From a holistic perspective, a major source of wastewater discharges is associated with increases in the violations of receiving water quality standards. The 1990 National Water Quality Inventory in the United States assessed, in relation to applicable water quality standards and designated beneficial uses of the water, about one-third of the total river miles, half of the acreages of lakes, and three-quarters of the estuarine square miles. Table 7.2.4 summarizes these results relative to supporting designated uses. About one-third of the three assessed water resources did not fully meet their respective designated uses (Council on Environmental Quality 1993). Table 7.2.5 indicates the causes and sources of pollution for the three types of water resources.
Figure 7.2.3 shows pollution sources for impaired river miles; Figure 7.2.4 shows pollution in estuarine waters. While they are not the only sources of pollution, municipal and industrial wastewater discharges contribute significantly to impaired water resources.
Table 7.2.6 summarizes violation rates of water quality criteria in U.S. rivers and streams from 1975-1989. FC bacteria violations are well above the rates for other constituents for each year. In addition, the percent of violations has declined for all listed parameters since 1975.
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