Emerging Issue of Polychlorinated Biphenyls in Radioactive Waste

Mark F. Marcus, Ph.D., Fluor Hanford, Analytical Services, P.O. Box 1000, G1-32, Richland, Washington

The environmental focus of cleanup action has been centered around the U.S. Environmental Protection Agency (EPA) Resource Conservation Recovery Act (RCRA) requirements. Recent studies have indicated that polychlorinated biphenyls (PCB) may also become an issue with some of our waste streams. This may then invoke EPA Toxic Substance Control Act (TSCA) requirements in addition to EPA RCRA.

PCB were mass-produced in the United States (U.S.) from 1930 to 1977. They were a key functional fluid for industry because of a unique set of properties which included higher heat transfer, flame proof, stable, high dielectric, excellent lubricating and cutting oils. Over one billion pounds were produced for U.S. use. These uses included transformer and capacitor oils, hydraulic fluids, cutting oil and fireproof paint. Because of these excellent properties, they were likely used in critical processes at Hanford.

The complexities of PCB are centered around the issue that there are 209 separate compounds, in various compositions of eight aroclor products. We are finding mixtures of two or three aroclors in recent samples that have been analyzed. Samples of water and solids with high activity backgrounds challenge the conventional regulatory methods. The desire to analyze at very low detection limits also drives the difficulty of this task.

The newest challenge may be to identify the coplanar tetrachlordibenzo dioxin (TCDD)-like congeners of PCBs. This is based on recent EPA toxicology work and is an indication that a select subset of the PCB modules is those of concern. These molecules are the coplanar congeners with specific chlorine substitutions. The base of this concern is structural similarity and believe similar activity to TCDD and tetrachlordibenzo furan (TCDF).

As waste materials are evaluated for disposal path, we should consider the potential issue that they may also contain PCBs. The different set of regulations and increasing concern around the potential toxicity of these material warrants this consideration.