Toxic Waste Part of Many Garden Fertilizers

Even though these products may exceed federal standards defining hazardous waste, the State of California is proposing new rules that would legalize the current practice of allowing these toxics to be mixed into fertilizers according to Dr. Bill Liebhart, a soil scientist in the Agronomy and Range Science Department at the University of California at Davis, who is also a veteran of the fertilizer industry.

State data analyzed by California Public Interest Research Group (CALPIRG) and Environmental Working Group (EWG) show that more than one sixth of the commercial fertilizers tested by the state from 1994 to 1998 exceeded federal hazardous waste thresholds.

A new report by the two environment groups, "As You Sow: Toxic Waste in California Farm and Home Fertilizers" shows "fertilizer manufacturers are using California gardens and farms as dumping grounds for toxic waste," said CALPIRG toxics director Jonathan Kaplan.

Each year, U.S. fertilizer manufacturers buy tons of waste from industrial facilities such as steel mills and smelters to obtain low cost plant nutrients such as zinc or iron, the environmental groups report. Industrial waste is often heavily contaminated with toxic chemicals.

Dr. Liebhart says cadmium, mercury and arsenic and maybe dioxin and other toxic organic materials could be components of the zinc-bearing waste mixed into fertilizers. These chemicals are known to cause cancer, reproductive and developmental problems.

"If this material went into a landfill, it would have to be treated as hazardous waste," Dr. Liebhart said.

"There are reputable good products out there, but people cannot tell which ones they are," the soil scientist said.

"I don't think there's any way to know how much land has been spread with industrial fertilizers containing toxic waste. This is a nationwide problem. I can't say whether 1/10 of one percent or 10 percent or 70 percent of the land has been spread with these materials. No one knows much about this. I can't prove this causes problems -- no one can prove it doesn't," Dr. Liebhart said.

There are safe sources of zinc for these crops. Many of the normal legitimate sources of zinc fertilizer have the needed 40 to 50 percent water solubility and no toxics, he said.

"We know that contaminants in waste-derived fertilizers can get into the food chain," said Dr. Liebhart. "Guessing the highest 'safe Liebhart for these contaminants is a risky business -- and if we're wrong, it may not be possible to clean up contaminated farm fields."

Home gardeners run risks of their own, the environmental groups allege. Laboratory tests of Ironite, a popular home fertilizer, showed every sample was contaminated with lead and arsenic at two to four times the federal hazardous waste threshold, the groups claim.

But Ironite Products Company, producer of Ironite, says misunderstandings about basic mineralogy are being used to create scare tactics over their fertilizer.

Responding to the allegations of the environmental groups, Ironite said the product is a "natural soil supplement and fertilizer not manufactured from any toxic waste product but rather from naturally occurring rock containing minerals."

Ironite said, "According to the United States Environmental Protection Agency and State of Washington oral LD50 testing methods in which the prescribed maximum dose of Ironite was fed to laboratory rats, Ironite is not considered toxic if accidentally ingested. In fact, Ironite was found safer than common table salt."

But the two environmental groups are not convinced. "Last year, Washington State health officials warned consumers that ingestion of less than half a teaspoon of Ironite could be toxic to small children," the groups said.

CALPIRG and EWG are urging California retailers to stop selling Ironite until the state requires that the package carry a health warning. "We see no justification for allowing products like Ironite on the market," said Bill Walker, California director of EWG. "At the very least, the label should inform consumers that the product contains high levels of persistent toxins."

But the whole controversy is based on misunderstanding, according to the company. Ironite contains small amounts of two naturally occurring minerals -- galena and arsenopyrite.

Galena is a combination of lead and sulfur molecules fused together by millions of years of heat and pressure. Arsenopyrite is a combination of arsenic, iron and sulfur, also fused together by millions of years of heat and pressure.

"The lead in galena and the arsenic in arsenopyrite are chemically bonded within the minerals, rendering these elements unavailable for uptake by plants and humans," said Paul Bergstrom of Knight Piesold, an environmental consulting firm in Denver cited by Ironite.

"The results of our risk assessment report found that prolonged use of Ironite does not represent a health risk to residents when applied as recommended on the label," said Will Humble of the Arizona Department of Health Services, Office of Environmental Health.