Tissue Element Levels and Heavy Metal Burdens in Bottlenose Dolphins That Stranded in the Mississippi Sound Surrounding the 2019 Unusual Mortality Event
ORCID
Landrau-Giovannetti: https://orcid.org/0000-0002-5732-5370; Reichley: https://orcid.org/0000-0002-4537-4335; Madrigal: https://orcid.org/0000-0002-6284-6541; Peterman: https://orcid.org/0009-0004-5296-6189; Kaplan: https://orcid.org/0000-0002-1992-4145
MSU Affiliation
College of Veterinary Medicine; Global Center for Aquatic Health and Food Security; Department of Pathobiology and Population Medicine; Department of Comparative Biomedical Sciences; Center for Environmental Health Sciences; Mississippi State Chemical Laboratory
Creation Date
2026-03-30
Abstract
In 2019, an unusual mortality event (UME) affected bottlenose dolphins (Tursiops truncatus) in the Mississippi Sound (MSS) following an extended dual opening of the Bonnet Carré Spillway (BCS), which prevents flooding in New Orleans. This resulted in low salinity, skin lesions, and electrolyte imbalances in dolphins. Additionally, the influx likely altered the MSS's environmental chemical composition, including levels of heavy metals and metalloids; thus, we quantified heavy metals, metalloids, and essential elements in the tissues of dolphins that stranded in the MSS before and after the 2019 UME. We hypothesized that levels of heavy metals and metalloids (such as mercury (Hg), arsenic (As), lead (Pb), and cadmium (Cd)) would not show significant changes post-UME. Indeed, we found no major changes associated with the UME in most metals; sodium (Na) and magnesium (Mg) levels were lower in several tissues after 2019, which correlated with the average yearly salinity measured from the MSS. Toxic metals and metalloids were detectable with some changes over time; however, the selenium (Se):Hg molar ratio increased in some tissues post-2019. Additionally, we confirmed that Hg can bioaccumulate, with positive correlations between Hg levels and dolphin size as assessed by straight length. Overall, our findings indicate that freshwater incursions into the MSS can alter dolphin exposure to essential and toxic elements.
Publication Date
6-18-2025
Publication Title
Toxics
Publisher
MDPI
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Landrau-Giovannetti, N., Murray, R., Reichley, S., Moore, D., Madrigal, T., Brown, A., Meredith, A., Childers, C., Sparks, D., Solangi, M., Linhoss, A., Peterman, B., Lawrence, M., & Kaplan, B. L. F. (2025). Tissue Element Levels and Heavy Metal Burdens in Bottlenose Dolphins That Stranded in the Mississippi Sound Surrounding the 2019 Unusual Mortality Event. Toxics, 13(6), 511. https://doi.org/10.3390/toxics13060511
