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Importance of analytically verifying chemical treatments

Rach, J. J., Gaikowski, M. P., and Olson, J. J., 1997, Importance of analytically verifying chemical treatments: The Progressive Fish Culturist, v. 59, no. 3, p. 222-228.

Abstract

Hydrogen peroxide is considered a low regulatory priority compound by the U.S. Food and Drug Administration. It is used to control fungal infections on fish eggs. We studied the treatment profiles of hydrogen peroxide in Heath, McDonald egg jar, and Clark-Williamson incubators during treatments intended to deliver an effective regimen of at least 500 mu L hydrogen peroxide/L (i.e., treatments of 500 and 1,000 mu L/L) for 15 min. Hydrogen peroxide concentrations decreased with increasing distance from the influent water in both Heath and Clark-Williamson incubators. The top treatment tray (tray 2) of the Heath incubator received more than 90% of the intended regimen during the 500 mu L/L treatment, whereas at 1,000 mu L/L, all trays had hydrogen peroxide concentrations at or above 500 mu L/L for 15 min. None of the compartments in the Clark-Williamson incubator received the intended therapeutic regimen when treated at 500 mu L/L. The McDonald egg jar system distributed the intended concentration for the designated treatment period in all jars, except those located directly below the influent water. Our results indicate that dilution of therapeutants applied through certain egg incubation systems significantly decreases the efficacy of treatments and may render them ineffective. The dilution characteristics of egg incubation systems should be assessed in order to ensure proper delivery of all intended chemical concentrations and exposure regimens. Suggestions for maintaining the minimum effective concentrations in evaluated incubators are included.