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The UK nitrate time bomb

Ward, Robert; Wang, Lei; Stuart, Marianne; Bloomfield, John; Gooddy, Daren; Lewis, Melinda; McKenzie, Andrew. 2013 The UK nitrate time bomb. [Speech] In: AGU Fall Meeting 2013, San Francisco, USA, 9-13 Dec 2013. (Unpublished)

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Abstract/Summary

The developed world has benefitted enormously from the intensification of agriculture and the increased availability and use of synthetic fertilizers during the last century. However there has also been unintended adverse impact on the natural environment (water and ecosystems) with nitrate the most significant cause of water pollution and ecosystem damage . Many countries have introduced controls on nitrate, e.g. the European Union's Water Framework and Nitrate Directives, but despite this are continuing to see a serious decline in water quality. The purpose of our research is to investigate and quantify the importance of the unsaturated (vadose) zone pathway and groundwater in contributing to the decline. Understanding nutrient behaviour in the sub-surface environment and, in particular, the time lag between action and improvement is critical to effective management and remediation of nutrient pollution. A readily-transferable process-based model has been used to predict temporal loading of nitrate at the water table across the UK. A time-varying nitrate input function has been developed based on nitrate usage since 1925. Depth to the water table has been calculated from groundwater levels based on regional-scale observations in-filled by interpolated river base levels and vertical unsaturated zone velocities estimated from hydrogeological properties and mapping. The model has been validated using the results of more than 300 unsaturated zone nitrate profiles. Results show that for about 60% of the Chalk - the principal aquifer in the UK - peak nitrate input has yet to reach the water table and concentrations will continue to rise over the next 60 years. The implications are hugely significant especially where environmental objectives must be achieved in much shorter timescales. Current environmental and regulatory management strategies rarely take lag times into account and as a result will be poorly informed, leading to inappropriate controls and conflicts between policy makers, environmentalists and industry.

Item Type: Publication - Conference Item (Speech)
Additional Keywords: GroundwaterBGS, Groundwater, Nitrate pollution
Related URLs:
Date made live: 14 May 2014 08:27 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/507241

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