The residues will be transported by a series of enclosed elevated conveyors to a fly-ash-conditioner surge hopper in the residue-handling building. The conditioned fly ash will be combined with the bottom ash on a vibratory conveyor that discharges the combined residues into containers for testing before they are transported to the ash landfill. The incinerator residues will be tested for PCBs, free water, and Toxicity Characteristic Leaching Procedure (TCLP) constituents. EPA's TCLP covers 40 contaminants, 8 metals and 32 organics (40 CFR 261.24). Residue that contains more than 2 ppm PCB will be put in the processed ELM tank to be fed back to the incinerators.
The induced draft fan for each incinerator train will draw the flue gas through the incinerator combustion chambers, boiler, SDA, and baghouse and discharge it to the atmosphere through two separate flues in a common stack. The stack is 250 feet tall, and each flue is 3.5 feet in diameter.
There will be a separate continuous emissions monitoring (CEM) system on each incinerator. Table 8 below lists the
monitors and their locations (Westinghouse, 1991c).
| TABLE 8 INCINERATOR CONTINUOUS EMISSIONS MONITORS | |
| Monitor | Location |
| In-situ wet oxygen analyzer | Combustor outlet |
| In-situ wet oxygen analyzers | Boiler outlet |
| Dry oxygen analyzer | Inlet of APC system |
| Carbon monoxide analyzers | Inlet of APC system |
| Carbon dioxide analyzers | Inlet of APC system |
| Sulfur dioxide analyzer | Inlet of APC system |
| Hydrogen chloride analyzer | Inlet of APC system |
| Wet oxygen analyzer | Stack flue |
| Dry oxygen analyzer | Stack flue |
| Sulfur dioxide analyzer | Stack flue |
| Nitrogen oxide analyzer | Stack flue |
| Hydrogen chloride analyzer | Stack flue |
| Opacity monitor | Stack flue |
The CEM system will record the data from all the analyzers and monitors on strip-chart recorders and will log the data into a computer that is dedicated to incinerator data acquisition and can perform calculations using the data received. The computer will record the carbon monoxide and oxygen average values at least once per minute and compile periodic (e.g., daily or hourly) reports. It will also record calibration data, maintenance data, reason codes for invalid data, and high emission levels. The CEM system will be linked so that unacceptable emission levels will trigger alarms in the control room and activate the automatic ELM feed cutoff mechanism.
Westinghouse plans to conduct two tests (Case A and Case B) during the trial burn. Table 9 shows the worst-case conditions that are to be demonstrated during each test (Westinghouse, 1991b).
TABLE 9
TRIAL BURN WORST-CASE CONDITIONS
Table 10 lists the proposed normal feed rates of MSW, ELM, and sewage sludge; the requested waste feed rate permit
limits; and the feed rates proposed for the trial burn. The permit applications did not explain why the feed rates of PCBs
during the trial burn were going to be kept at 80 pounds per hour (lb/hr), when Westinghouse requested a permit limit of
15,000 ppm PCB in the ELM, which would correspond with feed rates of more than 80 lb/hr during normal operation. The
data we have seen to date indicate that by the time the ELM is excavated, shredded and processed, transported to the
incineration facility, and mixed with sewage sludge, the PCB concentration in the actual ELM feed will probably be less than
15,000 ppm. PCB permits normally do not allow higher feed rates of PCBs than those burned during the trial burn.
| TABLE 10 PROPOSED WASTE FEED RATES (per Incinerator)1 | ||||
| Waste | Permit1 | Normal | Case A | Case B |
| MSW (tpd)2 | 172.0 | 143.6 | 171.9 | 129.2 |
| ELM (tpd) | 125.0 | 88.0 | 63.9 | 124.3 |
| Sludge (tpd) | 10.5 | 10.5 | 10.5 | 10.5 |
| Total (tpd) | 307.51 | 242.1 | 246.3 | 264.0 |
| PCBs (lb/hr)3 | 156.34 | 110.04 | 80.0 | 80.0 |
| 1 Maximum requested permit feed rates in TSCA/RCRA Incinerator Permit Application. Westinghouse did not request
maximum total feed rate in its permit application; however, if not specified, by default the total allowed feed rate would be
307.5 tpd. 2 tpd = tons per day 3 lb/hr = pounds per hour 4 Based on requested permit level of 15,000 ppm PCBs in ELM | ||||
Table 11 outlines the sampling and parameters for analysis that Westinghouse has proposed for the trial burn. Westinghouse
plans to analyze the flue gas for eight metals and a variety of organic products of incomplete combustion (PICs). The
application did not provide specific information on what metals and organics would be tested in the ELM waste or why
barium analysis was to be done on the flue gas samples but not on the ash residue samples.
