Assessment and Modeling of Workplace Exposure to Solar Ultraviolet Radiation in Makurdi, Nigeria

Abstract

Solar radiation though beneficial to life but the harmful effects of over exposure especially in Nigeria has been neglected and its measurement/prediction has received negligible attention in the literature. This study measured and modeled workplace exposure to solar ultraviolet radiation (SUVR) in Makurdi, Benue State, Nigeria. Digital broadband meter was used to measure solar power density in three site while polymer Polysolphone dosimeters were fitted on a human manikin and placed in the sun between 10:00 am- 4:00pm (6 hours) to quantify the amount of Solar UVR absorbed by three occupational workers (Traders, Fishermen and Staff/Students). Five dosimeters were deployed in each of the three sites for calibration to measure UV absorbance in J/m2 while seven in each site were used for body parts. UV/VIS-spectrophotometer was handily used to measure both post and pre-absorbance and the UV exposures were calculated. The UV index was also calculated. Result shows that, head top had the highest exposure values 7.19kJ/m2, 6.51kJ/m2 and 7.00kJ/m2, while the least values was under cloth cover 2.47kJ/m2, 2.08kJ/m2 and 2.20kJ/m2 for traders, fishermen and staff/students respectively. Similarly, the calculated cumulative exposures were 3289.36kJ/m2, 497.82kJ/m2 and 1515.60kJ/m2 at the market square, river bank and the campus respectively. These values were higher than international ICNIRP average value 30J/m2. UV index at market square was 9 (media graphic colour purple), while at river bank and BSU campus was 8 (media graphic colour reddish). High mean irradiant values with high UV index indicates high risk of harm from unprotected sun exposure. Therefore, use of sun protective clothing is recommended and reduce time in the sun especially between 1:00pm and 2:00pm to prevent over exposure that will lead to serious harmful effects especially at the market place.