Abstract: The influence of water quality from boreholes situated around the Nnewi industrial area was evaluated by assessing the heavy metal concentrations and health risks associated with human exposure. Water samples were collected from 16 different boreholes around eight industries at a monthly interval from May – October 2019 and November 2019 – April 2020 to cover the rainy and dry seasons, respectively. Water samples were analyzed for copper (Cu), lead (Pb), iron (Fe), zinc (Zn), chromium (Cr), and arsenic (As) using atomic absorption spectrophotometer (AAS). The results were compared with the World Health Organization (WHO) standards. Data obtained for both seasons indicate Cu had a mean value of (0.268±0.136 mg/L), Pb (0.014±0.013 mg/L), Fe (0.119±0.133 mg/L), Zn (0.572±0.220 mg/L), Cr (0.051±0.011 mg/L), and As (0.013±0.001 mg/L) respectively. All the heavy metal concentrations of the sampled water were within their various WHO permissible limits except As, Cr and Pb. The pollution index of As, Cr and Pb were greater than 1, showing heavy contamination of the water. Carcinogenic risk assessment of water via ingestion and dermal route for Cr and As were above the recommended safe limit of 1×10-6 which posed a cancer risk. The results show that borehole waters were contaminated with heavy metals in both seasons. It is, therefore, recommended that borehole water from the study areas should be treated before being used for various domestic purposes.Abstract: The influence of water quality from boreholes situated around the Nnewi industrial area was evaluated by assessing the heavy metal concentrations and health risks associated with human exposure. Water samples were collected from 16 different boreholes around eight industries at a monthly interval from May – October 2019 and November 2019 – April 20...Show More
Abstract: The main objective of this study is to explore seasonal impacts of the Madden–Julian oscillation (MJO) on tropospheric circulations affecting Ethiopia during Belg (March–May) rains and associated variability in precipitation. The data used daily rainfall, daily Madden-Julian (MJO) indices, daily Outgoing Longwave Radiation (OLR) and zonal and meridional wind data. The methods used for this study is Correlation and composite analyses are used to establish the association and the relationship between the MJO and rainfall over Ethiopia. A non-significant declining trend in annual rainfall across Ethiopia has been observed over the past three decades trend change per year over by -0.602 mm and P-Value 0.338. The mean length of wet spells 90 days over SNNPR and Southern Oromia Region, and with a least mean length of wet spell is 10 days over Afar, Tigray and western Amhara Region. The results reveals that there is a strong correlation between Ethiopian rainfall and MJO to the west of the region especially around Central and Southeastern parts of the Country. Out of phase (opposite) relationship between the west and the east is also indicating different rain causing mechanisms for the two regions. The rainfall amount also shown to depend on the configuration of the winds at lower and upper levels. Based on composite analysis extreme rainfall events shown to occur during preferential phases of the MJO. Phase 2 coincides with enhanced rainfall, high negative anomaly OLR values as well as westerly and easterly winds configuration at 200hpa and 850hpa while phase 5, 6 and 7 are associated with deficit of rainfall. The inclusion of other modes of variability such as Sea surface Temperatures (SSTs) and the Indian Ocean Dipole (IOD), as predictors recommended in predicting interaseasonal rainfall.Abstract: The main objective of this study is to explore seasonal impacts of the Madden–Julian oscillation (MJO) on tropospheric circulations affecting Ethiopia during Belg (March–May) rains and associated variability in precipitation. The data used daily rainfall, daily Madden-Julian (MJO) indices, daily Outgoing Longwave Radiation (OLR) and zonal and merid...Show More
