The hydrocarbon deposits of the Trenton Limestone Group of Indiana and Ohio (formed during the Ordovician period) were heavily exploited during the late nineteenth century. Few precautions were observed in closing and sealing the early gas and oil wells of the Trenton Field, so a potential exists for modern arsenic and sulfate groundwater contamination. An examination of Indiana State Board of Health well tests for cities throughout Indiana reveals slightly higher but not dangerous arsenic and sulfur concentrations in groundwater within the Trenton Field area. The locations of these higher levels suggest that the Trenton Field is only indirectly responsible for the contamination; rather, the probable cause may lie with the industrialization that was based upon the gas and oil supplies. An unusual combination of high arsenic, sulfate, and pH levels was found in two adjacent cities, Decatur and Portland. As Portland falls within the Trenton Field area but Decatur lies outside, this anomaly warrants further investigation.
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Copyright © 2001 by Vickie West.