Portland Public Schools warned employees and families Friday not to eat produce from any school garden, citing guidance from the Oregon Health Authority.

Fruits and vegetables grown on school grounds and watered with water from a school district spigot could contain dangerous levels of lead, according to Courtney Westling, the district's interim chief of community involvement and public affairs.

According to the Oregon Health Authority, lead can be absorbed by plants and accumulate in soil, so water containing lead above 15 parts per billion should not be used for irrigating or watering garden plants. Lead from flaking lead paint as well as from lead-contaminated water can find a pathway into garden produce.

Portland Public Schools completed water quality tests at every school fountain and fixture this summer and found excessive lead in at least one water source, and more often at dozens of water fountains and sinks, at all 88 schools sampled. At numerous schools, some of the highest lead readings were found at outdoor spigots.

It is fine to wash dishes or launder clothes in water containing more than 15 parts per billion of lead. But contaminated water should not be drunk, given to pets, used to wash food or used to grow food, the health authority says.

Oregon Health Authority hasn't tested any soil or vegetables at any school garden and didn't specifically tell Portland or any school district to tell people not to eat produce grown in gardens at school where lead test results exceeded 15 parts per billion, said spokesman Tony Anderson. He said his agency supports community gardens.

The most dangerous ways for humans to interact with lead is to breathe in tiny particles of it and for children younger than seven to swallow or breathe it.

-- Betsy Hammond