| TABLE 11 TRIAL BURN SAMPLING & ANALYSIS | ||
| Sample Type | Analytical Parameter | Sampling Method |
| ELM Feed | PCBs, Metals, Organics | Trowel - Several samples from the conveyor belt to be composited in a glass jar. |
| Flue Gas | Particulates, Hydrogen Chloride, Moisture | EPA Methods 4 & 5 - Isokinetic samples collected through sampling ports in the stack. |
| Metals: Silver, Arsenic, Barium, Cadmium, Chromium, Mercury, Lead, Selenium | EPA Multiple Metals Train - Isokinetic samples collected through sampling ports in the stack. | |
| Volatile PICs1: Chlorinated and aromatic hydrocarbons from EPA Method 8240 list of compounds | EPA VOST2 Method - Isokinetic samples collected through sampling ports in the stack. | |
| Semivolatile POHCs3 & PICs: PCB, PCDDs, PCDFs, & base/neutral/acid organics from EPA Method 8270 list of compounds | EPA Modified Method 5 - Isokinetic samples collected through sampling ports in the stack. | |
| Ash Residue | Metals: Silver, Arsenic, Cadmium, Chromium, Mercury, Lead, Selenium | Auger or Thief - Several samples from the residue storage bin to be composited. EPA SW-846 analytical methods to be used. |
| PCB, PCDD, PCDFs4 | ||
| TCLP Organics & Metals5 | ||
| 1 PICs = products of incomplete combustion 2 VOST = volatile organic sampling train 3 POHCs = principal organic hazardous constituents 4 PCB = polychlorinated biphenyl PCDD = polychlorinated dibenzodioxin PCDF = polychlorinated dibenzofuran 5 TCLP = Toxicity Characteristic Leaching Procedure--an EPA method to determine the leachability of 8 metals and 32 organics | ||
The following information regarding the means for controlling fugitive emissions comes from the Westinghouse TSCA/RCRA and air permit applications. Both incinerators will be operated with a negative pressure, so that outside air will be drawn into the incinerator if leaks occur at joints or openings in the system and will prevent fugitive emissions from escaping at those points. Pressure monitoring in several places in the incinerator will ensure a negative pressure throughout the incinerator. The key pressure sensors are connected to the automatic ELM waste feed cutoff system so that positive pressure readings will activate the waste feed cutoff.
Each opening through which residues discharge from the incinerator is through a water seal or a double-dump discharge device to prevent fugitive emissions at those openings. All the conveyors transporting the residues from the incinerator to the residue processing and handling area are enclosed. Slag from the afterburner and fly ash from the boiler are transported in closed containers to the residue processing area. In the residue processing area, dry residues are mixed with water to prevent dust generation during handling.
All vehicles delivering ELM and sewage sludge will be covered while transporting wastes to the facility (see Section II.3 for further discussion of transportation issues). The vehicles will be unloaded inside the ELM building, which will have a ventilation system designed to prevent PCB-contaminated dust from escaping. The fans in this building will exhaust through two three-stage high efficiency particulate air (HEPA) filters. Solid wastes will be held and processed in the incinerator bay building. The tipping floor area doors will be kept closed except during waste receiving. The combustion air for the incinerator will be drawn from the MSW tipping area to help prevent emissions of dust and odors from that area.
Only limited analytical data are available on the identity and concentration range of constituents, i.e., metals, volatile organic compounds, and semivolatile organic compounds, present in the ELM waste (see Waste Characterization section); similar information for the MSW and sewage sludge waste feeds was not presented in the permit applications.
In the Application for an Air Quality Permit, Westinghouse estimated the emissions from the incinerators based on the emissions testing data, incinerator design, and permit limitations of MSW incinerators worldwide. The contribution of constituents in the ELM due to the industrial wastes that were disposed in the old landfills and analytical data on constituents in Bloomington sewage sludge did not appear to be considered in the estimation of incinerator emissions.
The application acknowledged the presence of many metals and metallic compounds in the ELM waste and sewage sludge but did not provide data on their identity and concentrations (Westinghouse, 1991c). Westinghouse suggested that achieving 0.012 gr/dscf PM-10 in the stack gas will indicate that all metals in the waste feeds will be sufficiently removed and comply with EPA air program regulations. There is conflicting data on the mercury removal efficiency of the combination of SDA and FF proposed for this facility. Test data have shown average mercury removal efficiencies ranging from 0 to 95 for SDA/FF systems. In the December 1990 background information document, EPA summarized test data from two municipal waste combustors with SDA/FF systems and concluded that the systems had negligible mercury removal efficiency.
Westinghouse used four EPA air dispersion models and the assumptions, meteorological data, and protocols specified by the Indiana air program to estimate the maximum ground level concentration of hazardous constituents projected to be present in the incinerator stack emissions. Five years' worth of hourly meteorological data (1982 through 1986) were used in the models. Westinghouse calculated the ambient concentrations at a fairly standard array of receptor locations in all directions out to a distance of 15 kilometers from the incinerator. Ten more receptors were added to determine the specific concentrations at locations where sensitive receptors might exist. Those receptors were at Sanders Elementary Middle School, Bachelor Middle School, Bloomington courthouse, Bloomington Hospital, Lake View Elementary School, Monroe County Airport, Smithville School, Bloomington High School, St. Charles School, and Indiana University. The maximum ambient air concentration did not occur at any of the 10 sensitive receptor locations. The maximum annual average concentration at ground level (the dispersion coefficient) calculated using the EPA models was 0.0867 micrograms of chemical per cubic meter of ambient air per gram per second (g/m3/g/sec) of that chemical in the stack emissions. Section 6 of the Application for an Air Quality Permit contains a detailed discussion of the modelling that Westinghouse conducted.
