Sedimentary transport and fate of polycyclic aromatic hydrocarbons (PAH) from managed burning of moorland vegetation on a blanket peat, South Yorkshire, UK

• Published in: The Science of the total environment Vol. 449; pp. 81 - 94
• Main Authors: Vane, Christopher H., Rawlins, Barry G., Kim, Alexander W., Moss-Hayes, Vicky, Kendrick, Christopher P., Leng, Melanie J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01-04-2013; Elsevier
• Subjects: Applied sciences; burning; Calluna vulgaris; Chromatography, High Pressure Liquid; coal; Combustion; Continental surface waters; Exact sciences and technology; Fires; Geologic Sediments - chemistry; guidelines; Heather; heathlands; Moorland; Natural water pollution; PAH; Peat; Perylene; Plants; Pollution; Pollution sources. Measurement results; polycyclic aromatic hydrocarbons; Polycyclic Compounds - analysis; Principal Component Analysis; Reservoir; Sediments; Soil - chemistry; Soil and sediments pollution; sorption; Sphagnum; streams; United Kingdom; water reservoirs; Water treatment and pollution; watersheds; United Kingdom; Europe; British Isles; British Isles, England, South Yorkshire; Moorland; Heather; PAH; Reservoir; Combustion; Perylene; Sediments; Peat; Heathland and moor; Hydrocarbon; Pollutant behavior; Polycyclic aromatic compound; Burning; Persistent organic pollutant; Freshwater environment; Transport process; Pollution; Vegetation; Stream; Water pollution; Biological accumulation
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2013.01.043

This study reports the concentrations of 18 polycyclic aromatic hydrocarbons (PAH) from managed burning of moorland vegetation and compares them to PAH in catchment vegetation, underlying peats, head water suspended sediment (HSS), stream water and reservoir sediment cores. Total PAH ranged from 203 to 11,112μg/kg in the blanket peats, 101–290μg/kg in the fresh moorland vegetation, 4186μg/kg at the burnt site, 17,439μg/kg in the HSS, 56ng/L in the stream water and 987 to 7346μg/kg in the reservoir sediments. No total or individual PAH concentrations exceeded the published sediment quality guidelines. The perylene content of selected moorland vegetation (sphagnum, heather and bilberry) ranged from 10 to 18% as compared to only 2% for the sediment hosted PAH. A comparison of whole and <250μm fractions from the burnt surface layer revealed a near threefold increase in PAH concentration in the fine fraction and a change in the PAH distribution such that naphthalene>>phenanthrene>2-methylnaphthalene. Elevated total PAH contents were observed close to the blanket peat sediment surface (0–10cm) and then declined at greater depths. The high PAH content of the HSS was attributed to the high sorption capacity of the organic-rich particles (TOC 25.8% (wt/wt)). The distribution of individual PAH in reservoir cores and HSS was consistent and the results of the principal component analysis and isomeric ratios suggest mainly pyrolytic inputs, from either vegetation burning and coal combustion. A comparison of the reservoir core PAH profiles shows that the source(s) have remained largely unchanged since the reservoir construction in 1929A.D. reflecting consistent moorland management practices.
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► We report PAH from source (burning of moorland heather) to sink (reservoir core). ► PAH from managed burns differs from that from wildfires or agricultural debris. ► Perylene comprised 10–18% of moorland vegetation PAH but only 2% of sediment PAH. ► PAH were transferred from upland-source to reservoir-sink via suspended sediment. ► Reservoir sediment PAH source(s) have remained unchanged since 1929AD.