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A method for assessing the potential for confounding applied to ionic strength in central Appalachian streams
Glenn W Suter1, Susan M Cormier
1National Center for Environmental Assessment, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA. suter.glenn@epamail.epa.gov
Environmental Toxicology and Chemistry
|November 20, 2012
Summary
This study introduces a method to assess confounding variables in field data, improving causal relationship analysis. It successfully identified and addressed confounding factors affecting aquatic invertebrate health in streams.
Area of Science:
- Environmental Science
- Ecology
- Aquatic Biology
Background:
- Causal relationships from field data can be confounded by variables linked to both cause and effect.
- Assessing confounding is crucial for accurate environmental impact assessments.
Purpose of the Study:
- To present and apply a novel method for assessing confounding in environmental field data.
- To evaluate potential confounders in the relationship between ionic strength and benthic invertebrate assemblages in central Appalachian streams.
Main Methods:
- Developed a method weighing evidence for and against confounding by potential confounders.
- Identified 10 types of evidence and created a qualitative scoring system.
- Evaluated 12 potential confounders including habitat, nutrients, pH, and metals.
Main Results:
- Low pH was identified as a significant confounder and sites with pH < 6 were removed.
- Other potential confounders were systematically evaluated and eliminated based on the weight of evidence.
- The developed method proved useful and defensible for environmental assessments.
Conclusions:
- The presented method effectively assesses confounding in environmental field data.
- This approach can be applied to various environmental assessments, including contaminated site remediation and natural resource management.
- Accurate causal inference from field data is enhanced by rigorous confounding assessment.
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