PCBs in sealants. in water distribution reservoirs. Disposal of PCB-laden caulking material turned into a headache for East Bay MUD.

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1 PCBs in sealants in water distribution reservoirs Disposal of PCB-laden caulking material turned into a headache for East Bay MUD. Richard G. Sykes and Alex R. Coate E In a routine response to taste and odor complaints, the East Bay Municipal Utility District (EBMUD) drained and cleaned a 65-milgal reinforced-concrete reservoir used to store treated water. The polysulfide caulking material used to seal joints between floor panels was in poor condition and required replacement. The deteriorated caulking was analyzed to determine whether it would require special handling before disposal. Analyses indicated that the caulking contained about 20 percent polychlorinated biphenyls (PCBs). Tests confirmed that the caulk did not pose a threat to drinking water quality; however, it was inappropriately released to a nearby drainage course, thus contaminating soils. EBMUD is completing a $2-million remediation and restoration of the drainage course and is investigating PCBs in sealants in all its distribution system reservoirs. Unless disposed of properly, the PCB-laden sealants pose a tremendous liability for EBMUD and for other water utilities with similar facilities. ast Bay Municipal Utility District (EBMUD) supplies drinking water to about 1.2 million people in Oakland, Berkeley, and 33 other communities east of San Francisco Bay in California. The treatedwater distribution system includes 178 reservoirs installed between 1884 and Over 108 years, reservoirs both lined and covered open-cut structures have been built of redwood, welded and riveted steel, and reinforced concrete. The capacity of these reservoirs ranges from less than 100,000 gal to more than 150 mil gal. EBMUD drains Dunsmuir Reservoir In August 1992, the growth of algae in one of EBMUD s largest reservoirs, Dunsmuir Reservoir, was determined to be the source of taste and odor problems for customers in the local service area. Dunsmuir Reservoir is a dual-basin reinforcedconcrete box reservoir with a capacity of about 96 JOURNAL AWWA

2 Joints between the concrete floor panels of the Dunsmuir Reservoir, the interior of which is shown here, were sealed with a caulking material that was later found to contain PCBs. 65 mil gal 29 mil gal in the North Basin and 36 mil gal in the South Basin. When the reservoir was built in 1968, the joints between the concrete floor panels were sealed with a polysulfide caulking material widely used in potable water facilities during the 1960s and 1970s. Figure 1 shows the Dunsmuir Reservoir layout. During three weeks in late August and early September 1992, EBMUD drained about 25 mil gal from the North Basin and washed sediments from the reservoir floor. All drainage and wash water was discharged via a drain line and energy dissipator to a nearby drainage course commonly called Dunsmuir Creek. This drainage course flows through the Dunsmuir House and Gardens estate, a California-designated historic site and a federally designated national historic monument. The drainage course eventually enters San Leandro Creek, which flows into San Francisco Bay. After washdown was completed, an inspection of the reservoir s interior revealed that the joint caulking, having cracked and rippled, required replacement. In December 1992, EBMUD staff members analyzed a sample of the caulking material to determine whether any special handling would be required for disposal. The results of that sampling indicated that the caulk contained percent (150, ,000 mg/kg) of polychlorinated biphenyls (PCBs). In consultation with the California Department of Health Services, EBMUD collected water samples from the South Basin, which was still in service, to determine whether the caulk was affecting the drinking water. Sampling in late December 1992 and January 1993 did not detect PCBs above a detection limit of 0.1 µg/l. Subsequent sampling for PCBs in the distribution system at 12 locations for six months confirmed the absence of PCBs in the drinking water. Despite the determination that there was no threat to public health, EBMUD removed the South Basin from service in January 1993 as a precaution. From March to July 1993, the North Basin was sandblasted and rehabilitated. Old caulking material The Dunsmuir Reservoir incident alerts water suppliers that reservoir construction materials may result in environmental effects unrelated to water quality. PHOTOS: KAREN PREUSS and spent abrasive blast media were disposed of as hazardous wastes. The North Basin was refilled, tested, and returned to service July 15, Draining of the South Basin began immediately thereafter. During rehabilitation of both basins, the contractor was required to comply with all hazardous material regulations. In July 1993, the South Basin washdown proceeded just as with the North Basin, and again wash APRIL

