talking trash

Farm fields: ideal resting place for toxic waste?
Last summer, in a series of revelations that nearly snagged a Pulitzer Prize, Seattle Times writer Duff Wilson documented a nationwide practice of recycling some industrial wastes as fertilizer. Gaps in state and federal regulation were allowing toxic and radioactive wastes that contain nutrients to be combined with fertilizer and spread without notifying farmers, much less consumers.

According to Wilson's series:

  bullet "In Gore, Okla., a uranium-processing plant is getting rid of low-level radioactive waste by licensing it as a liquid fertilizer and spraying it over 9,000 acres of grazing land.


  bullet In Tifton County, Ga., more than 1,000 acres of peanut crops were wiped out by a brew of hazardous waste and limestone sold to unsuspecting farmers.


  bullet And in Camas, "highly corrosive, lead-laced waste from a pulp mill is hauled to Southwest Washington farms and spread over crops grown for livestock consumption."

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When Tom Witte and his sons were tested for toxins, high levels of antimony, lead, arsenic and cadmium were discovered. Some of the same elements were found in this abandoned liquid-fertilizer tank on his land in Quincy, Wash.
©Mike Siegel / Seattle Times. Used with permission.
  Since the series was published, the Environmental Working Group, a Washington, D.C., research organization, has been examining federal Toxic Release Inventory (TRI) data to substantiate some of the reports. "A total of 454 companies identified as farms and fertilizer manufacturers in the TRI received 271 million pounds of toxic waste in the period 1990 to 1995," the group reported. "Along with nutrients like zinc and nitrogen were copious amounts of lead, cadmium and all manner of solvents and other industrial chemicals -- 69 different types of toxics in all."

A public-health emergency?
How bad is the situation? Nobody knows. There's no evidence for damage to human health -- yet -- but it's hard to hear much enthusiasm for the status quo. Tom Witte and his sonsRegulators have begun to address the situation. The American Association of Plant Food Control Officials, an interstate group representing fertilizer regulators, has drafted a model state bill concerning heavy metals in fertilizers.

John Mortvedt, a retired soil scientist who spent 30 years studying fertilizer contaminants at the Tennessee Valley Authority's National Fertilizer and Environment Research Center, in Muscle Shoals, Ala., says uniform regulation would help ease the flow of materials that can sometimes be recycled beneficially.

He points out that "less than one percent of all commercial fertilizers used in the United States contain such recycled by-product." And if nutrients or soil improvements can be had cheaply, without placing a toxic burden on the landscape where our food is grown, the process seems unobjectionable.

Consolidated Papers, for example, recycled 161,000 tons of paper mill sludge in 1996 to farmers near its plant in Wisconsin Rapids, Wis. The nitrogen replaces conventional fertilizer. The organic matter in a material that resembles soggy cardboard helps the sandy soil hold more water and nutrients, says John Peters of the University of Wisconsin's Marshfield Experimental Station.

According to Greg Kester, the residuals coordinator at the Wisconsin Department of Natural Resources, Consolidated must analyze its sludge before disposal for 125 chemicals, including heavy metals, dioxin, and organic pollutants. Since the paper is no longer bleached with chlorine, "dioxin is not an issue," Kester says. Indeed, concentrations of TCDD, the most hazardous form of dioxin, were uniformly below one part per trillion in the 1997 analyses.

Although it's sometimes called "sludge," industrial wastes are distinct from sewage sludge, whose use on farmland has been extensively studied and regulated.

Nothing pure except love
In assessing the threat posed by using waste as fertilizer, it's important to remember that soils already contain some toxic metals and compounds. According to Mortvedt, the average farm soil contains about 10 parts per million of lead. The contaminants in industrial waste usually measure in parts per million or parts per billion levels, he adds, and when applied to the soil, "they are further diluted. They become inconsequential at some level."

And yet since nobody's testing this "fertilizer" today to find out what it contains, there's plenty of room to argue that the practice constitutes an unwise tampering with our food supply. (Speaking of which, did you catch our coverage of transgenic crops or food irradiation?) However, Mortvedt says tests performed by the U.S. Department of Agriculture and Food and Drug Administration on food obtained in supermarkets have shown steady or falling levels of some heavy metals over the past 15 years.

Still, when it comes to food, safer is better than sorrier, and consumers -- and farmers -- have the right to know what's being used. In view of the hazards, "Some type of regulation is probably merited, but if you are having to analyze every truckload of fertilizer, that is probably over-regulation," says Mortvedt. One approach would be to use the kind of risk-assessment that underlies the EPA's sewage sludge recycling rules.

If recycling industrial waste seems questionable, want to hear some more promising ideas?


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