Problem 4 – Methyl mercury Contaminated Fish Methylmercury (MM) is a common name for the organometallic cation [CH3Hg]+ which is an environmental toxicant found in ocean waters as a result of anthropogenic releases. The EPA reference dose (RfD) for MM is 0.1 g/kgd. The average consumption of fish for a person with an average weight of 70 kg is 7.5 g/d and the bioconcentration factor (BCF) of MM in tuna fish is 106 l/kg.
1) Write a paragraph (no less than 100 words) explaining the possible sources of MM contamination in the oceans? [Provide reference(s)].
2) Determine the MM concentration in fish (in g MM / kg of fish) that poses an unacceptable health risk to humans.
3) Assuming that the concentration of MM in tuna fish is equal to that determined above calculate the maximum safe concentration of MM (in g/l) in ocean water.
4) Compare the aquatic concentration value for MM calculated in the previous step with actual values measured in the Pacific Ocean and comment.
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