PUBLIC HEALTH ASSESSMENT
BLOOMINGTON PCB SITES
BLOOMINGTON, MONROE COUNTY, INDIANA
SPENCER, OWEN COUNTY, INDIANA
The PCB-contaminated materials that are mixed with municipal and industrial landfill waste at the Bloomington Consent Decree sites represent a wide range of heterogenous waste streams that are difficult to characterize fully in terms of contaminants and concentrations to be treated, including PCBs. Therefore, on the basis of the available data, it is difficult to determine the public health implications of using incineration or non-incineration technologies for remediation of the Bloomington PCB sites. Without the engineering design, operating plans, and results of site-specific treatability testing, we can evaluate the public health implications of non-incineration remedial technologies (NIRTs) only in general terms.
Fugitive emissions that are not properly monitored and controlled might pose a health threat to workers and nearby residents. Excavation and handling of contaminated media, including such preprocessing activities as blending, sizing, separating, shredding, and transportation, can be major sources of fugitive emissions of contaminants. Use of any of the ex situ (away from the original location) NIRTs for the Bloomington PCB landfill sites (except encapsulation technologies, such as landfilling, vaulting, and solidification) would require significant pretreatment to meet the material sizing requirements (less than one-eighth of an inch to a maximum of three-fourths of an inch, depending on the specific technology). This pretreatment would increase the likelihood of fugitive emissions.
If soil washing, solvent extraction, thermal desorption, or landfilling is selected as a treatment technology, further treatment of PCBs might be appropriate. These technologies do not destroy PCBs; except for landfilling, they concentrate PCBs. Non-incineration technologies other than bioremediation and solidification/stabilization require treatment or disposal of non-PCB byproducts and waste streams. Post-treatment waste streams and byproducts might create additional hazardous substance exposure potential for workers and the community.
The Westinghouse permit applications for the proposed Bloomington, Indiana, incineration facility appear to address many of the identified public health issues satisfactorily. However, it is not possible to predict all public health implications of the emissions from the proposed Bloomington incinerators because the proposed combination of wastes, i.e., municipal wastes; sewage treatment sludge; and PCB-contaminated soils, sediment, and excavated landfill material (ELM), has neither been sufficiently characterized nor previously treated in an incinerator. Few data on specific interactions of the contaminants released from waste incinerators are documented in the scientific literature. Almost all of our toxicologic data are from studies in which exposure levels greatly exceeded those typical of incinerator releases.
Information provided in the proposed incineration facility applications indicates that the estimated stack emission levels of contaminants would not reach levels of public health concern. However, there are few data to support those estimates. Better evaluation of the potential public health impacts of the stack emissions would require analysis of stack emissions from a full-scale or pilot-scale incinerator--similar to the proposed incinerator--that is incinerating the proposed combinations of wastes.
If the consent decree parties decide to proceed with incineration of the PCB-contaminated ELM, preliminary projections of the potential stack emissions would, at a minimum, require additional analysis of the waste feeds. The Waste Analysis Plan and Trial Burn Plan should then be revised to address additional constituents of public health concern and to provide for burning the maximum feed rate of PCBs that will be allowed in the facility permit. Protection of the off-site community, including first responder personnel and the public at large, is not addressed adequately in the existing contingency plans for the incineration facility and the ash landfill. Contingency plans for excavation and other activities at the individual PCB sites are not yet available.
ATSDR has recommended the following actions relative to technologies that might be used to remediate the Bloomington PCB sites:
1. Determine the potential public health implications if a non-incineration technology is selected for use at any of the Bloomington PCB sites. ATSDR is available to conduct a comprehensive review of the remediation design and operating plans and specifications of any non-incineration clean-up alternative proposed for implementation at the Bloomington sites. The Agency will work with representatives of EPA, the state of Indiana, the city of Bloomington, and the public to evaluate public health issues that might be associated with other specific remedial options.
2. Monitor and sample ambient air throughout the material handling and treatment processes to ensure that fugitive emission controls are effective.
3. Before building the proposed incinerator, test the planned combination of excavated landfill material, municipal solid wastes, and sewage sludge first in another similarly designed full-scale incinerator (if one exists) or at a pilot-scale facility to determine whether stable operating conditions are possible, what the stack emissions will be, and the concentrations of constituents of public health concern in the residuals.
4. Evaluate the preconstruction stack testing data for potential public health implications before construction of the facility.
5. Revise the Waste Analysis Plan and the Trial Burn Plan to address additional constituents of public health concern.
6. If the decision is made to dispose of the residuals in the proposed landfill in the Bloomington area, evaluate the landfill operating procedures for potential public health impacts from the management of ash and residuals.
