[Investigation of indium exposure in workers in indium smelting plant]

To investigate the internal and external exposure levels of indium (In)in workers in an In smelting plant, and to analyze its distribution characteristics.

A survey was performed in 63 employed workers with more than one year of experience working in an In smelting plant in 2014. The personal air samples for 31 workers were collected, and the whole blood, serum, and urine samples of all the 63 workers were collected to do the occupational health examination at the same time. In levels in all samples were determined by inductively coupled plasma mass spectrometry.

The smelter workers had a higher In exposure level in the air than the office workers (2.26 μg/m(3) vs 0.82 μg/m(3), P>0.05). There was a significant difference in In exposure level in the air between the workers doing different types of jobs (P<0.05). The In exposure levels in the air in the metathesis workers and electrolysis workers were 26.10 μg/m(3) and 20.99 μg/m(3), respectively, which were significantly higher than those in other workers (P<0.05). The smelter workers had significantly higher geometric means of In levels in the whole blood, serum, and urine than the office workers (0.44 μg/L vs 0.09 μg/L, P<0.05; 0.35 μg/L vs 0.09 μg/L, P<0.05; 0.26 μg/L vs 0.12 μg/L, P<0.05). There were significant differences in In levels in the whole blood, serum, and urine between the workers doing different types of jobs (P<0.05). The metathesis workers (13.0 μg/L, 4.02 μg/L, and 2.93 μg/L)and electrolysis workers (5.71 μg/L, 5.14 μg/L, and 4.26 μg/L)had higher In levels in the whole blood, serum, and urine than other workers. The In level in the whole blood was positively correlated with the In levels in the urine and serum (rs=0.601, P<0.05; rs=0.823, P<0.05). The In levels in the whole blood and urine were positively correlated with the In level in the air(rs=0.483, P<0.05; rs=0.428, P<0.05).

In the In smelting plant, the In concentrations in the air are lower than the standard value, but the workers have higher In levels in body. The In level in the whole blood is positively correlated with the In levels in the serum and urine. The In levels in the whole blood and urine are positively correlated with the In level in the air.