**6. Conclusion**

The scenario in Kuwait is somehow exceptional as the contamination is primarily caused by crude oil, which has been weathered under open environment for 25 years. The exposure to the environment has caused most of the volatile substance within the crude oil to evaporate into the atmosphere with heavy compounds left as residue. Due to the complex nature of contaminated soil and the undeniable fact that contaminations in different situations present a "cocktail" of various types of pollutants, therefore, different types of remediation dealing with different ranges of contaminants, limited success have been reported in remediation of contaminated soil. The higher levels and wider ranges of TPH have shown interesting patterns at Kuwait's oil lakes. Most importantly, these contaminated sites have not yet been restored, which poses continued potential hazards to the environment and human health. Therefore, it is also important to estimate the characteristic of the contaminated soil; the tests can be performed to simulate the field conditions and provide categorisation for the sample. Without this key information, it is impossible for the planning of land use and options of remediation to be taken into account. Based on the literature, bioremediation is unlikely to be successful given the high concentration of TPH and high concentration of the metal salt in Kuwaiti contaminated soil. Furthermore, thermal system is not allowed to be used in this project (UN conditions), and hence the technique based on decision tool with HOQ, soil washing, was selected to deal with this issue. Selecting a remediation scheme challenges decision-makers to compare and select the appropriate soil remediation techniques by making a tool of engineering decision based on a set of UN requirements.
