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LlVI CIIICIII vIl U:I !11 lllC /'IClU 1 Permitting approach is outlined in a recent article by Eugene Madsen in Environmental Science and Technology. Bioremediation for Madsen cites five types of evidence necessary to demonstrate in situ bioremediation of PCBs' PCB Disposal : Part 2 Commercial ' In situ recording of greater contaminant lasses from biodegradation than would be expected Operating from abiotic degradation Perm its • Assays with laboratory-incubated flasks demon- strating the presence of metabolically adapted microorganisms This is the second of two articles on permitting the bioremediation of polychlorinated i • In situ detection of unique microbial biphenvls (PCBs) under the Toxic Substances i metabolites Control Act (TSCA). The first, on research and development (R&D) permits, appeared in is- • In situ detection of increased protozoan popula- sue No. 6 of Bioremediation in the Field. I tions preying on contaminant-fed bacterial populations To obtain a commercial operating permit for the . In situ detection of decreased ratios of biode- bioremediation of PCBs, an applicant must prove that the process destroys PCBs as reliably as incin- eration without producing toxic bv-products or congeners emissions. To date, all of the permits issued by EPA Headquarters for the bioremediation of PCBs Madsen's method is rigorous, but rigor is needed have been for research and development; none to ensure that bioremediation has actually taken has been issued for commercial operation. None- Place, even for processes that appear to be theless, the Agency has been developing guide- effective. lines for the permitting procedure. The length of time required to permit bioremedia- tion for commercial operation has vet to be deter- mined. EPA Headquarters requires three EPA requires evidence that PCB successful runs before issuing a permit for a non- molecules have been biologically biological process. Because bioremediation is a degraded. lengthy process, three runs may not be a practical requirement for this technology. Instead, the Agency is considering requiring 3 years of suc- EPA will permit only processes that a company cessful research and development before issuing a can demonstrate to be effective—a threefold chal- commercial permit. EPA welcomes applications lenge. First, since the effectiveness of bioremedia- for R&D permits, which are usually issued for 1 tion varies widely from site to site, EPA requires year. This year may be seen as a trial period de- visual inspection of the site and laboratory stud- signed to demonstrate whether the technology ies to determine if the treatment is suitable for the will be commercially reliable in any situation at site in question. Second, since techniques that ap- anv site. pear promising in the lab may fail in the field, EPA EPA feels that the permitting process is justifiably further requires pilot-scale studies at the site. Fi- cautious because the technology for bioremedia- nall,v, once a technique has been shown to reduce tion of PCBs is still in its infancy. The public per- contaminant levels at the site, EPA requires evi- ceives bioremediation as a glamorous new dente that PCB molecules have been biologically technology that will soon solve hazardous waste degraded—not attenuated by nonbiological problems in sail, water, and air. Bioremediation processes. shows obvious promise, but if permitted proc- Determining the biological degradation of PCBs esses fail to perform, the public may become dis- illusioned with the entire bioremediation in soil is a complex undertaking, because PCB industry. molecules penetrate soil and can be sorbed, vola- tilized, transported, and attenuated by abiotic For more information on TSCA permitting for PCB reactions. EPA feels a conservative approach is disposal, contact Joan Blake of EI'A's Office of needed to make this determination_ One such Pollution Prevention and Toxics at 202-260-6236. 4