|Facts, Not Fear
Heavy Metals in Fertilizer
Why Recycled Products?
Use of recycled products in certain fertilizer materials is a well-known practice. The primary benefit of recycling is preservation of limited space in hazardous waste landfills and provides essential macro- and micro-nutrients for plant growth.
From an agronomic standpoint, recycled products do have a beneficial value. One prime example is zinc, an essential micro-nutrient used in California at extremely low rates. As much as 80 percent of zinc sources come from recycled materials. The materials zinc is manufactured from contain naturally occurring elements — including heavy metals.
Why the Concern Over Heavy Metals?
Metals are naturally occurring elements. All life forms, human and plant, need metals like copper, zinc, chromium and iron.
At extreme levels, some studies have shown links between heavy metals and cancer, kidney disease, and neurological and immune-system problems. Research from the Tennessee Valley Authority and the National Fertilizer, the Environmental Research Center and other institutions has shown, however, that the amounts found in fertilizer materials are well below health and safety standards. Agronomically speaking, heavy metals do have value. Copper, zinc, iron and manganese, to mention only a few, are all heavy metals with well-known agricultural benefits. The fertilizer industry is keeping a close watch on the stated levels of beneficial nutrients contained in recycled materials. Through continued research and best management practices, the industry strives to insure that recycled products in the form of fertilizers are used wisely.
Are There Regulations?
In California, fertilizer products are regulated by the state Department of Food and Agriculture (CDFA), under the Fertilizer Materials Act. With regard to recycled materials, CDFA recently issued a letter on April 10, 1997, stating that the department would only regulate materials that were "beneficial" to agriculture. Beneficial is defined by the willingness of a grower to pay for the material — if a grower is paid to accept the material for application to his/her land, it is a waste operation, not a beneficial use, and therefore not under the regulation of the department.
Portions of the industry using recycled products may be subject to the regulatory requirements of the federal and state hazardous materials laws administered by the State Department of Toxic Substances Control (DTSC). The impacted firms are those processing and recycling products from a waste, resulting from another industry process. How Is The Industry Responding?
CDFA's Fertilizer Advisory Board is also finishing a study on heavy metals in fertilizers. The study, entitled the Heavy Metal Assessment Project, is reviewing how the metals move in the soil, water and air, as well as the agronomic and health impacts they may or may not have. The purpose of the study is to obtain a better understanding of the positive and negative properties of heavy metals in agriculture, and potentially provide guidelines for the industry's use/application of products that contain them. The study is due for release in late July 1997.
The importance of continued research is two-fold: it protects both the consumer and the environment. The Washington League of Food Processors recently studied potato uptake of heavy metals. The results were very reassuring — the level of uptake in the plants was minuscule, and posed no health risks. Research in California will provide factual information on potential air and water impacts of heavy metals when found in fertilizer applications. Clearly, the industry is taking a pro-active stance on ensuring public safety.
Farmers need to be cautious when applying industrial waste products that do not come from a fertilizer dealer. Some manufacturers are utilizing the fertilizer industry as another channel or market for waste materials. As stated above, CDFA does not regulate products which a farmer is given free or paid to receive. Growers should always check the Material Safety Data Sheets (MSDS) for fertilizer products, and follow handling guidelines. If a grower has questions, s/he should check with their local fertilizer dealer and/or Certified Crop Adviser.
Environmentally, both the farmer and the agricultural industry stand to benefit from continued research of recycled materials into essential nutrients. It makes little sense to apply products that could harm the soil — economically, it would be akin to "shooting oneself in the foot." Since recycling of waste products began, the fertilizer industry has been cautious of negative impacts. Only through research will answers to the question of proper best management practices become clear.