Investigation of polychlorinated biphenyls (PCBs) in natural gas pipelines and distribution systems in Wisconsin

Abstract

Between January 28 and February 9, 1981, the Department of Natural Resources collected and analyzed 25 samples of oil from the state's natural gas pipeline supply and distribution system. Twenty-three samples were negative for PCB contamination at detection limits ranging from 1 to 50 mg/kg (p.p.m.). Two samples showed low level PCB contamination, quantified at 10 and 24 mg/kg respectively. Both positive samples were below the hazardous level (defined as 50 mg/kg (p.p.m.) or higher by federal regulations). Both positive samples were oil condensates collected from scrubbers designed to remove contaminants from the natural gas stream. The two scrubbers which yielded positive samples are located on major incoming pipelines that enter Wisconsin from the west and south. They are the first such scrubbers within the state boundary, so contaminants removed at these points came from a source(s) outside the state. This, plus the fact that all lubricating oils used at natural gas compressor stations within the state were negative for PCB, strongly suggests that we do not have a PCB problem in the natural gas distribution system within the state. Rather, the trace amounts identified at 2 peripheral locations on the system suggest out-of-state origin, probably residuals from isolated use of PCB-based lubricants some time in the past at compressor stations upstream from our state boundary. Sampling strategy, analysis, and interpretation of results are discussed in greater detail in the following text. The Wisconsin Department of Natural Resources was asked to provide assistance by the the U.S. Environmental Protection Agency, in determining whether a PCB problem existed in the state's natural gas supply and distribution system. The Department has checked lubricating oils used at all compressor stations in the state, and has checked oil condensates from selected gate stations and community distribution systems in Wisconsin. Only 2 of the 25 samples were positive for PCBs, and in both cases, the levels were below the hazardous level defined by federal regulation. Based on these findings, Wisconsin does not have a PCB contamination problem in its natural gas supply and distribution system. The evidence collected during this study suggests that the trace amounts of PCB identified at two peripheral locations on the system originated outside the state. It is recommended that the companies whose pipelines produced PCB-contaminated scrubber condensates pursue the source of this contamination by thoroughly testing lubricants and scrubber condensates from compressor stations and filter stations located upstream from the Wisconsin border. Specifically, the Department would like monitoring results from: