0141650 



limited opportunity to obtain these samples, the analysis of blood 

 may provide a good alternative. Blood lead levels are moderately 

 well defined in the literature and sampling and analysis are 

 relatively simple. The specific blood parameters of ALA-D and FEP 

 may provide a means of determining lead intoxication in the 

 future, but at the present, insufficient data exist to fully 

 utilize these parameters for livestock toxicolog ical evaluation. 

 Hair samples may be used to indicate long term chronic lead 

 exposure if a sufficiently large sample base is obtained. A hair 

 lead content of 10 ppm has been reported as indicative of exces- 

 sive lead exposure (Puis 1981). More detailed studies could make 

 use of biopsy tissues of liver and bone, and feces can be analyzed 

 to' determine dietary exposure (Decker et al . 1980). 



2.3.2 Livestock lead hazard level 



The data contained in Table 15, 16, 17, and 18 and other 

 publications were used to develop lead hazard levels in the 

 following sections. 



2.3.2.1 Toxic lead hazard levels for cattle 

 The 0.35 ppm toxic blood level selected for cattle is based 

 on several publications (Table 19). Buck et al . (1976) suggested 

 the level was indicative of probable clinical toxicosis. Buck 

 (1975) stated ".Concentrations >0.35 ppm in cattle should be 

 considered as evidence of unusual exposure," That statement was 

 based on the observation of 142 animals, of which 52 exhibited 

 symptoms of clinical lead toxicosis and had blood lead levels 

 ranging from 0.19 to 3.80 ppm, with a mean of 0.81 ppm lead. 

 Hammond and Aronson (1964) observed that, in acute lead poisoning 

 in cattle, blood lead levels were never less than 0.35 mg/1 . The 

 0.35 ppm blood lead concentration was reported by Puis (1981) as 

 indicative of toxicosis in cattle The value is supported by 

 other data from the reviewed literature (Tables 15 and 17). The 

 highest concentration of lead in cattle blood at which toxicosis 

 has not been noted is the 0.29 ppm reported by Sharma et al. 

 (1982) . 



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