Legacy soil contamination by crude oil from the First Gulf War : geochemical characteristics, spatial pattern and environmental risk

The first Gulf War resulted in large-scale oil spills in Kuwait. Selection of appropriate soil remediation methods needs to be informed by accurate soil characterization and this knowledge is currently lacking. The aim of this PhD study was to obtain insights into the geochemical characteristics of the aged contaminated soils and, using this knowledge, to develop 3-D predictive models for spatial distribution of the contaminated soils and remediation strategies based on site-specific environmental risk assessment. The soil-borne petroleum hydrocarbons were spatially variable. Most of lighter petroleum hydrocarbons in the oil lake area has already been emitted to atmosphere. Under desert climate conditions, downward migration of the spilled oil was limited due to a lack of rainfall. The downward moment of long-chain hydrocarbons tended to be slow because of their low mobility. The contamination depth was generally very shallow in the oil sludge pit due to the presence of a liner. The application of geostatistical interpolation techniques to the development of 3-D predictive models for the investigated sites suggests that this approach is appropriate for 3-D mapping of the soil-borne petroleum hydrocarbons. There was no evidence to show that groundwater was contaminated in the investigated area. Long-chain aliphatic hydrocarbons dominated the hydrocarbons in both the oil sludges and the contaminated soils. The pre-dominant presence of less toxic long-chain aliphatic hydrocarbons means that the hazardousness of the contaminated soils is likely to be much lower than what was thought. The findings obtained from this study have implications for developing cost-effective remediation strategies for the clean-up of the crude oil-contaminated soils. Multiple management and remediation strategies need to be developed and implemented in an integrated way. It may not be necessary to intensively treat the hydrocarbon fractions of insignificant toxicity in order to achieve cost-effective remediation goals