Table 12 summarizes the maximum emissions of various constituents listed in the Westinghouse permit applications and the
maximum projected annual average ground level concentrations of those constituents. The available health comparison
values, which will be defined and discussed in the next section, Public Health Considerations of Incineration, are also
included. The permit application included only the ambient air concentration for some constituents.
| TABLE 12 MAXIMUM EMISSIONS AND MAXIMUM AMBIENT AIR CONCENTRATIONS1 RESULTING FROM PROPOSED BLOOMINGTON INCINERATORS | ||||
| Contaminants of Concern | Emission Rate (lbs/hr) |
Ambient Air Conc.2 (µg/m3) |
Comparison Values3 (µg/m3) | |
| Antimony | 0.0008 | none | ||
| Barium | 0.000009 | none | ||
| Lead | 0.016 | 0.0002 | 1.5 3 mo.avg. |
NAAQS4 |
| Mercury | 0.26 | 0.0030 | 0.06 | Chronic EMEG (metallic) |
| Silver | 0.000008 | none | ||
| Thallium | 0.0002 | none | ||
| Arsenic | 0.000017 | 0.0002 | CREG (inorganic) | |
| Beryllium | 1.1x10-6 | 1.2x10-08 | 0.004 | CREG |
| Cadmium | 0.000056 | 0.02 0.0006 |
Chronic EMEG CREG | |
| Chromium (VI) | 0.000071 | 0.02 0.00008 |
Chronic EMEG CREG | |
| Hydrogen chloride (HCl) | 7 | 0.07 (Annual) |
7 | RfC |
| 41 (3 min) |
none | |||
| Particulate Matter (PM) | 6 | 0.057 (0.066) |
none | |
| PM-10 (< 10 microns) | 5 | 0.05 | none | |
| Sulfur dioxide (SO2) | 47 (3 hr) 14 (24 hr) |
0.13 | 80 | NAAQS |
| Nitrogen oxides (as NO2) | 51 | 0.6 | 100 | NAAQS |
| Benzo-a-pyrene | 0.0013 | 0.000013 | none | |
| Chloroform | 0.0071 | 0.000066 | 0.04 | CREG |
| Dibenzofuran | 2.8x10-8 | none | ||
| PCBs | 0.00054 | 5.0x10-6 | 1.0x10-3 | (See note 5) |
| 2,3,7,8-TCDD | 1.6x10-8 | 1.5x10-10 | 3.03x10-8 | (See note 6) |
| 2,3,7,8-TCDF | 7.3x10-8 | 6.7x10-10 | 3.03x10-7 | (See note 7) |
| Carbon monoxide | 21 | 0.23 | 10,000 (8 hr avg.) |
NAAQS |
| Fluorides (as HF) | 0.3 (1 hr) | 0.003 | none | |
| Sulfuric Acid (H2SO4) | 2.2 (1 hr) | 0.024 | none | |
| PCDD/PCDF8 | 5.3x10-6 | 2.8x10-8 | none | |
| 1 Based on maximum annual average ground level concentration predicted by modelling of emissions at 100% load to both incinerator trains 2 Numbers in () are values calculated by ATSDR, based on other Westinghouse numbers given in table 3 EMEG = Environmental Media Evaluation Guide (ATSDR) CREG = Cancer Risk Evaluation Guide for 1x10-6 excess cancer risk (ATSDR) RfC = Reference Concentration (EPA) 4 NAAQS = National Ambient Air Quality Standards, health-based standards established by EPA under Clean Air Act 5 Background level in a remote, undeveloped area (Eisenreich, 1981) 6 Most conservative state regulation: Kansas one-year regulation 7 Based upon TEF for 2,3,7,8-TCDF of 0.1 compared to 2,3,7,8-TCDD; TCDF = Tetrachlorodibenzofuran; TCDD = Tetrachlorodibenzodioxin; TEF = toxicity equivalent factor8 Polychlorinated dibenzodioxins and polychlorinated dibenzofurans | ||||
The TSCA/RCRA Incinerator Permit Application (Volume 2: Attachments D-5-1 through Section L) outlines the Westinghouse Contingency Plan for the incinerator facility and incineration operations. The RCRA Landfill Permit Application (Volume 7: Attachment E-3 through Reporting and Record Keeping) outlines the plan for the ash landfill facility and the landfilling operations. Overall, the plans include appropriate contingencies for on-site workers. As discussed in other portions of this Incineration section, on-site personnel will receive training on the following: routine maintenance inspection procedures, incinerator emergency operation procedures, preparedness and prevention procedures, and evacuation procedures. The designated emergency response coordinators will receive additional training in notification procedures. Personnel involved with the landfill operation are also required to take training on these procedures. Neither of the plans discussed contingencies for off-site workers or communities. On the basis of ATSDR's review, the following considerations should be added to both the contingency plans:
Each Bloomington PCB site that will undergo excavation will have individual worker health and safety plans and contingency plans. The comments above on the incinerator and landfill contingency plans will also be applicable to each PCB excavation area.
