An assessment of the emission of combustible gases in developing countries requires reliable analytical realtime monitors that can rapidly screen them with minimal handling. Considering the expensive nature of monitoring environmental pollutants, chemical sensors are expected to play a pivotal role in measuring and recording environmental data. The Drager X am 5000 was used to report emission levels of combustible gases in this study, namely; nitrogen dioxide (NO 2 ), sulphur dioxide (SO 2 ) and carbon monoxide (CO) at traffic and practising waste dumpsite in Freetown, the main city of Sierra Leone. Hourly average values for the three pollutants were recorded in the morning, afternoon and evening periods, respectively. The range of values were 18 -76 ppb for NO 2 , 211 -506 ppb for SO 2 and 11 -14 ppm for CO at traffic site; and 6 -16 ppb for NO 2 , 118 -276 ppb for SO 2 and 8 -15 ppm for CO at the dumpsite, respectively. There were significantly high hourly variations for NO 2 and SO 2 at the traffic site and for CO and SO 2 at the dumpsite. Evidence of peak values showed emission levels that were considered dangerous for human exposure. This pilot study revealed that combustible gases released in certain areas of the capital city are a concern for both public health officials and environmental advocates.

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Abstract:The analyses of industrial effluents at Sierra Leone Bottling Company Limited (SLBC) in Freetown, the capital city of Sierra Leone were conducted to assess its composition, and removal efficiency of physico-chemical parameters. Fifteen (15) samples were collected from the drain water (influent), pre treatment effluent and treated effluent (effluent) for five days. There were significantly higher concentrations of influents parameters relative to those of the corresponding effluents. The influent levels for pH, electrical conductivity and chloride were higher than permissible threshold. 80% of the samples at the influent point were within permissible guideline for TDS but all were in total agreement with the effluent samples for the same parameter. Comparative analyses showed significant reduction in values for pH, temperature, iron and chromium in the effluent samples relative to the influent samples and all of the other parameters did not show any statistically significant differences. The treatment plant was noted to be highly efficient in removing iron and chromium but least efficient for total dissolved solids and water temperature. Huge variances with respect to removing contaminants for chloride, electrical conductivity and total dissolved solids were observed. The average overall removal efficiency of contaminants in industrial effluents was low but the practice of treating industrial wastewater by SLBC was plausible. Considering the pollution load of certain parameters being investigated, it is imperative for the SLBC to initiate the process of setting up waste stabilization ponds (WSP) so as to contain industrial effluents for further examination before they are discharged into the environment.

Rural communities in sub-Saharan Africa (SSA) are always faced with the challenge of securing safe water for beneficial uses. Most communities lack a centralized water supply system and, thus, each residence utilizes the treatment method that they can afford. This study evaluated three treatment methods for drinking water in the Njala University and Mokonde communities in southern Sierra Leone. In the perceived natural treatment, residents in the Mokonde community believe that groundwater has been purified by the soil media and, hence, does not require further treatment. In the conventional treatment, the Njala University Water Works use sand filtration and chlorine disinfection to treat water from the Taia River. The third treatment method, first flush diversion, was introduced by Njala University researchers in 2014.We studied the populations of coliform bacteria and E. coli in untreated and treated water samples to determine if each of the treatment methods supported the beneficial use of drinking. This study concludes that the natural filtration does not remove pathogens in the well water. Even though the first flush and conventional treatments were efficient in reducing microbial populations in the water, the World Health Organization's 100% removal guideline was not achieved most of the time. Therefore, all three treatment methods did not support the beneficial use of drinking. Further treatment was needed to render the water potable.