LEAD LEVELS IN BLOOD FROM CATTLE RESIDING NEAR A LEAD SMELTER

Concentrations of Pb in whole blood from 222 cattle (Bos tarus L.) representing nine herds were determined. Lead blood levels were significantly (P less-than-or-equal-to 0.05) elevated for herds near a primary lead smelter compared to a background herd. Herd Pb blood levels were significantly correlated to distance from the smelter (r = -0.86), and to soil Pb concentrations (r = 0.96). They were also moderately correlated (r = 0.61) to vegetation Pb levels. Soil may be more important than forage as a source of Pb for these cattle. Immature cattle, less than 1 yr old, had higher (P less-than-or-equal-to 0.05) Pb blood levels than mature cattle. A total of 15 animals (all immature) exhibited Pb blood values above 35-mu-g dL-1. Twenty-one animals had elevated (22-35-mu-g dL-1) Pb blood levels. Most cattle (80%) tested near the smelter and all cattle from the background herd had Pb blood levels in the normal diagnostic range (1-21-mu-g dL-1).