UNDERGROUND HYDROCARBON PIPELINES IN THE UNITED STATES, AND THEIR RELATIONSHIP TO THE CONCENTRATION OF ARSENIC IN GROUNDWATER

Abstract

This is a study of USA pipelines and their contributions to the observed arsenic concentrations found in groundwater. A non-toxic species of the element arsenic, arsenate (AsO4)3+, which is found in abundance in rocks and soils, can reduce to the toxic arsenite (AsO3)3+, e.g., through the intermediary of arsenate-reducing bacteria. H2 gas, which is produced by way of cathodic protection of natural gas pipelines, is an alternative reducing agent that is made available in high abundance through anthropogenic activity. Natural gas pipelines in central New Jersey and eastern Pennsylvania utilize cathodic protection and traverse arsenate bearing bedrock. Over the next few years, more natural-gas transmission pipelines will be built through this region, which will increase the potential to mobilize arsenic (either via leakage or by cathodic protection). In this study, I use geospatial data on the locations and types of US pipelines, and published laboratory data on the concentrations of arsenic in wells and springs, to investigate whether the distance to pipelines is correlated with the concentration of arsenic at the measurement points. I find that arsenic concentrations are higher in samples taken close to pipelines and decrease as the distance increases, however, the rate at which these concentrations decrease and the range of said concentrations vary state-by-state.