"astelands: The threat of toxic fertilisers," released recently by the national and state Public Interest Research Groups (PIRG) of the United States, reveals that a total of 22 toxic metals, including arsenic and lead , were found in the common fertilisers in the US. Fertiliser products become contaminated when manufacturers buy toxic wastes from industrial facilities to obtain low cost plant nutrients such as zinc or iron.

Such industrial waste are often highly contaminated with persistent toxic chemicals, including heavy metals and dioxins. "When industrial facilities generate toxic waste, pass it off to fertiliser manufacturers and call it recycling, they're playing a dangerous game with our environment and our health" says Jeremiah Baumann, environmental health advocate for the US PIRG.

The fertilisers are 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 cease 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.

Spreading the contaminants found in fertilisers on farm soils is of particular concern because lead, cadmium , mercury and other contaminants persists 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 fertilisers says that eating food grown with contaminated fertilisers is the greatest single source of exposure to these contaminants for commercial products.

The fertiliser Institute of the US, an industry group, acknowledges that some fertiliser products contain very small amounts of metals that are no 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 fertilisers. However, the institute states that "three separate scientific studies on the safety of these metals in fertilisers have all come to the same conclusion - that they generally do not pose to human health or the environment."

The assessments were conducted by the CDFA, the EPA and the Fertiliser 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 fertilised soil, or ingestion of corps grown on fertilised soil. Accordingly to a PIRG report, between 1990 and 1995, 600 companies from 44 different states sent 270 million pounds of toxic waste to farms and fertiliser companies across the country.

The steel industry provided 30 per cent of this waste, which is used because of its high levels of growth-promoting zinc. Because fertilisers are sold directly to the public and farmers without warnings or information that inform consumers about the presence and quantity of toxic metals. Also, there is no indication on fertiliser labels whether the fertilisers have been further treated to meet federal land disposal standards.

Another report brought out by the US Environment Protection Agency states that agriculture is the biggest polluter of America's rivers and streams. It pollutes more than 1,73,000 miles of waterways with run-off containing soil particles, fertilisers, pesticides and animal wastes. Farming is responsible for 70 pr cent of waterway pollution, more than sewage treatment plants, urban storm water and pollution deposited from the air. Heavy dependence on soluble chemical fertilisers results in nutrient-rich runoffs reaching water bodies.

In Gore, Oklahoma, a uranium processing plant gets rid of low level radioactive waste by licensing it as a liquid fertiliser and spraying it over 9,000 acres of grazing land. At Camas, Washington, lead-laced waste from a pulp mill is hauled to farms and spread over crops destined for livestock feed. In Moxee City, Washington, dark powder from two Oregon steel mills is poured from rail cars into silos t Bay Zinc Co. under a federal hazardous waste storage permit. Then it is emptied from the silos for use as fertiliser. Wastes also come from the incineration of medical and municipal wastes, and from heavy industries, including mining, smelting, cement kilns and wood products.

The environment Protection Agency (EPA) of the US has always 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 majority of fertilisers made from recycled hazardous wastes are zinc micronutrients, which are applied sparingly to farmlands (typically, a few pounds per acre a year), and used to fertilise crops such as corn, potatoes, and fruit trees.

Currently, the EPA proposes to modify regulations for Zinc fertilisers made from recycled industrial wastes. These modifications will conserve natural resources, prevent pollution, and save money. The revised provisions are expected to improve and increase legitimate zinc recycling, and reduce contaminants levels in these types of fertilisers. While ensuring that recycled zinc fertilisers are beneficial and clean, regulatory restrictions on this industry will be streamlined, saving the sector around $7 million.

Virtually all stages in the US have regulatory programmes for fertilisers, which are administered by state agricultural agencies primarily to ensure that fertilisers meet the manufacturer's plant nutrient claims, and that they are accurately classified and labeled. Since the EPA regulates contaminants in only a very small percentage of the fertilisers currently on the market (perhaps as little as one per cent or less), the Agency supports and encourages these state efforts.

These reports once again raise the doubt over chemical inputs in agriculture. Though, in India, industrial wastes are rarely used for fertiliser production, self -sufficiency in this field still eludes us. We have to improve a large quantity of chemical fertilisers and, certainly, there is no check on imported fertilisers and pesticides. No one knows how many tones of toxic metals are being added in the soil and crops along with imported fertilisers. The PIRG report also raises the doubt over the quality of imported food items in terms of toxic metal and hazardous chemical content.