This research work has analyzed the geotechnical characteristics of two borrow pits around Afe babalola university. The research work was carried out by collection of soil samples from borrowpit 1 (beside Federal polytechnic, Ado-Ekiti, Nigeria) and borrowpit 2 (along Afe Babalola farm, Ado-Ekiti, Nigeria) and taken to the laboratory for soil test. The particle size analysis shows that the percentages passing number 200 British Standard sieve are 22.18% and 13.02% for borrowpits 1 and 2 respectively. Atterberg limit results show that borrow pit 2 has sandy particle sizes predominating. Hence the soil sample as a result of its particle size composition happens to be a cohesionless soil with no plasticity while pit 1 has liquid limit of 32.5%, plastic limit of 27.77%, plasticity index of 5% and shrinkage limit of 5.8%. The natural moisture content for the soil samples are 5% and 9.7% for borrowpit 1 and borrowpit 2 respectively. The specific gravity for borrowpit 1 and borrowpit 2 are 2.67 and 2.60 respectively. The soaked CBR value for the soil samples are 70% and 66%. The maximum dry density for the soil samples are 1.82Mg/m3 and 2.0Mg/m3 for borrowpit 1 and borrowpit 2 respectively. While that of Optimum moisture content are 16.24% and 13.5% for borrowpit 1 and borrowpit 2 respectively. The unconfined compressive strength (qu) for borrowpit 1 soil sample is 91.5kN/m2. The unconfined compressive strength of borrowpit 2 could not be obtained as it is a sandy material. Hence borrowpit 1 can be classified as A-2-4 material (silty or clayey gravel and sand) while borrowpit 2 can be classified as A-3 material (fine sand).
Geo-environmental hazards associated with abandoned borrow pits in Nigeria are on the rise and a major concern to citizens, environmentalists and governments. Several highway failure spots are directly linked to the action of erosion initiated by active or abandoned (inactive) borrow pits situated close to the roads. This study examines the negative environmental impacts of the continuous removal of soil from borrow pits in some areas of Ado Ekiti, Nigeria. Four borrow pits were selected; two active sites and two abandoned sites. At inception, topographical and 3-Dimensional maps of the borrow pits were drawn and modelled. The area of the borrow pits and the volume of overburden excavated soils were calculated. The soil over burden pressure at the average height of the borrow pits were measured. The active borrow pit sites were checked again after two months to know the difference in the volume of overburden removed in the pit for that period. The volume of soil removed from borrow pit 1 (Active site), 2 (Active site), 3(Abandoned) and 4 (Abandoned) are 37000 m3, 34000 m3, 114000 m3 and 81000 m3 respectively. Environmental assessment of the study area through photographs showed prevalence of landslides, erosion, flooding, vegetation removal and structural failure. The volume of soil overburden removed from the abandoned borrow pit is more than the volume extracted from the active sites, this significant change in the value of overburden removed causes significant change to the terrain of the borrow pit. Some measures were then suggested to curb the problem occurring from the uncontrolled and indiscriminate borrow pits excavation thereby improving environmental sustainability. This study serves as a basis for government to put in place laws that help protect the environment from indiscriminate mining of borrow pits.
The study examined the noise levels in selected areas within Akure Metropolis, Nigeria with a view to generate noise maps using ArcGIS which will help to identify high impact areas and support environmental management in the study area. Some selected areas within Akure metropolis were selected for this study namely; Oja-oba Market (commercial Land use), Ijoka (Residential land use), and the Federal University of Technology, Akure (Futa as an Educational Land Use). The digital sound level meter (IEC651 Type 2) was used to measure noise level in the morning (8:00am-9:00am), afternoon (1:00pm-2:00pm) and evening (4:00pm-5:00pm) for a period of 7days in each of the selected areas. The compiled data were imported into the ArcGIS 10.5 Software for analysis and geo-referencing whereby transforming the data and presenting it on noise contour maps. The study revealed that Sunday bus stop has the highest mean noise level with 64.3 decibel (A) while the lowest noise level was found in Olowookere street with 38.1 dB(A) for the Residential area. Ijomu recorded the highest noise level with 78.6 dB(A) and Erekesan market has the lowest noise level of 61.5 dB(A) for the commercial area. Finally, Northgate has the highest noise level, which recorded 76.3 dB(A) and the lowest noise level was recorded at Library area with 41.0 dB(A) for the Institutional area. 80% of the commercial area is exposed to the highest risk of noise pollution. The residential area was exposed to 18.7% noise pollution which makes the area suitable for housing. The institutional land use recorded 36.6% for total area exposed to noise pollution. This research has provided valuable information for decision makers as a guidance for noise pollution risk management and serve as a reference for future noise limit regulations to be executed in urban areas of Nigeria and other developing countries