After exposure of livestock to pyrethrins/pyrethroids/rotenone/amitraz, are residues in edible tissues expected to be high?

• A. Yes, residues are likely
• B. No, residues are unlikely
• C. Data are inconclusive
• D. Only if exposure is prolonged

Answer: (B)

High residues in edible tissues are not expected after exposure to these insecticides because they are cleared from the animal’s body very quickly. Pyrethrins are rapidly broken down by enzymes and excreted, and pyrethroids, though lipophilic, are also quickly metabolized to polar, easily excreted compounds. Rotenone is rapidly metabolized and eliminated, and amitraz is rapidly hydrolyzed to non-toxic metabolites that are passed out of the body. Because of this rapid metabolism and clearance, tissue levels stay low with normal use and appropriate withdrawal times. Only in cases of prolonged or excessive exposure without proper withdrawal would residues be more likely to be detectable.