Effects of heavy metals on health risk and characteristic in surrounding atmosphere of tire manufacturing plant, Taiwan.

The health and environmental effects of metal-containing carbon black (CB) particles emitted from a CB feeding area near a tire manufacturing plant were investigated. The mass ratios of PM 1 and PM 0.1 (UFPs) relative to TSP were 13.84% ± 4.88% and 50.84% ± 4.29%, respectively. The most abundant elements in all fractions were Fe, Al, and Zn. The mean percentage contributions of Al, Fe, Zn, Cu, and Co to the coarse particles ranged from 49.1% to 69.1%, thus indicating that the Al, Fe, and Zn contents in the CB particles were affected by workplace emissions. The ratios of the total mean deposition fluxes of atmospheric particle-bound heavy metals in the human respiratory tracts of workers/adults, workers/children, and adults/children were approximately 5.5, 11.0, and 2.0, respectively. The integrated risks of five elements via two exposure pathways to adults and children were 1.1 × 10 -4 and 1.7 × 10 -5 , respectively; these numbers reflect the high cumulative carcinogenic risk posed by these toxic metals to local residents (both adults and children; limit, 10 -6 ). These results demonstrate the potential health risk presented by particle-bound heavy metals to humans residing near tire manufacturing plants via inhalation and dermal contact exposure.