title: Using chemical, microbial and fluorescence techniques to understand contaminant sources and pathways to wetlands in a conservation site.
abstract: Nutrients and faecal contaminants can enter wetland systems in a number of ways, with both biological and potentially human-health implications. In this study we used a combination of inorganic chemistry, dissolved organic matter (DOM) fluorescence and Escherichia coli and total coliform (TC) count techniques to study the sources and multiple pathways of contamination affecting a designated sand dune site of international conservation importance, surrounded by agricultural land. Analysis of stream samples, groundwater and dune slack wetlands revealed multiple input pathways. These included riverbank seepage, runoff events and percolation of nutrients from adjacent pasture into the groundwater, as well as some on-site sources. The combined techniques showed that off-site nutrient inputs into the sand dune system were primarily from fertilisers, revealed by high nitrate concentrations, and relatively low tryptophan-like fulvic-like ratios<0.4Ramanunits (R.U.). The E. coli and TC counts recorded across the site confirm a relatively minor source of bacterial and nutrient inputs from on-site grazers. Attenuation of the nutrient concentrations in streams, in groundwater and in run-off inputs occurs within the site, restoring healthier groundwater nutrient concentrations showing that contaminant filtration by the sand dunes provides a valuable ecosystem service. However, previous studies show that this input of nutrients has a clear adverse ecological impact.
authors.affiliation: Bangor University, UK. Electronic address: jenrhymes@ceh.ac.uk.
authors.forename: J
authors.initials: J
authors.lastname: Rhymes
authors.affiliation: Centre for Ecology and Hydrology, UK.
authors.forename: L
authors.initials: L
authors.lastname: Jones
authors.affiliation: British Geological Survey, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Lapworth
authors.affiliation: British Geological Survey, UK.
authors.forename: D
authors.initials: D
authors.lastname: White
authors.affiliation: Bangor University, UK.
authors.forename: N
authors.initials: N
authors.lastname: Fenner
authors.affiliation: Bangor University, UK.
authors.forename: J E
authors.initials: JE
authors.lastname: McDonald
authors.affiliation: Bangor University, UK.
authors.forename: T L
authors.initials: TL
authors.lastname: Perkins
mesh_terms: D000383:Agriculture; D003247:Conservation of Natural Resources; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D004926:Escherichia coli / Q000254:growth & development; D005453:Fluorescence; D060587:Groundwater; D009566:Nitrates / Q000032:analysis; D014871:Water Microbiology; D014873:Water Pollutants / Q000032:analysis*; D053833:Wetlands
chemical_list: D009566:Nitrates; D014873:Water Pollutants
keywords: Dissolved organic matter fluorescence; Dune slacks; Ecosystem service; Faecal indicator bacteria; Groundwater; Sand dunes; Water chemistry