The Bloomington incinerator site is located in Monroe County, Indiana, slightly more than 50 miles southwest of Indianapolis. The site is about 7 miles southwest of the city of Bloomington in a rural area of Monroe County. Tables 13 and 14 contain site-area data from the 1990 Census of Population and Housing. The 5-mile area covers roughly 40 square miles and encompasses the areas potentially affected by the proposed incinerator. The site area includes the two census block groups that are immediately adjacent to the site. Data for Monroe County are included to provide a point of context.
The census figures for the 5-mile area and the site area are quite similar and generally do not differ substantially from those for the county. The location of a nursing home in the site area explains the relatively high percentage of persons aged 65 and older in the population. The percentages of those under age 10 and aged 65 and older are both relatively low for the county because of the presence of Indiana University in Bloomington (i.e., there is an excess of persons from ages 18 to 24, which lowers the percentages for other age groups).
More than three-quarters of residences in both areas are owner-occupied. Those percentages are relatively high and are
typical of areas with stable populations, because homeowners tend to move much less frequently than do renters. Many of
the area residents are likely to have lived in their current households for a number of years.
| TABLE 13 SITE AREA POPULATION DATA | |||
| Variables | 5-Mile Area | Site Area | Monroe County |
| Total Persons | 8,146 | 1,496 | 108,978 |
| Total Area, Square Miles | 40.55 | 7.09 | 394.38 |
| Persons per Square Mile | 198 | 211 | 276 |
| Percent Male | 50.1 | 48.8 | 48.3 |
| Percent Female | 49.9 | 51.2 | 51.7 |
| Percent White | 98.4 | 98.4 | 94.3 |
| Percent Black | 0.5 | 0.6 | 2.6 |
| Percent American Indian, Eskimo, or Aleut | 0.3 | 0.2 | 0.2 |
| Percent Asian or Pacific Islander | 0.5 | 0.5 | 2.5 |
| Percent Other Races | 0.3 | 0.3 | 0.4 |
| Percent Hispanic Origin | 0.7 | 0.7 | 1.3 |
| Percent Under Age 10 | 14.9 | 14.4 | 10.6 |
| Percent Age 65 and Older | 11.2 | 17.1 | 8.5 |
| Source: Census of Population and Housing, 1990: Summary Tape File 1A (Indiana) (machine-readable data files). Prepared by the Bureau of the Census. Washington, DC: The Bureau (producer and distributor), 1991. | |||
| TABLE 14 SITE AREA HOUSING DATA | |||
| Variables | 5-Mile Area | Site Area | Monroe County |
| Households* | 3,137 | 531 | 39,351 |
| Persons per Household | 2.56 | 2.61 | 2.39 |
| Percent Households Owner-Occupied | 77.6 | 82.1 | 54.8 |
| Percent Households Renter-Occupied | 22.4 | 17.9 | 45.2 |
| Percent Households Mobile Homes | 18.0 | 9.4 | 8.9 |
| Percent Persons Living in Group Quarters* | 1.4 | 7.5 | 13.9 |
| Median Value, Owner-Occupied Households, $ | 61,000 | 64,000 | 66,600 |
| Median Monthly Rent, Renter-Occupied Households, $ | 257 | 317 | 339 |
| * A household is an occupied housing unit but does not include group quarters such as military barracks, prisons, nursing
homes, and college dormitories.
Source: Census of Population and Housing, 1990: Summary Tape File 1A (Indiana) (machine-readable data files). Prepared by the Bureau of the Census. Washington, DC: The Bureau (producer and distributor), 1991. | |||
G. Public Health Considerations of Incineration
For traditional public health assessments of environmental contamination, public health implications are determined by an iterative process involving the use of contaminant-specific environmental data and health comparison standards, the determination of completed pathways of exposure, and the evaluation of toxicologic, epidemiologic, and community concerns data. Few data are documented in the scientific literature on specific interactions of the contaminants released from waste incinerators (Johnson, 1994b). ATSDR completed one health study and has several health studies in process in communities around several incinerators (ATSDR, 1994). A search of scientific literature yielded few other data. Given that this section addresses potential public health issues associated with a proposed technology rather than with actual environmental contamination, and that few data on health effects of incinerator emissions are available, a different process has been adopted. Three distinct approaches to describing public health considerations of the proposed incinerator are used. First, a relevant case study involving human exposures to a PCB incinerator was identified by a literature search. This case study is presented, and its relevance is evaluated in terms of potential issues of human exposure associated with the proposed incinerator. Second, a brief consideration of potential contaminants of concern is provided. And third, a public health overview of the proposed incinerator design, along with other information included in the application, is discussed relative to existing ATSDR guidance on evaluating public health implications of incinerators.
