A clear view through muddy water

Helen Jarvie (NERC) and Steve King (ISIS) with a river water sample.

Helen Jarvie (NERC) and Steve King (ISIS) with a river water sample.
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In recent years water quality scientists have become increasingly aware of the significance of nanoparticles (defined as <100 nm in size) in the transport of pollutants and their potential impacts on the ecology and health of streams and rivers.

While conventional techniques (such as microscopy) have advanced understanding, new methods are now required to characterise the structure, stability and interactions of these nanoparticles in aquatic environments. Small angle neutron scattering (SANS) on Loq has been used to study suspensions of complex mixtures of mineral and organic particles from river water, runoff from agricultural fields and river bed sediments. The smallest nanoparticles are typically clay minerals and the SANS studies have revealed the way in which these are linked together by large organic molecules, derived from decaying plants and micro-organisms. Preliminary results have provided new insights into these complex heterogeneous nanoparticle aggregates in river water. It seems that they have a ragged and porous ‘fractal’ shape, resulting in a much higher surface area than previously assumed. The larger the surface area, the greater the potential for pollutant uptake and transport.

HP Jarvie (NERC Centre for Ecology and Hydrology) and SM King (ISIS)

Research date: December 2007

Further Information

HP Jarvie and SM King, Environmental Science and Technology 41 (2007) 2868.

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