7. Integrate on-site contingency plans more effectively with the local emergency contingency plans. Conduct preplanning and hold meetings with the first responder community and emergency medical care providers--including firefighters, hazardous materials teams, emergency medical technicians, and hospital emergency room physicians and nurses--to ensure that both on- and off-site personnel fully understand each group's training, capabilities, and responsibilities. Make the community aware of the possible site-related emergencies that would result in their notification and possible shelter-in-place or temporary relocation.
8. Revise the facility Contingency Plan to address the six items listed in Volume II, Section V.E. of this PHA.
9. If funds are available, ATSDR should conduct or fund health studies of potentially affected residents before and after remediation of the six consent decree sites to evaluate the public health implications of the selected remedial technology or technologies.
This document responds to a request from Sen. Richard Lugar and Rep. Frank McCloskey for an evaluation of possible public health implications of a proposed incineration system and of public health considerations of other feasible treatment technology alternatives. This volume of the Public Health Assessment (PHA) for Bloomington PCB Sites examines public health issues regarding the selection and implementation of a remediation technology including excavation and transportation, waste characterization, an assessment of feasible non-incineration remedial technologies, a review of the proposed incineration facility, and community concerns related to site remediation.
During the years 1958 through 1977, Bloomington was the location of a large manufacturer of electrical capacitors containing polychlorinated biphenyls (PCBs). PCBs entered the environment when capacitors not meeting manufacturer's specifications and containing PCB fluids were hauled to and discarded in local landfills, limestone quarries, and dumps. PCBs also entered the environment at elevated levels via the discharge of contaminated fluids into the city sewer system, which resulted in the contamination of the Winston-Thomas Sewage Treatment Plant and the creek adjacent to it.
The consent decree for these sites requires that the approximately 650,000 cubic yards of PCB-contaminated soil and material from six sites be remediated. See the Introduction in Volume I for additional information about the consent decree. The first phase of the consent decree required removal and remedial measures to contain the six sites until the extensive excavation of PCB-contaminated materials begins. The second phase of the consent decree involves the permitting, construction, and operation of a municipal solid waste-fueled, high temperature incinerator that will incinerate the PCB-contaminated materials from all six consent decree sites. In the spring of 1994, all parties to the consent degree agreed to reevaluate the Bloomington sites to identify site-specific data gaps, remediation needs, and alternatives to using incineration as the method of remediation.
Environmental sampling/waste characterization has several different purposes and many different uses. For any hazardous waste site, sampling is conducted (1) to evaluate public health impact; (2) to determine the extent and mobility of the contamination in the environment; (3) to identify the most appropriate technology to remediate the contamination; (4) to ensure that the technology is designed for the site-specific situation; (5) to assure that, while the technology is in operation, it is not producing emissions or byproducts that affect public health adversely; (6) to assess worker health and safety; and (7) to ensure that the site has been adequately remediated.
The PCB-contaminated material at the six Bloomington sites is difficult to characterize. Most of the material (estimated volume of 650,000 cubic yards) is mixed with other landfill wastes. The sites have received an assortment of municipal, commercial, and industrial wastes. Food wastes; paper; cardboard; plastics; textiles; leather; yard wastes; wood; glass; tin cans; aluminum; other metals; leaves; consumer electronics; white goods (stoves, refrigerators, dishwashers, and clothes washers and dryers and commercial and industrial appliances); batteries; oil; tires; household hazardous wastes; construction debris, such as wood, steel, concrete, and dirt; agricultural wastes; industrial process wastes (from light and heavy manufacturing and from fabrication and chemical plants); and water and wastewater sludges might have been deposited at the facilities.
A local manufacturing company's electrical capacitors that did not meet quality control specifications were discarded at five landfills in Monroe County. PCBs were used as dielectric insulating fluids in those capacitors and were not drained before the disposal of the capacitors. The types of landfill waste material listed above are likely mixed with the PCB-contaminated waste. Some portions of the landfills might contain very high concentrations of PCBs, while other areas might have little or no contamination present.
Interim remedial measures have been taken at each of the landfill sites. Exposed capacitors and stained soils at certain locations have been removed and taken to the Interim Storage Facility. Many of the capacitors and related parts have been disposed of at an off-site incinerator. Although some post-remedial samples have been taken, they might not indicate the extent of the remaining PCB contamination. The samples indicate a range from non-detect to 22 parts per million (ppm) total PCB concentration. The samples did not identify concentrations of heavy metals or other organic compounds. It is difficult to characterize fully any landfill matrix (mixture of wastes). For example, core sampling might indicate the concentration of a discrete batch of non-PCB-contaminated waste material that was deposited at that location, which could yield a non-detect upon analysis for PCBs. Similarly, a sample might also indicate that an intact capacitor was penetrated during the boring operation for the sample collection process, yielding an extremely high concentration of PCBs. Neither sample could be used to determine an average representative concentration of the PCB-contaminated material. Because there was no known consistent distribution of industrial wastes and PCB-contaminated material in the landfills, it is unlikely that core sampling and analysis information would be helpful in the remedy-selection process. Sampling during any excavation and pretreatment activities would assess the waste characteristics and treatment requirements better and more practically. In addition, sampling during excavation and treatment is required to ensure the protection of worker health.
