A Comparison of Blood Lead Levels between Migrant and Native Lead Workers Before and After Implementation of a New Employment Permit System for Migrant Workers

Abstract

We compared the blood lead and other lead biomarkers between migrant and native workers with a focus on the impact of the legal employment permit system that was effective from 2003, which required employers to provide mandatory annual health examinations for migrant workers on lead biomarkers in 1997 and 2005. The mean blood lead level of migrant workers was 59.5 ± 19.4 μg/dl, yielding 47% of lead poisoning cases, which was significantly higher than that of native workers (36.8 ± 14.5 μg/dl; 11% of lead poisoning cases) in 1997 before enactment of the act. The overall mean blood ZPP levels and ALAU of migrant workers were significantly higher than those of native workers. In 2005, after new migrant worker regulations were instituted, the mean value of above lead biomarkers workers was still significantly higher than that of native workers, but the magnitude of the differences was smaller compared with the difference in 1997. We confirmed that the 2003 regulations played an important role in improving the health of migrant workers in the lead industry in terms of their blood lead levels and other lead biomarkers.