PRESTON – The level of arsenic found in the well that supplies water to Chenango County’s Preston Manor adult home is too high, according to federal Environmental Protection Agency standards, and must be filtered.

Arsenic is a naturally occurring substance that has been linked to cancer. In 2001, the EPA lowered the threshold for the toxin from 50 parts per billion gallons of water to 10 ppb. Periodic testing at Preston Manor shows arsenic at levels of 30 to 40 ppb.

“We were well below that level before they changed it,” said Isaiah Sutton, environmental health sanitarian for the Chenango County Public Health Department.

Social Services Commissioner Bette Osborne, whose department oversees Preston Manor, told members of the county’s Health and Human Services Committee on Tuesday that the county was given seven years to rectify the problem. She also said that it would take more than 50 years for such trace amounts of arsenic to harm a human being.