Saturation units for use in aquatic bioassays

Methods were developed for preparing liquid/liquid and glass wool column saturators for generating chemical stock solutions for conducting aquatic bioassays. Exposures have been conducted using several species of fish, invertebrate, and mollusks in static and flow-through conditions using these methods. Stock solutions for 82 organic chemicals were prepared using these saturation units. The primary purpose of stock generation was to provide a continuous and consistent amount of toxicant laden solution at a measured analytical level which would be available to test organisms for the test duration. In the present study, the glass wool column and liquid/liquid saturators were used to provide consistent stock concentrations, at times approaching saturation, for fathead minnow (Pimephales promelas) acute exposures. Attempts were made to achieve the maximum solubility of these compounds for comparison purposes to water solubility values available in the literature. Literature solubility values from a database by Yalkowsky et al. [1] provided information on temperatures and data quality which allowed comparison to values obtained from the present study. Twenty four compounds were identified and analyzed for the comparison of maximum obtainable solubility levels. Maximum saturator stock water concentrations were generally lower (R = 0.98) but were in close agreement with published water solubility values.