On Preventing Farmworker Exposure to Pesticide Drift in Washington Orchards

Abstract

Pesticide drift, or the off-target movement of pesticides, represents a key cause of not only crop damage and economic loss but also occupational and bystander illness. Nationally, drift has been shown to account for 37-68% of pesticide-related illnesses among United States agricultural workers. It remains a public health concern in the Pacific Northwest, especially among tree fruit workers. Unfavorable wind conditions and a lack of worker notification have been identified as leading contributing factors for acute illnesses resulting from occupational drift exposure. No study has systematically examined historical weather data as exposure determinants of drift events with occupationally-related pesticide illnesses. Our first aim seeks to understand the role of wind in pesticide drift events reported to the Washington State Department of Health and prevent such exposures in the future. A majority of drift events reported in Washington over the last two decades resulted from orchard airblast applications. The airblast sprayer has been a standard tool for tree fruit pesticide application technology since its rapid and wide-scale adoption in the 1950s. Over the last 65 years, a desire for more fruit-bearing trees has changed orchard canopies by reducing tree height and canopy volume. As a result, traditional airblast sprayer output no longer matches modern trees and thereby increases drift potential. New engineering controls such as tower sprayers have been promoted as methods to reduce drift, but few studies have examined how much these new technologies reduce worker exposure. While previous field studies have examined the use of metal cation tracers in spray deposition, our second aim evaluates new engineering controls by measuring potential worker exposure to orchard spray drift using novel micronutrient tracer methods. A high priority issue for drift exposure prevention in Washington has been improved communication between farms, handlers, and crew members. Currently, there is no system in place to notify workers or employers of applications that will be taking place on adjacent property. To investigate worker notification as a means to prevent exposure to drift, our third aim reviews existing agricultural notification systems and assesses the feasibility of a farm-to-farm notification system in Washington using interviews with tree fruit industry personnel.