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CH3041
METHYL MERCURY
• Methylation by microorganisms is an important feature of the Hg element cycle.
     Hg2+  ® CH3Hg+(aq) ® (CH3)2Hg(s)
Rapid methylation occurs in low pH lakes.
• Methylmercury
is very toxic & is
the major Hg species
(80%) found in fish.
• Humans absorb over
90% of the Hg in fish.
• WHO Hg ADI 40mg 
  fish 1 meal = 150mg
• Hg(II) is the most phytotoxic metal.
Anaerobic
bacteria