Occupational exposure assessment of heavy metals among construction workers in Rawalpindi Pakistan

Construction is one of the primary drivers of development and economic activity in Pakistan. Many activities are performed at the construction site including cement mixing, carpentry, and painting. Workers working in these activities are exposed to toxic heavy metals. Due to exposure to these heavy metals, subjects are at high risk of developing diseases mainly respiratory diseases. Human hair and nail samples of construction workers in Rawalpindi, Pakistan were collected to assess the heavy metals. Heavy metals such as Al, As, Cd, Cr, Ni, K, Pb, and Zn were analyzed in the hair and fingernails of the construction workers. To determine the level of selected heavy metals, Inductively Coupled Plasma optical emission spectrometry was used. Results revealed that Al was the highest with a mean concentration of 7.54 μg/g in all three groups. Whereas Cd was below the detection limit. Heavy metal concentration was high in hair (1.77 μg/g) in two groups including cement mixing and carpentry. However, in the carpentry group heavy metal concentration was high in nails (1.19 μg/g). Additionally, the workers of the carpentry group have higher metal concentrations when compared to the other two groups and this group was at high risk of toxic metal exposure. After the correlation analysis, the results revealed that age was significantly correlated to body burden of metals (r = 0.496, p ≤ 0.05). Moreover, some of the heavy metals in hair and nails were significantly correlated with each other. Since all groups, especially carpenters, show high levels of heavy metals, there is a need for regular monitoring of heavy metals at construction sites. Most importantly, the implementation of training programs is needed to raise awareness among construction workers.