Another important water-quality topic is pesticide occurrence in groundwater. According to data from the California Department of Pesticide Regulation, hundreds of pesticides were used in the county from 1995-2015, including 1,3 dichloropropene, glyphosate (Roundup) and methyl bromide. These were applied in quantities of more than a million pounds.
There hasn’t been a health risk assessment from using groundwater where these pesticides have been and are applied in Sonoma County because few samples have been collected and analyzed. Even though the cost is high, at least selected wells should be sampled for pesticides to determine if they occur in groundwater, and at what concentrations.
Data from such sampling could help determine if there is a health risk from the occurrence of pesticides in Sonoma County groundwater. It isn’t wise to ignore this potential health risk because many of the pesticides applied are known carcinogens.
According to a January 2018 report by the Sonoma County Department of Health Services, the childhood cancer rate in Sonoma County is the fourth-highest in California, and cancer was the leading cause of death in all age groups.