Heavy metals

Originally, it was a general term for metals with a density of over 5 g cm ^-3 , such as copper, iron, mercury, and lead, as opposed to light metals with a density of 4 g cm ^-3 or less, such as magnesium and aluminum, but in recent years it has often been used in connection with environmental pollution to mean metals with a high density that are toxic even at low concentrations. Examples include chromium, mercury, lead, thallium, and zinc. If ingested by the human body, they can cause neurological disorders (Minamata disease), cancer, kidney damage, and developmental disorders. Many of them are designated as target chemicals under the PRTR Act and the Poisonous and Deleterious Substances Control Act.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

元来，マグネシウム，アルミニウムなど密度4 g cm^－3 以下の軽金属に対する，銅，鉄，水銀，鉛など密度が5 g cm^－3 を超えるような金属の総称であるが，近年，低濃度でも毒性をもつ密度の大きい金属という意味で，環境汚染との関連で使われることが多い．たとえば，クロム，水銀，鉛，タリウム，亜鉛など．人体内に摂取されると神経障害(水俣病)，がん，腎臓障害，発育障害などの原因となる．PRTR法，毒物劇物取締法などの対象化学物質に指定されているものが多い．

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