hexavalent chromium

東京都江戸川区の大島小松川公園近くの排水溝が環境基準の３ 千倍を超す濃度の六価クロムに汚染されていることが東京農工大の研究グループの調査で分かりました。70年代に大きな問題となり、除去されたと思っていましたが、人間の英知なんて高が知れています。

Poisonous chromium 3,000 times over limit found in Tokyo drainage ditch

A research team has discovered that the poisonous substance hexavalent chromium was found at levels 3,000 times environmental safety limits in a Tokyo drainage ditch, it has been learned.

On March 27, the Tokyo Metropolitan Government's Bureau of Environment began dispatching workers to the site as part of a clean-up operation.

The ditch is located near Ojima Komatsugawa Park in Edogawa Ward. The area is a former industrial site purchased by the metropolitan government in 1973 and a large amount of slag had been dumped there. Back then, the metropolitan government is said to have removed the slag's harmful properties and buried it, using metal sheets to shield it off from the surroundings.

However, in February 2011 and April 2012, leaked groundwater containing hexavalent chromium was found in the area. In soil that was removed in order to get rid of the water, hexavalent chromium around 220 times the environmental limit was found. The metropolitan government was later criticized for not mentioning the finding to the Edogawa Ward Office or residents after it claimed "there were no effects on health."

Hexavalent chromium is used in metal coatings, pigments and hide processing, and is sometimes ejected from factories. It is highly poisonous, and can cause skin inflammation, ulcers and lung cancer. The Ministry of the Environment classifies it as a dangerous material.

http://mainichi.jp/english/english/newsselect/news/20130328p2a00m0na003000c.html

六価クロムは英語の文字通りの訳です。『大辞林』によると、「酸化数が六のクロムを含む化合物・イオン。三酸化クロム・クロム酸塩など。酸化力・毒性が強い。皮膚に触れると潰瘍を起こし、体内に入れば肝臓障害・肺癌などを起こす。鍍金(めつき)工場、クロム化合物製造工場などの廃液による水質汚染が社会問題となった。」とのことです。「酸化」が？の人は化学Iの復習を！（「還元」も！）（UG）