When you make the decision to purchase a pesticide at the store to kill bugs, pests, or weeds, do you select bifenthrin, cyhalothrin, imidacloprid or another active ingredient?  What chemicals, formulated to kill specific pests, do farmers or pest control professionals in your area frequently use?  Even though I am an experienced chemist, I currently do not know the answer to the second question.  We all rely on professionals and specialized agencies to inform us about the effectiveness of particular chemicals, their mode of action, and their potential effects on environmental and human health. We expect that the highest level of science and ethical standards will be considered for the approval or disapproval decisions on toxic chemicals made available to consumers or applied to the environment.

For the past few weeks, I have been reading about the US Environmental Protection Agency administrator’s decision to re-approve the use of a pesticide called chlorpyrifos after their 2015 decision to ban it and against the agency’s own scientific data.  This particular chemical substance kills bugs by interrupting their nervous system. For many years, this chemical has been linked to abnormal brain development in children who are exposed to low levels.  The dangers associated with chlorpyrifos led to a voluntary ban of the chemical for household use and tomato plants in 2000.  According to the US EPA’s website on this pesticide, the Human Health Risk Assessment work has been re-evaluated a number of times and in 2018, the court ruled to ban the chemical.

Given the public and environmental health risks chlorpyrifos poses, the European Union made the decision to eliminate its use.  For northwest and northeast Indiana farms, the application of chlorpyrifos is greater than 5.49 pounds per square mile, the highest use category, according to United States Geological Survey data.  Chlorpyrifos is not the only toxic chemical reintroduced in the US. The US EPA administrator is planning to expand the use of the insecticide sulfoxaflor.  It had been previously prohibited since research has shown the chemical is harmful to pollinators, the helpful insects.

I suggest the take-home messages for the use of chemicals designed to kill pests are to keep them to a minimum, know the health risks and pay attention to a decision that affects life and health.  Incidents of toxic chemical exposures have become too common and the full scope of risks associated with heavily dispersed chemicals are often not well understood.  While we have limited ability to control the industrial use of chemicals, we can make choices to minimize our purchases and uses.  We can also contact our elected officials about decisions that do not fully respect scientific findings and concern for public and environmental health.


Julie Peller Ph.D. is an environmental chemist (Professor of Chemistry at Valparaiso University ) and she leads the Environmental Ministry at Nativity of Our Savior in Portage IN. Julie has been writing a weekly column for church bulletins for the past ~5 years called the Green Junction and is helping to move the call of Laudato Si to action forward. Her Research Interests are in Advanced oxidation for aqueous solutions, water quality analyses, emerging contaminants, air quality analyses, Lake Michigan shoreline challenges (Cladophora, water, and sediment contaminants), student and citizen participation in environmental work

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