Asbestos fibers and trace metals in the blood of cattle grazing in fields inundated by asbestos-rich sediments.

During a major storm in 1975, a pasture was inundated with serpentinitic sediments which are rich in asbestos fibers and trace metals. Little natural revegetation has occurred at the site and dairy and beef cattle which continue to graze in and around the contaminated site are exposed to asbestos fibers by inhalation and ingestion. The effect of this material on the cattle was investigated in this study by analyzing blood samples from exposed and control animals for asbestos fibers, trace metals, and general blood chemistry. The analysis showed that at the time of exposure Ni and Mn values were significantly higher in the exposed animals than in the controls, and in six out of seven samples asbestos fibers were present as determined by STEM analysis. Once the animals were removed from the site, trace metal levels returned to normal but asbestos fibers were still present in three out of seven animals. Two of the control animals unaffected by the sediments also showed asbestos fibers and there were no relationships between the magnitude of fibers and trace metal content. This suggests that the sediments influence the blood chemistry of animals but the presence and magnitude of asbestos fibers in the blood can be influenced by other factors as well.