MAMMALS 



The mink is the most sensitive wildlife species tested for which data are 

 available (Table 4). Diets containing 6.7 to 8.6 mg Aroclor PCBs/kg fresh 

 weight killed 50% of the mink in 9 months; single dosages administered orally 

 produced LD-50 values of 750 to 4,000 mg/kg body weight, those administered 

 intraperitoneal ly produced LD-50s between 500 and 2,250 mg/kg body weight 

 (Table 4). Recent data (Aulerich et al. 1985) indicate that certain 

 hexachlorobiphenyls (HCBP), such as 3,4,5,3' ,4' ,5' HCBP, are extremely toxic 

 to mink; concentrations as low as 0.1 mg/kg fresh weight diet produced an 

 LD-50 in 3 months, and completely inhibited reproduction in survivors. 

 However, other HCBPs, such as 2,4,5,2' ,4' ,5' HCBP and 2,3,6,2 ' ,3' ,6' HCBP, 

 were not fatal to mink under similar conditions, and did not produce adverse 

 reproductive effects (Aulerich et al. 1985). Additional research is needed on 

 the toxicodynamics of PCB congeners. Signs of PCB poisoning in mink included 

 anorexia, bloody stools, fatty liver, kidney degeneration, and hemorrhagic 

 gastric ulcers (Aulerich and Ringer 1977). The reasons for mink sensitivity 

 to PCBs are unknown, but large variations in sensitivity to PCBs among species 

 are common, even among those closely-related taxonomically. The European 

 ferret ( Mustela putorius furo ), for example, is at least three times more 

 resistant than mink to Aroclor 1242 (Table 4). 



Rats fed diets containing 1,000 mg of Aroclor 1254/kg diet all died in 53 

 days; mortality started at day 28 (Hudson et al . 1984). These, and other 

 feeding studies, suggest that a total intake of about 500 to 2,000 mg of 

 Aroclor 1254 per kg body weight is the lethal level in rats for dietary 

 exposures of 1 to 7 weeks. Prior to death, rats showed lack of muscular 

 coordination, eyelid drooping, blanched retinas, morbidity, nasal secretions, 

 and (with Aroclor 1268) a reddish exudate from their eyes (Hudson et al. 

 1984). Some rats died at 100 mg Aroclor 1254/kg body weight administered 

 orally, or about 1/5 of the dietary LD-50 (Hudson et al. 1984). 



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