Changes in environmental regulations have had a major impact on how the long- term impacts of oil and chemical spills are assessed and controlled. For instance, cleaning contaminated ground-water and land in the UK is regulated by section 2A of the Environmental Act. Whilst this was implemented some time ago, there is still a degree of misunderstanding among remediation contractors of how the act affects potential liabilities resulting from land contamination. It is no longer advisable to solely rely on reference tables to evaluate targets for cleaning the environment.
The degree of remediation required at a contaminated site should generally be determined using a risk-based approach to underpin decision-making and regulatory approval. The fundamentals of assessing risk apply to environmental, human-ecological health, and building receptors. Execution of the Landfill Directives has led to increased disposal costs. As state policies retreat from a cultural dig and dump approach, technologies for on-site remediation are becoming more popular and economically acceptable (Tannenbaum, 2007, p.476).
These technological changes present risk assessment with a number of opportunities and challenges. Whilst implementation of on-site remedial technologies is increasingly favoured, the selection of inappropriate remedial targets or remedial processes can result in potential financial or legal liabilities. The assessments of how clean hydrocarbons should be is therefore significant to designing a suitable clean-up strategy.
However, application of risk assessment regulations to spill and other sites can be limiting, since fuel oils consist of a mixture of numerous different components. After a spill occurs, a number of processes such as volatilization and biodegradation can leave an environment contaminated by petroleum residues of extreme chemical complexity. Yet sound, defensible and practical decisions are required on how to manage the risks to human health from exposure to petroleum hydrocarbons in soil (Tannenbaum, 2007).