Levels of dissolved organic carbon and low pH levels enhance mobility of Hg making it more likely to enter food chain
Toxic effects cont.
Mercury compounds are acutely toxic to freshwater microorganisms
Freshwater fish show lethal response to mercury in acute concentrations starting at 30ug/L
The LC50/96-hour values for fish are less than 1 mg/L.
Many aquatic inverts. are very sensitive to mercury (esp. larvae)
Methyl mercury passes the blood brain-barrier and nuclear membranes to react directly with cellular and nuclear components
Accumulation of Hg in the brain, compared to blood and muscle, is much less is fish than mammals (lack external barriers and internal detoxification system)
Detoxification
The liver is the main site for methyl Hg biotransformation in animals
Methyl mercury from fish consumption (highly toxic) or breathing vaporous mercury (bodies are more adapted to reducing toxic effects)
Methyl mercury affects central nervous system and irreversible brain damage
2 Biggest Hg poisonings
“Mad Hatter”- during the industrial revolution, hat-makers used mercury nitrate to soften fur used as lining in hats. Toxic effected brains causing mental instability.
Japan - 1952, chemical co. dumped Hg into Minamata harbor; residents of local fishing villages contaminated; 100s affected and 68 died
Hazardous!!
DANGER! CORROSIVE. CAUSES BURNS TO SKIN, EYES, AND RESPIRATORY TRACT. MAY BE FATAL IF SWALLOWED OR INHALED. HARMFUL IF ABSORBED THROUGH SKIN. AFFECTS THE KIDNEYS AND CENTRAL NERVOUS SYSTEM. MAY CAUSE ALLERGIC SKIN REACTION. (MSDS 2008)
Bibliography
Chemistry Explained: Functions and Applications. “Mercury”