On-site workers involved with the operation or maintenance of a facility often experience the greatest exposure to contaminants from the facility. Review of the literature identified a National Institute for Occupational Safety and Health (NIOSH) health hazard evaluation that evaluated public health implications associated with occupational exposures at a PCB incineration facility (Singal and Roper, 1988).
The health hazard evaluation was conducted at a 6-year old commercial incinerator used for the combustion of hazardous waste, including large volumes of PCBs, that employed approximately 275 people. The wastes were received at the "kiln dock," where PCB capacitors and other solids were unloaded, put through a shredder, and then placed in a high-temperature rotary kiln. A ram-feed system was used to inject plastic drums of flammable liquid organic wastes into the incinerator. At the exit of the rotary kiln, residual solids (metal and ash) dropped into 55-gallon drums. Thermal oxidation units downstream from the rotary kiln maintained the temperature required for the complete combustion of PCBs. Via a closed system, liquid PCBs were pumped from the storage tanks and injected directly into the oxidation units. The flue gas went through the scrubber, which removed the hydrochloric acid formed in the combustion unit. The combustion products (CO2 and H2O) were discharged to the atmosphere through a small stack. Review of PCB environmental data collected by the plant showed 3 strata of exposure, with the highest exposures occurring at the kiln dock (where ambient air values ranged from 3 to 408 micrograms per cubic meter [µg/m3], with the majority of samples being 50 µg/m3 or greater).
The health hazard evaluation included an environmental evaluation and a medical survey (physical examination and sera testing). All 41 air samples collected had quantifiable levels of PCBs, ranging from .85 to 40 g/m3. Levels were highest at the kiln dock. All but one sample exceeded the NIOSH-recommended exposure limit of 1 µg/m3. The 56 surface sample wipes all had quantifiable levels of PCBs, with the majority of the samples from high-contact surfaces (e.g., attended machinery, control panels, and workbenches) exceeding 100 micrograms per square meter. Serum PCB levels of workers ranged from 2 to 385 parts per billion (ppb), with a mean of 62 ppb. Forty workers (49%) had serum PCB levels of 20 ppb or greater, and 16 (18%) had levels of 100 ppb or greater. Inverse correlations of serum PCB levels with age were statistically significant, but PCB levels did not correlate with duration of employment at the facility or time in current job.
This case study of the public health implications of a single PCB incinerator demonstrates that this remediation technology can create areas where PCB exposure can occur and can cause actual exposure of workers to PCBs. This case study did not evaluate the specific causes for the widespread contamination throughout the facility. However, it seems likely that this contamination could have resulted from both incinerator fugitive emissions and material handling. There appeared to be several steps in the incineration process that did not occur totally in a closed system and could have resulted in fugitive emissions. For example, the "ash drag" step occurred at the exit side of the rotary kiln, where residual solids (metal and ash) drop out of the system into 55-gallon drums for collection. Contamination found on workers' clothing, loading dock floors, and transfer areas indicated material handling problems. NIOSH recommendations for reduction of occupational exposures included improving contamination control, expanding decontamination strategies and facilities, restricting personnel access to PCB-handling areas, continuous monitoring of work areas for PCBs in the air and on work surfaces, and better safe workpractice education and enforcement by supervisory and safety personnel.
Lessons learned from this case study about potential public health implications of a PCB incinerator can be applied to information available from the incinerator applications for the Bloomington sites. Fugitive emissions should be minimized to below levels of health concern through the use of contamination control technologies. Most of the proposed incinerator process is within an enclosed or negative pressure system. The air pollution control equipment for the proposed incinerators will include continuous emission monitors. The FF baghouse will remove particulate matter from the flue gases.
Specific methods should address handling of contaminated material in ways that will minimize direct exposures to workers and releases into the environment. The Westinghouse application includes descriptions of ventilation and exhaust systems for the buildings where materials will be unloaded, of doors designed to prevent material handling emissions and odors, and of plans for remotely operated equipment to handle the ELM wastes. However, the proposed incinerator has a primary combustion chamber that is typically used for burning municipal wastes and that includes webbing that allows siftings to fall through. Consequently, there is concern that the contaminated soils and sediments could fall through the webbing before the materials have been decontaminated and might therefore have to be reincinerated several times to meet the treatment standards set by EPA and the state. This repetition would mean that the workers handling these contaminated wastes multiple times might experience increased exposure to PCBs and the other contaminants present in the wastes.
The TSCA/RCRA Incinerator Permit Application addresses decontamination only of trucks that haul ELM waste before they leave the incinerator facility and emergency equipment used in spill cleanup (Westinghouse, July 1991b). It does not address routine decontamination of the facilities and personnel.
The proposed incinerators would include continuous stack emission monitoring systems that should be able to detect releases of some contaminants at levels of health concern. Hydrocarbon monitors in the stacks could provide additional warning of process upsets and potential releases of PICs.
