The Niger Delta Region of Nigeria has suffered severe environmental pollution due to ever increasing oil exploration and exploitation activities in the region making the communities highly vulnerable to the effects of oil spill and other associated environmental degradation. Using eight soil samples collected from two oil-rich communities in two Local Government Areas of Delta State, the effects of oil spill on the load bearing properties of the soils were examined and used to develop regression models for the bearing capacity (for strip foundation footing) of oil contaminated soils. The triaxial test showed the mean values of the bearing capacity of the uncontaminated soil samples (which served as control) as 170.718 KN/m2 and 601.49KN/m2 . The samples were then thoroughly mixed with crude oil(to simulate the site conditions) at 5%, 10%, 15%, and 20%. The result of the triaxial test showed that oil reduces the bearing capacity of the soil and as the percentage increased to 20% oil, the bearing capacity dropped to 56.60KN/m2 and 61.50 KN/m2 respectively for the two study locations. Regression models were then developed to estimate the bearing capacity of the oil contaminated soils at any level of contamination in the study locations.
The study compared the air pollution tolerance indices (APTI) of five plant species and five ornamental shrubs in Enugu Urban Center. Laboratory analysis was performed on the four physiological and biological parameters including leaf relative water content (RWC), ascorbic acid (AA) content, total leaf chlorophyll (TCH) and leaf extract pH. These parameters were used to develop an air pollution tolerance index. Factor analysis and descriptive statistics were utilized in the analysis to examine the interactions between these parameters. Vegetation monitoring in terms of its APTI acts as a \'Bioindicator\' of air pollution. The study also showed the possibility of utilizing APTI as a tool for selecting plants or ornamental shrubs for urban heat Island mitigation in Enugu City. The result of APTI showed order of tolerance for plants as Anacarduim occidentale (23.20), Pinus spp (22.35), Catalpa burgei (22.57), Magifera indica (23.37), and Psidum guajava (24.15).The result of APTI showed increasing order of sensitivity for ornamental shrubs from ixora red (14.32), yellow ficus(12.63), masquerade pine(12.26), Tuja pine(11.000),to Yellow bush(10.60). The APTI of all the plants examined were higher than those of ornamental shrubs. Thus suggesting that plants in general were more tolerant to air pollution than ornamental shrubs. The ornamental shrubs with lower APTI values (sensitive) were recommended as bioindicator of poor urban air quality while plants with high APTI values (tolerant) are planted around areas anticipated to have high air pollution load. The result of this current study is therefore handy for future planning and as well provides tolerant species for streetscape and urban heat island mitigation.
The Editor in Chief, Journal of Experimental Research Department of Anatomy, Enugu State University of Science and Technology, College Of Medicine (ESUCOM), GRA Enugu, Nigeria.
Enugu State University of Science and Technology