title: Using artificial fluorescent particles as tracers of livestock wastes within an agricultural catchment.
abstract: Evidence for the movement of agricultural slurry and associated pollutants into surface waters is often anecdotal, particularly with relation to its 'particulate' components which receive less attention than 'bio-available' soluble phases. To assess the extent of movement of slurry particles artificial fluorescent particles were mixed with slurry and applied to a field sub-catchment within a headwater catchment. Particles were 2-60 μm in diameter and two different densities, 2.7 and 1.2 g cm(-3) representing 'inorganic' and 'organic' material. Water samples from the field and catchment outlet were collected during two storm events following slurry application and analysed for particle and suspended sediment concentrations (SSC). SSC from the field and catchment outlet always formed clockwise hysteresis loops indicating sediment exhaustion and particles of the two densities were always found to be positively correlated. Particles from the field formed clockwise hysteresis loops during the first discharge event after slurry application, but anti-clockwise hysteresis loops during the second monitored event which indicated a depletion of readily mobilisable particles. Particles from the catchment outlet always formed anticlockwise hysteresis loops. Particle size became finer spatially, between field and catchment outlet, and temporally, between successive storm events. The results indicate that slurry particles may be readily transported within catchments but that different areas may contribute to pollutant loads long after the main peak in SSC has passed. The density of the particles did not appear to have any effect on particle transport however the size of the particles may play a more important role in the 2-60 μm range.
authors.affiliation: Soil, Water and Air Team, Sustainable Soils and Grassland Systems Department, Rothamsted Research, North Wyke, Okehampton, Devon, EX20 2SB, UK. steve.granger@bbsrc.ac.uk
authors.forename: Steve J
authors.initials: SJ
authors.lastname: Granger
authors.forename: Roland
authors.initials: R
authors.lastname: Bol
authors.forename: Jane M B
authors.initials: JM
authors.lastname: Hawkins
authors.forename: Sue M
authors.initials: SM
authors.lastname: White
authors.forename: Pamela S
authors.initials: PS
authors.lastname: Naden
authors.forename: Gareth H
authors.initials: GH
authors.lastname: Old
authors.forename: Jon K
authors.initials: JK
authors.lastname: Marsh
authors.forename: Gary S
authors.initials: GS
authors.lastname: Bilotta
authors.forename: Richard E
authors.initials: RE
authors.lastname: Brazier
authors.forename: Christopher J A
authors.initials: CJ
authors.lastname: Macleod
authors.forename: Philip M
authors.initials: PM
authors.lastname: Haygarth
mesh_terms: D000383:Agriculture; D004784:Environmental Monitoring / Q000379:methods*; D005456:Fluorescent Dyes / Q000032:analysis*; D005618:Fresh Water / Q000737:chemistry; D058751:Livestock; D008372:Manure / Q000032:analysis*; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D005456:Fluorescent Dyes; D008372:Manure; D052638:Particulate Matter; D014874:Water Pollutants, Chemical