The landfill matrix represents a wide range of heterogenous (different) waste streams. The PCB-contaminated material might include heavy metals, flammable materials, oil and grease, or other hazardous organic compounds that could interfere with the operation of a system designed primarily for PCB treatment. Most hazardous waste treatment systems are better able to treat a fairly uniform waste stream in a homogeneous (uniform) matrix.
The PCB-contaminated material at the Winston-Thomas Treatment Plant could represent a more homogenous matrix. Soil-boring at the on-site abandoned lagoon showed total PCBs ranging from less than 1 to 290 ppm. The tertiary lagoon sludge samples showed ranges from 119 to 2,400 ppm.
The Interim Storage Facility includes excavated material from the Anderson Road Landfill and sediment from the adjacent pond, along with sediments from stream sites designated for cleanup. Table 1 indicates the estimated quantities of the remaining materials to be removed at the five other PCB sites. Current concentrations of PCBs and other contaminants that might be present in the Interim Storage Facility are not available. Additional sampling would help characterize the material in the Interim Storage Facility. The concentrations of contaminants at the storage facility might be representative of those found at other area landfills.
It is difficult to characterize PCB contamination in such wide-ranging matrices as those found at the Bloomington sites.
Because the performance and effectiveness of PCB remediation treatment systems might be influenced by concentration and
matrix, it is likely that extensive treatability and pilot testing would be needed before selection and implementation of a
treatment strategy. Once a technology is selected, the technology design, work plans and sampling plans should be shared
with public health agencies to ensure that public health is being protected.
| TABLE 1 SITE MATERIALS TO BE REMOVED* | |||
| Site (ranked by priority) |
Estimated Quantity of Material for Excavation (yd3) |
Approximate Area for Excavation (acres) |
Material for Excavation and Removal |
| 1. Neal's Landfill | 320,000a | 17.6 | All solid waste; 2 ftb of soil below solid waste; up to 2,000 yd3 from 5 sinkholes |
| 2. Lemon Lane Landfill |
176,000a,c | 9.3 | All solid waste to approximate 1958 contour level; remaining material and soil to where PCBs are found at less than 50 ppm and then 3 ft below this level |
| 3. Bennett's Dump | 55,000a | 4.6 | All solid waste; 2 ftb of soil below solid waste; no large quarried limestone blocks |
| 4. Neal's Dump | 14,000 | 0.5 | All solid waste; 2 ftb of soil below solid waste |
| 5. Winston-Thomas Facility |
50,000 | 19.7 | Tertiary lagoon--all liquid and 6 inches of sludge and soil on bottom and sides; sludge drying beds--all sludge and 2 ft of soil below beds; abandoned lagoons--all sludge and 2 ft of soil below lagoons; digesters and piping--all sludge and flushing water; trickling-filter rock media--all loose organic material |
| a This volume includes the clay cap installed because of the Consent Degree b Or to bedrock, if less c Estimated minimum Source: Consent Degree; Engineering-Science (Atlanta, Georgia) and the Ralph M. Parsons Company (Pasadena, California). Waste Material Excavation; Transportation, Storage and Reprocessing-Bloomington Project: Phase I - Preliminary System Screening. February 1986. | |||
ATSDR public health assessors have found that excavation and handling of soils at some Superfund sites and waste loading and repackaging at some Resource Conservation and Recovery Act of 1976 (RCRA) facilities have caused the release of airborne contaminants, resulting in exposure of workers and/or nearby residents (ATSDR, 1992). Inhalation of airborne contaminants is the most likely route of exposure for off-site populations during excavation and waste-handling. A less likely exposure route could be incidental ingestion of contaminated particulate material (dust) that settled onto surfaces off site. Depending on the contaminant(s) and site safety practices, on-site workers could be exposed via inhalation, dermal contact, and ingestion.
