Neonicotinoid Pesticides: Not Just a Bee Problem
PURPOSE: The purpose of this presentation is to inform the stormwater community that neonicotinoid pesticides are widespread in urban runoff and potentially causing chronic, cumulative toxicity in receiving waters.
MAIN IDEAS: After years of testing for pesticides in urban runoff, and having spot detections of various compounds here and there, the City of Santa Barbara Creeks Division is now seeing neonicotinoids in nearly every sample we collect. At the same time, there is more research coming out almost weekly about their potential impact on ecosystems, leading some scientists to say they are the “new DDT” (without the human-harm component).
The neonicotinoids have rapidly become the most widely used pesticides globally, and are used for agriculture, structural pest control, pet care, and home garden care. Systemic poisons, the neonicotinoids have been implicated for harming pollinators throughout the world. The United State Environmental Protection Agency (US EPA) and the California Department of Pesticide Regulation (CA DPR) are both reevaluating the registration of neonicotinoid pesticides with a focus on pollinator impacts. However, there is new and compelling evidence that the neonicotinoids are widespread in surface waters, are toxic at levels far below existing toxicity thresholds, and are likely harming aquatic and riparian ecosystems worldwide through food web effects. With most research conducted on inland agricultural areas, there are scant data on impacts to urban or coastal streams, coastal estuaries, and the marine environment. Imidacloprid, the most widely used neonicotinoid in California, was detected repeatedly in a pilot test of urban stormwater runoff in Santa Barbara, CA, at levels suggested to cause ecotoxicity. Physical characteristics such as long half lives in soil and high solubility (rapid leaching) in storm events, combined with the widespread impact on nontarget organisms combine to make this class of pesticides harmful to urban receiving waters. Given the neonicotinoids’ widespread use, documented ecotoxicity, and demonstrated presence in surface waters, it is urgent that the CA DPR and US EPA address storm water impacts. Municipalities with pesticide and/or toxicity TMDLs or monitoring requirements should consider neonicotinoid pesticide sampling and targeted outreac.
AUDIENCE ENGAGEMENT: The talk will include a question-and-answer callout where the audience is asked how to create the best and worst pesticide from stormwater perspective – and neonicotinoids will exemplify the worst (broad application, long half life in soil and plant material, rapid leaching and high solubility, and toxicity that is difficult to quantify using standard toxicity tests). In addition, a short segment of an outreach video that the City produced will be shown.
CONFERENCE THEME: This talk fits into the conference theme because it demonstrates how we have to stay on top of emerging contaminants to continue achieving water quality improvements. Complacency will lead to new poisons reaching our waterways, as one class of pesticides is replaced by another.