Effects of salinity on the absorption and elimination of residues of the fungicide ridomil in Procambarus clarkii (Girard, 1852) (Decapoda: Astacidea: Cambaridae)

Abstract We explored the pharmacokinetics of the antimicrobial agent ridomil in the crayfish Procambarus clarkii (Girard, 1852) under different salinity conditions. The concentration of ridomil in hemolymph, liver, and muscle of individuals soaked in ridomil in fresh water and brackish water with a salinity of 3‰ was determined by high-performance liquid chromatography. Hemolymph was in line with the first-order absorption, two-compartment open model, and the liver and muscles were in line with the first-order absorption, one-compartment open model. The maximum concentration(Cmax) in the hemolymph in fresh and brackish-water groups were 296 mg l–1 and 452 mg l–1, respectively. The maximum time (Tmax) of hemolymph in the fresh and brackish-water groups were 8h and 24h, respectively. The Cmax in liver and muscle in the freshwater group were 4,125 mg l–1 and 2,702 mg l–1, respectively, and 2,362 mg l–1 and 2,274 mg l–1, respectively, in the brackish-water group. The Tmax of liver and muscle in the freshwater group were 0.25 h and 18 h, respectively, 36 h and 24 h, respectively, in the brackish-water group. Results indicate that the concentration of ridomil in the hemolymph was lower in the freshwater group than that in the brackish-water group, but the concentration in liver and muscle tissues in the freshwater group was higher than that in the brackish-water group. Salinity can therefore affect the drug absorption rate of ridomil in the hemolymph of Procambarus clarkii.