U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

March 1999


Published in Environmental Toxicology and Chemistry, Vol. 18, No. 11, pp. 2533–2537, 1999.


Female boat-tailed grackles poisoned with 3-chloro-p-toluidine hydrochloride (CPTH) were analyzed by necropsy and gas chromatography–mass spectrometry (GC-MS). The necropsies identified the presence of a white precipitate in the pericardium, which had been previously reported as a characteristic of CPTH-exposed birds. The GC-MS method, which utilized deuterated CPTH as a surrogate, quantified CPTH residues in the breast tissue and gastrointestinal tract of CPTH-exposed birds. Comparison of these techniques indicated that the GC-MS method was more accurate for assessing CPTH poisoning in birds. Regression analyses of consumption versus residue data indicated that the sum of breast and gastrointestinal residues can be used as an estimator of CPTH exposure. Comparison of CPTH residues in grackles with toxicity data for a variety of scavenger and predator species provided risk quotients of less than 0.1. Analysis of these data suggests that secondary hazards associated with the use of CPTH as an avicide for the control of pest birds are minimal.