0141639 



A sheep liver concentration of 13 ppm cadmium was selected 

 based on the study of Doyle and Pfander (1975). These authors 

 have reported reduced growth in lambs was associated with 13.2 ppm 

 cadmium in liver tissue. Reduced feed efficiency and reduced 

 growth were reported for sheep with liver cadmium concentrations 

 in the 40 to 60 ppm range (Table 12), and Puis (1981) reported a 

 toxic concentration of cadmium in sheep liver to be 50 to 600 ppm. 

 The 13 ppm hazard level for this parameter should be used with 

 caution until additional data are obtained. 



The toxic hazard level (>20 ppm) of cadmium in sheep wool 

 (hair) is based on the >20 ppm cadmium Wright et al . (1977) found 

 in the wool of sheep fed toxic levels of cadmium (as cadminate) 

 over a 49 week period. Doyle and Pfander (1975) noted cadmium 

 levels of 0.7 to 1.22 ppm in the wool of sheep fed 5 to 60 ppm 

 cadmium (as CdCl2) over a 163 day period, but these levels also 

 overlap typical background values (Table 9) . 



2.3 Lead 



2.3.1 Lead literature review 



The literature search revealed a considerable amount of data 

 on lead levels in various animal tissues and other substances 

 (Tables 15-18). These data suggest that lead levels in kidney and 

 liver, which accumulate lead, and blood are good indicators of 

 lead toxicosis. Concentrations of lead in these three tissues are 

 elevated in all documented cases of lead toxicity. Furthermore, a 

 considerable volume of data on background or control levels is 

 also available (Ruhr 1984, Doyle and Younger 1984, Zmudski et al. 

 1983, Burrows and Borchard 1982, Schmitt et al . 1971, Dollahite et 

 al. 1978, Buck et al. 1976). Fewer data are available on lead 

 levels in spleen, heart, brain, pancreas, bone and hair (Tables 

 15-18) . 



Blood lead levels appear to be a good indicator of chronic 

 toxicosis but are not as dependable for diagnosis in acute or 

 subacute cases. This lack of diagnostic accuracy may result from 

 an initial rapid rise of blood lead following metal ingestion and 



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