An infant apparently made mentally and physically impaired after ingesting water with high levels of arsenic linked to the wartime Japanese military, began speaking and walking this month, his family said.
It has been four months since the parents of the 20-month-old boy in the town of Kamisu, Ibaraki Prefecture, stopped using the tainted well water in the powdered milk they fed him.
The baby said "papa" in mid-July, his first meaningful utterance, and began walking several days later.
The common assumption in Japan is that babies begin speaking and walking at around 12 months. From two months, the boy had been given powdered milk dissolved in water from the well, which a probe in March found had arsenic levels 450 times the safety limit for drinking water.
When he was 6 months old, doctors said the boy's development was retarded, and they later diagnosed him with cerebral palsy. Experts, however, have not been able to explain how the poisoning has affected, or will affect, his health due to insufficient data.
Masahiro Tsuchida, vice director of the prefecture-run Ibaraki Children's Hospital, has been trying to devise methods to treat children suffering from arsenic poisoning. He said of the child's progress, "I think it's a result of the removal of unhealthy factors that had curbed his development."
About 530 wells in the town have been found to contain arsenic levels above environmental limits.