The impact of roads on the socioeconomic development and progress of any country cannot be quantified. A geotechnical investigation of subsoils along Isinbode-Ara road, stretching in southeastern to northwestern direction of 7 km distance within Ekiti State, Southwestern Nigeria, was carried out. This investigation follows the British Standard Institution, such as moisture content, particle size distribution, specific gravity, Atterberg limit, compaction, consolidation and California bearing ratio. Results of investigation showed that the moisture content, specific gravity, liquid limit, plastic limits and plasticity index ranged from 7.2-25.9%; 2.64-2.77; 24.0-61.1%; 19.2-26.2% to 4.35-38.90%, respectively. Grain size distribution showed the fine and coarser fractions range from 13.0-66.5% to 32.6-84.8%, respectively. The maximum dry density and its optimum moisture content ranged from 1.48-2.07 g/cm 3 to 11.3-30.3%, respectively. Soaked CBR results ranged from 3 to 44%. Two classes of subsoils, namely A-2-4 and A-2-6 (granular materials) and A-6 and A-7-6 (clayey soils), were identified and rendered suitable and unsuitable road construction materials, respectively. This investigation revealed that the subsoils are poor road construction materials due to its fine fractions and plasticities, which should be put into consideration during its foundation design and construction stages.

Groundwater samples were collected randomly from hand-dug wells in parts of Ado Ekiti metropolis and were subjected to its quality assessment and characterization. Physicochemical and bacteriological analyses were carried out following standard methods (APHA 2012). Hydrochemistry of the present study revealed relative mean concentration of the cations in the order: Na + > Mg 2+ > Ca 2+ > K + , and that of the anions as Cl − > HCO 3 − > SO 4 2− > NO 3 − , respectively. The microbial test shows that E. coli tested positive in all the samples and their colonies are classified dominantly as satisfactory pollutant free state. Pollution index of groundwater results revealed an insignificant state of pollution of the groundwater. Deduction from the Pipers, Gibbs plots and chloro-alkaline indices results revealed the imprints of natural weathering, ion-exchange processes and anthropogenic activities influencing the groundwater quality. Factor analysis result also confirms the prevailing activities of natural geological forces and municipal contaminations acting on the groundwater. The hydrochemical processes coupled with the permeable nature of the aquifer media and high precipitation will influence groundwater flow and ultimately pose pollution risk to the aquifers and eventually the populace of these areas in years to come.

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Thirty-five (35) groundwater samples from Owo area were analyzed for physicochemical parameters. Results show that the mean value of pH is 6.32, TDS is 208.92 mg/l, temperature is 28.77°C, EC is 545.16 μs/cm; TH is 111.09 mg/l, SO4 is 71.73 mg/l, Cl is 0.07 mg/l, HCO3 is 14.09 mg/l, Na is 25.06 mg/l, Ca is 37.07 mg/l, K is 24.36 mg/l and Mg is 4.41 mg/l. The results were compared to the WHO and NDSQW standards. All parameters were within the permissible limit except EC in well OW6 and K is above the stipulated standards in 69% of the total samples. The high concentration of K is linked to the use of NPK fertilizer in the area for agricultural purposes. The groundwater belongs to Ca-Na-K-SO4 and Na-Ca-SO4 water type respectively. The ionic concentration in the groundwater is due to the dissolution of the rock that makes up the aquifer. Plagioclase and silicate-bearing rocks are the sources of major ions in the water. SAR, PI, RSBC and KR reveals that groundwater in the area is good for irrigation purpose. DRASTIC model further revealed that groundwater in the area is less vulnerable to contamination under the current environmental conditions.