Fall Watershed Gathering with Nichole Warwick on Biocides in the Environment

On October 25, 2025 about 25 members and supporters of the Watershed Council met in the Sebastopol Library on a rainy Saturday to hear Nichole Warwick explain the hazards of biocides in our environment, and how to respond.

Nichole has a long list of credentials, having founded or co-founded several organizations concerned about the effects of biocides on our health and the health of our ecosystems, including Sonoma Safe Ag Safe Schools (SASS). She said she began to take action not as a scientist or activist, but when she was diagnosed with breast cancer at the age of 37 as a mother of small children.  She first concentrated on the presence of biocides near schools. After managing to attract public attention to that hazard, she then addressed other public spaces like parks.

From 2021 to 2023, Nichole was a SASS Co-Principal Investigator on a study of the exposure potential from groundwater and air in the central part of our watershed that tested for 187 toxics from biocides (herbicides, fungicides and insecticides). With funding from the California Breast Cancer Research Program, data were collected by the U.S. Geological Survey and then analyzed by the University of California at San Francisco. To monitor biocide exposure in the air, six privately owned parcels were selected where small silicone bands were set up to detect pesticide drift. To measure exposure in ground water, two wells were monitored. The results of the study were published in 2023 report that can be found at https://www.sonomasass.org/_files/ugd/6612ef_4dba7873561547dcb02647b6b4beea7c.pdf

The general findings of the study showed that pesticide drift was detected at all sites sampled throughout the community of Graton.

SASS hopes to use the study report for education on the health risk of biocides and community conversation about biocides in our current agricultural system.  See the AGVWC Resources tab for more info on biocides and safer products and techniques for growing fruits, vegetables and ornamentals.

Nichole pointed out that acceptable levels of exposure to pesticides and other chemicals are set by the EPA; however, those levels are for an adult male weighing 180 pounds with a one-time exposure. She pointed out that those “acceptable” levels are very likely not acceptable for a small child who would be exposed for more than half the days of the year.

Activists alone cannot solve this problem, shared Nichole, “We need more voices at the table so we can find ways to work together, so we can change together; we need storytellers who will shine the light on the good things that are going on”.


Please check the Resources Page of the AGVWC Website for more information on Biocides in our watershed and safer, non-toxic alternatives.

Consider joining the Biocides Working Group of AGVWC and help plan for a local future with less toxics.  Contact Woody with questions or to join the working group.