title: Spatial analysis of Carbon-14 dynamics in a wetland ecosystem (Duke Swamp, Chalk River Laboratories, Canada).
abstract: A detailed survey was conducted to quantify the spatial distribution of (14)C in Sphagnum moss and underlying soil collected in Duke Swamp. This wetland environment receives (14)C via groundwater pathways from a historic radioactive Waste Management Area (WMA) on Atomic Energy Canada Limited (AECL)'s Chalk River Laboratories (CRL) site. Trends in (14)C specific activities were evaluated with distance from the sampling location with the maximum (14)C specific activity (DSS-35), which was situated adjacent to the WMA and close to an area of groundwater discharge. Based on a spatial evaluation of the data, an east-to-west (14)C gradient was found, due to the influence of the WMA on (14)C specific activities in the swamp. In addition, it was possible to identify two groups of sites, each showing significant exponential declines with distance from the groundwater source area. One of the groups showed relatively more elevated (14)C specific activities at a given distance from source, likely due to their proximity to the WMA, the location of the sub-surface plume originating from the WMA, the presence of marsh and swamp habitat types, which facilitated (14)C transport to the atmosphere, and possibly, (14)C air dispersion patterns along the eastern edge of the swamp. The other group, which had lower (14)C specific activities at a given distance from the groundwater source area, included locations that were more distant from the WMA and the sub-surface plume, and contained fen habitat, which is known to act as barrier to groundwater flow. The findings suggest that proximity to source, groundwater flow patterns and habitat physical characteristics can play an important role in the dynamics of (14)C being carried by discharging groundwater into terrestrial and wetland environments.
authors.affiliation: International Atomic Energy Agency (IAEA), Vienna International Centre, PO Box 100, 1400 Vienna, Austria. Electronic address: t.yankovich@iaea.org.
authors.forename: T L
authors.initials: TL
authors.lastname: Yankovich
authors.affiliation: Environmental Technologies Branch, Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario K0J 1J0, Canada.
authors.forename: K J
authors.initials: KJ
authors.lastname: King-Sharp
authors.affiliation: Environmental Technologies Branch, Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario K0J 1J0, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Carr
authors.affiliation: K + S Potash Canada, 300-201 21st Street East, Saskatoon, SK S7K 0B8, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Robertson
authors.affiliation: Environmental Technologies Branch, Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario K0J 1J0, Canada.
authors.forename: R W D
authors.initials: RWD
authors.lastname: Killey
authors.affiliation: Radioecology Group, Centre for Ecology & Hydrology, CEH Lancaster, Lancaster Environment Centre, Library Av., Bailrigg, Lancaster LA1 4AP, United Kingdom.
authors.forename: N A
authors.initials: NA
authors.lastname: Beresford
authors.affiliation: School of Environment and Life Sciences, Room 323, Peel Building, University of Salford, Manchester M5 4WT, United Kingdom.
authors.forename: M D
authors.initials: MD
authors.lastname: Wood
mesh_terms: D002244:Carbon / Q000032:analysis*; D002250:Carbon Radioisotopes / Q000032:analysis; D060587:Groundwater / Q000032:analysis; D009864:Ontario; D011834:Radiation Monitoring; D062206:Spatial Analysis; D014872:Water Movements; D053833:Wetlands
chemical_list: D002250:Carbon Radioisotopes; D002244:Carbon
keywords: Atmospheric dispersion; Carbon-14; Environmental monitoring; Radionuclide; Specific activity; Wetland