contains some mercury. Mercury is not a necessary part of the diet for humans. Taken in all at once, mercury can cause severe health problems. Mercury can also cause
health problems if it is ingested over a long period. This fact provides further information about mercury and fish.
Which fish have the most and least mercury?
Salmon Running / GlennFleishman
Fish that are older and higher on the food chain have the highest concentration of methyl
mercury, for example, tilefish, swordfish, tuna, and shark. Fish that have the least mercury are salmon, flounder, pollack, and catfish. FDA has
produced a list of fish with their mercury levels. Information about the levels
of mercury in fish varies by location. It is important to be aware of warnings of excess mercury in fish caught in local waters. Remote wilderness
lakes and streams can sometimes have high levels of mercury, even though they appear to be
clean.
What is mercury?
Banned Mercury-in-Glass Thermometer / Andres Rueda
Mercury is element in three forms in the environment: elemental,
inorganic, and organic. Most people have seen elemental mercury in thermometers. In this form, mercury is a shiny, silver-colored, metallic liquid. Mercury also
takes inorganic and organic forms. Soils and rocks contain inorganic mercury.
Bacteria transform inorganic mercury into organic mercury.
Exposure to mercury can cause health problems. Fish may contain excess amounts
of organic mercury.
Where does organic mercury come from?
Students belongings wait to be screened for mercury contamination / usepagov
Bacteria in water and soil turn inorganic mercury into organic mercury.For example, some types of bacteria can change mercury into its most toxic form, methyl mercury.
Volcanic activity and the break down of rocks and soils release inorganic
mercury into the atmosphere. Inorganic mercury also enters the atmosphere by the human activity. Coal burning power plants, paint and paper
manufacturing, for example. . Mercury is also used in
medicines, and,cosmetics.
When the amount of inorganic mercury in the atmosphere increases then the amount of
organic mercury also increases by the activity of bacteria.
Why do fish have high amounts of methyl mercury?
source:
http://ja.wikipedia.org/wiki/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:Dimethylmercury2.png
Industrial use of mercury has caused inorganic mercury levels to increase.
This has increased mercury levels in oceans, rivers and lakes. Bacteria living in the water have
more inorganic mercury and create more methyl mercury. Plants and small animals
that live in the water ingest methyl mercury. Fish that eat these plants and small animals begin
to stock mercury in their bodies. Larger fish that eat the small fish also stock
mercury. When humans eat too many fish that have large amounts of mercury,
they can also get excess mercury in their bodies and develop health problems.
I think this matter isn't just a problem of those people who eat fish in daily life, but also problem of people who throw away garbage which contain mercury. So we must be aware of substance which we throw away, because we, Japanese have many industrial products which contain chemical substance. We have to make more effort to decrease amount of mercury in fish which cause people severe health problems.
References：
http://www.sfphes.org/water/FactSheets/fish_facts.pdf
http://translate.google.co.jp/translate?hl=ja&langpair=en|ja&u=http://www.sfphes.org/water/FactSheets/fish_facts.pdf&prev=/translate_s%3Fhl%3Dja%26q%3D%25E9%25AD%259A%25E9%25A3%259F%25E3%2580%2580%25E6%25B0%25B4%25E9%258A%2580%26tq%3DMercury%2Bfish%2Bmeals%26sl%3Dja%26tl%3Den%26start%3D30
