No abstract

Water security, as a sustainable development goal, ensures that sustainable water supply is consistently available to every individual. A water supply systems assessment matrix was designed as a tool for assessing water supply systems (WSS) in low-income countries; with selected urban, peri-urban, and rural Nigerian communities as case studies. Sustainability of the WSS was assessed through established criteria against five sustainability factors. Sanitary surveys were conducted to evaluate the risks associated with the WSS using Sanitary Inspection Forms through which the Sanitary Risk Scores (SRS) were derived. For sustainability, the WSS were ranked as Very High, High, Medium and Low Sustainability, and for SRS as Very High, High, Intermediate and Low Risk. A Sustainability and Risk Assessment Matrix (SRAM) was designed using sustainability evaluation and risk assessment for the WSS. The WSS in the rural areas are more ‘Secure’ than those in urban and peri-urban towns, and boreholes are more ‘Secure’ than hand-dug wells, but none of the public water point is scored ‘Secure’. The paper concludes that SRAM provides a cost-effective method of classification and may serve as a pre-water quality and source sustainability assessment tool, especially in low-income countries, as part of the measures to achieve water security.

The focus of this study was to portray the spatial pattern of air quality across seasons in the eight sampled farm settlements using air quality indexes and assess the clusters of monitored air pollutants. The concentrations of air pollutants were determined using in-situ portable gas detectors and particulate counter. The AQI for each criteria pollutants (CO, O3, TSP, PM10, SO2, and PM2.5) was calculated using AQI formulae of the United States Environmental Protection Agency and mapped using the Inverse distance weighting (IDW) interpolation method in the Geographic information systems (GIS) environment. Principal component analysis (PCA) was used to group the parameters and estimate the interrelationships between the loadings of the parameters in each component. The AQI ranges of pollutants which deviated from the acceptable good status are CO (71.98 – 238 and 88.85 – 220.93), NO2 (10.14 – 107.07 and 10.84 – 72.88) and PM2.5 (12.90 – 70.85 and 12.56 – 54.02) for the dry and wet seasons, respectively. There were five and four PCs with eigenvalues > 1, accounting for 69.75% and 61.73% of the total variance during the wet and dry season, respectively. The parameters in each component are as follows; PC1 - TSP, PM10, PM2.5, Bacteria and fungi; PC2 - CO and Temperature; PC3 - relative humidity and O3; PC4 - CO2; PC5 - NO2 and SO2 for the wet season and PC1 - TSP, PM10, PM2.5, Bacteria and fungi; PC2 - NH3 and NO2; PC3 - CO2 and O3; PC4 - Temperature and relative humidity during the dry season. Biomass burning, engine exhausts and fine-particulate related activities are sources of air pollution and such may pose negative implication to human health and environment. Therefore, the use of alternative biomass disposal, regular servicing of processing engines and the wearing of protective wears against dust are recommended.

The quest for safe drinking-water is very high in the ongoing period of environmental pollution. Generally, anthropogenic activities resulting from increasing population and urbanization are major sources of pollution to groundwater. This paper assesses the variation in groundwater distribution in Abeokuta city, Ogun State, Nigeria to determine the water quality status. Secondary groundwater quality data across a period of fifteen years (2001 – 2015) were retrieved from the database of the Department of Water Resources Management and Agro-meteorology, Federal University of Agriculture, Abeokuta, Nigeria to establish the status and examine the spatial and temporal variation. The data was subjected to statistical and geo-statistical analysis. Results showed that temperature, pH and electrical conductivity have a dominant range of 28.0 – 29.9 ºC, 7.01 – 7.50 and 201 – 600 µS/cm, respectively. The major cations Ca2+, Mg2+, Na+ and K+ have respective dominant concentration range from below detection limit (bdl) – 80mg/L, bdl – 30mg/L, 11 – 20 mg/L and bdl – 10 mg/L, while the major anions Cl-, HCO3-, NO3- and SO42- have respective dominant concentration range of 11 – 30, 101 – 200, 1.60 – 4.00 and bdl – 10 mg/L. High (> 1000 µS/cm) conductivity values are detected in parts of the city, which may be due to high concentrations of magnesium, calcium, potassium, chloride and bicarbonate. Only few parts (5.7%) of the city have poor water quality status, while groundwater quality in about 45.7% and 48.6 % of the city may be classified as good and excellent water quality, respectively. The spatial trend showed that groundwater in the core townships of Abeokuta such as Itoku and the environs should not be encouraged for direct consumption without prior treatment. But generally, the groundwater in most part of Abeokuta metropolis is safe for domestic use, though requires some form of household treatment before drinking.