21 research outputs found
High temporal resolution monitoring of multiple pollutant responses in drainage from an intensively managed grassland catchment caused by a summer storm
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