Hydrogeochemical and salinity appraisal of surficial lens of freshwater aquifer along Lagos coastal belt, South West, Nigeria.

In order to determine the hydrogeochemical processes and salinity status of the surficial lens of freshwater aquifer in the Lagos coastal basin, physicochemical parameters and hydrogeochemical tools were employed in this study. These tools include existing methods such as Piper diagram, Durov diagram, Gibb's diagram, statistical analysis and geochemical modelling, and the newly proposed cationic contribution evaluation and ionic ratio bivariate plots. The Piper plot revealed that chemical facies is rich in (Ca, Mg, Cl and HCO3) and (Ca and HCO3) for the groundwater in both wet and dry seasons while Mg-Cl and Na-Cl water types characterised the lagoon and the Ocean, respectively. The surficial aquifer is an essentially freshwater in the dry season and partly saline in the wet season due to flash flood, marine aerosol precipitation and infiltration from the surrounding brackish surface waters. The Ca2++Mg2+ vs total cation (TZ+); HCO3 -/Ca2+vs Ca2+/Mg2+ and HCO3 -/Ca2+ vs Ca2+/Na+ plots as well as geochemical modelling indicated that carbonate weathering is the dominant chemical process controlling the groundwater chemistry for both seasons. In a descending order, water-rock interaction, ion exchange and evaporation are the geochemical processes controlling the groundwater quality in the area. Besides the natural processes, factor analysis revealed the imminent influence of anthropogenic activities (industrial and domestic) on the groundwater chemistry indicated by the presence of Mn, Fe, Ni, Cd, Pb, Cu and NO3 above the permissible limit of drinking water standard, particularly in the wet season. In addition to the successful application of the proposed ionic plots, the study justifies the importance of multiple tools application in the hydrogeochemical deductions and recommends consistent monitoring of the shallow aquifers in the Lagos coastal basin.

Origin and residence time of shallow groundwater resources in Lagos coastal basin, south-west Nigeria: An isotopic approach.

Knowledge of the source of water in the Lagos coastal basin (LCB) groundwater system was to be found vital to the future development and management of the system. Stable and radioactive isotopic measurements have been employed to unravel the source of recharge and residence time of the shallow groundwater system, based on the sampling conducted in 2016 and 2017 on groundwater, surface water and rainfall. The concentration of tritium in the groundwater samples were very low and ranged from less than 1 to 2.8 TU, while measured 14C contents ranged from 59.1 to 88 pMC. The δ18O values of groundwater samples ranged from 4.81 and 3.98 ‰, while the δ2H values ranged from -24.75 and -19.70 ‰ for the wet and dry seasons, respectively. The obtained results indicated non-existence of paleo recharge; rather all groundwater in the basin were found to be essentially of meteoric origin with intermittent surface water contributions. Moreover, shallow groundwater and surface water have considerable variations in isotopic compositions, reflecting evaporation and preservation of seasonal fluctuation. Though there was an observed generally low tritium content, however, it proved useful in the identification of recent active recharge taking place across the basin. The deduced radiocarbon age reflected the presence of "modern water" and thus supports the presence of present recharge to the groundwater system. Therefore, the source of the shallow groundwater recharge was actively renewable particularly during the wet season and thus water exploitation is potentially sustainable in the basin.

Morphology of colorectal carcinoma among Nigerians: a 30-year review.

BACKGROUND: The incidence of colorectal carcinoma has been on the increase in the developing countries, including Nigeria, as a result of change in diet and adoption of western lifestyle. OBJECTIVES: The aim of this review is to highlight the prevalence, age and sex distribution, anatomical location, and morphological characteristics of colorectal carcinomas in Ilorin, Nigeria. MATERIALS AND METHODS: This is a retrospective study of all cases of histologically diagnosed colorectal carcinoma in the University of Ilorin Teaching Hospital, Ilorin, Nigeria, over a 30-year period (January 1979-December 2008), using the departmental record and histological slides of the cases. RESULT: A total of 241 cases of colorectal carcinoma were reported, 144 cases (60%) in males and 96 cases (40%) in females with a male: female ratio of 1.5:1. The peak age of occurrence for males was between 51 and 60 years, while that of the females was between 41 and 50 years. The malignancy was found in the rectum in 60.2% of the cases, while the least affected site is the descending colon (1.2%). The exophytic occluding masses were found in 82.2% of the cases, and the most common histological type is adenocarcinoma (77.2%) with well-, moderately, and poorly differentiated forms constituting 52.3%, 32.8%, and 14.9% respectively. Of the 241 cases that were seen over the last 30 years, 93 cases (38.6%) were seen in the last 5 years. CONCLUSION: Colorectal carcinoma is no longer a rare disease in Nigeria. The surge in the incidence reported in the last 5 years in this center calls for a pragmatic action in its control, with emphasize on colonoscopic screening for those with family history, and possibly making digital rectal examination a mandatory aspect of clinical examination, because most colorectal carcinomas are within the reach of examining finger.

Morphology of Colorectal Carcinoma among Nigerians: A 30-Year Review

Background: The incidence of colorectal carcinoma has been on the increase in the developing countries; including Nigeria; as a result of change in diet and adoption of western lifestyle. Objectives: The aim of this review is to highlight the prevalence; age and sex distribution; anatomical location; and morphological characteristics of colorectal carcinomas in Ilorin; Nigeria. Materials and Methods: This is a retrospective study of all cases of histologically diagnosed colorectal carcinoma in the University of Ilorin Teaching Hospital; Ilorin; Nigeria; over a 30-year period (January 1979-December 2008); using the departmental record and histological slides of the cases. Result: A total of 241 cases of colorectal carcinoma were reported; 144 cases (60) in males and 96 cases (40) in females with a male: female ratio of 1.5:1. The peak age of occurrence for males was between 51 and 60 years; while that of the females was between 41 and 50 years. The malignancy was found in the rectum in 60.2of the cases; while the least affected site is the descending colon (1.2). The exophytic occluding masses were found in 82.2of the cases; and the most common histological type is adenocarcinoma (77.2) with well-; moderately; and poorly differentiated forms constituting 52.3; 32.8; and 14.9respectively. Of the 241 cases that were seen over the last 30 years; 93 cases (38.6) were seen in the last 5 years. Conclusion: Colorectal carcinoma is no longer a rare disease in Nigeria. The surge in the incidence reported in the last 5 years in this center calls for a pragmatic action in its control; with emphasize on colonoscopic screening for those with family history; and possibly making digital rectal examination a mandatory aspect of clinical examination; because most colorectal carcinomas are within the reach of examining finger