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Outrage in San Francisco: City Gives Residents 'Organic' Compost Containing Toxic Sewage Sludge

The city's actions are a wake-up call that the entire nation regularly consumes foods grown on fields fertilized with sludge.

When San Francisco, one of the greenest cities in America, offered its residents free compost, many were excited to take it. After all, purchasing enough compost for even a small 10 x 10-foot garden can cost over $50, and generating one's own compost in high enough quantities for such a garden takes a long time.

Few of the gardeners who lined up to receive the free compost at events like last September's Big Blue Bucket Eco-Fair suspected that the 20 tons of free bags labeled "organic biosolids compost" actually contained sewage sludge from nine California counties. On Thursday, March 4, angry San Franciscans returned the toxic sludge to the city, dumping it at Mayor Gavin Newsom's office in protest.

Sewage sludge is the end product of the treatment process for any human waste, hospital waste, industrial waste and -- in San Francisco -- stormwater that goes down the drain. The end goal is treated water (called effluent), which San Francisco dumps into the Pacific Ocean and San Francisco Bay. But the impurities and toxins removed from the water do not go away. With the water removed, the remaining byproduct is a highly concentrated toxic sludge containing anything that went down the drain but did not break down during the treatment process. That usually includes a number of heavy metals, polycyclic aromatic hydrocarbons, pharmaceuticals, steroids, flame-retardants, bacteria (including antibiotic-resistant bacteria), fungi, parasites and viruses.

On its Web site, San Francisco's Public Utilities Commission describes a "green" process, in which its own sludge is treated until it qualifies as "Class B Biosolids" and is then applied to farmlands in Solano and Sonoma counties. A small percentage undergoes further treatment to qualify as "Class A Biosolids" -- that's the stuff San Francisco's gardeners have been receiving as free "compost" since 2007. (The major difference between Class A and Class B is the amount of fecal coliforms present in the sludge. While it's lower in Class A, studies show it regrows in the compost after the treatment process is over.)

Along with San Francisco's sludge, the "compost" contains sludge from eight other California counties (Alameda, Contra Costa, Marin, Napa, San Mateo, Santa Rosa, Solano and Sonoma) and equal parts yard waste and wood chips. But the fact that the sludge qualifies by law as safe to spread on farms and gardens does not make it so.

The EPA only requires treatment plants to kill off any fecal coliforms in the sludge and ensure that nine heavy metals (arsenic, cadmium, chromium, copper, lead, mercury, molybdenum, selenium and zinc) are not present in unacceptable levels. But that only cleans up a tiny fraction of the harmful substances present in the sludge. A recent EPA study of 84 sludge samples from around the country found 27 metals, three pharmaceuticals (Ciprofloxacin, Diphenhydramine and Triclocarban), four anions (nitrates/nitrites, fluoride and water-extractable phosphorus), three steroids (Campesterol, Cholestanol and Coprostanol), and a number of toxic flame-retardants in nearly every single sample tested.

Many of the other contaminants tested for showed up in a high percentage of samples as well. While the study did not take into account whether these sludge samples were intended for spreading on agricultural land, nearly every one of the samples legally qualified as Class A or Class B biosolids and could have been spread on farm fields. (The study noted that the few samples with molybdenum, nickel or zinc exceeding federal limits for land application sent their sludge to landfills or incinerated it.)

When confronted by angry gardeners who had been duped into applying toxic sludge to their gardens, city and state authorities defended their actions. The California Association of Sanitation Agencies insisted that because San Francisco has "virtually no industrial facilities within its borders or sewer service area," the waste was not a combination of "industrial, commercial, hospital, and household wastewater." But, according to Organic Consumers Association, the San Francisco Public Utilities Commission (SFPUC) has documented the following in San Francisco sludge alone: p-Isopropyltoluene (an industrial chemical used in the manufacture of paint, furniture, etc); 1,4-Dichlorobenzene, a disinfectant, deodorant and pesticide; Tolulene (an aromatic hydrocarbon widely used as an industrial feedstock and as a solvent); 1,2,4-Trimethylbenzene (a product of petroleum refinery distillation); and Phenol (used in the manufacture of drugs, antiseptics, nylon and other synthetic fibers). [Full disclosure: I am on the policy advisory board of Organic Consumers Association.]

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