The Process of Biodegrading

• Bacteria, fungi, arthropods and millions of other microorganisms ingest, dissolve and chew materials in soil, creating nutrients in their bodies. Nonbiodegradable pesticide chemical compounds often kill the microorganism population in soil. Some pesticides are transmuted by microorganisms, returning soil to its healthy balance. Metabolites and inert ingredients are added to pesticides to enhance performance or break down the chemicals in the environment. "Often the metabolite is more harmful than the parent pesticide," according to Beyond Pesticides Least Toxic Service Directory.
  
  

Active and Inert Ingredients

• The inert ingredients in many common commercial nonbiodegradable pesticides are trademarked secrets that the manufacturer is not required to reveal. The EPA does not routinely test the effects of the combination of inert and active ingredients in nonbiodegradable pesticides. Inert ingredients are not chemically, biologically or toxicologically inert. Many nonbiodegradable pesticides indicate on their labels that they contain 75 to 95 percent inert ingredients not revealed to the public.
  
  

Toxic Synergy

• Roundup is the world's top-selling nonbiodegradable weed killer pesticide. Its active ingredient, glyphosate, has an EPA toxicity category 3 rating of slightly toxic and slightly irritating. Its inert ingredients in combination with glyphosate cause cell death and reproductive abnormalities, according to a University of Caen, France, investigation. Roundup is sprayed on fields that grow genetically modified food crops.
  
  

Pesticide Resistance

• Nonbiodegradable pesticide weed control products do not completely eradicate the weeds they target, according to the New York Times. Weed species such as ragweed and horseweed now grow in fields of food crops that have been sprayed with Roundup designed specifically to eradicate those weeds. Use of chemical pesticides creates chemical-resistant weed species.