title: Mercury and selenium levels in lemon sharks (Negaprion brevirostris) in relation to a harmful red tide event.
abstract: Tissue levels of mercury (Hg; total, organic) and selenium (Se) were assessed in juvenile lemon sharks (Negaprion brevirostris) from Florida nearshore waters collected during a harmful algal bloom (HAB, brevetoxin) event and compared with sharks not exposed to HABs. In all sharks studied, total Hg levels in the muscle were generally present in a molar excess over Se (which may protect against Hg toxicity) and mean muscle Hg levels (0.34 microg/g) exceed safe human consumption guidelines. While there was generally no difference in tissue Hg and Se levels following exposure of sharks to HABs, hepatic Hg levels were significantly lower (56% reduction) in the HAB-exposed sharks compared to controls. As Hg and HABs are globally increasing in scope and magnitude, further work is warranted to assess their interactions and biotic impacts within aquatic ecosystems, especially for a species such as the lemon shark that is classified as a near-threatened species by the International Union for the Conservation of Nature.
authors.affiliation: Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA.
authors.forename: Dong-Ha
authors.initials: DH
authors.lastname: Nam
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Adams
authors.forename: Eric A
authors.initials: EA
authors.lastname: Reyier
authors.forename: Niladri
authors.initials: N
authors.lastname: Basu
mesh_terms: D000818:Animals; D057097:Harmful Algal Bloom; D008628:Mercury / Q000378:metabolism*; D012643:Selenium / Q000378:metabolism*; D012754:Sharks / Q000378:metabolism*
chemical_list: D008628:Mercury; D012643:Selenium