Traces of a banned and highly toxic insecticide that has never been
Used or manufactured in Japan have been found in animals such as crows and monkeys in the eastern part of the country, the Environment Ministry said Friday.

The detected amounts of the organochlorine insecticide, called Mirex,
were extremely small and posed no direct threat to human beings,
ministry officials said.

The officials said they believe the chemical may have come to Japan in
the atmosphere or via sea currents and are investigating possible
routes.

Mirex was found in monkeys, raccoon dogs, dolphins and three kinds of
wild bird inhabiting the Kanto region, including Tokyo. This is the
first time that land animals in Japan have tested positive for mirex,
which is banned in developed countries due to its toxicity and
persistent residue.

The densities were below 6 nanograms per gram of tissue, the officials
said. A nanogram is one-billionth of a gram.

"It is possible for mirex pollution to spread to countries that have no
record of using it," said Shinsuke Tanabe, an environment chemistry
professor at Ehime University's Center for Marine Environmental
Studies. Tanabe was the first to detect Mirex and other substances in dolphins and whales in seas near Japan in June.

The ministry said the insecticide had been used in the United States
until the 1970s but Japan has never manufactured nor imported it. It is
used overseas, especially against ants, but was found to be carcinogenic in experiments on laboratory rats.

Mirex, like dioxin and polychlorinated biphenyl, is a persistent
Organic pollutant (POP) that is highly toxic and does not easily break down in nature.

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