A microbial and chemical water quality study of sixteen individual wells in rural southern Cochise County, Arizona

This paper is part of a larger water quality study for Arizona (Marrero-Ortiz et al., 2009) and looks more closely at 22 water samples from 16 wells less than 250 feet deep in rural areas of southern Cochise County, Arizona. Nine wells were positive for total coliforms, four wells tested positive for fecal coliforms and one well tested positive for Escherichia coli. Nine wells were positive for enterococci and 13 were positive for Aeromonas hydrophila, some with very high levels. Fourteen of 21 possible metals were detected. All 16 wells contained barium. Ten wells were above limits for at least one primary contaminant (e.g., uranium or coliforms). Nine of the wells exceeded safe limits for at least one secondary contaminant (e.g. aluminum or total dissolved solids). Also found were weak correlations between microbes and metals including enterococci and arsenic, and Aeromonas hydrophila and manganese and uranium.