Nuclear magnetic resonance imaging (MRI) of diesel oil migration in estuarine sediment samples

Abstract

Magnetic resonance imaging (MRI) provides a means of monitoring the change in position and the eventual breakdown of oil within sediments. The multidimensional technique allows the position of nuclei (most commonly protons) to be located within a known volume of substrate, e.g. sediment, hence offering a method of assessing the harming potential of oils in near-shore environments. Two-dimensional (2D) and three-dimensional (3D) MRI analyses of the measurement and movement of oil in estuarine sediments show that, using appropriate parameters, movement of the oil can be both observed and quantified. To aid the quantification a sample holder fabricated from polyvinylsiloxane, an inert material visible in magnetic resonance images has been used as an internal intensity standard. The results show the great potential of MRI in studying protonated contaminants in these materials, notwithstanding the presence of paramagnetic species in estuarine sediments which might distort the image. Sediments studied thus far have been collected from the Tay Estuary, Northeast Scotland.