Groundwater and soil pollution caused by (PAHs) spills, mostly from the oil industry and petrol stations in urban areas, represent a major environmental concern worldwide. However, infiltration into groundwater is decreasing due to the natural attenuation processes of PAHs in the vadose zone, which protect invaluable groundwater resources against contamination. This study was conducted to evaluate the effect of improper management of the petroleum industry on the groundwater and soil surrounding the petrol station and an oil refinery unit and, furthermore, to prepare the polluted risk intensity (PRI) map. Fifty-one soil samples and twenty-five water samples were analyzed for Light Non-aqueous Phase Liquid (LNAPLs), and one soil sample for Dense Non-Aqueous Phase Liquid (DNAPLs); furthermore, six soil samples analyzed for Tetraethyl Lead (TEL) analysis. The results showed that seventeen wells were polluted with LNAPLs and the soils were highly contaminated with different DNAPLs components and mainly was in the form of Polycyclic Aromatic Hydrocarbons (PAHs). Seven factors introduced to the GIS platform to produce PRI map, which is the distance to source, depth to water table, slope, lineaments, lithology, soil, and recharge rate. The final map revealed that the eastern and western parts of the study area are at a very high-risk level, whereas the center is at a very low to low-risk level.

In this study, a geotechnical centrifuge has been used to study the unsaturated hydraulic properties of rock samples from the chalk aquifer, SE England. This method allows rapid measurement of hydraulic properties in a controlled environment, in contrast to previous studies on the chalk unsaturated zone, which required either an extended period (years) of data monitoring in the field or extended experimental periods (weeks) in the laboratory. Three types of specially built sensors were used to monitor water flow through chalk samples: a water pressure transducer to measure matric potential, frequency domain reflectometry probes to measure the volumetric water content and pressure transducers to measure the volume of water passing through the sample. Chalk samples were tested during wetting and draining processes to understand any hysteresis occurring during periodic recharge of the aquifer. Before undertaking physical tests of chalk samples in the centrifuge, a theoretical model of chalk hydraulic behaviour under centrifugal force was developed. This model was used to define and justify the instrumentation plan of the physical model and predict the shape of the soil moisture characteristic (SMC) curve and unsaturated hydraulic conductivity ( K _u ) function. The results were then evaluated and compared with the experimental results. These results show that chalk samples can be successfully tested under centrifuge conditions and hydraulic properties can be measured, including soil moisture characteristic curves and hydraulic conductivity. Supplementary material: Calculation spread sheets are available at https://doi.org/10.17033/DATA.00000283