3 water was discharged to the drainage course. However, after the South Basin was drained and about one third of the sediment on the basin floor was washed down and discharged to the drainage course, work was halted because of concerns about high turbidity in the discharged water. Problems were compounded by the absence of a defined plan of action for addressing environmental and public health hazards posed by the caulking material. PCBs found in reservoir sediments In August and September 1993, EBMUD collected several sediment samples from the reservoir and Dunsmuir Creek drainage course. Sampling results indicated the presence of PCBs in the reservoir sediments at about 1.0 mg/l. PCBs in the drainage course ranged from <1.0 to 500 mg/l; the highest concentrations were closest to the discharge point. On identifying PCBs in the drainage course, EBMUD immediately notified the five local regulatory agencies but inadvertently failed to contact the California Department of Fish and Game (CDFG). CDFG, a key agency providing oversight for the investigation and remedial activities, should have been included earlier in the proceedings. EBMUD also hired a consultant to assess and remediate the contamination. Between Sept. 29, 1993, and Feb. 25, 1994, about 2,100 tons of soil were excavated along 2,000 lin ft of the drainage course. This material was sampled, analyzed, and disposed of in an appropriate waste-disposal facility. Samples were then collected at more than 600 locations in the drainage course. The PCB concentrations of these samples averaged 0.16 mg/l. For soils, the preliminary remediation goal should generally be 1.0 mg/l for sites in residential areas. 1 A risk assessment prepared for the potential PCB exposure in the drainage course confirmed that postremediation PCB concentrations provided appropriate public health protection. Concurrent with the site cleanup, a drainage course restoration plan was submitted for review and approval to the US Army Corps of Engineers, the CDFG, and the nonprofit organization that manages the Dunsmuir House and Gardens. Grading and revegetation of the drainage course, designed according to initial comments from these agencies, were completed in November Monitoring and reporting on the effectiveness of the restoration actions will continue for at least five years. Costs for remediation FIGURE 1 Layout of Dunsmuir Reservoir and drainage course (1 in. = about 250 ft) MacArthur Freeway (I-580) EBMUD property line Underground facilities South Basin North Basin FLOW Reservoir drain line Energy dissipator Dunsmuir house and gardens Drainage course ( Dunsmuir Creek ) N 98 JOURNAL AWWA

4 Wash water discharged to a drainage course contained high concentrations of PCBs, necessitating soil removal as far as 2,000 ft downstream. and restoration will exceed $2 million. These costs could have been avoided if there had been an understanding of the threat posed by the deteriorated caulking material and an appropriate strategy had been developed for responding to that threat. PCBs widely used from 1950s to 1970s PCBs were first produced commercially in PCBs are compounds consisting of carbon, chlorine, and hydrogen atoms that can exist in a large number of variations. They are chemically inert and fire-resistant. PCBs were widely used in the 1950s, 1960s, and 1970s in electrical equipment, hydraulic fluids, heat-exchange fluids, metal-working fluids, inks, dyes, coatings, lubricants, fluorescent light ballasts, carbonless copy paper, adhesives, and caulking compounds. For more than 40 years, the use of PCBs for electrical fluids was required by building safety codes in most high-rise buildings, schools, and hospitals where risk of fire or explosion was a major concern. An estimated 1.2 bil lb of PCBs were produced in the United States. 2 4 In the late 1960s and early 1970s, PCBs were found to be widespread in the environment. They were detected in meat, eggs, milk, and cereal, and they were shown to accumulate in fish, wildlife, and humans. 5 On the basis of the widespread presence of PCBs, a 1968 PCB poisoning incident in Japan, and studies correlating PCB consumption with tumors in rats, production of PCBs was banned in 1976 in the Toxic Substances Control Act (TSCA 40CFR 761). 4,5 Additional regulations were imposed in the 1980s by the US Environmental Protection Agency (USEPA). TSCA and subsequent regulations focused primarily on the removal of electrical capacitors and transformers containing PCBs. PCBs can accumulate in the environment and harm some animals and aquatic life. A reversible skin disorder in humans, known as chloracne, can be caused by prolonged dermal contact with PCBs. Acute and chronic exposure can also cause liver damage. Generally, the toxic effects depend on the degree of chlorination in the PCB compound. 3,5 The general public perceives PCBs as extremely dangerous, although the potency for one highly chlorinated compound has been revised downward and some of the less chlorinated varieties have been found not to cause cancer in humans with high chronic exposure. 4,5 PCBs are identified as a hazardous chemical under the Occupational Safety and Health Administration Hazard Communication Standard (29 CFR Part ) and are listed by the International Agency for Research on Cancer as an animal carcinogen. The USEPA considers PCBs to be a potential human carcinogen. 3,6 EBMUD working to prevent repeat of problem EBMUD has learned a number of valuable lessons from the Dunsmuir Reservoir incident. It has taken strong measures to ensure against the occurrence of similar events, thereby protecting the public, EBMUD employees, and the environment. EBMUD employees did not recognize the environmental threat associated with the caulking, because no one anticipated that PCBs would be present in the reservoir construction materials. In addition, communication within EBMUD and between EBMUD and regulatory agencies was poor. Problems were compounded by the absence of a defined plan of action for addressing environmental and public health hazards posed by the caulking material. After reviewing the chronology of events and available data, EBMUD determined that the primary source of PCBs in Dunsmuir Creek was particulate caulk dislodged during rehabilitation and washdown. Because of poor handling and disposal practices, these PCBs were inappropriately released to the drainage course. It did not appear that normal reservoir drain- APRIL

