[MARMAM] Mercury-Selenium Relationships in Liver of Guiana Dolphin

Jose Lailson Brito joselailson at uol.com.br
Tue Jul 31 18:18:40 PDT 2012

Dear colleagues,

The following article has just been published on line in PLOS ONE:

Lailson-Brito J, Cruz R, Dorneles PR, Andrade L, Azevedo AdF, et al. (2012)
Mercury-Selenium Relationships in Liver of Guiana Dolphin: The Possible
Role of Kupffer Cells in the Detoxification Process by Tiemannite
Formation. PLoS ONE 7(7): e42162. doi:10.1371/journal.pone.0042162


Top marine predators present high mercury concentrations in their tissues
as consequence of biomagnification of the most toxic form of this metal,
methylmercury (MeHg). The present study concerns mercury accumulation by
Guiana dolphins (Sotalia guianensis), highlighting the selenium-mediated
methylmercury detoxification process. Liver samples from 19 dolphins
incidentally captured within Guanabara Bay (Rio de Janeiro State, Brazil)
from 1994 to 2006 were analyzed for total mercury (THg), methylmercury
(MeHg), total organic mercury (TOrgHg) and selenium (Se). X-ray
microanalyses were also performed. The specimens, including from fetuses to
30-year-old dolphins, comprising 8 females and 11 males, presented high THg
(0.53–132 mg/g wet wt.) and Se concentrations (0.17–74.8 mg/g wet wt.).
Correlations between THg, MeHg, TOrgHg and Se were verified with age
(p,0.05), as well as a high and positive correlation was observed between
molar concentrations of Hg and Se (p,0.05). Negative correlations were
observed between THg and the percentage of MeHg contribution to THg
(p,0.05), which represents a consequence of the selenium-mediated
methylmercury detoxification process. Accumulation of Se-Hg amorphous
crystals in Kupffer Cells was demonstrated through ultra-structural
analysis, which shows that Guiana dolphin is capable of carrying out the
demethylation process via mercury selenide formation.

The article is available online at:

Best regards,
Jose Lailson

Dr. José Lailson Brito Junior
Professor Adjunto
Universidade do Estado do Rio de Janeiro
Faculdade de Oceanografia
Laboratório de Mamíferos Aquáticos e Bioindicadores
Rua São Francisco Xavier, 524 4º andar sala 4002 bloco E
Maracanã, Rio de Janeiro - RJ
CEP 20.550-013
Tel:21-2334-0065 / 2334-0795
Fax:21-2334-0621 / 23340795
email: lailson at uerj.br ou joselailson at gmail.com
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