Toenail Metal Concentration as Biomarker of Heavy Metal Exposure among Welders

This study examined the concentration of heavy metal accumulated in the toenail of welders and compared to the concentration of airborne heavy metal exposure in the breathing zone of the welders. Ten selected welders with adequate toenail growth were asked to clip all ten toenails for analysis. The heavy metal concentration in the welder’s breathing zone was collected by using mixed cellulose ester filters by using low flow rate air sampling pump. Both toenails and airborne sample filters were analyzed for thirteen elements (Be, Al, Cr, Mn, Fe, Co, Ni, Cu, As, Mo, Ag, Cd and Pb) by using inductively coupled plasma mass spectrometry (ICP-MS). The results of the study show airborne concentration of chromium (maximum value of 0.788 mg/m3) and manganese (maximum value of 3.937 mg/m3) in the welder’s breathing zone exceeded the permissible exposure limit of Malaysian regulation. In addition, there was a similar trend obtained from the average concentration of heavy metal in breathing zone air sampling and the average accumulation of heavy metal in welder’s toenail. The results of the study suggest that toenail accumulation was a reliable biomarker for continuous heavy metal exposure among the investigated welders.