This study assessed the potential of using visible-near infrared diffuse reflectance spectroscopy to determine the effect of tillage (ploughing) on oil-contaminated sites. Crude oil contaminated samples were collected from the Ikarama, Bayelsa State, Niger Delta, Nigeria. 62 and 20 samples were collected from untilled and tilled (ploughed) sites, respectively. All samples were analysed in the laboratory with an Analytical Spectral Device spectrometer with a spectral range of 350 to 2500 nm. Principal component analysis was performed on the soil spectral data using chemometric. Sequential ultrasonic solvent extraction was also carried out followed by gas chromatography coupled to mass spectrometry analysis to validate the visible-near infrared diffuse reflectance spectroscopy sensitivity and ability to detect change due to hydrocarbons profile changes. 27% and 15% concentrations of polycyclic aromatic hydrocarbons were present in the untilled and tilled sites, respectively. Gas Chromatography-Mass Spectrometry analysis also showed that PAHs and allkanes concentrations in the untilled site ranged from 0.05 to 48.493 mg/kg and 0.07 to 528.147mg/kg, respectively. For the tilled (ploughed) site, the concentrations for polycyclic aromatic hydrocarbons and alkanes quantified by Gas Chromatography-Mass Spectrometry ranged from 0.04 to 0.742 mg/kg and 0.06 to 159.280mg/kg, respectively. In addition, non-metric Multidimensional scaling was carried out using Primer version 6 to investigate the statistical significance of the hydrocarbon profiles and concentrations of the samples. To minimise the extent of overlap of the samples, the 82 samples collected were reduced to 49 samples (43 untilled and 6 tilled). Results show that visiblenear infrared diffuse reflectance spectroscopy may be a valuable tool for grouping hydrocarbon contaminated soils into hydrocarbon content and concentrations.

The use of Digital Shoreline Analysis System was used to determine shoreline changes in Ikoli River, Yenagoa, Bayelsa State. Shoreline data were extracted from satellite imagery over thirty years (1991-2021). The basis of this study is to use Digital Shoreline Analysis System to determine erosion and accretion areas. The result reveals that the average erosion rate in the study area is 1.16 m/year and the accretion rate is 1.62 m/year along the Ikoli River in Ogbogoro Community in Yenagoa, Bayelsa State. The mean shoreline length is 5.24 km with a baseline length of 5.2 km and the area is classified into four zones to delineate properly area of erosion and accretion based on the five class of Linear regression rate, endpoint rate and weighted linear rate of which zone I contain very high erosion and high erosion with an area of landmass 255449.93 m2 of 38%, zone II contain moderate accretion, very high accretion and high accretion with a land area of 1666816.46 m2 with 24%, zone III has very high erosion and high erosion with an area of landmass 241610.85 m2 of 34 % and zone IV contain moderate accretion and high accretion with land area 30888.08 m2 with 4%. Out of the four zones, zone I and II were found to be eroding with 72% and zone II and IV contain accretion with 28%. The result shows that 44% of the area have been eroded. Therefore, coastal engineers, planners, and shoreline zone management authorities can use DSAS to create more appropriate management plans and regulations for coastal zones and other coastal parts of the state with similar geographic features.