OCCUPATIONAL EXPOSURE TO FUGITIVE GASES (CO AND H2S) AND ALTERED OXYGEN LEVELS AMONG WASTE HANDLERS IN SELECTED DUMPSITES IN KENYA

Abstract

Solid wastes disposal sites provide a livelihood to many waste pickers. Sporadic fires within the dumpsites and waste decomposition lead to the emissionof fugitive gases such as carbon monoxide (CO) and Hydrogen Sulphide (H2S). Increased CO and H2S in ambient air also reduce oxygen (O2) gas levels which can cause negative health effects to the dumpsite workers. This study assessed the levels of CO, O2andH2Sin selected dumpsites. The sites assessed were in Thika (Kiambu County), Ngong (Kajiado County), and Kawangware (Nairobi County) while control sites for the three dumpsites were located within a radius of 300 metres from the edge of each dumpsite. Levels of CO, O2 and H2S were determined using a Multi-gas monitor (model GX2012) during working time at the dumpsites and control sites away from the active dumps. Data was entered into SPSS version 20.1 for analysis. The ANOVA and student t-test were done at a 95% confidence interval. The active dumpsite CO gas mean values were 14.5 ±0.42ppm in Thika, 10 ±0.43ppm in Ngong and 14.5 ±0.34ppm in Kawangware, hence were higher compared to control sites (0ppm). The dumpsite H2S gas levels in Thika and Ngong were both 0.5 ±0.1 ppm, while Kawangware levels were 0.25 ±0.1 ppm. These readings were higher compared to control sites (0.0ppm). The mean dumpsite O2levels were 20.53% ±0.08 hence significantly lower than from the control sites (20.90± 0.10%). The study revealed that workers in the three sites were exposed to fluctuating O2levels which should not fall below 18% by volume, elevated levels of CO (13.00± 2.60) ppm and H2S (0.042 ±0.14ppm). These were higher compared to the control sites (0±0.1ppm). This calls for an effective dumpsite gas monitoring and control design to prevent increasesbeyond regulatory levels.