In an effort to protect themselves against the dangers of synthetic fertilizers, home gardeners often choose “organic” fertilizers. Buyer beware: organic fertilizers can be equally dangerous.We recommend that consumers, including farmers, avoid using any manure, including poultry. Here’s why. In 1980 the poultry and beef industry asked the FDA to lift the prohibition on feeding animal feces to other animals. This created a cost saving waste-exchange program for these large industries. The cattle industry would rid themselves of what the FDA referred to as the 4-D cattle, i.e., dead, dying, diseased or disabled, by feeding their remains as a protein source to poultry (chickens and turkeys). Poultry feces would then be fed as a nitrogen source to cattle. What this means to the consumer is that prions that cause mad-cow and Creutzfeld Jacobson’s Disease (the human variant CJD) may be in both these manures. Obviously, it has ramifications to the food supply as well. Bovine bone and blood meal should also be avoided.
For more information on poultry manures and the threat to our food supply check out our Earth Island Journal article from 2006.
Unless you know exactly where the manures come from and the inputs to the animals, manures are best avoided for the same reasons human sewage should not be used.
For your own protection we recommend that you keep a sample of each fertilizer you use and that you take a background sample of your home garden. See Recommendations for Farmers.
Heavy Metals
Heavy metals are very toxic even in small amounts. Don’t let the industry fool with their clever spins about “trace metals” and other analogies that make levels like 1 ppm (one part per million) sound benign. In most cases, 1 ppm is nothing to worry about, but in others it is. For example, 1 ppm of mercury would exceed what is allowed into Subtitle C hazardous waste landfills, and 1 ppm of cadmium is more than some countries allow in their fertilizers. Look for fertilizers that don’t contain either of these toxins.
Recommendations for Farmers
Because one farmer against a fertilizer giant is sure to be a long and costly legal battle should there ever be a problem, we recommend that farmers protect their farms and families by taking the following steps:
1. Analyze your soil and save samples.
2. Ask for split samples of all agricultural products applied to your land. To be sure you are getting a representative sample, ask for it and take it directly from what is being applied to your field.
3. Request a copy of the MSDS (Material Safety Data Sheet) for each product you are purchasing. You may want to rethink your purchase if the MSDS has a disclaimer regarding the merchantibility of the material as a product or if it requires that any unused portion be properly disposed in accordance with federal hazardous waste law (RCRA).
4. Retain samples of feed and minerals fed to animals and ask for a MSDS for these as well.
5. Whenever purchasing farmland analyze the soil for heavy metals prior to purchase.
If your crops, livestock or property are harmed the only proof you will have is what you have collected in advance of the damage. All laboratory analysis should be conducted through an independent lab that is not affiliated with agricultural dealers.
Farmers who lease their land should be extra vigilant. In Washington State a loophole in the law gives those who lease land the same authority over it as the land owner. Whether other states have similar loopholes we do do not know. Dennis DeYoung’s land was damaged after he leased the land to another farmer who was paid handsomely to spread waste on it. Knowing the background levels of metals in your soil and retaining a sealed sample is the best protection you can provide to yourself if you choose to continue to use synthetic fertilizers.
Fertilizer Analysis & Databases
When reviewing the various databases and other fertilizer analysis available (see Reports and other Useful Information below) please keep in mind that many times the analysis provided is not independent. Analysis conducted by the state is best.
Also, be wary of analysis with high detection limits, e.g., cadmium <10 ppm. This kind of analysis is not sensitive enough to provide you with meaningful results, nor would it be protective of human health. In all cases where results are represented behind a “<” sign you should assume that the level of contaminant is equal to that behind the “<” sign.
Levels at which fertilizer may be toxic
Toxicity is one of four characteristics for which a solid waste may be deemed hazardous. Ignitability, corrosivity and reactivity are the other three. Toxicity is a characteristic most often measured by the Toxic Characteristic Leaching Potential (TCLP), a meaningless test with regard to fertilizer since it does not consider plant uptake, run-off, airborne particulates or bioaccumulation in soil. The TCLP was designed to simulate the leaching that would occur in a municipal landfill that contains 95% household waste and 5% hazardous waste. It has nothing to do with fertilizer.
That being said, the following total metal estimates are the lowest levels at which a hazardous waste could be disposed in a lined Subtitle C, i.e., hazardous waste, landfill:
Arsenic 100 ppm
Cadmium 2.2 ppm
Chromium (total, i.e., both III and VI) 12 ppm
Lead 15 ppm
Mercury 0.5 ppm
Zinc 86 ppm