CHLORINATED BENZENES AS PHYSIOLOGICAL MARKERS FOR COYOTES

We evaluated pentachlorobenzene (PeCB) and 1,2,4,5-tetrachlorobenzene (TeCB) as new, longterm physiological markers of coyotes (Canis latran s) for multipurpose research use. Captive coyotes were administered or al doses of 65, 130, 260, and 520 m of PeCB in sesame oil. and samples of serum, wet (fresh) and dry feces, and adipose tissue were collecte d at 10 intervals over 168 days to measure concentrations of the marke r. The PeCB concentrations in serum declined at an exponential rate ov er time. There were positive correlations between concentrations of Pe CB in serum. wet and dry feces, and adipose tissue. Intramuscular inje ction of 65 mg of PeCB resulted in similar PeCB sample concentrations as the 65 mg oral dose. Oral administration of 50 mg of solid technica l PeCB, along with 50 mg solid TeCB, resulted in lower sample concentr ations than the 65-mg oral dose in oil (P = 0.02). Oral doses of 99 mg PeCB and 48 mg of TeCB in mineral oil produced relatively similar (1. 8 times) PeCB concentrations in serum and feces for 28 days. Sample co ncentrations resulting from single and combined oral doses of PeCB (99 mg) and TeCB (48 mg) did not differ (P = 0.85). We detected no pathol ogical effects on coyotes from the doses of PeCB and TeCB administered in this study as assessed by visual observations. measurement of body condition, and examination of serum biochemistry and hematological pa rameters. We believe PeCB offers considerable potential for multiple r esearch applications as a long-term physiological marker for coyotes b ecause it permits researchers to correlate PeCB levels with other acti vities such as bait ingestion or livestock predation. Marking properti es of TeCB are similar to PeCB but may have restricted application bec ause TeCB is of limited solubility in oil vehicles.