mum 

 o 



.. , . ;, ', : 01418S5 



be of use in determining the period of exposure. Very high levels 

 of pancreatic zinc (1887 and 2795 ppm dry weight) have been 

 observed by Allen et al . (1983) and Miller et al . (1970). Maxi 

 levels for kidney accumulation of zinc appear to be in the 2000 t 

 3000 ppm (dry weight) range with liver levels usually somewhat 

 less. Insufficient data exist to compare organ accumulation among 

 different species at high intake levels. Although the pancreas, 

 liver and kidney of livestock provide an excellent means of 

 determining zinc exposure, they are rarely available on a large 

 scale. Blood serum levels provide an alternative and have shown a 

 good correlation to dietary zinc up to 1500 to 2000 ppm. Zinc 

 intake above this level does not produce corresponding increases 

 in serum zinc (Ott et al . 1966c, 1966d). 



Zinc levels in hair have been used with some success for 

 determining zinc exposure. A number of factors, including age, 

 species, color and sex may affect the zinc content of hair (Miller 

 et al. 1965b). These investigators also found considerable varia- 

 tion in hair zinc content among animals otherwise similar in age, 

 color, breed and sex. Ronneau et al . (1983) found that the 

 concentrations of the essential elements Na , K, Se, and Zn in 

 hair were nearly constant with age but the accumulation of certain 

 metals was primarily a characteristic of each individual. Elemen- 

 tal concentrations in cattle hair studied by Ronneau et al . (1983) 

 also demonstrated a good correlation (r = 0.69) of inter-elemental 

 ratios such as iron to zinc. These authors suggested that such 

 ratios may be more useful as a "fingerprint" of contamination. 



A study of horse mane hair in an area with heavy metal 

 contamination found that high zinc levels were associated with the 

 highest concentrations of lead and cadmium (Lewis 1972). Individ- 

 ual variations at some sites studied by Lewis (1972) were also 

 large, but there was no attempt to compensate for age, color of 

 hair or other factors. Ronneau et al. (1983) concluded that 

 absolute concentrations of heavy metals in hair are of limited 

 usefulness but they may be useful for large-scale determination of 

 pol lution . 



65 



