Monday, August 27, 2007

Toxic Fertilizers

The recycling of hazardous industrial wastes into fertilizers introduces several dozen toxic metals and chemicals into the nation's farm, lawn and garden soils, including such well-known toxic substances as lead and mercury. Many crops and plants extract these toxic metals from the soil, increasing the chance of impacts on human health as crops and plants enter the food supply chain. The steel industry provided 30% of this waste. Used for its high levels of zinc, which is an essential nutrient for plant growth, steel industry wastes can include lead, arsenic, cadmium, chromium, nickel and dioxin, among other toxic substances. With little monitoring of the toxics contained in fertilizers and fertilizer labels that do not list toxic substances, our food supply and our health are at risk. 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. Inadequate labeling requirements mean consumers do not have the necessary information to make informed decisions about products at the time that they are purchased to best protect the health of their families.

Each of these metals is suspected or known to be toxic to humans and the environment. Nine metals, like arsenic and lead, are known or suspected to cause cancer and ten metals, like mercury, are linked to developmental effects. Beryllium is a suspected carcinogen, chromium and arsenic are known to cause cancer and barium can cause kidney and lung damage. Three of the tested metals – lead, cadmium and mercury – are also persistent bioaccumulative toxins (PBTs). PBTs persist for long periods of time in the environment – some indefinitely – and they can accumulate in the tissues of humans and wildlife, increasing the long-term health risks at even low levels of exposure. These three metals cause cancer, birth defects, or reproductive problems. Children are most susceptible to the toxic effects of most metals, especially lead, which has been the subject of intense government efforts to reduce lead exposure to children. Products like fertilizer are of great concern as children spend more time on or near the ground and are often exposed to ground level substances through hand-to-mouth behavior.

Toxins in fertilizers accumulate in agricultural soils, become available for plant uptake, and run off into waterways.

Farming, especially single-crop farming, requires consistent and dependable soil conditions. The introduction to farm soils of toxic substances like lead and cadmium can adversely affect growing conditions and result in increased toxic accumulation as these metals are highly persistent in soils. This can negatively affect critical growing requirements, such as soil acidity or the solubility of beneficial metals like zinc in the soils.

Some crops are more likely than others to absorb non-nutrient toxic substances from soils. For example, fruits and grains can absorb lead, and lettuce, corn and wheat can absorb cadmium from soils. This means that our food supply is at risk of contamination by toxic substances that could threaten human health.

The overall health of waterways has declined dramatically over the last quarter-century. Most of our rivers, lakes, and estuaries are still too polluted for safe fishing or swimming. Agricultural runoff is a common cause of waterway pollution. A recent report found that metals are the second most common pollutants found in lakes, ponds, reservoirs, and estuaries. In fact, agriculture is the industry most responsible for lake pollution. The introduction of toxic substances from fertilizers to agricultural environments will only add to their concentrations in waterways.

Toxic fertilizers must be banned.

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