Pilot study to test breast milk pesticide levels in mothers and infants

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Dr. Marie Bourgeois, research assistant professor at the USF College of Public Health, has designed a pilot study to examine health disparities, infant vulnerability and pesticide exposure.  The study, titled “A Pilot Study of Malathion, Atrazine, Carbaryl and Chlorpyrifos in the Breast Milk of Women in Suburban and Agricultural Communities of Central Florida,” is funded through the University of Kentucky Southeast Center for Agricultural Health and Injury Prevention.

Bourgeois will be working with Dr. Raymond Harbison, Dr. Michael Fant and the Florida Association of Farmworkers to gather and analyze the data for the study.  The pilot phase is set to conclude by September.

Bourgeois came up with her idea after giving a lecture to a group on biomonitoring, the process by which toxicologists are able to assess drug and chemical exposures using tissues and body fluids.  After the lecture, a woman said Bourgeois was welcome to use her banked breast milk.

Marie Bourgeois, PhD, MPH

Marie Bourgeois, PhD, MPH

From there, Bourgeois said she started to think about the differences between agricultural and residential or suburban populations, and whether she could use breast milk to evaluate the level of infant pesticide exposure in those populations.

“It seemed to me that there might be significant differences in their pesticide exposures,” she said.  “I expect the agricultural group will be exposed to them occupationally.  The suburban population will be more likely to have consumed something with trace amounts of pesticide in or on it.”

Using breast milk allows Bourgeois to check the level of pesticide exposure in not only the mothers, but in their infants, too.

“Lactational transfer is just a fancy way of saying transferred from mom to baby via breast milk,” said Bourgeois.  “We already know that a variety of lipophilic substances can be transferred this way.  Breast milk is often an infant’s only form of nutrition.  Because their metabolisms are still developing, infants have few metabolic defenses against this kind of exposure.”

The breast milk study is broken down into a few different procedures.  First, it will be necessary to find women willing to donate breast milk in the name of scientific discovery.  FAF will recruit women from the agricultural sector, which means the women will either be the spouses of a agricultural workers or workers themselves.  Bourgeois will recruit suburban mothers from Tampa and St. Petersburg.  The breast milk samples will be collected and frozen until there are enough to analyze.

Nursing mom

“We plan to use HPLC, or high-performance liquid chromatography, for analysis,” said Bourgeois.  “However, one of our graduate students has experience with gas chromatography, so we may be able use to that.”

Ultimately, Bourgeois believes that the agricultural cohort will show higher concentrations of pesticides in their breast milk.

“It is unlikely to be a dangerously high concentration, but I am willing to bet it will be significantly higher,” she said.

From there, she and the others will look to see which pesticide is in the highest concentration.  Based on the results, the study may change to include other pesticides.

Even though the study is still in the recruiting stage, Bourgeois has wasted no time in planning the next step.  She hopes to use the pilot data to support a larger grant application. This will allow her to expand both the study population and the number of pesticides assayed.

The data from the project will provide a closer look at pesticide exposure in two vulnerable populations — agricultural workers and infants.

“We need to characterize the potential pesticide burden faced by these infants,” Bourgeois said.  “After all, infants are ultimately helpless.  There have been studies done indicating that children from agricultural communities may have higher rates of learning disabilities and birth defects. We need to start figuring out why that is.  Women are told that breast milk is healthiest for their babies. What if that isn’t always the case?”


Story by Shelby Bourgeois, College of Public Health writing intern.

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