Novel biological recycling water purification system for use in fish toxicology studies.

Abstract

A major problem with fish toxicity testing has been maintaining an adequate supply of healthy, acclimated fish in the laboratory setting from which test populations can be obtained. The build-up of metabolic waste (ammonia) in holding tank environments leads to a stressful situation for the fish, resulting in mortality or erroneous toxicity data. Ammonia is the principal nitrogenous waste product of catfish and is excreted primarily as the toxic unionized ammonia from the gills. The purpose of this study was to develop a novel biological filter system which facilitates the nitrification process, thereby removing or controlling the build-up of toxic metabolic waste products in holding tanks in the laboratory. This system would provide a healthy, non-stressful environment for blue channel catfish (Ictalurus Punctatus) fingerlings prior to their use in LC50 determinations of various insecticides, herbicides, and fungicides currently employed in the vicinity of catfish ponds or farms.