An experimental plot sprayer, with a new mixing chamber and water measuring system, was developed to minimize operator exposure to pesticides during mixing and rinsing. Premeasured herbicide samples in 50-ml capped test tubes are emptied into the mixing chamber, and water is measured, rinses the test tube, and drains into the chamber to produce the spraying volume. This system eliminates operator contact with the chemicals and can be flushed quickly between plots to eliminate contamination. Rinsing efficiency with atrazine was greater for a suspension than a wettable powder formulation but less than 0.1% of the initial concentration was detected in water following the first or second rinsing.