PCBs appeared in several samples of air taken from the Bloomington area sites in the early 1980s, before interim actions
were taken. No PCBs were detected in samples taken around the perimeter of the Anderson Road Landfill from September
1986 through October 1987, before the landfill's excavation. No information on sampling locations and methodologies was
provided. PCBs and volatile organic compounds were not reported above detection limits (detection limits not provided)
during quarterly air sampling at the Winston-Thomas site from April 1988 to February 1993. Air sampling data was not
available for the Bennett Stone Quarry site. Tables 2 through 4 summarize findings of the PCB air sampling and analyses
conducted on and around the other Bloomington sites (ISDH, 1994).
| TABLE 2 PCB AMBIENT AIR SAMPLING FOR NEAL'S DUMP (Interim Action 12/83) | |||
| Date | Location | 8-hr. Low Volume (µg/m3) |
24-hr. High Volume (µg/m3) |
| 6 to 7/83 | A (on-site hotspot) | 1 | 23 |
| B (on-site hotspot) | 61 | 61 | |
| Upwind off site | -- | 1 | |
| Downwind off site | -- | < 1 | |
| 7/84 | A (on-site former hotspot) | 1 | 3 |
| TABLE 3 PCB AMBIENT AIR & SOIL GAS SAMPLING FOR LEMON LANE LANDFILL (Interim Action 5/87-9/87) | |||
| Date | Location | 8-hr. Low Volume (µg/m3) |
24-hr. High Volume (µg/m3) |
| Ambient Air Sampling Before Interim Action | |||
| 6 to 7/83 | A (on site) | 30 - 89 | 43 - 45 |
| B (on site) | 60 - 194 | ND | |
| C (on site) | 6 - 20 | 13 - 34 | |
| 1 (downwind off site) |
NA | 0.3 - 1 | |
| 2 (downwind off site) |
NA | NA | |
| Upwind off site | < 1 | < 1 | |
| Soil Gas | |||
| 4/87 | 23 samples 15 locations |
ND | |
| Ambient Air Sampling During Interim Action | |||
| 6 to 9/87 | personal | 1 - 30 | |
| perimeter | 1 - 21 | ||
| µg/m3 = micrograms per cubic meter ND = not detected (detection limit not provided) NA = not analyzed | |||
| TABLE 4 PCB AMBIENT AIR SAMPLING FOR NEAL'S LANDFILL (Interim Action 12/83) | |||
| Sampling Location |
Type of Sampling |
Pre-Cleanup (1983) Concentration Range (µg/m3) |
Post-Cleanup (1985) Concentration Range (µg/m3) |
| A | 8-hr LV | 5 - 11 | 0.4 - 1 |
| 2 cm | 550 - 1050 | 2 - 3 | |
| 30 cm | 56 - 120 | 1 - 2 | |
| 60 cm | 30 - 49 | 0.9 - 1 | |
| 120 cm | 10 - 23 | 0.7 - 1 | |
| 180 cm | 6 - 13 | 0.4 - 0.6 | |
| C | 8-hr LV | 5 - 12 | 2 - 3 |
| 24-hr LV | 5 - 14 | 3 - 5 | |
| 2 cm | 941 - 1108 | 12 - 21 | |
| 30 cm | 111 - 157 | 4 - 6 | |
| 60 cm | 40 - 62 | 2 - 5 | |
| 120 cm | 15 - 21 | 2 - 3 | |
| 180 cm | 9 - 16 | 2 - 3 | |
| E | 8-hr LV | 7 - 18 | ND - < 0.04 |
| D-2 | 24-hr HV | 0.8 - 2 | 1 - 1.4 |
| D-3 | 24-hr HV | 0.8 - 2 | 0.8 - 1.2 |
| D-4 | 24-hr | 0.3 - 0.7 | 0.4 - 0.6 |
| U | 24-hr HV | 0.08 - 0.09 | 0.2 - 0.3 |
| µg/m3 = micrograms per cubic meter ND = not detected (detection limit not provided) LV = low volume air sampler cm = centimeters above the ground HV = high volume air sampler | |||
Results of air samples collected after interim actions were completed indicate that the interim measures reduced or eliminated PCB emissions into the air. If excavation or other activity removes or breaches the caps or covers, the opportunity for exposure will again be present. Excavation activities will disturb the soil and uncover contaminated areas, further increasing the potential for fugitive emissions from the sites.
Other contaminants might be present in old municipal waste landfills, as described in the waste characterization section, and might also become airborne via particulate transport or volatilization. The potential for off-site exposure to PCBs or other contaminants depends on the amount of contaminated material present, the location of the nearest receptor population, and the precautions in place to reduce or avoid air emissions. On-site workers could be exposed if they do not use proper personal protective equipment.
Excavation and handling of contaminated soils and other matrices can be conducted safely. Control measures that can be used include any or all of the following: dust suppression methods for particulate-borne contaminants (e.g., spraying and fogging); vapor suppression foam for volatile compounds; and building an enclosure over the area to be excavated and treating the exhaust air to remove contaminants. However, additional obstacles that could pose safety hazards and cause contamination of areas near the sites come along with these control measures. For example, using foam, water, or other liquid might result in slippery work conditions that could cause worker injury, work slowdown, or contaminant migration off site via water runoff. Safety hazards associated with excavation projects inside enclosures include temperature extremes, levels of airborne contaminants unsafe for workers (inhalation hazards along with flammable/explosive hazards), and visibility problems.
