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The Myth of Pesticides

by André Leu

The Rigorously Tested Myth

One of the greatest myths is that all agricultural poisons are scientifically tested to ensure their safe use.

A. Registered agricultural and veterinary products

Most agricultural poisons are mixtures of one or more chemicals called the active ingredient(s) mixed with other mostly toxic products, such as solvents or surfactants that are defined as "inerts".

Only the active ingredient is individually tested to determine a safety level for the Average Daily Intake (ADI). The actual registered product, which is the mixture of chemicals used by farmers, is not tested for long term effects such as cancers, hormone disruption, birth defects, nervous system damage and immune system damage.

Testing of Roundup, a mixture of the active ingredient Glyphosate, solvents and surfactants shows that this compound is more toxic than the active ingredient Glyphosate. In fact Glyphosate barely works as a herbicide without the addition of these 'inert' chemicals. 20

Most of the 7200 registered agricultural and veterinary products used in Australian food production are not tested for health and reproductive effects. This applies in most other countries, meaning there is no scientific data to determine safety levels for the actual products used on our food.

B. Chemical cocktails in food and water

Another important issue is that several different toxic chemical products are applied in the production of most foods. These can be a combination of herbicides, pesticides, fungicides and some of the synthetic fertilizer compounds.

Most foods contain a cocktail of small amounts of these toxic chemicals, which are absorbed when eaten. A study by the U.S. Center for Disease Control found a cocktail of many toxic chemicals in the blood and urine of most Americans tested.3,4, 5

Regulatory authorities assume that because each of the active ingredients is below the ADI that the cocktail is also safe. They do not test for the safety of these combinations of chemical—the chemical cocktails that we ingest everyday. Recent studies raise serious concerns. The emerging body of science demonstrates that many chemical cocktails act synergistically. This means that instead of 1+1= 2, the extra effect of the mixtures can mean 1+1= 60 or even 1000 in toxicity.

A study in the journal Toxicology and Industrial Health showed that combinations of low doses of commonly used agricultural chemicals can significantly affect health.

In experiments conducted by Warren Porter et al at the University of Wisconsin-Madison, mice were given drinking water with combinations of pesticide, herbicide and nitrate, at concentrations currently found in groundwater in the USA. They exhibited altered immune, endocrine (hormone) and nervous system functions. The effects were most noticeable when a single herbicide (Atrazine) was combined with nitrate fertilizer. 6

Atrazine is widely used in many agricultural industries including sugar cane and grain production. Atrazine is also one of the most persistent herbicides polluting much of the drinking water in the Midwestern USA, and in parts of Europe and Australia. It is measurable in corn, milk, beef and other foods in the USA and Europe.

Porter showed that the influence of pesticide, herbicide and fertilizer mixtures on the endocrine system may also cause changes in the immune system and affect fetal brain development. Of particular concern was thyroid disruption in humans. This has multiple consequences including effects on brain development, level of irritability, sensitivity to stimuli, ability or motivation to learn and an altered immune function.

A later experiment by Porter and colleagues found that very low levels of a mixture of the common herbicides 2,4-D, Mecoprop, Dicamba and inert ingredients caused a decrease in the number of embryos and live births in mice at all doses tested. Very significantly the data showed that low and very low doses caused these problems. 7

The Very Small Amount Myth—'The residues are too low to cause any problems'

The current model of toxicology (science of poisons) works on the notion that the lower the dose the less the effect of the poison. When animal testing shows that a certain dose level of poison causes no observable ill effects, this dose becomes the basis for determining the Average Daily Intake (ADI). Authorities then claim that any residue levels below the ADI are too low to cause health problems.

Research shows that the toxicology used by our authorities is inadequate in determining the safety of chemical compounds. 3,4

A significant numbers of studies show that compounds considered to have very little toxicity in parts per million (ppm) have a range of adverse effects in parts per billion (ppb). These compounds disrupt our hormone systems at levels 1000 times lower than previous research stated was safe. Agricultural chemicals have been shown to mimic hormones such as estrogen, blocking hormone receptors or stopping hormone activity. These chemicals have been implicated in lower sperm counts, increases in breast, uterine, testicular and prostate cancers and deformities in the genital-urinary tracts.4

An example of this is Atrazine—one of the worlds most commonly used herbicides. Two peer reviewed studies conducted by Tyrone Hayes showed that levels 1000 times lower than currently permitted in our food cause severe reproductive deformities in frogs. 8,9

Sara Storrs and Joseph Kiesecker of Pennsylvania State University recently confirmed Hayes' research. They exposed tadpoles of four frog species to Atrazine. 'Survival was significantly lower for all animals exposed to 3 ppb compared with either 30 or 100 ppb... These survival patterns highlight the importance of investigating the impacts of contaminants with realistic exposures and at various developmental stages.' 10

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