5 ing and filling activity would result in PCB accumulation in reservoir water or sediment. The Dunsmuir Reservoir incident alerts water suppliers that reservoir construction materials may result in environmental effects unrelated to water quality. EBMUD has initiated a number of activities aimed at preventing a repeat of the Dunsmuir Reservoir incident at its other treated water reservoirs. A reservoir materials investigation is currently under way. Initially, this investigation included a review of specifications, drawings, and construction records for all 178 EBMUD distribution reservoirs to determine which ones might contain PCBs in construction materials. This research identified 84 reservoirs with materials potentially containing PCBs. These materials were identified as mastic, polysulfide, butyl, and EPDM, an elastomer made from ethylene propylene diene monomer. Another 21 reservoirs contain asphalt panel liners or are sealed with latex and oil or latex and asphalt panels. No analytical data are available to determine whether these materials contain PCBs. The remaining 73 reservoirs are not suspected of containing PCBs; they were built with sealants known to be PCB-free (e.g., polyurethane) or were built without the use of sealants or liners (steel and redwood tanks). EBMUD has begun the second step of the reservoir investigation, a sampling and analysis program to quantify the PCBs in suspected reservoirs. This program has been broadened to include evaluation of the potential threats to water quality or the environment by other construction materials e.g., asbestos, coal tar, and asphalt. Samples of coatings and sealants are being collected and analyzed for PCBs and inorganic compounds using modified procedures for evaluating the leachability of hazardous materials specified in California Title 22, Division 4.5, Chapter 11. Should the leachate from any compounds be found at concentrations considered hazardous according to Chapter 11 or exceeding 100 times the drinking water maximum contaminant level specified in Title 22, Division 4.0, Chapter 15, the drinking water also will be sampled for comparison with drinking water standards required by Chapter 15. This drinking water sampling will supplement EBMUD s existing, extensive program for monitoring the distribution system. Information from the investigations will be compiled, and risks will be assessed and ranked. Ultimately, a plan and schedule for rehabilitating any reservoirs found to contain PCBs or other hazardous substances that exceed Title 22 trigger levels will be prepared and carried out after regulatory agency review. Until an appropriate rehabilitation plan is completed, EBMUD must continue to use its reservoirs and to drain and clean them as necessary to ensure delivery of high-quality water. To these ends, a pilot study is being conducted to establish appropriately protective procedures for draining and cleaning reservoirs that may contain PCBs or other hazardous materials and to evaluate filtration systems to remove PCBs from reservoir sediments. Conclusion PCBs in reservoir construction materials present an enormous potential liability for some water suppliers. A large concrete reservoir like EBMUD s Dunsmuir Reservoir could contain tons of PCBs. For EBMUD, it does not appear that PCBs in sealants present a significant threat to the quality of drinking water. However, preventive measures must be taken so PCBs are not released to the environment during reservoir cleaning or rehabilitation. The potential for threats to the public health and the environment can increase if this material is dispersed into creeks, waterways, or other areas. Remediation of the contamination from a single reservoir could cost millions of dollars. Early identification of this potential problem and an appropriate reservoir management and rehabilitation plan are essential to protect public and environmental health and to respond costeffectively to this threat. References 1. USEPA. Guidance on Remedial Actions for Superfund Sites With PCB Contamination. Office of Solid Waste Emergency Response, Directive US Environmental Protection Agency, Washington, D.C. (Aug. 1990). 2. PCB Backgrounder. Monsanto Company, St. Louis, Mo. (July 1990). 3. SITTIG, M. Handbook of Toxic and Hazardous Chemicals and Carcinogens. Noyes Publications, Park Ridge, N.J. (2nd ed., 1985). 4. PCBs: Is the Cure Worth the Cost? American Council on Science and Health, New York (Apr. 1989). 5. KIMBROUGH, R.D. Polychlorinated Biphenyls: How Do They Affect Human Health? Health and Envir. Digest, 2:7 (Aug. 1988). 6. Material Safety Data Sheet for Polychlorinated Biphenyls. Monsanto Company, St. Louis, Mo. (Oct. 1988). About the authors: Richard G. Sykes is regulatory manager for East Bay Municipal Utility District (EBMUD), th St., Oakland, CA Sykes, who has 11 years of experience in the environmental engineering field, has been with EBMUD nearly six years and previously worked as a consulting engineer. He has a BA in English, a BS in resource studies and environmental science, and an MS in environmental engineering, all from the University of California at Berkeley. A member of AWWA and the California Water Pollution Control Association, he has published his work previously in JOURNAL AWWA and received AWWA s 1990 Education Division Award for the best paper. Alex R. Coate is environmental compliance manager at EBMUD. 100 JOURNAL AWWA