|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|6327582||1619766||2015||8 صفحه PDF||سفارش دهید||دانلود رایگان|
- We used chemistry, fluorescence and bacterial counts to study multiple pathways of contamination to a wetland site.
- Contamination sources are primarily fertilizers, causing exceedance of nutrient thresholds in groundwater within the site.
- Contamination pathways into the site include groundwater, surface runoff, and streams, with minor input from on-site grazers.
- The site attenuates nutrient and bacterial concentrations providing an ecosystem service, but with adverse biological effects.
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 <Â 0.4Â RamanÂ units (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.
Journal: Science of The Total Environment - Volume 511, 1 April 2015, Pages 703-710