The Toxicity of Nitroguanidine and Photolyzed Nitroguandine to Freshwater Aquatic Organisms

Abstract : The acute toxicity of nitroguanidine (NGu) to ten species of freshwater aquatic organisms was determined. Fish exposed to NGu for 96 hours included fathead minnows (Pimephales promelas), bluegills (Lepomis macrochirus), channel catfish (Ictalurus punctatus), and rainbow trout (Salmo gairdneri). Invertebrates, which were tested for 48 hours, included water fleas (Daphnia magna), amphipods (Hyallela azteca and Gammarus minus), midge larvae (Paratanytarsus dissimili), and aquatic worms (Lumbriculus variegatus). The acute toxicity of NGu was very low; less than 50 percent of any of these organisms exposed to NGu were killed at concentrations up to the solubility limit of NGu in water, which ranged from about 1,700 mg/L at 12 C (trout tests) to about 3,000 mg/L at 22 C (most other species). Complete photolyzation of NGu with ultraviolet light greatly increased NGu toxicity. The toxicity of phi-NGu decreased with time but was still much more toxic than NGu. Originator-supplied keywords include: Acute toxicity, Algae, Amphipod, Aquatic toxicology, Bluegill, Channle catfish, Daphnia magna, Fathead minnow, Fish, Gammarus minus, Hyallela azteca, Ictalurus punctatus, Invertebrates, Lepomis macrochirus, Lumbriculus variegatus, Midge larvae, Nitroguanidine, Oligochaete, Paratanytarsus dissimilis, Pimephales promelas, Photolysis, Rainbow trout, Salmo gairdneri, and Selenastrum capricornutum.