The suitability of Goro Dong (Lake) water for human consumption has been examined using the Weighted Arithmetic Water Quality Index Method. Water samples were collected from the lake in the month of March 2017 and subjected to standard physicochemical tests. Parameters used for the water quality analysis include pH, Electrical Conductivity, Total Hardness, Total Alkalinity, Total Dissolved Solids, Total Suspended Solids, Sodium, Magnesium, Calcium, Chlorides, Sulfates, Nitrates, Dissolved Oxygen and Biochemical Oxygen Demand. The drinking water standards employed included those of World Health Organization (WHO), Nigeria Industrial Standard (NIS) and Indian Council of Medical Research (ICMR). Results revealed that the observed values of all the parameters were within the permissible limits provided by the employed standard agencies. However, the overall Water Quality Index (62.34) indicated that the water quality is poor and thus require minor treatments before drinking.
This study estimated recurrence periods of earthquakes in Zimbabwe using exponential distribution model. The data for this study were extracted from a catalogue, the Advanced National Seismic System (ANSS) owned by Northern California Earthquake Data Centre UC Berkeley, USA. The selected data consisted of earthquake events with magnitude Mb 4.0 for the study area from 1st January, 1901 to 31st December, 2001 (100 years) with focal depth from 0 – 700 km within latitudes 15°S – 22°S and longitudes 25°E – 34°E. A total number of 81 events were employed in the study. The formulated hypothesis was tested using Chi square test and Independent t-test. The findings of this study revealed that experimental distribution of earthquakes have no significant difference with theoretical distribution of earthquakes in Zimbabwe. This implies that Zimbabwe earthquake data follow exponential distribution. The return periods for magnitude 4.2 and 6.2 were estimated to be 4.00 and 47.48 years respectively. It has been observed that as the magnitude increases towards higher magnitude, the return period increases except at magnitude 4.7 where it decreased. Therefore, the occurrence of minor to light earthquakes is more frequent than stronger ones: therefore, the probability of occurrence of earthquakes of low magnitude (up to 4.0) is higher than for earthquakes with magnitude of 6.0 and above. As a result, Zimbabwe may not likely experience any serious earthquake (magnitude 6.0 or greater) until the year 2048, considering that the last 6.0 magnitude event - with an estimated return period of 47.48 years - occurred in 2001. Nevertheless, earthquake occurrence cannot be predicted with certainty yet: earthquakes are in fact naturally unpredictable, due to sensitivity of catalogues to small events, saturation of magnitudes and differences in data collection by seismic stations and networks.
Kushkarani river basin (172 Sq.km), a Chottonagpur plateau fringe river basin of Mayurakshi master stream. Most part of the basin is characterized by coarser lateritic soil with greater erodibility and high potentiality of erosion. Seasonal fluctuation of rainfall energized the process of weathering and generation of regolith. Present work thrusts on identification of soil erosion potential areas based on multi criteria decision approach. Seventeen parameters are employed in this work (i.e. drainage frequency, drainage frequency, soil type, hydraulic gradient, NDVI, ferrous mineral etc.) and weighted linear combination is used for extracting results. For estimating different potential soil erosion zones Revised Universal Soil Loss Equation (RUSLE) is used. RUSLE is computed using Arc GIS 9.3 and ERDAS Imagine 9.2 softwares. For validating these models, surface lowering rate measured by pegging operation and 107 sites of have been selected for measured. From the analysis it is noticed that the region where soil erosion potentiality is very high, is also experienced high rate of soil erosion (>19 tons/ha./year) and upper catchment is highly susceptible for erosion. Stream frequency, stream density, relatively steeper slope, coarser soil texture, exposed land etc. are some of the major reasons behind such accelerated erosion. Surface lowering measured from field also shows high lowering rate in the erosion susceptible region (>1.73 mm/year). These growing soil erosion especially fertile top soil loss is negatively impacted agriculture and sediment accretion within channels. People in most part of the basin area depend on agriculture, so, soil loss issue is linked with livelihood challenges of them.
Agriculture monitoring and managements is a key factor in the food production and food security. Mainly, crop identification and area quantification are most important factors in yield estimation and predictions. In arid lands, water is a limiting factor for the agriculture expansion and development. Conventional methods for both crop discrimination and crop water requirements are very expensive and unbearable economically. Remote sensing has been employed several decades ago in the different agricultural activities. Crop discrimination, water requirements and even weed and pest control could be achieved via remote sensing and geographical information systems. This paper utilizes remote sensing data in combination with ground meteorological data to calculate the Actual Crop Evapotranspiration (ETa) under modern irrigation systems conditions. Moreover, it also tries to discriminate between different crops and calculate area per crop type. Four Landsat8-OLI images were used to calculate the Land Surface Temperature (LST) during the different growth stages of the 2014 winter corps season. The dates of these satellite images were chosen to fall in the different growth stage of the crops in the study area. Ground meteorological data were used to estimate Reference Evapotranspiration (ETo) using the FAO Penman-Monteith (FPM) equation. Land surface temperature and Air Temperature (Tair) were used to observe the water distribution conditions of the study area by the means of mapping the Water Deficit Index (WDI). The WDI and Potential Crop Evapotranspiration (ETc) were used to calculate ETa. The supervised maximum likelihood classification method was employed for crop mapping using spectral signatures collected from different ground training sites through different field visits during the growing stages of the growing season. The use of multi-temporal Normalized Difference Vegetation Index (NDVI) resulted in a classification accuracy of 93% with a kappa coefficient of 0.90. The crop water requirement was affected by the decreasing surface and air temperature. Crop type and different growth stages were detected through applying Multi-temporal images.
Environmental assessment is a key to prevent the occurrence of a potential disaster which can arise due to various reasons in the mining field especially active mining of rare metals. This present paper monitors the physico-chemical effect of active mining of rare-metal (Sn, Nb and Ta) and bacteriological assessment of surface water in the active rare-metal mining site. The negative environmental impact exceeded the positive which includes; landscape destruction, ecological destruction, pollution and accidental hazards while the positive impacts are; an increased human population which promoted the agricultural practice and increased settlements.
Twenty-one (21) water samples and twenty-three (23) eluvial soil samples were collected from the stream within the area and analyzed using the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) method. The pH, EC and TDS of the surface water were measured with an appropriate instrument. The surface water is slightly alkaline and moderately soft while the EC and TDS were below the recommended range. All the trace elements analyzed for the surface water were all below MPL. The bacteriological analysis revealed the presence of the disease-causing bacteria makes the water unsafe for domestic use (even though the water is free from the presence of heavy metals) and can trigger gastrointestinal illnesses, diarrhoea and vomiting. The metal assessment in the soil samples was calculated using Contamination index and Geo-accumulation index revealed that Arsenic (As) and Cadmium (Cd) are anthropogenically inputted into the environment and have moderately polluted the environment.
There is a need for implementation and enforcement of an environmental law which may just be a means of pollution control within mining districts.