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Test Results of San Francisco's Sludge Don't Satisfy Critics

When activists dumped processed sewage compost on the steps of San Francisco City Hall in March, the stunt was meant to draw national attention toward a supposed hypocrisy afoot in the greenest city in America.

San Francisco, activists claimed, was poisoning its residents by giving away “toxic sewage sludge,” a mixture of treated sewage and yard waste for use on home gardens that’s a stew of all that goes down the city’s drains and sewers.

Reeling from the controversy, the San Francisco Public Utilities Commission immediately suspended the giveaway program and this summer completed a series of expensive tests in an effort to prove its safety. Results in hand, the commission pronounced the “biosolids compost,” as it is officially called, no worse than the packaged fertilizers sold at commercial garden stores. The giveaway program, however, remains in limbo until a September commission meeting.

The controversy, which is far from over, is part of a national debate on what to do with the country’s 3 million dry tons of sewage sludge produced each year. Proponents see biosolids as a resource that improves soil nutrients and recycles waste back into the natural system. Yet a growing number of communities are opposing the use of biosolids out of fear that it spreads harmful contaminants and pathogens, and in some cases smells bad.

“Toxic sewage sludge shouldn’t be used, period,” said John Stauber of the newly formed Food Rights Network and author of the 1995 book “Toxic Sludge Is Good for You.” “We’re not talking about human manure. We’re talking about everything that goes down the drain is ending up in sludge.”

In California, concerns have been notably fierce. In Kern County, the state’s breadbasket, a county ban on the land application of processed sewage sludge from Los Angeles was upheld by the U.S. Ninth District Court in a precedent-setting case. (The U.S. Supreme Court refused to take Los Angeles’ appeal in June.)

Inadequate and outdated

Meanwhile, communities like San Francisco that have permitted its use have been doing so under federal regulations. Some independent experts, however, say that the U.S. Environment Protection Agency’s regulatory rule, to which San Francisco is abiding, is inadequate and outdated.

“The EPA rule came out in 1993 and was based on science from the 1970s and 80s,” said Murray McBride, a soil chemist and head of the Cornell University Waste Management Institute.

McBride, who studies biosolids, said that many other chemical compounds appearing in the waste are not routinely tested before land application. The EPA requires testing for nine heavy metals, but not dangerous and long-lasting chemicals like DDT and PCBs, which have been phased out for more than three decades but still appear in the environment.

Nor do the testing requirements take into account a host of emerging chemicals of concern that have been introduced into the environment in higher concentrations over time, like endocrine-disrupting flame retardants, phthalates and the antibacterial agent triclosan.