photo by Kevin Lallier

At this point, most people are at least somewhat aware that pesticides cause a great deal of environmental harm. Less well known are the effects pesticides have on individual and public health. Here, I give you 5 compelling reasons to avoid pesticides.

A quick note: This list is a little data-heavy.  To start, it will help to read through the bold lines first, and then go back to see the data behind each claim.

1. Acute exposure can kill you.

“Late in the afternoon of April 1, 1990, a three-year-old girl playing in front of her trailer home in California’s San Joaquin Valley suddenly lost control of her body and began foaming at the mouth. By the time the girl arrived at the local emergency room, she was near death. She recovered eventually. A report filed with the California Department of Pesticide Regulation concluded the child had been poisoned by aldicarb, a highly toxic insecticide that works the same way on people as it does on bugs — like nerve gas. ‘Somebody had parked a tractor with pesticide material on it right in front of the play area,’ said Michael O’Malley, the author of the report and a physician at the University of California, Davis.”
– Matt Crenson, Associated Press, December 9, 1997

Some common symptoms of over-exposure include burning, stinging, or itchy eyes, nose, throat and skin; nausea, vomiting, diarrhea, wheezing, coughing, headache. These symptoms can range from mild irritation to death. These symptoms are often misdiagnosed and not attributed to pesticide poisoning. [Peel Public Health]

2. Chronic exposure to pesticides can lead to neurological damage, including Parkinson’s and Alzheimer’s disease.

Several studies have shown a link between pesticide exposure and the onset of Parkinson’s disease, Alzheimer’s disease, as well as other neurological conditions such as epilepsy. The main path of exposure is airborne: breathing pesticides. Recently, UCLA researchers looked at Central Valley residents diagnosed with Parkinson’s disease, and found that “years of exposure to the combination of these two pesticides [the herbicide paraquat and fungicide maneb] increased the risk of Parkinson’s by 75 percent. Further, for people 60 years old or younger diagnosed with Parkinson’s, earlier exposure had increased their risk for the disease by as much as four- to six-fold.” [ScienceDaily]

Dr. Patrick Carr of the University of North Dakota finds that low doses of pesticide exposure induces physical changes in the brain, shown in a PET scan. These changes correlate to “a loss of neurons in particular regions of the brain.” Other regions not experiencing a loss instead express different amounts of neurotransmitter chemicals, altering the delicate chemical balance in the brain. [MPRNews]

3. Chronic exposure to pesticides increases the chance of developing endocrine and reproductive disorders. Here are two pesticides to use as case studies:

DDT:
Young women exposed to DDT (in the 1950s) have a greater chance of developing breast cancer later in life. From the Pesticide Action Network – UK:

One recent study found higher levels of miscarriages among women exposed to DDT, and reproductive disorders associated with DDT are well documented in animal studies[6,7]. Another recent study found developmental delays among babies and toddlers exposed in the womb[8]. Other studies have linked DDT to reduced breastmilk production, premature delivery and reduced infant birthweights[9,10]. DDT is classified by US and international authorities as a probable human carcinogen[11].

DDT is now banned in the US, but is being revived for use as an anti-malaria agent in developing nations. I mention DDT because it shows you the egregious effects of using pesticides that have been poorly studied. Additionally, DDT is still present in our air.

Atrazine:
Atrazine has been one of the top two selling pesticides in the US, also commonly found in household pesticide sprays. Many studies on frogs and rodents have shown that atrazine causes developmental disorders and delays and compromises healthy immune function. Most significantly, atrazine causes male frogs and rodents to feminize and produce ovaries and eggs. Animal studies have predictive value in humans, as hormone functions are very similar among all animals. Tyrone Hayes, professor of Integrative Biology at UC Berkeley (whose course I took, he is absolutely amazing, by the way), has done extensive work on this subject and is a prime example of science activism. His website, atrazinelovers.com informs the public about all deleterious effects of atrazine and is backed up with extensive research data. His site states,

similar to atrazine’s induction of prostate cancer and mammary cancer in laboratory rodents, men exposed to atrazine in a Syngenta production facility in Louisiana developed prostate cancer at 8.4 times the rate of unexposed factory workers [9, 10] and women whose well water was contaminated with atrazine were more likely to develop breast cancer when compared to women who lived in the same area, but who do not drink well water [11].

4. Pesticide spray can drift through the air, being carried thousands of miles from where it was originally sprayed. They contaminate our waterways, and can be found in drinking water.

Pesticides can be detected miles from agricultural sites, can be detected in rainfall, as well as in the air. A study by the US Geological Survey in 2000 revealed that “every rain and air sample collected from the urban and agricultural sites had detectable levels of multiple pesticides. The magnitude of total concentration was 5-10 times higher at the agricultural site as compared to the urban site.” In this study, methyl parathion was the pesticide with highest concentration in both air and rain samples. Additionally, even though two decades have passed since the ban of DDT in the US, a metabolite of DDT (p,p’-DDE) was detected in every air sample collected from the agricultural site and in over half the air samples from the urban site.

Atrazine:
Atrazine is highly mobile and can travel as far as 600 miles from the initial point of application. Every year, a half million pounds of atrazine returns to the US in the form of rain and snowfall. It is also the most common groundwater contaminant, and has persisted in France where it has not been applied for 15 years. [atrazinelovers.com]

The EPA allows an average of 3 ppb (parts per billion) of atrazine to be present in drinking water. This is a running average, and does not consider the maximum level that could possibly be present during peak use of atrazine. “Concentrations as low as 0.1 ppb have been shown to alter the development of sex characteristics in male frogs.” [NRDC]

5. Persistent pesticide use over long periods of time results in lower crop yields, reduced soil fertility, and increased susceptibility to attack by new forms of pests and disease.

Soil fertility and crop yield:
Pesticides reduce activity of beneficial microflora in soil, therefore while yields are initially high, they will decline over time due to loss of soil health and fertility. I will have to save discussion of beneficial microflora in soil for a different entry, but in essence, soil health depends on a large variety of factors. These include a combination of beneficial bacteria (rhizobia), fungi (mycelia), worms, etc, working together to aid plants in nutrient absorption. A study by Tulane University Professor John McLachlan reveals the inhibitory effects pesticides have on these beneficial microflora and fauna, and how this translates to declining yields over time, as well as declining soil health (the ability to continue to grow crops).

Genetic diversity for resistance to pest and disease outbreak:
Industrial agriculture also promotes growing crops in monoculture, which means to grow only one species of crop, eliminating any genetic diversity. Genetic diversity is an asset which protects against new diseases. Pests, viruses, and bacteria are all constantly mutating. If an invading pest arrives with a powerful new mutation, a monoculture cannot withstand the pest attack. However, a genetically diverse set of crops will have a greater chance of withstanding the attack, as some variations may have better protection against new intruders than others. Don’t put your eggs in one basket! Such extensive pesticide use increases a monoculture crop’s vulnerability to disease and also accelerates pesticide resistance in weeds. [PANNA]

To end on an optimistic note: The amount of detectable pesticide residues in human urine drops immediately after switching to an organic diet. [Chengsheng Lu et. al]

For further reading:

• Pesticides in rain in four agricultural watersheds in the United States
• NYTimes: Debating Just How Much Atrazine is Safe In Your Drinking Water
• Chronic dietary exposure to low-dose mixture of Genistein and Vinclozolin modifies the reproductive axis, testis transcriptome, and fertility
• Harvard School of Public Health: Pesticides Exposure Associated With Parkinson’s Disease
• Daily Mail UK: Breathing pesticides can trigger MS and Parkinson’s disease