"To Nullify Lead, Add a Bunch of Fish Bones"

"OAKLAND, Calif. — Alaskan pollock is usually the faux stand-in for crab meat or the main ingredient in fast-food fish sandwiches. But now the flaky fish is moving into a new realm — as part of the solution to one of the nation's longest-running toxic waste problems.

Today, there is more lead contamination in America's cities than any federal or state agency could ever afford to clean up and haul away. So scientists and regulators are trying a new strategy, transforming the dangerous metal into a form the human body cannot absorb, thus vastly reducing the risk of lead poisoning.

The principle is straightforward, said Victor R. Johnson, an engineer with Civil & Environmental Consultants Inc. 'The fish bones are full of calcium phosphate,' he said. 'As they degrade, the phosphates migrate into the soil.' The lead in the soil, deposited by car exhaust from the decades when gasoline contained lead or from lead-based paint residue, binds with the phosphate and transforms into pyromorphite, a crystalline mineral that will not harm anyone even if consumed."

Felicity Barringer reports for the New York Times July 20, 2011.