The Environment Ministry began drilling Friday in a search for toxic substances around an arsenic-tainted well in a town where five other arsenic-tainted wells were found the previous day, all near the site of former wartime poison gas facilities.
The drilling around the well in Kamisu, Ibaraki Prefecture, had been scheduled for earlier but had been delayed by the discovery of more tainted wells.
The prefectural government announced Thursday that arsenic was detected in five other wells in Kamisu some 1 km away from the original well, whose water was found in March to contain 450 times more arsenic than the nationally acceptable level.
Some 20 people, including children, have shown symptoms of arsenic poisoning, and the national government last week announced a relief package to pay for their medical treatment. The arsenic is believed to come from the sites of poison gas facilities operated by the Imperial Japanese Army during World War II.