Spatial relationships of population size, source water type, and distance with copper concentrations in public water systems of the state of Ohio

This dissertation examines five hypotheses. The first four hypotheses sought to identify relationships between copper (Cu) concentrations and source water type and public water system (PWS) population size for PWSs located within the state of Ohio. The fifth hypothesis sought to determine if there is a relationship between copper concentration and distance of sample sites from water treatment plants (WTP) in the greater Cincinnati area PWS.; Studies have shown that excessive consumption of Cu is detrimental for human health. To address these concerns, the United States Environmental Protection Agency enacted the Lead and Copper Rule in 1991. This study showed that immediately following promulgation of the Lead and Copper Rule (LCR), Ohio PWSs that had ground water sources were shown to be somewhat more likely to be in noncompliance with the 1.3 mg/L maximum level contaminant level goal (MCLG) established by the LCR (p = 0.068). Thirty-eight of the thirty-nine PWSs that were in noncompliance had ground water sources. After a history of water treatment, there was not a strong statistical relationship between PWS copper concentration and source water type (p = 0.624). However, when Cu data for PWSs immediately following promulgation of the LCR were combined with Cu data for PWSs after a history of treatment were combined, there was a statically significant relationship between PWS with ground water sources and exceedence of the 1.3 mg/L Cu MCLG (p = 0.044).; Statistically, there was no indication that PWSs with smaller population sizes (i.e. >50,000) were more likely to have exceeded the 1.3 Cu MCLG immediately following promulgation of the LCR (0.551). However, it should be noted that all thirty-nine of the PWSs in noncompliance with the 1.3 MCLG were those with population sizes >50,000. Likewise, after a history of applying water treatments, PWSs with population sizes >50,000 were not found to have a statistically significant relationship with exceedence of the 1.3 copper MCLG ( p = 0.951). However, when Cu data for PWSs immediately following promulgation of the LCR were combined with Cu data for PWSs after a history of treatment, there was a statically significant relationship between PWS with ground water sources and exceedence of the 1.3 mg/L Cu MCLG ( p = 0.054).; Assessment of Cu data for the greater Cincinnati PWS determined that there was no significant relationship between Cu concentration and distance from water treatment plant (WTP).