TABLE 4-1 Parameters Found in Water Quality Standards to Measure Impairment of Aquatic Life, Human Health, and Recreational Water Use in Pennsylvania

Designated Use

Impairment Causes in 303(d) Report

Water Quality Parameter to Determine Impairment

Aquatic life


Iron, manganese





Nitrite plus nitrate

Salinity, total dissolved solids, chlorides

Total dissolved solids, chlorides, osmotic pressure

Other inorganics


Organic enrichment

Dissolved oxygen

Thermal modification



Ammonia nitrogen, fluoride, phenolics

Excess algae growth

Not listed


Not listed

Other habitat alteration

Not listed

Suspended solids

Not listed


Not listed

Flow alteration; water or flow variability

Not listed

Oil and grease

Not listed


Not listed


Not listed

Human health

Chemicals in fish

Federal food and drug standards used


Pathogens (surrogate)

Fecal coliforms, total coliforms



As explained above, impairment of waters for designated uses can be determined by comparison of water quality to standards for specified uses or by bioassessment protocols. Causes of impairment may be determined by physical, chemical, or biological analysis of water samples; bioassessment protocols; or observation of environmental conditions in a reach of a stream or river. Causes of impairment are identified by descriptors such as siltation, metals, pH, low dissolved oxygen, and nutrients. However, the 2004 Pennsylvania Integrated Water Quality Monitoring and Assessment Report (PADEP, 2004a) does not present data on concentrations of impairment-causing contaminants or data on the degree to which water quality is impaired. Without detailed data for each reach of stream or river, it is not possible to determine how severely surface waters are impaired, even when impairment is caused by one or more pollutants.

According to the most recent assessment of surface water by the Commonwealth of Pennsylvania (PADEP, 2004a), 83,161 miles of streams (82 percent of total) in Pennsylvania have been assessed, and the remaining 15,182 stream-miles (18 percent) are scheduled for assessment. Of those assessed, 57,801 river-miles (82 percent) support their aquatic life and fish use designations, and 10,762 (18 percent of the assessed and 13 percent of the total stream-miles) are classified as impaired. The two largest sources of impairments specified are abandoned mine drainage (4,040 miles impaired) and agriculture (3,903 miles impaired). Three sources related to runoff (urban runoff, road runoff, and small residential runoff) account for an additional 3,007 miles impaired. Four sources related to wastewater handling and treatment (municipal point sources, on-site wastewater, combined sewer overflows, and package plants) account for 744 miles impaired.

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