Toxic Sludge: Is it Good for You?

Can toxic waste be turned from a disposal problem into a useful and benign fertilizer? That’s the question some scientists and activists are asking about a product that is routinely used by farmers and home gardeners to feed their soils.

The U.S. Environmental Protection Agency says it “has continually encouraged the beneficial reuse and recycling of industrial wastes, including hazardous wastes, when such wastes can be used as safe and effective substitutes for virgin, raw materials.”

The key words, opponents would argue, are “safe” and “effective.” In the mid-1990s, fertilizers sickened small-town Washington farmers and killed their crops, the farmers say. The big problem, according to reporter Duff Wilson who broke the story in the Seattle Times, was that companies did not disclose the potentially dangerous chemicals their fertilizers contained, such as heavy metals.

There have been many reports of sludge-related illnesses. A 2002 scientific study published in Cornell University’s New Solutions (co-authored by E cover girl Summer Rayne Oakes) tracked symptoms, including headaches and respiratory problems, involving 328 people in 39 incidents in 15 states. The study concluded that greater investigation of health claims is needed, and that the practice of spreading sewage sludge on the soil surface “appears to present a particularly high risk.”

In 2003, a coalition of 73 groups, including the Organic Consumers Association (OCA), petitioned the Environmental Protection Agency (EPA) to place a moratorium on the land application of sewage sludge. An OCA spokesperson said the food supply was being “poisoned” by the sludge. But the petition was denied.

Patricia Martin, who was mayor of Quincy, Washington when Wilson wrote his stories, says that current rules fail to protect the public. Her group, Safe Food and Fertilizer, wants the federal government to force state regulators to cap various contaminants at set amounts.

Others say that reforms have already occurred. “Everybody understands the need to look for these contaminants because of the Duff Wilson episode,” says Rufus Chaney, a U.S. Department of Agriculture (USDA) scientist. Companies meet safe metal limits that states set, he says.

The Washington farmers got what they paid for, says George Latimer, who monitored fertilizers during the scare as the Texas State Chemist. Small-time dealers might sell their contaminated sewage sludge before regulators can stop them, Latimer says, but people who buy only well-known fertilizers are safe. “I don’t think, in general, that the consumer needs to be concerned about heavy metals in fertilizers,” he says.

But Shiou Kuo, soil scientist and professor at Washington State University’s Puyallup Research and Extension Center, sounds a cautionary note. If plants do not pick up metallic “so-called trace elements,” he says, they will remain in the soil, and could run off into surface water.

States such as Texas follow Canadian standards, which have tighter metal limits. Many other states” rules are a lot less demanding: Chaney, meanwhile, says Canada’s rules are excessive.

While both countries” fertilizer labels still list only beneficial ingredients, not potentially dangerous metals, some states now maintain on-line databases that itemize the ingredients of fertilizers. Martin says that current laws allow farmland to be “used as a disposal site.” And to that Kuo adds, “Once you find out there is a problem, it’s too late.”