Document: OUI-3-62-5

Patterns of drinking water quality violations: A broad-scale indicator of changes in aquatic ecosystems in the southeastern U.S.

MEIER, O.W.*

Western Kentucky Univ., Bowling Green, KY 42101, U.S.A. ¹

Abstract:
If one begins with an image of the classic hydrologic cycle, then the pattern of human water use appears as a subcycle appended to and impinging upon the hydrologic cycle. The primary input to the human water use system - "source water" from a proximal aquatic ecosystem - undergoes chemical treatment, filtration, and disinfection by water treatment facilities, followed by distribution for human consumption and a wide range of uses. The output of the human water use system - discharge of "wastewater," treated or not - becomes a major input to the aquatic ecosystems that serve as source water for human communities downstream. An examination of patterns of water treatment plant violations of Maximum (Allowable) Contaminant Levels (MCLs) throughout the southeastern U.S. from 1996 through 1998 was undertaken as an broad-scale indication of sustainability problems that are developing in aquatic ecosystems. Patterns for the four most prevalent MCL violations are examined in detail: coliform bacteria, nitrate, total trihalomethanes, and turbidity. Raw data were taken primarily from the EPA SDWIS (Safe Drinking Water Information System) database. Patterns of coliform MCLs suggest that these violations are concentrated in coastal areas, plus central Florida and Appalachian regions. The density of coliform violations also appears to be increasing over time. Nitrate MCL violations are not common, but they do appear repeatedly over time in particular regions of the Carolinas and in central Florida. Specific agricultural and livestock practices in these areas are suspected to be the primary cause of this problem.

Keywords: water quality, water treatment, system, coliform

This abstract is being presented at: 8:45 AM in session:
Oral Session #70: Aquatic Ecology.