Mercury contamination and potential health risk to French seabirds: A multi-species and multi-site study - IRSTEA - Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (<b>anciennement Cemagref</b>)
Journal Articles Science of the Total Environment Year : 2024

Mercury contamination and potential health risk to French seabirds: A multi-species and multi-site study

Alain Ward
  • Function : Author

Abstract

Mercury (Hg) is a naturally occurring highly toxic element which circulation in ecosystems has been intensified by human activities. Hg is widely distributed, and marine environments act as its main final sink. Seabirds are relevant bioindicators of marine pollution and chicks are particularly suitable for biomonitoring pollutants as they reflect contamination at short spatiotemporal scales. This study aims to quantify blood Hg contamination and identify its drivers (trophic ecology inferred from stable isotopes of carbon (δ$^{13}$C) and nitrogen (δ$^{15}$N), geographical location, chick age and species) in chicks of eight seabird species from 32 French sites representing four marine subregions: the English Channel and the North Sea, the Celtic Sea, the Bay of Biscay and the Western Mediterranean. Hg concentrations in blood ranged from 0.04 μg g$^{-1}$ dry weight (dw) in herring gulls to 6.15 μg g$^{-1}$ dw in great black-backed gulls. Trophic position (δ$^{15}$N values) was the main driver of interspecific differences, with species at higher trophic positions showing higher Hg concentrations. Feeding habitat (δ$^{13}$C values) also contributed to variation in Hg contamination, with higher concentrations in generalist species relying on pelagic habitats. Conversely, colony location was a weak contributor, suggesting a relatively uniform Hg contamination along the French coastline. Most seabirds exhibited low Hg concentrations, with 74% of individuals categorized as no risk, and < 0.5% at moderate risk, according to toxicity thresholds. However, recent work has shown physiological and fitness impairments in seabirds bearing Hg burdens considered to be safe, calling for precautional use of toxicity thresholds, and for studies that evaluate the impact of Hg on chick development.
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Dates and versions

hal-04693483 , version 1 (10-09-2024)

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Prescillia Lemesle, Alice Carravieri, Gauthier Poiriez, Romain Batard, Aurélie Blanck, et al.. Mercury contamination and potential health risk to French seabirds: A multi-species and multi-site study. Science of the Total Environment, 2024, 952, pp.175857. ⟨10.1016/j.scitotenv.2024.175857⟩. ⟨hal-04693483⟩
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