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U.S. Geological Survey (USGS) scientists evaluated a nonlethal method to estimate mercury in the embryos of 23 bird species using mercury content in eggshells. This method was effective for a wide range of ages and species.
Peterson, S.H., Ackerman, J.T., Eagles-Smith, C.A., Hartman, C.A., and Herzog, M.P., 2017, A critical evaluation of the utility of eggshells for estimating mercury concentrations in avian eggs: Environmental Toxicology and Chemistry, doi:10.1002/etc.3777 (Advanced Web release).
Ackerman, J.T., Herzog, M.P., Hartman, C.A., Isanhart, J., Herring, G., Vaughn, S., Cavitt, J.F., Eagles-Smith, C.A., Browers, H., Cline, C., and Vest, J., 2015, Mercury and selenium contamination in waterbird eggs and risk to avian reproduction at Great Salt Lake, Utah: U.S. Geological Survey Open-File Report 2015-1020, 164 p.