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of 10 to 700 ppm (wet weight) (Puis 1981) and liver levels of 5 to 

 300 ppm (wet weight) (Puis 1981). Chronic lead exposure may 

 produce kidney and liver lead levels 50 ppm (wet weight) (Table 

 18). Kidney tissues with 12 ppm lead have been reported in cattle 

 killed from lead toxicosis (Every 1981) and levels as low as 4.5 

 ppm in foal kidney have been associated with chronic lead poison- 

 ing (Schmitt et al . 1971). Levels of lead have been reported for 

 spleen, heart, brain, bone, pancreas, hair and milk for several 

 species (Tables 15-18). These values are generally an order of 

 magnitude less than corresponding levels in kidney and liver 

 tissues and are thus, subject to greater analytical error in de- 

 termining the degree of lead toxicosis. Elevated lead levels in 

 hair have been associated with chronic lead toxicosis in horses 

 (Lewis 1972). A study of elements in cattle hair has determined 

 that there are large variations in elemental concentrations among 

 individuals within the same group and that lead levels in cattle 

 hair show only a slight correlation to other metals (Ronneau et 

 al. 1983). Significant correlations (p = 0.01) between hair and 

 liver concentrations of cattle were found by Russell and Schoberl 

 (1970). Dorn et al. (1974) found one to two orders of magnitude 

 increase in lead concentrations in hair of cows exposed to 

 industrial pollution when compared to controls. 



Levels of lead in milk are generally low, but have been used 

 to estimate the degree of chronic lead poisoning. Milk lead 

 levels are usually about two orders of magnitude less than kidney 

 and liver samples and thus milk samples are less sensitive and 

 more prone to contamination. Murthy et al . (1967) reported 

 background levels of lead in milk from cattle ranged from 0.023 to 

 0.079 ppm with a mean of 0.047 ppm. Hammond and Arcnson 11964) 

 reported a mean and range of .0.009 and 0.006. to 0.013, respec- 

 tively, in 8 animals. Lead levels in cattle milk indicative of 

 toxicosis have been given as 0.10 to 0.25 ppm (Puis 1981). This 

 author also indicated that a dietary intake of 100 ppm lead was 

 associated with lead toxicosis. 



In summary, it appears that kidney and liver tissues offer 

 the best indication of lead toxicosis. Because of the expense and 



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