An air monitoring and air sampling program must be employed throughout the excavation and material handling process to ensure effective control of fugitive emissions. Ideally, air monitoring should provide real-time information on which to base decisions on whether work should be continued, stopped while additional emission suppression techniques are effected, or stopped completely while on-site personnel and/or nearby residents are relocated. Air sampling and subsequent laboratory analyses should be used to confirm the results of real-time sampling.
As discussed in the Waste Characterization section, old landfills that contain municipal and industrial wastes could contain a variety of solid and liquid wastes. Some of these wastes might pose a worker safety and health problem, and some might pose a public health concern. Excavation of these types of landfills might result in air releases of pressurized materials, venting of methane gas, fires, and explosions. Because there is limited information about most older landfills that contain municipal and industrial wastes, it is difficult to predict what materials will be encountered and determine what contaminants to monitor for in the air, and, therefore, to ensure that nearby communities will be safe.
B. Material Handling and Storage
Dry, dusty materials should be kept damp with a water spray or otherwise stored or enclosed in a manner that will prevent windborne transport of contaminated particulates. Wastes containing volatile organic compounds should be stored under conditions that safely collect and remove gases released from the wastes. Wet wastes or process effluents should be stored in chemically compatible, leak-resistant containers. Storage areas for such liquid-bearing materials should have dikes or be designed to contain leakage.
Preprocessing of wastes (e.g., blending, sizing, separating, and shredding) or post-treatment of waste streams and byproducts (e.g., quenching, stabilizing, further treatment on site, and preparation for transport off site), might cause releases of fugitive emissions. These emission sources should be adequately considered, and waste processing areas should be designed to minimize the potential exposure to workers on site as well as to people living or working nearby (ATSDR, 1992).
The application for the Bloomington incineration permit indicates that pretreatment will include material sizing (via shredding) to 2 inches (Westinghouse, 1991b). Other ex situ technology categories generally require material sizing prior to treatment as follows: dechlorination (one-fourth to one-half inch), soil washing (less than one-eighth inch), solvent extraction (less than one-fourth inch), and thermal desorption (one-fourth to two-thirds of an inch) (ATSDR, 1994). Although not specified in the Expert Panel Report, it is expected that sizing requirements for bioremediation and stabilization technologies would also fall within the one-eighth to three-fourths of an inch range. Fugitive air emission control requirements will most likely vary depending on the technologies used for screening, shredding, and sizing. As the size requirement decreases, the likelihood that there will be fugitive emissions increases. Moisture content and types of debris will also greatly impact the ability to size and process materials.
The means of transporting hazardous waste to the treatment facility should be carefully considered. Routes should be selected to minimize the potential for a traffic accident and a subsequent contaminant spill and should avoid residential and play areas if at all possible. Care is also needed to avoid spills and releases of contaminants during on-site transportation (ATSDR, 1992).
The application for the incineration permit includes discussions of primary and preferred or secondary haul routes and the identification of chosen routes for transporting waste material from each of the consent decree sites to the incinerator location (Westinghouse, 1991a). The individual haul routes from each site to the incinerator location were well researched; selection criteria included speed limit, road width, number and width of lanes, shoulder types and widths, side slopes, drainage features, and surface conditions. Also taken into consideration were surrounding population and property use (e.g., agricultural, commercial, or residential); future roadway improvements; estimated population increase; and likely subsequent construction. When locations with sensitive populations (e.g., day-care centers, schools, and recreational facilities) were found along primary and preferred routes, additional investigation was conducted before transportation routes were selected (Westinghouse, 1991a).
The application also specifies that there will be no transportation of waste material on roadways during peak traffic hours (generally between 6:30 and 8:30 am and between 4 and 6 pm). Daily haul schedules will minimize encounters with school buses, and haul drivers will be instructed to practice caution around school buses. The application also addresses vehicle maintenance (although no maintenance schedule is outlined), weather condition evaluation, and worker training (although no specific training course is outlined) (Westinghouse, 1991a).
Locations of the nearest firefighters, emergency medical technicians (EMTs), and hospitals have been identified. If a waste hauling vehicle accident or a waste material spill occurs, contingency plans will be implemented to mitigate further contaminant migration and to avoid human exposure to the waste material contaminants (Westinghouse, 1991a).
D. Waste Streams and Residuals
The same considerations for material handling and transportation as discussed for the Bloomington PCB-contaminated waste will be given to the residuals (ash) produced by the incinerators (Westinghouse, Sep 1991). Similarly, if a non-incineration remedial technology is selected, material handling considerations should be addressed for concentrated PCB end products, solvents, and other materials if they contain levels of contamination that are of public health concern.
