April 18, 2008 

Most people understand the benefits of using pesticides to control pests, but more and more of us also are concerned about the possible harmful effects of pesticides on the health and safety of our family and pets.

In this discussion, pesticides include insecticides, which kill insects, and herbicides, which kill weeds. Some other pesticides include fungicides, which kill fungi, and acaricides, which kill spiders, mites, and ticks.

Farm Family Study

Researchers at the University of Minnesota wanted to find out if pesticides get into the bodies of pesticide applicators and their families. They also wanted to know if practices used to prevent pesticide exposure actually reduced pesticide concentrations in the bodies of applicators.

This study looked at 95 farm families. The three pesticides of interest were:

•  

• glyphosate, a herbicide commonly sold as Roundup®,
• 2,4-D, a herbicide found in many weed control products, and
• chlorpyrifos, an insecticide sold as Lorsban® and Dursban®.

To look at pesticide levels, researchers took blood and urine samples from applicators and their immediate family.

Family Exposure

The study showed that chlorpyrifos and 2,4-D often were found in the bodies of applicators. But, what was unexpected was that low levels of some pesticides were also found in spouses and children, even when spouses and children did not have direct contact with the pesticides.

In this study, 100% of family members (farmers, spouses, and children), had detectable amounts of the insecticide chlorpyrifos in their bodies.

The highest amounts of pesticide were found in applicators who did not follow pesticide label instructions. These applicators:

• Did not wear chemical resistant gloves while mixing pesticides
• Spilled the pesticide during mixing and spraying operations
• Had skin contact with pesticides during handling
• Repaired spray equipment without wearing chemical-resistant gloves
• Smoked during mixing and spraying operations

Conversely, farmers who carefully followed label instructions and observed safety precautions had lower levels of pesticides in their bodies.

Risks from Pesticides

The health risk of an individual to a pesticide is a function of its toxicity and the exposure to the pesticide. This idea is expressed by the risk formula:

Risk = Toxicity x Exposure

Pesticide toxicity is often measured by how much pesticide is needed to kill a rodent population. A small amount of one pesticide might produce a toxic effect, while a much larger amount of another may not. The signal words on the pesticide label indicate the acute toxicity that may occur with exposure to the pesticide.

Danger = high toxicity
Warning = moderate toxicity
Caution = low toxicity

Type of Exposure

The route of human exposure to a pesticide also impacts the toxic effect. Pesticides can enter the human body three ways:

1. by absorption through the skin or eyes (dermally),
2. through the mouth (orally), and
3. by breathing into the lungs (inhalation).

Lower Your Risk

To reduce the risk of pesticides, choose low toxic products whenever possible and reduce exposure by using chemically resistant gloves and other PPE as recommended on the label. Or, hire someone else to apply the pesticide.

For more details about pesticide risk, see Managing the Risk of Pesticide Poisoning and Understanding the Signs and Symptoms (EC2505).

Clyde Ogg
Extension Pesticide Safety Educator