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Can Preserved Museum Specimens Be Used to Reconstruct Fish Mercury Burden and Sources through Time?
Citation:
Lepak, R., S. Janssen, J. Ogorek, C. Dillman, J. Hoffman, M. Tate, AND P. McIntyre. Can Preserved Museum Specimens Be Used to Reconstruct Fish Mercury Burden and Sources through Time? Environmental Science & Technology Letters. American Chemical Society, Washington, DC, 10(2):165-171, (2023). https://doi.org/10.1021/acs.estlett.3c00009
Impact/Purpose:
Our study tests whether liquid preservation of fish impacts the methylmercury concentrations and mercury isotope values in fish and ultimately, we concluded liquid preserved fishes are comparable to contemporary collections and thus suitable for spatiotemporal studies if researchers focus on methylmercury explicitly.
Description:
To evaluate the utility of preserved fish for reconstructing historical and spatial patterns of mercury (Hg) exposure, we experimentally tested the stability of Hg concentrations and Hg stable isotope ratios under standard museum practices of specimen preservation. We found that loss of unidentified constituents during preservation increased Hg concentrations in fish muscle. Low-Hg fish reared in the laboratory were susceptible to exogenous contamination with inorganic mercury (iHg) when preservative fluids were intentionally spiked or iHg leached passively from contaminated wild fish in the same container. This contamination impacted Hg isotope values of total Hg, but the conservative nature of methylmercury allows us to quantitatively correct for iHg contamination. Our findings validate the potential to use fish from the world’s museums to generate spatiotemporal baselines for the Minamata Convention on Mercury, but we recommend a set of precautions to maximize inference strength. Selecting the largest specimens of a target species helps dilute any iHg contamination. Specimens should be drawn from lots that were not comingled with fish from other collections to minimize risk of iHg transfer among fish with different contamination histories. Finally, focusing on low-lipid species will enhance the comparability of Hg concentrations between historical and contemporary collections.
URLs/Downloads:
DOI: Can Preserved Museum Specimens Be Used to Reconstruct Fish Mercury Burden and Sources through Time?
https://pubs.acs.org/doi/10.1021/acs.estlett.3c00009