Polychlorinated biphenyls option

While industrial practice requires a trial burn and a facility may not operate until the data are accepted, industrial facilities obtain approval to process many different waste streams based on a single trial burn. In special situations, particularly with toxic materials such as polychlorinated biphenyls, both a surrogate burn and a trial burn would be required. RCRA regulations offer the option of allowing the use of data from another facility, under certain conditions, in lieu of a trial burn. However, industry has used this mechanism at only a few sites with similar units. It has been used twice by the CMA for the Tooele, Utah, disposal facility. The CMA should pursue this mechanism with the respective regulatory authorities. The committee believes that chemical agent disposal facilities are treated similarly to industrial facilities with respect to the conduct of trial bums. 

Problems that have been solved in the risk assessment of single substances have not been solved equally well in mixture assessments. Even the most generic question in prospective risk analyses— What is a safe level —poses problems. Often the mixture composition is unknown, and the mixture problem is then that the safe level would only be applicable to that particular mixture. Even if the mixture composition is well characterized, the safe exposure or concentration level would apply only to mixtures with the same or similar concentration ratios between the mixture compounds, as in cigarette smoke, diesel exhaust, or some polychlorinated biphenyl (PCB) mixtures. One option in such cases is to set a safe level for the mixture by using one of the mixture components as an indicator compound for the whole mixture. If the concentration ratios between the mixture compounds vary, there is no unique safe mixture concentration, but an infinite number of possible safe concentration combinations. 

Hunt, G. T, P. Wolf, and P. F. Fennely. 1984. Incineration of Polychlorinated Biphenyls in High-Efficiency Boilers A Viable Disposal Option, Environmental Science and Technology, vol. 18, pp. 171-179. 

Abstract. Polychlorinated biphenyl (PCB) can be destroyed in a variety of ways. Currently, for PCB concentrations >500 mg/kg, incineration at an ANNEX I (or equivalent) facility is generally the only EPA approved method. There are additional options for destruction of liquids containing PCB at concentrations <500 mg/kg. Use of a high-efficiency boiler is an attractive option. Also, EPA has selectively approved chemical dechlorination for PCB concentrations <1%. 

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