@RISK Aids Great Salt Lake Wetlands Clean-Up
With over 2,000 acres along the shores of the Great Salt Lake, the Kennecott Southshore Wetlands is an important habitat for migratory shorebirds and waterfowl. Kennecott Utah Copper, the second largest copper producer in the United States, wants the wetlands to remains vital.
Concerns over high levels of selenium in the wetlands led Kennecott Utah Copper to engage ecological modeler Dr. John Toll and a team of wildlife and toxicology experts in an ecological risk assessment study. The study’s objective was to estimate the impact of selenium on birds in the area and determine the proportion of the nesting bird population potentially at risk from selenium exposure.
@RISK Used to Assess Wildlife Exposure to Selenium
The team started with extensive sampling of aquatic macroinvertebrates to characterize selenium concentrations across the wetlands. Palisade’s BestFit was used to match the collected data to a representative probability distribution function. @RISK was then used to multiply the selenium concentration distribution function by a probabilistic trophic transfer factor (TTF). The TTF is a bioaccumulation model created using BestFit and data collected from around the western United States by the U.S. Fish & Wildlife Service. The probabilistic TTF models the movement of selenium from macroinvertebrates to eggs.
The @RISK and BestFit modeling produced spatially distributed egg selenium concentration predictions. That model was calibrated by Bayesian Monte Carlo analysis, using a small number of site-specific egg samples and observed nest location data. According to Dr. Toll, “We used @RISK’s Monte Carlo analysis to account for uncertainty in food and egg selenium concentration observations due to sampling and measurement error, and uncertainty in bioaccumulation predictions from site-to-site variability.”
@RISK Credited with Accuracy and Wildlife Preservation
Better Water Quality Criteria and a New Sanctuary
As part of its commitment to environmental stewardship, Kennecott Utah Copper also has created the 3,670-acre Inland Sea Shorebird Reserve on the south shore of the Great Salt Lake. The wetland and associated upland communities provide important feeding, staging (resting), and breeding habitats to migratory waterbirds. The Reserve now attracts about 150,000 migratory shorebirds and waterfowl each year, and provides habitat for many other wildlife species.
1. EPA. 2004. Notice of Draft Aquatic Life Criteria for Selenium and Request for Scientific Information, Data and Views. Federal Register 69(242): 75541-75546. December 17, 2004.
2. Toll, J.E., L.M. Tear, D.K. DeForest, K.V. Brix and W.J. Adams. 2005. Setting Site-Specific Water Quality Standards Using Tissue Residue Criteria and Bioaccumulation Data. Part 1: Methodology. Environ Toxicol Chem 24(1): 224-230.
3. Brix, K.V., J.E. Toll, J.E., L.M. Tear, D.K. DeForest and W.J. Adams. 2005. Setting Site-Specific Water Quality Standards Using Tissue Residue Thresholds and Bioaccumulation Data. Part 2: Calculating Site-Specific Selenium Water Quality Standards for Protecting Fish and Birds. Environ. Toxicol Chem 24(1): 231-237.