IV. NON-INCINERATION REMEDIAL TECHNOLOGIES (NIRTs)
This section includes a brief description of each of the technology categories, general information on whether they have been used to treat PCB-contaminated media, and information on data that will be needed for accurate assessment of the potential public health impact of each technology category. Because site-specific technologies have not been selected for the Bloomington PCB sites, it is not possible to prepare site-specific discussions of each technology category. If, after revisiting a site, the consent decree parties select a non-incineration technology for remediation, ATSDR can help review the technology work plan and provide comments and recommendations to ensure public health protection. For additional information and references on the technology categories and on technologies within the categories, see the Non-Incineration Remedial Technologies section in the report Proceedings of the Expert Panel Workshop To Evaluate the Public Health Implications of the Treatment and Disposal of Polychlorinated Biphenyls-Contaminated Waste (ATSDR, 1994).
This technology category involves the use of microorganisms to degrade chlorinated organic chemicals. Bioremediation treatment can occur in situ, or the contaminated material can be excavated and treated ex situ. Refer to Section III of this report for a discussion of the possible public health impacts of excavating and handling contaminated media.
Sequential anaerobic-aerobic biological treatment appears to offer promise for treating PCB-contaminated material. The following soil and matrix characteristics might inhibit the effectiveness of the microbiological processes: (1) low bioavailability; (2) the presence of co-contaminants, such as heavy metals or oil and grease; (3) the presence of unknown compounds that are toxic or inhibitory to microorganisms; and (4) nutrient limitations. It is not generally possible to predict whether bioremediation can work effectively at a particular site. That determination requires treatability studies to determine whether microorganisms capable of dechlorinating and/or degrading the PCBs already exist in the waste material. It is also necessary to determine whether anaerobic dechlorination and/or aerobic degradation can occur in the waste matrix.
Data gaps for bioremediation typically include the need for identification of microorganisms capable of dechlorinating PCBs, limited volatile emissions data, a lack of data on the ranges of PCB concentrations that can be dechlorinated (although concentrations up to 5,000 milligrams per kilogram [mg/kg] of PCBs in sediment samples have been treated at bench scale), final end product concentrations based on performance history, established procedures to control the process, and estimates of treatment rates and costs. The bioremediation of PCBs has been extensively researched over the past 6 to 8 years; however, data from site-specific field applications are quite limited. To determine whether human exposures to hazardous substances could occur, emissions, residuals, and byproducts should be fully characterized during treatability studies, pilot-scale tests, and full-scale operations.
Chemical dechlorination technologies involve the destruction or transformation of PCBs by removing chlorine atoms from the PCB molecule. Certain processes in this treatment technology category have proven effective for dechlorination of PCBs in soils. No known applications of this technology category exist for PCB-contaminated municipal solid waste material or for sewage treatment sludges. It would be necessary to excavate all of the material to be treated, reduce its size (usually to around one-fourth to one-half inch) and suspend it in a liquid phase. Refer to Section II of this report for a discussion on the possible public health impacts of excavating and handling of the contaminated media.
Data gaps for the dechlorination technologies include air emission data, information on toxicity of any remaining chlorinated compounds, and performance history data. Without information on the potential for air emissions and residual contamination, it is not possible to predict possible human exposures to site- and process-related contaminants. To determine whether human exposures to hazardous substances could occur, emissions, residuals, and byproducts should be fully characterized during treatability studies, pilot-scale tests, and full-scale operations.
This technology category uses a water-based process that scrubs soils mechanically to remove contaminants. One process removes contaminants from soils and sediments by either dissolving or suspending them in the wash solution. Another process uses physical separation techniques to concentrate the contaminants by particle size. Soil washing concentrates contaminants and reduces their volume. It has potential for treatment of PCB-contaminated soils and sediments.
Because of the high levels of organic material (humic acid, organic carbon, etc.) in the sludges and municipal solid waste (MSW), soil washing might not be applicable. In addition, if the PCB-contaminated media in Bloomington consist of fine-grained soil or sediment or contain more than 30% silt or clay, soil washing might not be feasible, since the PCBs will bind to the organic material under those conditions. Soil washing is an ex situ treatment requiring excavation of the contaminated media. Pretreatment requires sizing to less than one-eighth of an inch. Refer to Section II of this report for a discussion of the possible public health impacts of excavating and handling the contaminated media.
The following data gaps that might affect public health have been identified for this technology category: air emissions data, performance history information, and the selection criteria for soil washing scavengers. Because this technology does not destroy the contaminant either on site or off site, treatment of the concentrated contaminant waste stream is required. Sampling and analyses of emissions, residuals, and byproducts should be performed during treatability studies, pilot-scale tests, and full-scale operations to evaluate the potential for human exposures to hazardous substances.
