Relationships between total and organic mercury concentrations in tissues and length of common dolphins (Delphinus delphis) from the Portuguese coast

Biomagnification of Mercury and Selenium in Blue Shark Prionace glauca from the Pacific Ocean off Mexico

“…In our study, we did not find a 1:1 Hg to Se relation; however, some published information mention that some predators have high mercury amounts, but do not show toxic effects, which suggests that the presence of both metals gives protection to some organisms [49][50][51]. This selenium antagonist protection has been found mainly in marine mammals [46,52], in which high mercury levels have been found, without an apparent effect on these animals. Other mechanisms of chelation of mercury is from the interaction with metallothioneins, proteins with a high content of thiol groups (sulphydryl) that play a homeostatic role in the control and detoxification of heavy metals [46].…”

“…This selenium antagonist protection has been found mainly in marine mammals [46,52], in which high mercury levels have been found, without an apparent effect on these animals. Other mechanisms of chelation of mercury is from the interaction with metallothioneins, proteins with a high content of thiol groups (sulphydryl) that play a homeostatic role in the control and detoxification of heavy metals [46]. It would be necessary to research the physiology of these animals to determine the capture, distribution, and elimination of mercury and establish the true toxic risk for marine organisms.…”

“…This sequestration would also explain the variability in the amount accumulated in each tissue, and the elimination of each metal in the body [5,45]. Detoxification of mercury may also result of formation of granules within hepatocytes (liver), so that mercury is transformed into less toxic inorganic forms, such as inert mercuric selenide, called tiemannite (HgSe) [46].…”

Spatial distribution and enrichment of mercury in surface sediments off the northwest coast of Baja California, Mexico

“…Uno de los metales más tóxicos para la biosfera es el Hg (Lacerda y Solomons 1998), el cual tiene una gran afinidad con la fase particulada (Hurley et al 1994) y, en sedimentos costeros contaminados, su concentración comúnmente evidencia la evolución histórica de la contaminación con este metal (Gobeil y Cossa 1993). Por lo tanto, la información en este contexto es importante para identificar el riesgo potencial de contaminación y toxicidad de Hg para el medio marino y los seres humanos (Besada et al 2006, Cecilio et al 2006. …”

“…In contaminated coastal sediments, its concentration is an indication of the historical evolution of Hg pollution (Gobeil and Cossa 1993). Information in this context is therefore relevant to identify the potential risk of Hg contamination and toxicity in the marine environment and humans (Besada et al 2006, Cecilio et al 2006 …”