Once More Into The Valley of BioSludge Rode the Tranquil Gardener

Gardening used to be so simple. You'd bury a dead fish, poke some corn seeds into the soil, and wait for rain. Or you'd rake up some horse manure and chop it into the soil. Or, when manure was scarce, you'd use plant wastes to make compost and put that into the soil.

Today you fire up your automobile, drive to a garden center, buy bags of soil amendment, sacks of fertilizer, and plastic flats of mass-produced flowers and vegetables. You plant them according to directions, irrigate with a hose, and watch your garden grow. But if you're concerned about how your gardening fits into the larger picture and about what's going into the soil and into your body, you might begin to worry about what's really in that bag of fertilizer, whether the plastic flats are recyclable, whether the workers who produce the flowers are decently-paid, and whether the water that comes out of the hose is clean. Eventually you may find yourself, as I did, poring over the EPA's 2009 Targeted National Sewage Sludge Survey and wondering how pesticides, pharmaceuticals, flame retardants, and steroids ended up in your store-bought compost.

When Kellogg Garden Products VP and corporate spokesperson Kathy Kellogg Johnson emailed me about my recent column “Trust but Verify," she suggested I apply that standard to things I read on the internet as well as to bagged soil mixes. She's right, of course. I let her know that I had previously contacted Kellogg's to ask whether their “N-rich” compost contained composted sewage sludge, aka bio-solids. I was told that it didn't. I believe them, in part because N-rich seems too coarse and woody to be biosolids but also because Kelloggs has been under such public scrutiny lately that I doubt they'd fudge on sludge.

Ms. Johnson did admit that 4 of Kellogg's 276 products do contain biosolids (identified as compost on their labels) and she went on to defend bio-solids as a sustainable product. Some of the controversy surrounding Kellogg arose from an article by Mitch Anderson in which he claimed that “70 percent of Kellogg's fertilizers are made with biosolids." It seems his source was a 2008 page on the website of the Twin Cities Metropolitan Council. I checked with the Metropolitan Council and learned that the page no longer exists and no one knows the source of the 70 percent figure; the person who wrote it no longer works there. So I guess that particular figure will have to remain unverified. However, since the 4 products containing biosolids (Amend, Gro-mulch, Nitrohumus, and Topper) are Kellogg's biggest sellers, it's conceivable that, in terms of volume, biosolids comprise more than just 1.5 percent of Kellogg's sales.

Regardless of the amount of biosolids sold by Kellogg, it's clear Kellogg considers them safe. The National Organic Standards Board does not agree and specifically excludes sludge from organic production. I've always thought sludge was a problem, not because of the composted night soil, which has been used as a fertilizer for thousands of years, but because it contains heavy metals and those other substances found in the EPA's survey. I recall our own EBMUD making a brief foray into the bagged sludge market a couple of decades ago. Everyone I knew was much too wary to buy a bag. Today some of our sludge, categorized as Class B biosolids, goes to farms in the San Joaquin Valley to fertilize cotton, alfalfa and other non-edible crops. The rest is used to cover landfills.

For my part, I'll no longer trust any soil amendment that lists compost as an ingredient, at least until the state of California takes over registering soil amendments. Even then I'll exercise a healthy skepticism. I guess one of the most distressing facets of modern life is that we're continually called upon to take risks with our health, weighing known and unknown hazards in the environment with the assurances of experts. In this network of distant commercial relationships, we are utterly dependent on the kindness and competence of strangers. Our waste-water system, like the storm drains that funnel hydrocarbons, pesticides, and other nasty stuff from the streets into the estuaries, was not designed to separate out toxic chemicals. Everything that goes down everyone's drain ends up in the sludge. In their survey the EPA found a couple of antimicrobials in every sludge sample they tested. Microbes are the garden's engine room. They run on the highest quality fuel. Despite Ms. Kellogg's confidence in the purity of her biosolids, I'd rather not take the chance that the fuel I give the microbes might be poisoning them.

No, gardening is not simple anymore. After years of regularly mixing peat and vermiculite to make organic seed starting mix, I learned that the vermiculite dust I'd been inhaling may well have contained asbestos, courtesy of WR Grace & Co. And the fish Squanto buried under that hill of corn would now likely be contaminated with mercury courtesy of coal-fired power plants. As we continue to reap what we and others have sown, trusting but verifying seems frustratingly difficult but increasingly necessary.