Water Quality in the Lower Susquehanna River Basin, Pennsylvania and Maryland, 1992-95

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Summary of major issues and findings--
Lower Susquehanna River Basin Study Unit

Location map of the study unit

Water from 30 percent of the wells sampled and about 20 percent of the streams sampled would exceed the U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Level (MCL) for nitrate-nitrogen of 10 mg/L as N (milligrams per liter as nitrogen) if not properly treated before use as drinking water (p. 8).

Nitrate concentrations in the Susquehanna River at Harrisburg were generally less than 2 mg/L, which is considerably below the MCL for nitrate in drinking water of 10 mg/L (discussed above) (p. 8).

The main nitrogen source in the Study Unit is animal manure used as an agricultural fertilizer (p. 9).

The concentration of total nitrogen in the Susquehanna River's inflow to the Chesapeake Bay has decreased in the 1985-96 time period (p. 11).

Concentrations of pesticides in water from the wells and streams sampled rarely exceeded levels established as drinking-water standards (p. 12-14).

Total coliform bacteria were detected in water from nearly 70 percent of the household wells sampled, indicating that the water should not be used for drinking without treatment (p. 15).

None of the concentrations of the volatile organic compounds detected in samples from wells used as drinking-water supplies exceeded the MCLs or Lifetime Health Advisory Levels established by the USEPA (p. 16).

Radon, a product of the radioactive decay of uranium, is present in ground water throughout the Lower Susquehanna River Basin (p. 17).

Correlations were found between the concentrations of trace elements in streambed sediments and the concentrations in livers of bottom-feeding fish for only 3 of 11 elements regarded as common contaminants (p. 18).

No organic contaminants were detected in whole fish at levels considered harmful to human health; however, some contaminants in streambed sediment were detected at levels harmful to aquatic life (p. 19-21).

Fish communities inhabiting the seven streams in long-term monitoring basins were related to the bedrock type (p. 22-23).

U.S. Geological Survey Circular 1168

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Suggested citation:
Lindsey, B.D., Breen, K.J., Bilger, M.D., and Brightbill, R.A., 1998, Water Quality in the Lower Susquehanna River Basin, Pennsylvania and Maryland, 1992-95: U.S. Geological Survey Circular 1168, on line at <URL:>, updated April 2, 1998 .

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Last modified: Thu Jul 2 16:35:35 1998