836/2011. The maximum levels (MLs) of Hg are still not set by the
European Commission (EC, Regulation No. 1881/2006 amended by the
EU, Regulation No. 420/2011) [2,3]. In Brazil, the monitoring of this
element in animal tissues is regulated by PNCRC [4] that fixed the value
at 30 μg Kg−1 of Hg in some animal tissues (bovine, swine, and poultry
muscle), but for equine muscle and other animal tissues as bovine kidney
and swine kidney, still there are no fixed values.
Mercury is released into the natural environment via atmospheric
pathways, from natural sources as volcanic emissions, biomass burning,
oceans, vegetation, wetlands, and anthropogenic sources such as
discharge of industrial waste by mining activities, combustion, use of
pesticides, and burning of fossil fuels [5]. The amount of mercury mobilized
and released into the environment undergoes a sequence of complex
transformations and cycles between land, atmosphere, and ocean
[5] at one of the three chemical forms of mercury: elemental mercury
(Hg0
), inorganic mercury (Hg2
2+ and Hg2+), and organic mercury
(methylmercury — MeHg) [6,7]. Through this redistribution mercury
accumulates in animal tissues and fishes and eventually is taken up by
humans through the food chain. Concern over environmental pollution