Browsing by Author "Old, G. H."

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    Assessing multiple novel tracers to improve the understanding of the contribution of agricultural farm waste to diffuse water pollution
    (2010-12-31T00:00:00Z) Granger, S. J.; Bol, R.; Dixon, L.; Naden, P. S.; Old, G. H.; Marsh, J. K.; Bilotta, G.; Brazier, R.; White, S. M.; Haygarth, P. M.
    A study was undertaken on drained and undrained 1 ha grassland lysimeters to assess the effectiveness of multiple novel tracing techniques in understanding how agricultural slurry waste moves from land to water. Artificial fluorescent particles designed to mimic the size and density of organic slurry particles were found to move off the grassland via inter-flow (surface + lateral through-flow) and drain-flow. Where both pathways were present the drains carried the greater number of particles. The results of the natural fluorescence and delta C-13 of water samples were inconclusive. Natural fluorescence was higher from slurry-amended lysimeters than from zero-slurry lysimeters, however, a fluorescence decay experiment suggested that no slurry signal should be present given the time between slurry application and the onset of drainage. The delta C-13 values of >0.7 mm and <0.7 mm material in drainage were varied and unrelated to discharge. The mean value of >0.7 mm delta C-13 in water from the drain-flow pathways was higher from the lysimeter which had received naturally enriched maize slurry compared to the lysimeter which received grass slurry indicating a contribution of slurry-derived material. Values of <0.7 mm delta C-13 from the same pathway, however, produced counter intuitive trends and may indicate that different fractions of the slurry have different delta C-13 values.
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    High temporal resolution monitoring of multiple pollutant responses in drainage from an intensively managed grassland catchment caused by a summer storm
    (Springer Science Business Media, 2010-01-31T00:00:00Z) Granger, S. J.; Hawkins, J. M. B.; Bol, R.; White, S. M.; Naden, P. S.; Old, G. H.; Bilotta, G. S.; Brazier, R. E.; Macleod, C. J. A.; Haygarth, P. M.
    This work presents data on a suite of diffuse pollutants, monitored in a stream draining an intensively managed grassland on a 30 min time step during a period of intense rainfall to better understand their sources and pathways. Nitrite (92 mu g l(-1)), particulate phosphorus (107 mu g l(-1)) and soluble phosphorus (74 mu g l(-1)) exceeded environmental limits during base flow. Concentrations of nitrate and nitrite were decreased during the storm event, whereas all other pollutants generally increased and exceeded environmental limits where specified, especially when associated with a small subsidiary hydrograph on the rising limb of the main hydrograph. Total pollutants loads, when using a 60 min sampling frequency, would have led to significant over and under-estimations depending on which 60 min sample set was used. In the worst case, loads of ammonium could have been under-estimated by 35% or over estimated by 25% with errors being associated with loads on the rising limb of the hydrograph and more specifically a small subsidiary hydrograph. This subsidiary hydrograph may have occurred as a result of runoff from the farm hard standings within the catchment. Incidental transfer of pollutants associate with this runoff have masked the overall grassland pollutant response. To better understand these different source areas and pollutant dynamics, there is a need for novel tracing techniques to elucidate their relative contribution and pathways.