Mercury in pilot whales: possible limits to the detoxification process

Quantifying mercury isotope dynamics in captive Pacific bluefin tuna (Thunnus orientalis)

“…The % MMHg values (the fraction of THg present as MMHg) of the squid and sardine were 99.0 ± 7.0% (n = 3, 1 SD), and 76.2 ± 4.0% (n = 3, 1 SD), respectively. These values confirm previous results from the literature that most Hg in these food sources is in the form of MMHg (Caurant et al, 1996;Joiris et al, 1999;Das et al, 2000). Mean d Hg values were previously reported in commercial food pellets composed mainly of marine by-catch .…”

Concentrations and Interactions of Selected Essential and Non-Essential Elements in Bowhead and Beluga Whales of Arctic Alaska

“…The tendency for Hg:Se molar concentrations to converge on a 1:1 ratio was offered as evidence that Se complexation with Hg was the probable mode of detoxification in marine mammals, occurring through an active process rather than by passive coaccumulation. While this perception was profound, subsequent researchers have suggested that deviations from this 1:1 molar status indicate abnormality, or even toxicity unaccompanied by detected evidence of compromised health (Arima and Gakura, 1979;Caurant et al, 1996). Findings of the present study do not counter the recognized relationship of Hg with Se, or the premise that this association could be the primary mode of Hg detoxification in marine mammals.…”

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

“…La elevada tolerancia de los delfines al mercurio, sin síntomas aparentes de intoxicación, da indicios de procesos de desintoxicación . La elevada acumulación en el hígado está íntimamente relacionada con procesos de desmetilación, es decir, con la presencia de proteínas ligadas al mercurio (Palmisano et al 1995, Caurant et al 1996. Como resultado de estos procesos, el mercurio se acumula tanto en forma orgánica como inorgánica, siendo el monometilmercurio su forma orgánica más tóxica.…”

“…El mercurio total se midió directamente por espectrometría de absorción atómica en un analizador de mercurio dolphins to Hg, without presenting any apparent symptoms of poisoning, indicates the occurrence of detoxification processes . High accumulation in liver is closely linked to demethylation processes (Honda et al 1983, Thomson 1990, Frodello et al 2000, and namely to the presence of Hg binding-proteins (Palmisano et al 1995, Caurant et al 1996. As a result of these processes, Hg is accumulated in both inorganic and organic forms, monomethylmercury being the most toxic organomercury compound (Pinho et al 2002.…”