Employees at the incinerator would receive training on required personal protective equipment, decontamination procedures, visual and audible emergency alarm systems, and inspection of all major pieces of incinerator and emergency equipment.
The incinerator applications address many of the case study issues that directly affect public health considerations. The case study also points out the need for additional information on several topics if Westinghouse should decide to proceed with construction of the incineration facility.
2. Potential Contaminants of Concern
Contaminants of concern are the site-specific chemical substances that health assessors select for further evaluation of potential health effects. Identification of contaminants of concern involves evaluating actual contaminant concentrations at the site, assessing the quality of these environmental data, and determining the potential for human exposure. This process was followed to identify site-specific contaminants of concern for the six consent decree PCB sites in the Bloomington area and is discussed in Volume I (Final Report: Preliminary Data Evaluation and Pathway Analyses Report for Consent Decree PCB Sites) under the Environmental Contamination and Other Hazards section for each site.
Westinghouse was required to include estimates of the possible stack emissions in its permit applications (see Table 12). The estimates reflect information in a database of emissions from MSW incinerators. The estimates of organic emissions derived from that database might be conservative for chemicals generally found in MSW stack emissions for two reasons: (1) MSW incinerators typically do not operate their ABCs at temperatures as high as those proposed for the Bloomington incinerators, and (2) old MSW incinerators usually operate their APC equipment in the temperature range that is believed to promote the post-combustion formation of dioxins and furans. However, the estimates of organic compounds, metals, and halogens might not be conservative for the proposed incinerators because the old landfills that are to be remediated contain industrial wastes, including Westinghouse's PCB wastes, as well as MSW, and Westinghouse did not address their contribution to the stack emissions.
Since there is limited data on the metal concentrations or the concentrations of organics other than PCBs in the landfills (see Waste Characterization section), it is not possible to say what the total public health implications are for the two proposed Bloomington incinerators. However, we discuss the potential public health implications of the emissions should EPA and Indiana place permit conditions on the facility that limit emissions to those in the Westinghouse permit applications.
The contaminants and expected concentrations estimated to be in the emissions from the incinerator are summarized in Table 12. Eleven of the 25 contaminants listed in Table 12 do not have existing health comparison values. In traditional public health assessments, where contaminants actually exist at measured concentrations but for which no health comparison values exist, contaminants without health comparison values are selected for further evaluation in the pathways analysis. Consequently, if the incinerator is built, it might be important to include a determination of the concentrations of these contaminants in the test burns and initial ambient air monitoring. This information is necessary for any future public health evaluation involving pathway analysis and toxicologic evaluation.
Ten of the remaining 14 contaminants have ATSDR health screening values (mercury; arsenic; beryllium; cadmium; chromium; hydrogen chloride; chloroform; PCBs; 2,3,7,8-TCDD; and 2,3,7,8-TCDF) and 4 (lead, sulfur dioxide, nitrogen oxide, and carbon monoxide) have national ambient air quality standards, which are health values established by EPA under the Clean Air Act. None of these contaminants have estimated concentrations that exceed their respective comparison values. In a traditional health assessment, based simply on these estimated concentrations, these contaminants would not be selected as contaminants of concern for further consideration in the Pathway Analyses section and Toxicologic Evaluation subsection. However, it is important to emphasize that the expected concentrations are only estimates to be expected under ideal operating conditions for the proposed incinerators. Further consideration should be given to whether actual concentrations of all of these contaminants should be determined during the trial burns and initial air monitoring.
Another factor used to select contaminants of concern is community concern related to a particular chemical. PCBs constitute the primary contaminant of community concern for remediation by the proposed incinerator. As part of ATSDR's Bloomington PCB Project, ATSDR assembled a group of health experts to discuss and summarize health issues associated with PCBs (ATSDR, 1994). This group concluded that the potential health effects from exposure to PCBs is a complex subject. While considerable research has been done in this area, there is much that remains unknown or uncertain, and new research on this subject continues to expand our knowledge about the toxicity of these chemicals. Cancer has been a major focus of health research on PCBs to date. Experiments have shown that PCB mixtures with elevated concentrations of chlorine are carcinogenic in laboratory animals. However, studies of humans exposed to PCBs have been equivocal and inconclusive with respect to cancer. Public health concerns about adverse reproductive and developmental outcomes caused by PCB exposure have been increasing over the last few years. Other changes (such as chloracne) described in previous studies of PCB-exposed workers are less important for populations with environmental exposures. However, other health concerns related to PCB exposure, including immunological effects and neurological effects, require further study.
3. Public Health Overview of the Proposed Incinerators
The data that impede an accurate assessment of the public health impact of incineration can be divided into two categories--those associated with the technology and the facility itself and those related to environmental health (Johnson, 1994a). ATSDR developed the document Public Health Overview of Incineration as a Means To Destroy Hazardous Wastes (ATSDR, 1992) to provide guidance for addressing potential public health issues involving Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) incinerators. The nine key items that ATSDR considers when evaluating CERCLA incinerators are listed below in bold print, along with brief descriptions of how the proposal for the incinerator addresses these items.
