Biomonitoring of chromium for residents of areas with a high density of electroplating factories

The high density of electroplating factories in the geographic middle of Taiwan has prompted concern over the potential for exposure to harmful metals. The present study aimed to determine the levels of chromium in whole blood (B-Cr) of residents living in the high vs. low factory-density areas,and to examine the relations to gender and age. A total of 660 residents who had not moved within the 5 years preceding the study were sampled according to the stratified random sampling approach, at ages 35 - 44, 45 - 54, and 55 - 64 years, for both genders. Chromium determinations (n = 641) were made using a graphite furnace atomic absorption spectrometer. The geometric mean ( 95% C. I.) of B-Cr was 0.357 (0.34-0.38) mu g/l. The International Federation of Clinical Chemistry(IFCC) nonparametric 0.95 reference limits of B-Cr was estimated to be < 0.905 mu g/l. B-Cr levels decreased with increasing age. Subjects in the areas with a high density(0.38 mu g/l, 95% C.I.:0.36-0.40) of electroplating factories had significantly higher B-Cr levels, compared to residents of the low-density(0.27, 0.25-0.30) areas and to the general population from western countries. The health significance of the elevated B-Cr remains to be determined.