Highly toxic insecticides that are banned in Japan and under a global treaty have been detected in several parts of the country, the Environment Ministry said Friday.
The insecticides -- mirex and toxaphene -- are believed to have arrived in Japan via atmospheric fallout or tidal deposits, the ministry said.
"The amounts detected do not pose an immediate threat to human health, but we need to tighten controls on international management of chemicals and insecticides," a ministry official said.
According to the results of a ministry survey in fiscal 2004 on pollution by chemicals, mirex was detected at all 17 atmospheric observation points nationwide and was found in fish, shellfish and birds at all 22 wildlife observation points.
The insecticide was also found in water at 18 points and in mud at 55 points, the ministry said.
Toxaphene was not detected in water or mud, but was found in the atmosphere in a variety of places, according to the ministry.
Mirex and toxaphene are highly toxic and do not easily decompose naturally. All production, use, export and import of them are banned under the Stockholm Convention.
The convention, which took effect in May with 151 signatory countries, is a global treaty to protect human health and the environment from persistent organic pollutants, which are chemicals that remain intact in the environment for long periods.