Toxicological Risks of Agrochemical Spray Adjuvants: Organosilicone Surfactants May Not Be Safe

This review paper examined the toxicity of “inert” ingredients and spray adjuvants designed to increase the effectiveness of pesticides. They found that most adjuvants have the potential to harm non-target organisms even on their own without pesticide active ingredients. Many aquatic organisms are susceptible to adjuvant toxicity, and many terrestrial insects are vulnerable to synergisms from mixes of adjuvants and insecticides. Organosilicone surfactants are particularly toxic to bees, as all of these adjuvants tested impaired honey bee olfactory learning more than the other non-ionic adjuvants. By analyzing California pesticide use records, the authors discovered that the use of spray adjuvants, especially organosilicone surfactants, has been increasing in almond orchards during bloom while bees are also present. Increased use of adjuvants, along with tank mixing with certain fungicides may be contributing to bee declines. The authors recommend that adjuvants and other ingredients be disclosed to help determine the total chemical exposure to people and the environment from pesticide use.