Naled and dichlorvos in water and aquatic organisms from a canal and rice fields near Sacramento, California

Ultra-low volumes of naled are applied by aircraft over rice fields and canals to reduce adult mosquito populations near Sacramento, California. Each summer, the pesticide is applied approximately 7-10 times between July and October. Naled and its major degradate (dichlorvos) were quantified in water, biofilm, and invertebrates following aerial applications. In 2020, samples were collected before the naled application season, after 3 rice field and 5 canal applications, and immediately after an application. In 2021, water and crayfish samples were collected before the naled application season, after 3 applications, and at intervals (1, 3, 5, and 7 days) following an application. A few opportunistic samples (including dragonflies and [...]