Assessment of Levels of Occupational Exposure to Magnetic Fields and Ultraviolet Radiation among Welders in Greater Accra Region – Ghana

Abstract

Welders make up a large group of workers in Ghana and can be found in various factories and worksites engaged in welding of numerous metals, especially in the sectors of construction, manufacturing, maintenance and repair. The shielded metal arc welding (SMAW) is the most commonly employed welding method in these industries. This welding process can also produce hazardous levels of ultraviolet (UV) radiation and extremely low-frequency (ELF) magnetic fields (MFs) from the welding arc. It is therefore necessary to ensure that the UV radiation and MF exposure of the welders are within the safe exposure levels prescribed by recognized international organizations such as the International Commission on Non-Ionizing Radiation Protection (ICNIRP) whose limits have also been adopted by the Radiation Protection Institute (RPI) in Ghana and the American Conference of Governmental Industrial Hygienists (ACGIH). The primary objective of this study was to quantify the level of UV radiation and ELF MFs exposure to welders from the arc of SMAW in factories or worksites in Ghana and compare them to guidelines set by these international bodies. Results from the measured Ultraviolet C (UVC) irradiance levels, EUVC ranged between 0.16 ± 0.08 W/m2 and 10.46 ± 1.96 W/m2 with its corresponding permissible exposure duration, tmax-uvc per day ranging from 5.74 s to 367.35 s. The measured Ultraviolet-A (UVA) irradiance levels, EUVA ranged between 0.88 ± 0.03 W/m2 and 23.72 ± 6.66 W/m2 with its corresponding permissible exposure duration, tmax-UVA per day ranging from 421.59 s to 11363.64 s. These results were compared to international guidelines by the ICNIRP and ACGIH and suggested that UV radiation coming from the SMAW process is actually hazardous to the eyes and skin of the welders since the total exposure time of the welders exceeds the permissible exposure durations. The magnetic flux densities ranged from 4.01 ± 0.72 μT to 196.46 ± 4.86 μT and the expected induced current density in the head, Jhead and trunk, Jtrunk of the welders ranged from 0.01 to 0.62 mA/m2 and 0.03 to 1.23 mA/m2 respectively. Therefore, these results are within the ICNIRP Reference Level and Basic Restriction of 500 μT and 10mA/m2 respectively. Analysis of the responses from the questionnaire administered to the welders suggested that radiological safety practices among the welders were not adequate and most of them occasionally experienced common symptoms of health effects related to UV radiation and magnetic field exposure.