Historically, incinerators have been effective in decontaminating PCB-contaminated materials. They are capable of remediating areas contaminated with organic wastes to levels that are protective of public health. Typically, the decontaminated soils can be returned to the area, and the public can use the area safely after remediation has occurred. The Bloomington CERCLA sites, however, are not just collections of contaminated soils, sediments, and sludges that are typical of other CERCLA sites where incineration has been used for remediation. There are PCB-contaminated sludges at the Winston-Thomas Sewage Treatment Plant, contaminated stream sediments in the Interim Storage building (and possibly more to be excavated), and contaminated soils from all the landfill sites. However, there is also a substantial volume of contaminated municipal and industrial wastes buried in the five landfills. Westinghouse proposes to use the City of Bloomington's municipal waste as the fuel for the primary combustion chamber to burn the Dillman Road Sewage Treatment Plant sludges as well as the old PCB-contaminated municipal wastes and sewage sludges. Incinerators have been used for a number of years to treat MSW, sewage sludges, and industrial wastes separately; however, ATSDR staff members are not aware of any other incinerator that has burned this combination of wastes (ATSDR, 1994). Generally, incinerators are designed differently for each of these different types of wastes. ATSDR staff members are not aware of cases where sewage sludge or contaminated soils have been incinerated in a facility with a primary combustion chamber such as the one proposed to be built in Bloomington. The proposed technology is not proven to be appropriate for the materials to be burned. Data to determine whether the proposed design will result in an incinerator that will treat the PCB-contaminated soils and sludges adequately are not available.
In selecting a site for a CERCLA incinerator, proximity to residential and other populations and local meteorologic conditions is considered to ensure that the location minimizes prevailing wind transport of air emissions to affected populations.
When a dense residential population is in proximity to industrial facilities such as incinerators, the number of people who might be potentially exposed to emissions from the facility is increased (Johnson, 1994a). The site selected is in a sparsely populated area on the outskirts of Bloomington. The facility design includes a number of features that should control fugitive emissions from the waste unloading areas and the residuals handling areas. Therefore, we do not anticipate that nearby residents will experience any public health effects from fugitive emissions at this site provided proper operational procedures are instituted.
Recognized, acceptable, and when possible, EPA-approved air modeling is used to help screen and identify potentially impacted areas.
The Westinghouse permit applications used four EPA air dispersion models and the assumptions, meteorological data, and protocols specified by the Indiana air program to estimate the maximum ground level concentration of hazardous constituents projected to be present in the incinerator stack emissions. Ten receptor populations were selected to determine the specific concentrations at locations where sensitive populations might exist. The predicted maximum ambient air concentrations did not occur at any of these locations (Westinghouse, 1991c).
Trial burns, with appropriate stack sampling and analysis, and subsequent continuous emissions monitoring are conducted to demonstrate that the incinerator performs as specified.
The permit applications include the provision for both trial burns and continuous emissions monitoring. This is particularly important, since waste characterization is not sufficient to predict the incinerator's emissions. The ABC, which is designed to have residence time of more than 4 seconds at temperatures above 2,000F, and the APC equipment and its operating temperatures and procedures appear to be designed to minimize the organic and halogen species in the stack gases. The APC equipment as designed appears to be capable of minimizing emissions of metals with the possible exception of mercury. However, without knowing the concentration of the various metals in all the waste feeds, it is not possible to estimate the levels of metals emissions or to say whether they will be below levels of public health concern. Because the combination of wastes under consideration has not been burned before under similar conditions, it is not possible to estimate the stack emissions and their potential public health impacts accurately. If the consent decree parties decide to incinerate the ELM wastes, we recommend that they perform additional analysis of the waste feeds before construction of the facility and conduct an evaluation of stack emissions from a pilot-scale facility.
Adequate training is provided to incinerator operators to ensure that the incinerator is operated in a manner that does not adversely affect the operators' or the community's health.
Westinghouse has outlined in the TSCA/RCRA Incinerator Permit Application an employee training program that should prepare employees to operate the incinerator facility and handle emergencies appropriately. Proper operation of the incinerators on a continuous basis as well as during emergencies is critical to preventing or minimizing public health effects from incinerators. The employees are to be trained in the procedures outlined in the Contingency Plan so they will know what to do in an emergency. They will also receive training on the Preparedness and Prevention Procedures for the facility. These procedures include discussions of personnel protection equipment to be worn by employees entering the ELM processing room; the double door system to prevent fugitive emissions during unloading of ELM waste; washing empty ELM trucks before leaving the ELM processing building; visual and audible emergency alarm systems; detailed inspection schedules for all the major pieces of equipment related to the incinerator, residue handling, and ELM waste processing and transfer facilities; and inspection of all the emergency equipment and supplies.
An active inspection program is instituted.
Proposed criteria for the training of operators and employees include the establishment of and compliance with detailed inspection schedules for all equipment and facilities pertaining to the incinerator (Westinghouse, July 1991b).
Where the incinerator must be at a site close to neighboring populations, local ambient air monitors are used to detect possible site releases to the air requiring corrective or emergency action.
