Toxic Wastes Found in Fertilizers

By Cat Lazaroff

WASHINGTON, DC, May 7, 2001 (ENS) - Americans are unknowingly purchasing fertilizers made from industrial toxic waste, turning farms and gardens into dumping grounds for the waste, charges a new report. The report lists 20 fertilizers that contain levels of toxic metals that exceed limits set on wastes sent to public landfills.


Heavy metals in fertilizers can wash into nearby waterways, contaminating drinking water and harming wildlife. Here, Agricultural Research Service technician Jeff Nichols collects a water sample from the Walnut Creek watershed in Ames, Iowa (Photo by Keith Weller. All photos courtesy Agricultural Research Service)
"Waste Lands: The Threat of Toxic Fertilizer," released last week by the national and state Public Interest Research Groups (PIRG), reports on tests of 29 fertilizers bought in 12 states. A total of 22 toxic metals were found in the fertilizer products, including arsenic and lead.

"It's unacceptable for fertilizer manufacturers to use farms and gardens as a dumping ground for toxic waste," said Jeremiah Baumann, environmental health advocate for U.S. PIRG. "When industrial facilities generate toxic waste, pass it off to fertilizer manufacturers, and call it recycling, they're playing a dangerous game with our environment and our health."

Fertilizer products become contaminated when manufacturers buy toxic waste from industrial facilities to obtain low cost plant nutrients, such as zinc or iron. Such industrial wastes are often highly contaminated with persistent toxic chemicals, including heavy metals and dioxins.

Fertilizers were purchased in 12 states and tested by Frontier Geosciences, an independent laboratory based in Seattle and accredited by the U.S. Environmental Protection Agency (EPA). The fertilizers were found to contain arsenic, lead, mercury, cadmium and chromium, among other toxic metals, and the toxic chemical dioxin.

Many of these contaminants are known to cause cancer, reproductive and developmental toxicity or other serious health effects. Lead, mercury, cadmium and dioxin are known to accumulate in the fatty tissues of animals and humans.

Arsenic has been in the public spotlight as a result of the Bush administration's decision to reconsider new limits on arsenic in drinking water.


Adding fertilizer can increase crop yields. Here, soil scientist Eton Codling notes excellent corn growth on treated soil (Photo by Scott Bauer)
The results come as the EPA is reviewing comments on a proposed rule to limit heavy metals and dioxin for zinc fertilizers and label these fertilizers for toxic substances.

"There is no justification for putting products that contain toxic wastes on the lawns where our children play, or on the land where we grow our food," said Baumann. "EPA should not just be limiting the amounts of toxic waste in fertilizers - they should be prohibiting toxic wastes in fertilizers."

Spreading the contaminants found in fertilizers on farm soils is of particular concern because lead, cadmium, mercury and other contaminants persist in soil for decades, and can be absorbed by food crops. A California Department of Food and Agriculture (CDFA) assessment of the health risk posed by toxic fertilizers says that eating food grown with contaminated fertilizers will be the greatest single source of exposure to these contaminants for commercial products.

The Fertilizer Institute, an industry group, acknowledges that "some fertilizer products contain very small amounts of metals that are not beneficial to plant growth. These metals occur in products because they occur in nature as part of the ore bodies or in the raw materials used to make fertilizers," such as recycled wastes, states the Institute's website.

However, the Institute states that "three separate scientific studies on the safety of these metals in fertilizers have all come to the same conclusion - that they generally do not pose a threat to human health or the environment."


Heavy metals can accumulate in crops, creating a danger to human health
The assessments were conducted by the CDFA, the EPA and The Fertilizer Institute, the industry group says. All three assessments considered the impact of metals on farm families, both children and adults, who might be exposed through skin contact, breathing dust, unintentional ingestion of fertilized soil, or ingestion of crops grown in fertilized soil.

The state of California is now in the process of establishing limits for three metals in fertilizer products - arsenic, cadmium and lead - based on the results of the CDFA assessment.

The EPA study, available at:, first studied the patterns of fertilizer use, exposure and levels of metals in fertilizer, and then analyzed various exposure pathways for farm families and runoff into water bodies. EPA concluded "hazardous constituents in fertilizers generally do not pose harm to human health or the environment."

The Fertilizer Institute said it has established safe screening levels for 12 metals in fertilizer products, and has compiled a database of actual measured levels of metals in fertilizer products. This database comes from a survey of fertilizer companies, a literature survey and data provided by state regulatory officials.

"When the safe screening levels are compared to actual measured levels, measured levels are generally far below safe levels," the industry group says. "This means there are large margins of safety."


Technology can reduce the amount of fertilizer used. Mounted on a high clearance sprayer, crop canopy sensors monitor plant greenness, which is translated into a signal by an onboard computer that controls the application rate of nitrogen fertilizer (Photo by James Schepers)
But the new report by U.S. PIRG and the state PIRGs argues that stricter criteria and safety standards are required to keep toxic wastes in fertilizers from harming the public.

According to the report, between 1990 and 1995, 600 companies from 44 different states sent 270 million pounds of toxic waste to farms and fertilizer companies across the country. The steel industry provided 30 percent of this waste, which is used because of its high levels of growth promoting zinc.

Because fertilizer labeling laws only require beneficial nutrients, like zinc or phosphate, to be listed, fertilizers are sold directly to the public and farmers without warnings or information that informs consumers about the presence and quantity of toxic metals. Also, there is no indication on fertilizer labels as to whether the fertilizers have been further treated to meet federal land disposal standards.

All commercial fertilizers made from recycled materials such as hazardous wastes, and produced for the general public's use are subject to the federal Land Disposal Restrictions (LDRs). Land disposal restriction standards, which are limits set to keep hazardous wastes from leaching from a lined landfill, exist for 13 of the 22 metals found in the fertilizers tested.

Twenty fertilizers tested higher than the LDR's mandated levels of concern. One fertilizer, The Andersons 0-0-0, 36 Percent Zinc, exceeded six levels of concern, and contained the highest levels of antimony, cadmium, chromium, nickel, silver and lead of any fertilizer tested by the PIRGs.


The Department of Agriculture's compost research facility in Maryland tests technologies for turning farm, urban and industrial wastes into fertilizer (Photo by Ken Hammond)
While exceeding these levels of concern is not an indication that a fertilizer has violated the law, the amounts of metal contaminants measured in the report indicate that some tested fertilizers have the potential to violate federal regulations.

The PIRG report recommends that the EPA and state environmental agencies ban the use of hazardous wastes for manufacturing fertilizers, and adopt expanded right to know provisions for all hazardous wastes going into fertilizer. Fertilizers should not be exempted from hazardous waste treatment, storage and disposal tracking requirements, the report notes.

"We know that contaminants in waste derived fertilizers can get into the food chain," said U.S. PIRG's Baumann. "Guessing at the highest 'safe level' for these contaminants is risky business, and if we're wrong, it may not be possible to clean up contaminated farmland."