Grain Size Distribution Characteristics Variation in Oily Contaminated Sandy Soils Due to Long Term Aging Effect in Al-Ahmadi Field at Kuwait

Abstract

Almost three decades on, the negative environmental impacts arising from the burning of over 600 oil wells in Kuwait following the 1991 Gulf War are still evident. At the time of the incident, the Kuwaiti desert region became polluted with hydrocarbon, with a number of ‘oil lakes’ forming, causing critical harm to local land. This paper discusses the shifts in particle size distribution (PSD) found in soil taken from Kuwait’s Al-Ahmadi oil field, caused by aging sandy soil polluted with hydrocarbon. The analysis of changes in PSD was achieved using 16 contaminated and uncontaminated soil samples, with the samples undergoing PSD analysis along with Unified Classification Soil System (UCSS), Scanning Electronic Microscopy (SEM) and Gas Chromatograph Mass Spectrometer (GC-MS) analyses.The analyses revealed a significant reduction in the mean values of both sand and silty/clay particles, which fell from 44.6% to 9.0% and 7.8% to 3.4%, respectively. The analyses also showed a significant increase in the mean values of gravel particles, rising to 44.6% from 6.1%. These results obviously clarify that the overall outcome of the alteration in soil gradation was a poorer one, which may be due to bigger particles forming out of fine particles as a result of oil contamination. The results presented in this paper are intended to support the treatment (soil washing and cement stabilisation) of contaminated sandy soil based on the insights gained into how soil grain size distribution is impacted by oil contamination.