Survey of multi-metal levels in blood samples of the preschoolers in Taiwan

Abstract

Background—Advanced techniques for multiple trace metal analysis in the past decades substantially improved the measurement of trace metals in biological sample, which was widely used as biomarkers for environmental metal exposure. Meanwhile, low level multi-metal exposure caught more attention in Taiwan in recent years. Aims— The present study was conducted to profile the multi-metal exposure levels in ambient environment with the blood sample of preschool children in Taiwan, and to tentatively explore the significant factors influencing the distributions of these metals. Methods—In total, based on a stratified random sampling strategy, 934 kindergarten students were recruited from all around this island country from April to October 2011 after their parents have signed a statement of consent. Venous blood sample was drawn from each participant and analyzed for metal levels with inductively coupled plasma mass spectrometry. Results—The geometric means (geometric standard deviation) for blood metal levels were 18.6 ug/L (1.56) for lead, 0.183 ug/L (1.96) for cadmium, 13.7 ug/L (1.42) for manganese, 928 ug/L (1.25) for copper, 4329 ug/L (1.25) for zinc, 3.03 ug/L (1.94) for arsenic, 4.32 ug/L (2.01) for mercury. Lead exposure were associated household income and parental educational levels (p < 0.0001) as well as paternal occupation (p<0.0003) and incense-burning at home (p=0.0012). Blood copper, zinc, arsenic and mercury levels were associated with geographic location and township level (p<0.001). No dominant factor was identified for cadmium and manganese levels in blood samples. Conclusions—Significant factors affecting multi-metal levels in blood samples still could be identified in Taiwan, especially for lead, copper, zinc, arsenic and mercury. This inference should be considered and incorporated into the future prevention program in order to further reduce the environmental metal exposure.