The permit applications for the Bloomington incinerators facility do not address monitoring of ambient air. Perimeter air monitors could be installed to ensure that on-site employees and the employees at the Dillman Road Sewage Treatment Plant (the closest neighbor) are not exposed to fugitive or stack emissions or both at levels of health concern. It is also advisable to install air monitoring stations in other nearby residential neighborhoods to determine whether the ground level emissions projected by the modelling are exceeded to the extent that concentrations reach levels of public health concern.
Proper management of residual ash is part of the design and operation of the incinerator.
The residuals from the incinerators are to be transported in closed containers for disposal in a landfill designed for hazardous waste. If Westinghouse employees ensure that the containers are properly sealed before the trucks leave the incinerator facility and there are no traffic accidents, no public exposure would occur, and the transportation of the residuals should not affect public health adversely. ATSDR staff members have not reviewed the landfill design or operating procedures, so we are unable to comment on the potential for public health impacts from that facility. The consent decree parties are considering remedial options other than incineration and landfilling of residuals for the ELM wastes. If in the future the decision is made to go back to the original plan of incineration and burial of the residuals, ATSDR can at that time, if needed, evaluate the potential public health impacts of the landfill operation.
Procedures consistent with the community right-to-know philosophy are instituted.
The consent decree parties are reevaluating each of the Bloomington area PCB sites and options for remediating the sites. They are holding public meetings to involve the public in the site remediation selection process. We anticipate that the consent decree parties will continue this openness and involve the public throughout the permitting and operating phases of the project.
Public health assessments report and address concerns that community members living near hazardous waste sites have shared with ATSDR. Community concerns are collected in various ways, most often through such one-on-one meetings as public availability sessions, which offer community members the opportunity to speak individually with ATSDR staff members.
At a February 18, 1993, public availability session in Bloomington, Indiana, ATSDR and Indiana State Department of Health (ISDH) staff members learned that members of the community had numerous health concerns, primarily related to exposures to PCB contamination in the Bloomington area. ISDH addressed those concerns in the Community Health Concerns Evaluation subsection of Volume I of this public health assessment.
In addition, there was a high level of community concern regarding the proposed use of incineration as the selected remediation alternative. This document is intended to respond to those specific questions about potential public health implications of the incineration process. It also contains ATSDR's evaluation of public health considerations concerning other possible remediation technologies.
Additional opportunities for receiving community concerns will be available during the public comment period of this public health assessment. ATSDR will conduct public availability sessions to receive additional community concerns related to public health considerations of remedial treatment technologies. The final version of the public health assessment will address any comments received.
ATSDR will also solicit comments on the Proceedings of the Expert Panel Workshop To Evaluate the Public Health Implications of the Treatment and Disposal of Polychlorinated Biphenyls-Contaminated Waste that was conducted in Bloomington September 13-14, 1993. Any comments received will be addressed in the final draft of that document. However, because that document was not intended to evaluate Bloomington site-specific concerns, any site-specific comments or concerns received during the public comment period for that document will also be addressed in the final version of this public health assessment. ATSDR will address all comments and concerns that are received during the availability sessions and public comment periods.
ATSDR is aware of the following community concern related to remedial technologies:
What are the public health implications of leaving the PCB contamination in place?
Contaminant migration to the groundwater and landfill leachate discharges to surface waters are the primary potential public health concerns. The landfill caps and fences that were installed as interim measures should temporarily prevent any direct contact with PCB-contaminated soil or other contaminated municipal or industrial solid waste. However, the long-term effectiveness and integrity of the present containment systems are questionable, since those facilities do not meet the current standards that would be required for a modern state-of-the-art landfill or other containment remedy.
Additional contaminant releases could occur if erosion of the present cap occurs. Contamination could spread through surface runoff or through air releases caused by blowing particulates, landfill gas, or volatilization of contaminants. Although the PCB contamination triggered the investigation and interim remedial actions at the Bloomington sites, any final remedial alternative will need to evaluate the potential releases of other contaminants (municipal/industrial or hazardous waste) that might have been disposed at those sites.
The Final Report: Preliminary Data Evaluation and Pathway Analyses Report for Consent Degree PCB Sites, dated April 1994 and prepared by the ISDH, evaluates available data on a site-specific basis for each of the consent degree sites for current and future potential public health exposures, assuming no further remedial activity. For additional site-specific information from the ISDH document, please see pages 27 to 36 (Anderson Road Landfill), pages 38 to 49 (Bennett Stone Quarry), pages 51 to 71 (Lemon Lane Landfill), pages 73 to 82 (Neal's Dump), pages 84 to 108 (Neal's Landfill), and pages 111 to 128 (Winston-Thomas Facility).
As part of this Agency's commitment to evaluate the public health impacts of the Bloomington sites, ATSDR is available to review the environmental data developed for the evaluation and selection of a remedial technology, including long-term storage options. ATSDR is available to work with EPA to develop any information that is needed to identify and address potential public health implications.
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