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Assessing background levels of specific conductivity using weight of evidence
Citation:
Cormier, S., L. Zheng, G. Suter, AND C. Flaherty. Assessing background levels of specific conductivity using weight of evidence. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 628-629:1637-1649, (2018). https://doi.org/10.1016/j.scitotenv.2018.02.017
Impact/Purpose:
Naturally occurring background is considered in many ecological and human health epidemiological assessments. We describe a process for evaluating several types of evidence to assess background concentrations. The types of evidence include physical properties, measured concentration, distribution of low-concentration sites, biological properties, and data quality and sufficiency. Evidence is generated, evaluated and synthesized using weight of evidence. The process is illustrated using an example from the Eastern U.S for concentrations of salt in streams measured as specific conductivity. This method provides a rigorous, transparent method to perform and report estimates of background concentration that incorporates all relevant evidence. This assessment method could be used to determine if a benchmark, criterion, or restoration goal is appropriate to apply throughout an ecoregion or between two areas.
Description:
Abstract Background levels of a regional attribute, such as aquatic specific conductivity (SC), may be assessed using the basic assessment approach of planning, analysis, and synthesis. We demonstrate the approach by assessing whether the background SC is sufficiently similar in streams of Ecoregion 70 in West Virginia and Ohio. During planning, we identified five relevant considerations to assess background SC: physical properties, measured SC, the distribution of low SC sites, biological properties, and data quality and sufficiency. These diverse types of evidence were generated and then evaluated and synthesized using weight of evidence. In this example, the background SC was similar between the two areas in Ecoregion 70, the Western Allegheny Plateau (WAP) in the eastern United States for some assessment applications, but it cannot replace site specific measurements and verification at the stream reach scale. Where data sets are small, sampling designs, or the percentage of anthropogenic inputs may influence estimates of background SC, we suggest that information about regional properties, related to and affected by SC, that are available in other areas can be used to determine the similarity of background SC between the two areas.
URLs/Downloads:
DOI: Assessing background levels of specific conductivity using weight of evidence
NIHMS-1019294.PDF (PDF, NA pp, 1393.447 KB, about PDF)
https://www.ncbi.nlm.nih.gov/pmc/articles/pmc7079169