RESUMO
Space geodetic and optical imaging techniques are employed to assess the coastal vulnerability index (CVI) in order to adapt to the contemporary approach to coastal classification. Satellite altimeter, Satellite Pour l'Observation de la Terre (SPOT) and integrated multi-satellite retrievals for GPM (IMERG) were among the satellite data used. The variables were deemed adequate based on the spatiotemporal estimates, then were quantified through expert-weighted scores and integrated into a single index over the Terengganu coastal area. The CVI findings performed better with eight variables, showing higher overall accuracy (70.83%), Kappa coefficient (59.02%), and area under curve (AUC) (0.8) than the conventional six variables. Vulnerability rankings are distributed relatively evenly across the Terengganu coast, with the moderate (2) ranking being the most predominant at 27.2% of the total area. Space geodetic and optical imagery techniques prove highly beneficial to CVI assessment, offering a viable alternative to traditional methods, especially for broader-scale coastal management.
RESUMO
This study investigates hydrocarbon pollution in the Ahoada community of the Niger Delta region of Nigeria. The study uses a geographic information system (GIS) for mapping oil spill hotspots in the region. The resistivity method was used to delineate the extent of hydrocarbon pollution to a depth of 19.7 m in the Ahoada area of the region. Three categories of soil samples, impacted soil (IMS), remediated soil (RS), and control soil (CS), were collected and analyzed for the presence of BTEX, PAH, TPH, TOC, and TOG. The concentrations of the samples from the IMS and RS were compared to that of the CS to determine the extent of pollution. The GIS mapping shows that the most polluted areas in the Niger Delta Region are Rivers, Bayelsa, and Delta states. Results of the geophysical images revealed contaminants' presence to depths beyond 20 m at some locations in the study area. The highest depth of contaminant travel was at Ukperede. Soil samples' analysis showed that the range of concentrations of TPH in IMS at Oshie was 17.27-58.36 mg/kg; RS was 11.73-50.78 mg/kg which were higher than the concentrations of 0.68 mg/kg in the CS. PAHs are more prevalent in Ukperede, ranging from 54.56 to 77.54 mg/kg. BTEX concentrations ranged from 0.02 to 0.38 mg/kg for IMP and 0.01-2.7 mg/kg for RS against a CS value of 0.01 mg/kg. The study revealed that there are characteristically high resistivity values in the samples which were corroborated by the findings from the resistivity survey. TOC was found to be higher in the IMS and RS than in the CS, demonstrating that a significant quantity of the hydrocarbon has undergone appreciable decomposition.
