An approach to the diazinon toxicity in the European eel: bioaccumulation studies

Abstract

The acute toxicity effects of diazinon on European eel ( Anguilla anguilla) were examined using short-term exposures in static conditions. In these conditions the 96-h median lethal concentration (LC 50) was 0.086 mg/1. In addition, the eels were exposed to two sublethal diazinon concentrations, 0.042 and 0.056 mg/1 (1/2 and 2/3 LC 50 96-h, respectively) for different exposure times, till a maximum of 96 h, and bioaccumulation and clearance of this insecticide in liver, muscle, gill and blood tissues were studied. BCF values of diazinon after 96 h exposure to 0.042 mg/l were 1850 in liver, 875 in gill and 775 in eel muscle. BCF values of diazinon over a 48-h exposure period to 0.056 ppm were 800 in liver, 1600 in muscle, 2300 in gill and 2730 in blood tissue. BCF i were calculated after 48 h exposure as 0.30, 0.60 and 0.84 for liver, muscle and gills, respectively. Upon removal from diazinon-containing water the contaminated fish rapidly eliminated diazinon. The excretion rate constant ( K 2) of diazinon was higher in liver than in the other tissues after both treatments. Diazinon half-lives were less than 48 h in all the analysed tissues.