Malathion: Neurotoxic Pesticides in Our Homes


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Malathion molecule Credit: National Institutes of Health.

Malathion molecule. Image credit: National Institutes of Health.

For as long as there have been farming communities, we humans have sought ways to maximize the fertility of our crops. Whether farmers rotated their crops season after season, or monitored the rising and setting of the stars to harvest the produce, there seemed to be a limit to how much the average farmer could maximize his or her yield.

The farm-chemical boom of the 20th century, however, promised a ‘cheap and easy’ way to help the farmer and society.

Farm Chemicals: Help or Harm?

The so-called painless answer was based upon modifying the soil and the plant with chemicals.

The farm-chemical revolution may have benefited countless lives and saved communities (possibly countries as well), but the repeated application of pesticides to the soils and crops has not been a positive factor. The resultant distressed water tables and pesticide over-exposure impacts all. (The negative impact to future generations could impair the United States’ standing as a world-class economy.)

Pesticides and You

Farm pesticides are slowly creeping into daily urban settings. It may be a little-known fact that we use insecticides like malathion on a daily basis to control the mosquitos carrying the West Nile virus,  in shampoo to combat lice in children and to fight bed bugs as well. Since the general public is utilizing organo-phosphates on a regular basis, you may find malathion or its metabolite in many places other than the farmland. Why is this a problem? We call malathion a safer insecticide but it and other organo-phosphates are neurotoxins.

Maloxin molecule. Image Credit: National Institutes of Health,

Maloxin molecule: causes convulsions if enough passes the blood/brain barrier. Image Credit: National Institutes of Health

Malathion is “Less Harmful”

The specific problem with malathion is this: It is an organo-phosphate but possesses lower toxicity threshold than other organo-phosphates. In other words, it takes more of this chemical to be harmful, but you may find it in higher overall concentrations.

One may ask why  science considers malathion to be ‘less harmful’?  We can sum up the physical properties of malathion in the following terms:

  • Malathion is unstable to sunlight but it is mobile in many different types of soil or environs (e.g. carpet or bedding).
  • The half-life for this chemical can vary between 1 to 17 days.

The problem with Malathion is its ‘moniker of safety’—due to its lack of stability under variable conditions and uses in the consumer sector to combat lice or bed bugs.

Less toxic organo-phosphates, like Malathion, should come under scrutiny in the coming years. (It should be mentioned; we regularly find malathion in one form or another in water supplies. How much and how often is a matter of the seasonal application.)

Toxicity of Organo-Phosphates

Why are organo-phosphate compounds toxic? Once the malathion compound passes into the blood stream, the liver (utilizing Cytochrome P450) attempts to break down the compound to a non-toxic form. The result, unfortunately, is a more toxic form of the compound—Malaoxon. It is Malaoxon that finds its way to the ‘nerve-endings’ of peripheral nervous system, which can cause paralysis and possibly convulsions.

Malathion and Malaoxon: Toxic Pesticides

Malathion breaks down into Malaoxon; both are toxic. Although Malathion is a potent pesticide, our nation’s kids risk excessive exposure to both compounds with every lice or bedbug treatment. Because we truly do not know the effects of (long-term) low-level exposure to our youth, it may turn out badly for all involved.

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