Lead in Bay Is Traced to Old Slag Heap

State researchers on Monday identified the underwater remains of a decades-old slag heap as the source of lead contamination in Monterey Harbor.

The Water Resources Control Board said a $50,000 study linked the slag pile to high lead concentrations in mussels.

Researchers recommended sampling other organisms to determine the extent of lead contamination in the food chain as well as further study into the feasibility of cleaning up the slag pile.

Monterey County health officials have posted warnings about the contamination, which was studied under contract by A. Russell Flegal of the San Jose State University Foundation and the state Department of Fish and Game.

In an unrelated report also announced Monday, the state water board said DDT is slowly being released into the aquatic environment of the Salinas Valley from soils that have absorbed it for four decades.

Contamination Range

Researchers reported finding DDT concentrations of two parts per million in fish of the lower Salinas River--twice what the National Academy of Sciences estimates as hazardous to fish and wildlife but still within the 5 ppm public health standard for human consumption.

The Blanco Drain was identified as a likely source of DDT contamination, based on tests of drain sediments and of soil from fields adjacent to the drain.

The study recommended buffer strips and berms between the fields and the drain to reduce the release of DDT to the Salinas River and Monterey Bay.

Researchers noted that tests of unwashed vegetables grown in the area have shown no DDT or extremely low levels of the pesticide.