Oil production, agriculture, and groundwater quality in the southeastern Gulf Coast Aquifer, Texas.

Associations between groundwater quality and land use were evaluated in the southeastern Gulf Coast Aquifer, Texas. Data from 19234 oil/gas wells and 256 water wells were mapped with a geographic information system (GIS) and statistically analyzed. Water wells near oil/gas wells had significantly higher levels of chloride, bromide, and total dissolved solids (TDS). Bromide-chloride ratios were also higher at water wells near oil/gas wells. Shallower water wells had significantly higher chloride, bromide, TDS, and nitrate concentrations. Nitrate concentrations were higher beneath cropland compared to other land uses. Results of this study suggest that oil/gas production and agriculture have impacted water quality in the Gulf Coast Aquifer.