October 1, 2013

Fruits and vegetables are essential to a healthy diet. When we’re in a store picking out a beautiful piece of fruit, we don’t stop to ask ourselves, “Were pesticides used in the growing process of this apple? Who harvested this apple and how much were they exposed to these pesticides?” Juan Muniz, PhD, a toxicologist and faculty member in the College of Nursing and Health Profession’s Department of Nutrition Sciences, conducts research that aims to answer these questions by working with migrant workers on an up-close and personal level.

Muniz came to Drexel in June 2012 and brought with him his ongoing research on the impact that exposure to pesticides has on migrant workers in Oregon. “Our goal is to be able to determine the levels of exposure in the workers. The second goal is trying to train and educate these workers on how to reduce exposure,” Muniz said.

Pesticides are sprayed on produce during different stages of the growth process, including the early flowering stages of growth for some plants as well as just prior to harvesting. While the Environmental Protection Agency has guidelines for how a worker should dress during the pesticide application process and how long they should wait after application until they can go back into a treated field, the guidelines are not always followed. This may be due in part because workers are paid by how much produce they pick and not by how many hours they work.

Unfortunately, field workers are not able to wear long sleeved shirts, pants and gloves in the summer while they are picking because of the heat and the way that these garments restrict movement. Wearing clothing with less coverage can impact workers’ pesticide exposure levels. Sometimes, a crop may be ready for harvesting before it is safe to go into the field after pesticides have been sprayed. Entering the field at this time is potentially hazardous to the workers’ health, though the incentive to harvest the maximum amount of crops is high.

Two of the pesticides often used in the United States are a chlorinated pesticide and a pesticide with a phosphorus compound. According to Muniz, these chemicals stay in a worker’s bloodstream and tissues for a long time and cause slow but consistent, severe damage to the exposed worker’s DNA. Pesticides with the phosphorus compound were derived from the chemical compounds used in nerve gas during chemical warfare. These chemicals are effective because they attack the nerve cells of the insects. “So if they can damage the nerve cells of an insect, they will also do the same to you,” said Muniz. This neurotoxic chemical can cause brain damage in humans and can also lead to cancer.

Muniz and his team in Oregon tested samples of migrant workers’ urine, blood and cheek tissue to record the level of exposure and damage to each worker. One of the tests Muniz does on the workers’ cells to check for DNA damage is called the comet test. If a worker is exposed to pesticides and the chemicals produce damage, the DNA will split into different pieces. In the comet test, Muniz takes a worker’s white blood cells and puts them in an electric field. The process produces a spread of the DNA that looks like a comet. He uses this spread to determine how much damage was done to the DNA.

The migrant workers aren’t the only ones being exposed to pesticides. Migrant workers typically live in “migrant camps,” which are pop-up camps that have communal bathrooms and showers. In the migrant camps, sometimes a family will share just one room. When the workers come home to camp from the fields, they bring pesticide remnants back to their family members. The pesticides can cause developmental problems in migrant workers’ children and reduce the amount of brain cells that are able to develop healthily.

Muniz has a team of “promotores” who teach the migrant workers how to limit their exposure to pesticides and limit their children’s exposure as well. The team educates the workers to take a shower right after work and put all of their contaminated clothes in a place away from the children. They also teach them to change out of their contaminated boots and wash their clothes separately from their children’s. The team tests the workers for pesticide exposure levels before and after they complete education sessions to test the efficacy of the messages and implementation.

Although they teach the workers to limit their exposure as much as possible, it is impossible to keep the workers 100% pesticide-free. “You cannot completely eliminate it because of the way they have to work. They have to work, they have to pick fruits and vegetables by hand,” Muniz finished.