J. Crilly et al., EVALUATION OF BLOOD AND TISSUE LEAD AS ESTIMATORS OF EXPOSURE IN SHEEP, Irish journal of agricultural and food research, 37(1), 1998, pp. 17-28
From 1992 to 1994, samples of whole blood, liver, kidney, muscle and b
one were collected at slaughter from 70 lambs which had grazed on a re
-vegetated tailings pond of a lead/zinc mine for periods ranging from
49 to 168 days, together with similar samples from 24 unexposed contro
l lambs. Concentrations of Pb in blood, liver, kidney and bone in the
exposed lambs were significantly higher than those in the controls in
each of the 3 years although tissue levels in all cases remained below
2 mg/kg wet weight, the maximum permitted for human consumption under
current Irish legislation. While blood Pb levels generally showed a g
ood correlation with those in liver, kidney and bone, a greater degree
of overlap between exposed and control lambs for blood values compare
d to tissue values reduced the sensitivity and specificity of blood Pb
as an indicator of Pb exposure. The Pb content of liver, kidney and b
one provided better discrimination of animals exposed to the tailings
and this suggests that these tests are more suitable for inclusion in
environmental monitoring programmes.