Pesticide Decontaminants

Depending on the particular pesticide, chlorine bleach, caustic soda (lye, sodium hydroxide) or lime can be used to decontaminate most spills. Many pesticides, especially the organophosphate pesticides, decompose when treated with lye or lime. Fewer pesticides are decomposed by bleach (sodium hypochlorite). Other pesticides cannot be effectively decontaminated, and should only be treated with detergent and water to help in removal. Check the pesticide label and Material Safety Data Sheet (MSDS) for information on cleaning up spills. Only use a little liquid. Sprinkle absorbent material on the clean-up solution, and then put the absorbent material into the disposal container with the other contaminated materials.

A practical guide for applying decontaminants is as follows:

Percent AI% ingredient Amount of decontaminant needed
1-10% Use an amount of decontaminant equal to the quantity of pesticide spilled.
11-79% Use an amount of decontaminant equal to 1.5 times the quantity of pesticide spilled,
80-100% The amount of decontaminant used should be equal to twice the quantity of spilled pesticide

WARNING: There is a slight potential for creating toxic by-products when using these procedures. In critical situations, samples of affected components (soil, sediment, water, etc.) should be taken and sent to a laboratory for analysis in order to determine if decontamination was successful.

Lye (caustic soda) or Lime

Pesticides amenable to treatment using lye or lime may be decontaminated when mixed with an excess quantity of either of these materials. These materials can be used in either the dry form or in solution. A 10% solution of lye or lime can be made as follows:

Mixing directions: Mix 0.75 pounds of lye or lime in 3.5 quarts of water to make 1 gallon of 10% solution.

Caution: Lye can cause severe eye damage to persons not properly protected. Protect against contact by wearing unventilated goggles, long-sleeved work clothes with coveralls, neoprene gloves, and chemical-resistant apron. An approved respirator also should be worn. Do not use lye on aluminum surfaces.

Bleach Treatment

Certain pesticides can be degraded by treatment with bleach (sodium hypochlorite). Generally, one gallon of household bleach, which contains approximately 5 percent sodium hypochlorite, should be used per pound or gallon of pesticide spilled. If bleaching powder is used, first mix it with water (one gallon of water per pound of bleach), and add a small amount of liquid detergent. For safety purposes, a preliminary test must be run using small amounts of bleach and the spilled pesticide. The reaction resulting from this test must be observed to make sure the reaction is not too vigorous. Do not mix chlorine bleach with amine-containing pesticides or store near them. Co-mingling of these materials can cause a violent reaction resulting in fire. Calcium hypochlorite is not recommended as a decontaminating agent because of the fire hazard.

Compiled by Ron Gardner

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