A study on the lethal toxicity of Aminocarb to freshwater crayfish and its in vivo metabolism

Abstract

Adult crayfish (Oraonetes limosus) were exposed to 0.1, 1.0, 5.0, 10.0, 25.0, 30.0, 40.0, 50.0 and 60.0 ppm of aminocarb in water at 15°C under laboratory conditions for 144 h. No apparent behavioral changes were observed in crayfish exposed to 0.1, 1.0 and 5.0 ppm of aminocarb during the experiment. Symptoms of acute toxicity were apparent at concentrations ≥ 10 ppm, and mortality occurred at and above 25 ppm. The LC₅₀, 96 h, to adult crayfish was about 33 ppm.

The parent compound and its metabolites, MA (4‐methylamino‐m‐tolyl N‐methylcarbamate) and AM (4‐amino‐m‐tolyl N‐methylcarbamate), were detected in crayfish 96 h after exposure to various concentrations of aminocarb. The primary metabolite detected was MA which accounted for 75% to 95% of the body residue. The highest total residue (Aminocarb + MA + AM) was 40 ppm detected in crayfish exposed to 60 ppm of aminocarb for 96 h.

Key words:

• Aminocarb
• Metabolites
• Crayfish
• Lethal Toxicity
• Residues