FAQ

What is the Farm Family Exposure Study?

The Farm Family Exposure Study is a biomonitoring study involving 95 farm families (farmer-applicators, spouses and children). It measured the actual amount of pesticides absorbed into the body by analyzing the urine of study participants over a five-day period around a pesticide application.

Why was the study conducted?

The study was conducted to gather factual, scientific information about actual exposure – especially for farm spouses and children – from real-world use of pesticide products commonly applied on farms. Biomonitoring is the most accurate way of determining such exposure. The scope of this study is unprecedented in terms of the amount of data collected on farm spouses and children. The data will be very important in educating applicators and their families about how exposure can occur and ways to reduce it.

What is a biomonitoring study?

Biomonitoring assesses human exposure to chemicals by measuring chemicals or their metabolites in human blood, urine or other tissues. The Farm Family Pesticide Study measured pesticides or pesticide breakdown products in urine.

Who conducted the study?

The research was conducted by investigators at the University of Minnesota. Their research protocol, mid-study report and final report was reviewed by an advisory committee comprised of experts in epidemiology and exposure assessment from several universities and the U.S. Environmental Protection Agency.

Who sponsored the research?

The study was conceived by scientists from Bayer CropSciences, Dow AgroSciences, DuPont, FMC, Monsanto, Syngenta. These companies formed a task force to manage the study under the auspices of CropLife America – a trade association for agricultural companies. The companies and the American Chemistry Council co-sponsored the study.

What pesticides were studied?

The study focused on two herbicides 2,4-D and glyphosate (Roundup) and one insecticide, chlorpyrifos (Lorsban/Dursban). The products are widely used on many farms and glyphosate and 2,4-D are used in residential applications.

What did the study cost?

Approximately $2 million.

Where was the study conducted?

Farm families were studied in Minnesota (45 families) and South Carolina (50 families).

These two states have very different climates, types of pests, and pesticide use patterns. The variety across the two states was meant to make the study applicable to a wide range of farming circumstances.

CONDUCT OF THE STUDY

How did you recruit the farm families?

Farmers were identified from lists of pesticide applicators that were randomly sorted to ensure a population-based sampling from each state. The University of Minnesota contacted applicators to see whether they were eligible for the study and whether they were willing to comply with the study protocol. The Institutional Review Board of the University of Minnesota reviewed the procedures for contacting study subjects to insure that study participants were informed of the intent of the study and the intended use of their information for scientific purposes prior to their agreeing to participate in the study.

What were the criteria?

The families had to live on farms and apply one of the study pesticides to at least 10 acres of farm land within 1 mile of the family residence. Participating family members had to include the applicator, spouse and at least one child age 4 to 17. Each participant had to agree to collect urine specimens 24 hours a day for five days.

How was the study conducted?

Families agreed to begin collecting urine on the day before pesticide application to establish a baseline. Urine samples were collected 24 hours a day during the day of application and the next 3 days after application. The samples were analyzed with a method capable of detecting pesticide traces in urine as low as 1 part per billion. One part per billion is equivalent to one millionth of a gram in 1 liter of urine.

Who analyzed the samples?

Morse Laboratories of Sacramento, CA did the 2,4-D and chlorpyrifos analyses, and Monsanto’s Environmental Sciences Research Laboratory did the glyphosate analyses. The investigators arranged for the Environmental Protection Agency to re-analyze a number of the 2,4-D and chlorpyrifos samples as a quality control check. They also arranged for the Centers for Disease Control to perform confirmatory analyses on the glyphosate samples.

Why is urinalysis a good way to analyze exposure?

The pesticides included in this study are are excreted largely in urine, either as the parent compound (glyphosate and 2,4-D) or as a metabolite (chlorpyrifos). Therefore, the concentration in urine allows for the determination of the amount of pesticide that people actually absorbed. In addition, the collection of urine is a non-invasive procedure, unlike collecting blood or skin samples.

Did each family use all three pesticide products studied?

No. Most used only one, but some families used two of the products.

Why weren’t other products included?

Given the number of participants, and not wanting to have too few data points per chemical, three pesticides were judged to be optimum. Three pesticides, divided over the 95 families, provided appropriate numbers for statistical analysis.

How do the data collected from the Farm Family Exposure Study relate to the ongoing epidemiologic research?

The Farm Family Exposure Study was conducted to provide much-needed information about actual exposure from real-world use of pesticides. The Farm Family Study Task Force is making results known on a regular basis to epidemiologic investigators. Data from this study should be helpful to epidemiologists to help refine the exposure assessments in their studies, which tend to rely on unverified questionnaire information about pesticide use.

RESULTS OF THE STUDY

What did the study show about actual pesticide exposures?

For farmers, the amount of exposure varies markedly by chemical. Also, use of chemical resistant gloves when handling pesticides can greatly reduce the amount of pesticides that get into the body.

For farm spouses and children, there was very little indication of pesticide exposure resulting from the on-study application for those who were not directly involved in pesticide use activities. Urinary concentration of pesticides among spouses and children, on average, did not increase significantly, if at all, from baseline concentrations determined the day before pesticide application took place. Perhaps the most important finding of the study is that users of pesticides can reduce their exposures and the exposures of their families to de minimus or non-detectable levels if they follow appropriate procedures in using these products.

Was there a pattern of behavior linked to higher exposures?

Typically, higher urinary concentrations were associated with practices that are not recommended, such as not wearing chemical resistant gloves while mixing and loading pesticides, smoking while repairing leaky equipment without gloves, using fingers to break the seal on containers or carrying pesticide in an open container.

What activities explained the higher values in children?

The higher values involved direct contact with chemicals in the mixing or application area. These activities included teen-agers working as a co-applicator, touching containers without gloves, and even playing barefoot in the area where pesticides were being mixed and loaded. These exposures could have been prevented or minimized.

Were there any participants in the study who had no increased exposure?

The vast majority of spouses and children did not have an appreciable increase in urinary pesticide concentration as a result of the studied pesticide application. Most applicators showed an increase in urinary pesticide concentration as a result of the application, though some didn’t have detectable levels either before or after the studied application.

Did certain activities, such as washing clothes or playing with pets increase the exposure of spouses and children?

No. There was very little increased exposure among children and spouses, including those who washed clothes or played with pets. Pesticide levels were somewhat higher for children who helped with the application or spent considerable time in the immediate vicinity of pesticide activities. For farmers, urinary concentration of pesticides was associated with direct handling of pesticides and specific work practices, such as not wearing gloves.

Was there any correlation between urinary concentrations and proximity of the field to the home?

No.

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