Occupational Exposure and Determinants of Heavy Metal Accumulation in Welders: A Biomonitoring Study in Arba Minch Town, Ethiopia

Abstract Heavy metals from welding activities pose significant health risks to workers, especially in developing nations such as Ethiopia, where safety measures are inadequate. This study examined the levels of heavy metals, including lead (Pb), cadmium (Cd), chromium (Cr), manganese (Mn), copper (Cu), and nickel (Ni), in the fingernails of welders in Arba Minch Town, and evaluated the various factors that influence metal accumulation. Fingernail samples were collected from 35 welders and 18 non-welders using a random sampling method. The fingernail samples were subjected to acid digestion with a HNO3 and H2O2 mixture (2:1), and the heavy metal concentrations were determined by Atomic Absorption Spectroscopy. The effect of factors such as age, work experience, life style habits (Substance use) and use of personal protective equipment’s (PPE) on the level of heavy metal accumulation in workers was evaluated. The mean concentrations of all heavy metals (Pb, Mn, Ni, Cu, Cr, and Cd) were found to be elevated and statistically significant (p < 0.05) in the fingernails of welders compared to those of the non-welding cohort. Welders who smoked showed elevated concentrations of nickel (15.19 ± 4.27 µg/g) and manganese (14.42 ± 3.16 µg/g) compared with non-smokers. Welders with the highest levels of Pb (80.83 µg/g) and Cu (110 µg/g) did not use personal protective equipment (PPE), consumed khat and cigarettes, and had over 10 years of work experience in welding. Age and work experience were positively correlated with the predicted coefficient (r) values for Mn, Ni, Cd, Cu, and Pb. The results suggest that welding workers in Arba Minch Town are subjected to elevated levels of toxic heavy metals owing to prolonged exposure to welding fumes. Continuous biomonitoring is crucial for evaluating the occupational risks faced by welding workers due to heavy metal exposure and other chemicals.