Mercury concentrations in Seaside Sparrows and Marsh Rice Rats differ across the Mississippi River Estuary.

Autor: Bonisoli-Alquati A; Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA, 91768, USA. andreabonisoli@gmail.com., Jackson AK; Purchase College SUNY, Department of Environmental Studies, Purchase, NY, 10577, USA., Eagles-Smith CA; U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA., Moyo S; Louisiana State University, Department of Biological Sciences, Baton Rouge, LA, 70803, USA., Pérez-Umphrey AA; School of Renewable Natural Resources, Louisiana State University and LSU AgCenter, Baton Rouge, LA, 70803, USA., Polito MJ; Louisiana State University, Department of Oceanography and Coastal Sciences, Baton Rouge, LA, 70803, USA., Snider AM; School of Renewable Natural Resources, Louisiana State University and LSU AgCenter, Baton Rouge, LA, 70803, USA., Williams ST; School of Renewable Natural Resources, Louisiana State University and LSU AgCenter, Baton Rouge, LA, 70803, USA., Woltmann S; Center of Excellence for Field Biology, and Department of Biology, Austin Peay State University, Clarksville, TN, 37040, USA., Stouffer PC; School of Renewable Natural Resources, Louisiana State University and LSU AgCenter, Baton Rouge, LA, 70803, USA., Taylor SS; School of Renewable Natural Resources, Louisiana State University and LSU AgCenter, Baton Rouge, LA, 70803, USA.
Jazyk: angličtina
Zdroj: Ecotoxicology (London, England) [Ecotoxicology] 2024 Oct; Vol. 33 (8), pp. 959-971. Date of Electronic Publication: 2024 Jul 24.
DOI: 10.1007/s10646-024-02789-1
Abstrakt: Mercury (Hg) concentrations and their associated toxicological effects in terrestrial ecosystems of the Gulf of Mexico are largely unknown. Compounding this uncertainty, a large input of organic matter from the 2010 Deepwater Horizon oil spill may have altered Hg cycling and bioaccumulation dynamics. To test this idea, we quantified blood concentrations of total mercury (THg) in Seaside Sparrows (Ammospiza maritima) and Marsh Rice Rats (Oryzomys palustris) in marshes west and east of the Mississippi River in 2015 and 2016. We also tested for a difference in THg concentrations between oiled and non-oiled sites. To address the potential confounding effect of diet variation on Hg transfer, we used stable nitrogen (δ 15 N) and carbon (δ 13 C) isotope values as proxies of trophic position and the source of primary production, respectively. Our results revealed that five to six years after the spill, THg concentrations were not higher in sites oiled by the spill compared to non-oiled sites. In both species, THg was higher at sites east of the Mississippi River compared to control and oiled sites, located west. In Seaside Sparrows but not in Marsh Rice Rats, THg increased with δ 15 N values, suggesting Hg trophic biomagnification. Overall, even in sites with the most elevated THg, concentrations were generally low. In Seaside Sparrows, THg concentrations were also lower than previously reported in this and other closely related passerines, with only 7% of tested birds exceeding the lowest observed effect concentration associated with toxic effects across bird species (0.2 µg/g ww). The factors associated with geographic heterogeneity in Hg exposure remain uncertain. Clarification could inform risk assessment and future restoration and management actions in a region facing vast anthropogenic changes.
(© 2024. The Author(s).)
Databáze: MEDLINE
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