An application of nuclear magnetic resonance imaging to study migration rates of oil-related residues in estuarine sediments

Organisations such as the Marine Control Pollution Unit of the Department o f Transport are at present testing the suitability of burial and landfarmin g of oily residues in sandy coastal environments as an alternative to landf ill sites. The tendency for oil related compounds to sorb to sediments has been extensively investigated, but this has not permitted the 'observation' or measurement of advection/diffusion processes or the breakdown of these compounds within sediments. MRI, which is a multidimensional technique allowing the position of nuclei (most commonly protons) to be charted within a volume, provides a means of monitoring advection and diffusion of oil within sediments, thus offering a method of assessing the harming potential of oils in near-shore environmen ts. A three dimensional MRI analysis of the movement of oil in an organic s ubstrate and in three related estuarine sediments show that, using appropri ate parameters, movement of the oil can be both observed and quantified. Th e results presented in terms of the % change of oil distribution within eac h sediment sample, show the great potential of MRI in studying protonated c ontaminants in these materials.