Like soil washing, solvent extraction concentrates the contaminant and reduces the volume of contaminated material. This technology uses solvents to extract contaminants from a matrix. Solvent extraction technologies have been used on a pilot scale; commercial-scale applications to treat PCB-contaminated soils should be available within the next few years. This technology is also applicable to sediments and some types of sludges. It is in commercial use for extracting PCB from oils, making it a good technology for cleaning transformers and capacitors. Solvent extraction becomes less efficient if the waste has any of the following characteristics: elevated levels of organic matter, too much moisture, and too high a concentration of volatile organic contaminants.
The contaminated material would require excavation. Pretreatment also requires reducing material size to less than one-fourth of an inch. Refer to Section II of this report for a discussion of the possible public health impacts of excavating and handling the contaminated media.
Data gaps that might affect public health include air emissions, performance history information, residual and byproduct characterization, and the selection criteria for solvents. Because this technology does not destroy the PCBs, it is necessary to treat the concentrated end product further. Sampling and analyses of emissions, residuals, and byproducts should be performed during treatability studies, pilot-scale tests, and full-scale operations to evaluate the potential for human exposures to hazardous substances.
Thermal desorption or thermal separation is a process that uses temperatures high enough to volatilize or vaporize organic compounds from contaminated media but not to destroy them. Thermal desorption, another contaminant concentration and volume reduction process, is available for commercial treatment of PCB-contaminated soils. The technology has been used to treat PCB-contaminated soil and sediment. It has not yet been proven for treatment of PCB-contaminated biological sludges, municipal solid waste, or PCB-contaminated capacitors. Too much moisture reduces the desorption efficiency. With proper treatability studies and pretreatment, thermal desorption might be applied to waste from municipal landfills.
All of the contaminated material would require excavation and reduction to one-fourth to three-fourths of an inch. See Section II of this report for a discussion on the possible public health impacts of excavating and handling the contaminated media. Additional characterization of the Bloomington PCB sites is necessary to determine whether the use of thermal desorption technologies is appropriate.
The most significant data gap is air emissions. Along with emissions, residuals and byproducts should be fully characterized during treatability studies, pilot-scale tests, and full-scale operations to evaluate the potential for human exposures to site- and process-related substances.
F. Solidification/Stabilization
Solidification/stabilization makes hazardous waste less soluble and less mobile. Solidification involves encapsulating waste into a solid material of high structural integrity. This process does not necessarily form a chemical bond between the solidification additive and the contaminant; it might form a mechanical bond. Stabilization chemically converts the contaminants to a less mobile, less soluble, or less toxic form. Cement, lime, and binders are examples of materials used as solidification/stabilization additives.
This technology is used to stabilize contaminated materials for acceptance into a landfill or for acceptance back to the site of excavation. The process increases the volume of contaminated materials 25% to 30%. Historically, solidification/stabilization has been used to treat metals and other inorganic compounds. With currently available technology, stabilization of inorganic compounds is generally more successful than stabilization of organic compounds.
The uncertainty of the effectiveness of the technology for contaminants in organic waste, including PCBs, is a data gap. Risks of contaminants leaching into the environment at very low levels still exist. The potential for leaching should be determined in a treatability study before pilot or full-scale implementation of this technology. Additional bench- and pilot-scale investigations are needed to determine the suitability of the technology for treatment of PCB-contaminated material.
Landfilling of PCB-contaminated material is regulated under the Toxic Substances Control Act (TSCA). Landfills must be authorized by the Environmental Protection Agency to receive PCB waste. One of the permitted facilities, located in Emelle, Alabama, is owned and operated by Chemical Waste Management Inc.; another landfill is in Model City, New York.
The following factors influence site selection for a landfill: (1) waste characteristics, (2) topography, (3) subsurface geology and hydrogeology, (4) site access, (5) land use, (6) environmental sensitivity, and (7) cost. Leachate and gas emissions create potential for contamination of air, surface soil, subsurface soil, and groundwater, among other media, if engineering controls are not provided. Therefore, some primary long-term considerations for landfills are the sufficiency and longevity of containment systems (flexible membrane liners, clay liners, etc.); leachate and gas collection and management systems; and monitoring.
Data gaps for landfilling and other land disposal or storage techniques include accessibility and geologic suitability of a proposed site, long-term performance data of the containment system(s), and possible leachate and air releases that might bypass or break through the contaminant collection systems.
