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Mercury Condition Index Tool

July 11, 2022

The Mercury Condition Index Tool uses existing data of mercury concentrations in invertebrates, fish, and birds within national parks to estimate a park level Condition Index (and associated uncertainty) for mercury, based on its potential risk to fish and wildlife health. The tool employs a series of logic steps to convert provided data into standardized units, based upon both basic stoichiometry and published relationships of mercury concentrations in different tissues, then calculates a condition score for each taxon per park by comparing measured mercury concentrations with existing risk benchmarks associated with either tissue or dietary estimates. The taxonomic condition scores are then integrated to calculate a park-specific score, which equates to a Condition Index category of "poor", "moderate", or "good". A confidence score is then assigned to each data row and summarized for each park based upon variability in the available data, as well as sample sizes and number of locations represented in a park.