PCB-contaminated Sites

For many years, the EPA took the position that real property that is contaminated with polychlorinated biphenyls (PCBs) could not be sold unless the site was remediated. The EPA changed its interpretation in 2003 to permit the sale of PCB-contaminated real estate.  

The EPA s earher interpretation had relied on the statutory prohibition on distributing PCBs in commerce. The EPA s revised policy is not founded on any statutory analysis other than an assertion that the earher conclusion is not compeUed by the statute, and instead relies on the policy objective of not imposing barriers to economic redevelopment of real property and the recognition that its prior policy may have delayed cleanups. 

Contracts for the purchase and sale of businesses broadly address the same basic questions. All parties need to know in detail what is being transferred or merged, for what price, in what condition, and what happens if the business or assets are not in the promised condition. In addition, the parties need to consider what operational responsibihties each will have to the other after the Closing, if any, such as supply or service obhgations. TSCA requirements may play a role in deahng with some of these issues. 

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Leigh MB, P Prouzova, M Mackova, T Macek, DP Nagle, JS Fletcher (2006) Polychlorinated biphenyl (PCB)-degrading bacteria associated with trees in a PCB-contaminated site. Appl Environ Microbiol 72 2331-2342. 

It has become clear over the past ten years that the 1980s demonstration of anaerobic microbial dechlorination of PCBs is probably the most important discovery in the field of PCB biotransformations since Ahmed and Focht first demonstrated in 1973 that PCBs were biodegradable. Many new anaerobic microbial activities have been enriched and characterized from anaerobic fresh water and marine environments and heavily polluted industrial sediments. These anaerobic cultures are capable ofdechlorinating PCBs, thereby transforming highly chlorinated Aroclors to lower-chlorinated mixtures. This natural attenuation process is an important contributor to PCB degradation and detoxification in the environment and can form the basis for intrinsic remediation of many PCB-contaminated sites. 

When one considers the approaches that can be utilized to biologically treat PCB-contaminated sites, a hierarchy is apparent based upon ease of cleanup, time frame, and cost, and this hierarchy can be summarized as follows. 

The results from these and other laboratory studies have now led to the testing of various PCB bioremediation approaches in pilot demonstrations. The field trials are designed to demonstrate the applicability of field-scale treatment of soils, with the ultimate goal of commercial-scale bioremediation of PCB-contaminated sites, or demonstrated efficacy of intrinsic bioremediation. 

PCBs have been used as coolants and lubricants in transformers, capacitors, and other electrical equipment because they do not burn easily and are good insulators. The manufacture of PCBs was stopped in the United States in 1977 because of evidence that they build up in the environment and can cause harmful health effects. Cleanup of PCB-contaminated sites is an ongoing controversy. 

An ATSDR scientist provided one additional comment on Chapter 4, suggesting that ATSDR reconsider including discussions on specific clean-up levels for PCBs in soils (page 302), since some readers might infer that the listed levels should apply to all PCB-contaminated sites. If ATSDR retains the information on soil clean-up levels, one panelist recommended that the profile indicate the soil depth over which these levels apply. 

The principal direction of the published photochemical research to date has been to elucidate pathways which might be responsible for the degradation of these refractory substances in nature. This basic research has not been extensively applied either to on-or off site treatment of hazardous substances. In this chapter we extend the existing PCB photochemistry literature by considering this potential. The development and fabrication of a prototype surface photoreactor, and its preliminary evaluation at a PCB-contaminated site are described. Photochemical treatments may be applicable to many other classes of hazardous chemicals as well including the polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF) about which this monograph is chiefly concerned. 

Generally we can note that polychlorinated organic compounds like PCBs are very resistant to various bioremediation procedures and physical-chemical treatments are the most used for heavily contaminated sites. For remediation of PCB-contaminated sites the following technologies can be recommended. 

In humans, total PCB concentrations in maternal milk were elevated (> 1.1 mg/kg milk fat) in 4 of 122 cases in the New Bedford Harbor vicinity, Massachusetts. At least one female was occupationally exposed, as judged by the congener profile and history. PCB exposures from fish consumption were likely, but not from residence adjacent to a PCB-contaminated site. In all 4 cases, their newborns were full-term and healthy. 

The EPA had interpreted the ban on transferring PCBs to prohibit transferring PCB contaminated real property if the contamination occurred after the ban went into effect in 1978. The EPA had required the owners of PCB contaminated sites to clean up the sites and receive EPA s approval of the cleanup before the sites could be sold. In 2003 the EPA reversed its position and opined that the earher interpretation was not compelled by the statute. The EPA s reversal was based on two policy considerations, first, that a transfer would not affect the status quo of the PCB contamination and therefore would not increase risks posed by the PCBs, and second, that a prohibition on transfer unless a site is cleaned up could thwart the purchase of an ongoing business, resulting in loss of jobs. 

Fedi S, Carnevali M, Fava F, Andracchio A, Zappoli S, Zannoni D (2001) Polychlorinated biphenyl degradation activities and hybridization analyses of fifteen aerobic strains isolated from a PCB-contaminated site. Res Microbiol 152 583-592... 

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