A constant pressure sprayer pressurized by CO2 is commonly used during the development of new pesticide compounds. CO2 may cause acidification of the water and thus affect the behavior of the compound being tested. In the present study samples of water from 30 different sources were pressurized to 275 kPa (40 psi) by CO2 during five minutes and the pH was measured in the water emerging from the nozzle and in that remaining in the sprayer tank. The results showd a market reduction of pH values in all samples after pressurization. The pH values rose slightly after emergence from the nozzle. The reduction in some cases was drastic, reaching 4.91 pH units in one of the samples. These findings suggest that the results of pesticide test that involved CO2 pressurized sprayers shoud be interpreted with caution.
Constant pressure sprayer; pesticide trials; herbicides; water acidity