Pesticide Exposure Risk in Iowa Schools

Nearby Croplands Increase Pesticide Exposure Risk in Iowa Schools

1. Corn and soybeans account for about 99 percent of the planted acreage in Iowa, according to the U.S. Department of Agriculture.
2. In recent years, Iowa farmers treated 95 percent of corn and soybean acres with pesticides and herbicides, notes an investigative report by IowaWatch.org.
3. The Pesticide Bureau of the Iowa Department of Agriculture and Land Stewardship (IDALS) controls pesticide registration and applicator licensing, and investigates pesticide misuse complaints, including pesticide drift. The Bureau has records of 722 pesticide misuse complaints from 2012 to 2017 (through Aug. 1), according to its “Pesticide Drift – Frequently Asked Questions” document.  The number is likely to be conservative, since the records reflect only reported cases.  Most of the pesticide misuse cases reported in that period —  589 (81.6 percent) — are agriculture-related.
4. “Forty-one states, including all of those in the agricultural Midwest, have no regulations requiring buffer zones around schools and day cares to protect young children from pesticide chemicals, should they accidentally drift off target from nearby crop fields,” explains an investigative report by the Midwest Center for Investigative Reporting.

Methodology

1. M.H. Ward, et al (2006), in their research article, “Proximity to Crops and Residential Exposure to Agricultural Herbicides in Iowa” published in Environmental Health Perspectives, note “Rural residents can be exposed to agricultural pesticides through the proximity of their homes to crop fields.”
2. They found that “Increasing acreage of corn and soybean fields within 750 m of homes was associated with significantly elevated odds of detecting agricultural herbicides compared with homes with no crops within 750 m,” and that “Herbicide concentrations also increased significantly with increasing acreage within 750 m.” Ward, et al. conclude that “Crop maps may be a useful method for estimating levels of herbicides in homes from nearby crop fields.”
3. We applied the same research approach to school buildings. After all, drifting agricultural pesticides are unlikely to discriminate between houses and schools when the winds carry them.
4. The distance of 750 meters (the standard used by Ward, et al.) equals 2460.63 feet. We conservatively used the distance of 2000 feet to calculate potentially harmful proximities of croplands to Iowa public school buildings.
5. Using Google maps, we mapped all 1321 PK-12 public school buildings in Iowa according to:
   • their immediate adjacent proximity to crop fields (sharing a property line or across the street)
   • their proximity within 2000 feet of crop fields.

Our Findings

1. There are 1321 PK-12 public school buildings in Iowa and 333 public school districts, according to the 2017-2018 Iowa Public School Building Directory
2. Iowa’s PK-12 public schools serve 485,147 students, and employ 36,412 full-time and part-time teachers.
3. 33.5 percent of Iowa PK-12 public school buildings are adjacent to cropland—that is, they share a border, or are directly across the street from cropland. This means 148,042 students and teachers in Iowa attend and work in school buildings that are adjacent to cropland.
4. 89.6 percent of Iowa PK-12 public school buildings (1183) are within 2000 feet of cropland. This means 444,559 students and teachers in Iowa attend and work in school buildings that are nearby (within 2000 feet of) cropland.
5. The urban West Des Moines Community School District in Polk County is the only district of Iowa’s 333 public school districts that has no students in buildings adjacent to or within 2000 feet of cropland.

Data

[Click here for table with Google map links to all of Iowa’s 1321 PK-12 public school buildings.]