Risk assessment of heavy metal assosiated with dermal exposure in incense workers in small household factories at Roi-Et province, Thailand

Abstract

The Ngooleum village in Roi-et province is one of the largest producers of incense stick in the northeastern region of Thailand. An exposure of heavy metal through dermal contact is concerned because packaging is the main production process that involves of several heavy metals contact. Thirty-five small household factories were selected randomly to collect heavy metal residues on one packaging worker’s hands of each factory. The average residue concentrations (±SD) of Ba, Cd, Cr, Mn, Ni, and Pb on worker’s hands were 11.03±2.31 mg/kg, 1.13±0.23 mg/kg, 2.77±0.83 mg/kg, 7.06±1.92 mg/kg, 8.20±2.22 mg/kg, and 3.55±1.32 mg/kg, respectively. The dermal absorbed dose (DAD) of female workers (n=30) of Ba, Cd, Cr, Mn, Ni, and Pb were 1.48×10[superscript-7] mg/kg-day, 1.54×10[superscript-9] mg/kg-day, 3.68×10-8 mg/kg-day, 9.55×10-8 mg/kg-day, 1.12×10[superscript -7] mg/kg-day, and 4.76×10[superscript-8] mg/kg-day, respectively. The risk in term of hazard quotient (HQ) of Ba, Cd, Cr, Mn, Ni, and Pb were 3.02×10[superscript-5], 1.28×10[superscript-4], 2.45×10[superscript-3], 1.59×10[superscript-4], 5.60×10[superscript-4], and 1.13×10[superscript-4], respectively and hazard index (HI) for six heavy metals was 3.44×10[superscript-3]. Another dermal absorbed dose (DAD) from male workers (n=5) of Ba, Cd, Cr, Mn, Ni, and Pb on worker’s hands were 1.80×10[superscript-7] mg/kg-day, 1.72×10[superscript-9] mg/kg-day, 4.79×10-8 mg/kg-day, 1.11×10[superscript-7] mg/kg-day, 1.23×10[superscript-7] mg/kg-day, and 5.83×10[superscript-8] mg/kg-day, respectively. The hazard quotient (HQ) of Ba, Cd, Cr, Mn, Ni, and Pb were 3.67×10[superscript-5], 1.43×10[superscript-4], 3.19×10[superscript-3] , 1.85×10[superscript-4], 6.14×10[superscript-4], and 1.39×10[superscript-4], respectively and the hazard index (HI) was 4.31×10[superscript-3]. In conclusion, Both the HQ values for single heavy metal and HI value for six heavy metals were greatly below one indicated incense workers may not be greatly risk from these heavy metals via dermal route.