H. General Considerations of NIRTs
Table 5, taken from the report Proceedings of the Expert Panel Workshop To Evaluate the Public Health Implications of the Treatment and Disposal of Polychlorinated Biphenyls-Contaminated Waste (ATSDR,1994), summarizes the stages of development of the various non-incineration technology categories with respect to the treatment of PCB-contaminated media. The table outlines the possible Bloomington PCB site non-incineration treatment options. For example, contaminated material associated with the Winston-Thomas site is categorized as sewage treatment sludge. Landfilling is the only proven non-incineration PCB treatment technology for this waste matrix. The table shows that solvent extraction works on a field or pilot scale, but it has not been used on a commercial or full-scale basis. PCB-contaminated media in the Anderson Road Landfill (now located in the Interim Storage Facility), Bennett Stone Quarry, Lemon Lane Landfill, Neal's Dump, and Neal's Landfill could contain soil, sediment, and municipal solid waste. Therefore, single or multiple technologies could be considered or necessary for treatment. Without more detailed site characterization and information on treatability and pilot-scale testing, this table should not be used as proof that a technology is applicable--or not applicable--to a Bloomington PCB site.
Table 6, also from the proceedings of the expert panel workshop, summarizes the general material handling or treatment
requirements of a non-incineration remedial technology category. Except for bioremediation, all treatment technologies that
have shown promise or have been proven to remediate PCBs require that the contaminated material be excavated. Except
for landfilling, all technologies require material sizing. The technologies under consideration usually require sizing materials
from less than one-eighth inch to a maximum of three-fourths of an inch, depending on the specific technology. Compared to
the 2-inch shredding requirement for incineration (see the Incineration section of this PHA), this is a significant pretreatment step.
| TABLE 5 NIRT TREATMENT CAPABILITIES OF DIFFERENT PCB-CONTAMINATED WASTE MATRICES | |||||
| Technology Category | Matrix | ||||
| Oil | Soil | Sediment | Municipal Solid Waste | Sewage Treatment Sludge | |
| Bioremediation | U | E | E | E | E |
| Dechlorination | P | A/P | E | U | U |
| Soil Washing | NA | A | E | N | N |
| Solvent Extraction | P | A | E | N | A |
| Thermal Desorption | NA | P | E | U | U |
| Solidification/Stabilization | N | E | U | U | U |
| Landfill | N | P | P | P | P |
| N = not generally feasible NA = not applicable U = unproven E = emerging technology (bench- or pilot-scale testing phase of development; performance data available) A = applied technology (field demonstration phase of development, additional performance data and cost data available) P = proven technology (technology developed to the point of commercialization) | |||||
| TABLE 6 NIRT PCB TREATMENT REQUIREMENTS | |||||
| Technology Category | Treatment Requirement | ||||
| In situ/Ex situ | Material Sizing | Other Pretreatment |
Post-Treatment (PCBs) |
Post-Treatment (Other) | |
| Bioremediation | I/E | Y (Ex situ) | M | N | N |
| Dechlorination | E | Y | N | N | M |
| Soil Washing | E | Y | N | Y | Y |
| Solvent Extraction | E | Y | N | Y | Y |
| Thermal Desorption | E | Y | M | Y | M |
| Solidification/Stabilization | I/E | Y | M | N | N |
| Landfill | I | N | N | Y | Y |
| I = in situ treatment E = ex situ treatment Y = yes N = no M = depends on waste matrix and process | |||||
If soil washing, solvent extraction, thermal desorption, or landfilling is selected as a treatment technology, further treatment of PCBs might be appropriate. These technologies do not destroy PCBs; except for landfilling, they concentrate PCBs. Non-incineration technologies other than bioremediation and solidification/stabilization require treatment or disposal of non-PCB byproducts and waste streams. Post-treatment waste streams and byproducts create additional hazardous substance exposure potential for workers and the community.
I. Public Health Considerations of NIRTs
Any or all of the technologies discussed might be applicable to several or all of the Bloomington PCB sites. If additional characterization of the sites occurs and a non-incineration remedial technology is selected, public health considerations can be better addressed at that time. It is not possible to determine public health implications of a technology without evaluating a minimum of the engineering design and the results of the treatability tests. Very few of the technologies have significant enough performance histories for treating PCB-contaminated matrices to allow ATSDR to predict the human exposure pathways or the contaminants of health concern. The same is true for the amount of available air sampling data. While many technology vendors report that air emissions are "below detection limits" or "insignificant," they do not report information about the sampling and analysis methodologies and the analytical detection limits. The information they present does not help to determine potential public health implications of a technology.
The most likely exposure routes that would result from use of any of the technologies would be the inhalation pathway and ingestion of or dermal contact with any residuals that might remain in the treated material. ATSDR is not implying that air emissions, byproducts, and residual contaminants that will occur with any of the technologies are necessarily of public health concern. The most significant sources of exposure might indeed be the excavation and the handling of the waste to be remediated. However, unless these potential hazards are considered and investigated from the treatability test through the full-scale operation, it will be impossible to determine the public health impacts of any of the remedial technologies.
The following table summarizes the key factors that ATSDR considers when evaluating a non-incineration remedial technology.
TABLE 7
SUMMARY OF PUBLIC HEALTH CONSIDERATIONS
FOR NON-INCINERATION REMEDIAL TECHNOLOGIES
