Agencies Close Deal to Buy, Restore S.F. Bay Salt Ponds

State and federal officials Monday completed a $135-million deal to buy and restore 16,500 acres of salt ponds in South San Francisco Bay, with a provision requiring a salt manufacturing company to clean up the ponds as part of their reconversion to tidal marsh.

The final agreement, authorizing the purchase of the acreage from Cargill Inc., sets in motion the largest wetlands restoration project on the West Coast. The multicolored ponds ring the southern rim of San Francisco Bay. The deal also includes some ponds farther north at the mouth of the Napa River that feeds into the bay near Vallejo.

The restored marshland should help clean the bay by functioning as a natural filter and help bring back fish and shorebirds that were abundant there.

Gov. Gray Davis, in announcing the conclusion of six months of negotiations, said that turning the industrial salt ponds back into tidal marsh provides “an unprecedented opportunity to improve the physical, biological and chemical health of the San Francisco Bay.”

Furthermore, he said, he appreciated Cargill’s commitment to assume responsibility for the initial cleanup of lead and other contaminants and then retain liability if other toxic problems surface after the state assumes control of the salt ponds.

Aside from announcing a final deal, state officials released the first details of an environmental assessment of the ponds, which have been used to produce salt from evaporated seawater since the days of the California Gold Rush.

Some environmentalists had been concerned that 150 years of evaporation might have concentrated toxic mercury that washed into the bay, largely from mine tailings and the processing of gold. They feared that the hidden cost of cleanup might make restoration of the ponds prohibitively expensive to taxpayers.

Checking sediment samples and toxins in snails and fish, environmental consultants found that mercury contamination was similar to adjacent sloughs in the south end of the bay, but higher than average levels in other parts of the bay. The highest levels of mercury were found in nearby ponds already owned by the U.S. Fish and Wildlife Service.

The consultants also found lead, probably from lead-based paints, and some lubricating oil in the soil surrounding residences at the Napa salt plant site.

Cargill has promised to remove those pollutants from the soil, some lead shot from a skeet shooting range, and lower the salinity in all of the ponds as required by state water pollution officials.

State officials said the full report on the pollutants will be released publicly in January before the state Wildlife Conservation Board gives final approval to the agreement.