The toxicology and metabolism of chlorothalonil in fish. 1. Lethal levels for Salmo gairdneri, Galaxias maculatus, G. truttaceus and G. auratus and the fate of super(14)C-TCIN in S. gairdneri .

LC sub(50) values of chlorothalonil (TCIN) to Salmo gairdneri, Galaxias maculatus, G. truttaceus and G. auratus for 24, 48 and 96 h were determined using a flow-through apparatus. All values were lower than those previously reported for various fish species. The influence of decreased oxygen concentration and co-exposure of acephate on LC sub(50) values of TCIN to Salmo gairdneri was also investigated. Uptake of super(14)C-chlorothalonil in internal organs of Salmo gairdneri was measured during a 96 h exposure to 10 mu g/l in water. The primary site of accumulation was the bile. Levels in all other organs were in the mg/kg range and increased with time of exposure. Protein binding was observed in the liver. Release of polar labelled metabolites was constant with time over 96 h depuration, with 0.5% being TCIN. All organ levels dropped during this time. The possible route of TCIN metabolism is discussed.