Mercury pollution Miyuki Kashiwaki Mikako Takahashi Mari Matsumoto
About fishes take in mercury
Mercury is released from a volcano and so on, in nature.
Methyl mercury is always made by microorganisms, so certainly fishes contain methyl mercury.
The fish with the highest concentrations of mercury are swordfish, tuna and large-sized fishes, deep-sea fishes, and whales.
Methyl mercury is stored in their body by a food chain.
However, for the general public, if we don’t eat many highest fishes continuously, our level of mercury doesn’t become high.
Numerical value of mercury
Distribution and excretion of mercury
The absorbed mercury is distributed in diverse organs, especially the liver and kidneys.
Hair containing many amino acid (cysteine) embed methyl mercury. And the methyl mercury to be an index of methyl mercury quantity. The brain has a mechanism which blood-brain barrier defend a poison.
But methyl mercury coupled with cystine can penetrate this obstacles easily and enter the brain. The methyl mercury that containing in body slowly discharged for urine or stool. A period that quantity of methyl mercury to be half (half life) are generally 70 days (a half life of nursing women to be short about 45 days). It figured 3% of methyl mercury which contained in body are staying after a year.
So, the methyl mercury stay long time in body if it once contained.
What is mercury ?
Metallic mercury is used in thermometers. Mercury is also used in fluorescent lamps, etc.
“ Mercury” includes “Metallic mercury”, ”Inorganic mercury”, ”Organic mercury”.
Metallic mercury is used in thermometers, in fluorescent lamps and so on. Metallic mercury is used in gold mining in the Amazon. This causes environmental pollution.
Methyl mercury , a kind of organic mercury, is made from inorganic mercury. This accumulates in fishes and shellfishes in a food chain.
Inorganic mercury contains mercuric oxide used antiseptic .And inorganic mercury contains mercury sulfide the most part of mercury in nature. This is used lacquer ware and paint of Shinto shrine for materials for Chinese red .