Complex contaminant mixtures in multistressor Appalachian riverscapes

Area of Science:

• Environmental Science
• Water Quality Assessment
• Ecotoxicology

Background:

• Mountaintop mining in Appalachia pollutes streams, but studies often focus narrowly on salinization and selenium.
• Regional water quality assessments need to consider a broader range of inorganic contaminants.

Purpose of the Study:

• To conduct a comprehensive survey of inorganic contaminants in Appalachian streams across various land uses.
• To identify the primary sources and patterns of water chemistry variation in the region.

Main Methods:

• Conducted a survey of 170 stream segments with diverse land use histories.
• Utilized principal component analysis to identify key water chemistry variations and their correlations with land use.

Main Results:

• Three main pollution sources identified: contemporary mining (dominant ions, sulfate, selenium), legacy mining (trace metals), and development (sodium, chloride).
• Headwater streams showed distinct pollution profiles (reference, development-only, mining-only), while larger streams frequently exhibited mixed contaminant mixtures (47%).
• Only 21% of larger streams maintained reference water chemistry.

Conclusions:

• Land use, particularly mountaintop mining and residential development, creates complex, mixed contaminant profiles in Appalachian streams.
• Larger streams are disproportionately affected by accumulated pollutants from multiple sources, including mining and wastewater.
• Effective water quality improvement requires a comprehensive, multicontaminant remediation strategy.