Mercury exposure in mammalian mesopredators inhabiting a brackish marsh
Bioaccumulation of environmental contaminants in mammalian predators can serve as an indicator of ecosystem health. We examined mercury concentrations of raccoons (Procyon lotor; n = 37 individuals) and striped skunks (Mephitis mephitis; n = 87 individuals) in Suisun Marsh, California, a large brackish marsh that is characterized by contiguous tracts of tidal marsh and seasonally impounded wetlands. Mean (standard error; range) total mercury concentrations in adult hair grown from 2015 to 2018 were 28.50 μg/g dw (3.05 μg/g dw; range: 4.46 – 81.01 μg/g dw) in raccoons and 4.85 μg/g dw (0.54 μg/g dw; range: 1.52 – 27.02 μg/g dw) in striped skunks. We reviewed mammalian hair mercury concentrations in the literature and raccoon mercury concentrations in Suisun Marsh were among the highest observed for wild mammals. Although striped skunk hair mercury concentrations were 83% lower than raccoons, they were higher than proposed background levels for mercury in mesopredator hair (1 – 5 μg/g). Hair mercury concentrations in skunks and raccoons were not related to animal size, but mercury concentrations were higher in skunks in poorer body condition. Large inter-annual differences in hair mercury concentrations suggest that methylmercury exposure to mammalian predators varied among years. Mercury concentrations of raccoon hair grown in 2017 were 2.7 times greater than hair grown in 2015, 1.7 times greater than hair grown in 2016, and 1.6 times greater than hair grown in 2018. Annual mean raccoon and skunk hair mercury concentrations increased with wetland habitat area. Furthermore, during 2017, raccoon hair mercury concentrations increased with the proportion of raccoon home ranges that was wetted habitat, as quantified using global positioning system (GPS) collars. The elevated mercury concentrations we observed in raccoons and skunks suggest that other wildlife at similar or higher trophic positions may also be exposed to elevated methylmercury bioaccumulation in brackish marshes.
Citation Information
| Publication Year | 2021 |
|---|---|
| Title | Mercury exposure in mammalian mesopredators inhabiting a brackish marsh |
| DOI | 10.1016/j.envpol.2020.115808 |
| Authors | Sarah H. Peterson, Josh T. Ackerman, C. Alex Hartman, Michael L. Casazza, Cliff L. Feldheim, Mark P. Herzog |
| Publication Type | Article |
| Publication Subtype | Journal Article |
| Series Title | Environmental Pollution |
| Index ID | 70217295 |
| Record Source | USGS Publications Warehouse |
| USGS Organization | Western Ecological Research Center |
Related Content
Hair and blood total mercury concentrations in raccoons and striped skunks from Suisun Marsh 2016 to 2019
Sarah Peterson
Wildlife Biologist
Josh T Ackerman
Research Wildlife Biologist
Christopher "Alex" Hartman
Wildlife Biologist
Michael Casazza
Research Wildlife Biologist
Mark Herzog
Wildlife Biologist
Related Content
- Data
Hair and blood total mercury concentrations in raccoons and striped skunks from Suisun Marsh 2016 to 2019
Total mercury concentrations were determined in hair and whole blood of raccoons and skunks in Suisun Marsh from 2016 to 2019. Individual skunks and raccoons were identified by a unique identifier (Animal_ID) and some animals were sampled multiple times. This dataset includes animal sex, age class, the date the sample was collected, animal body mass, head length, and head-to-torso length. The - Connect
Sarah Peterson
Wildlife BiologistEmailPhoneJosh T Ackerman
Research Wildlife BiologistEmailPhoneChristopher "Alex" Hartman
Wildlife BiologistEmailPhoneMichael Casazza
Research Wildlife BiologistEmailPhoneMark Herzog
Wildlife BiologistEmailPhone