Lead accumulation in open water wet ecosystems in the Border Marsh region of New Brunswick and Nova Scotia
LE3 .A278 2013
Bachelor of Science
Environmental & Sustainability Studies
Open water wet ecosystems (OWWE) in the Border Marshes region (BMR) provide productive avian and invertebrate habitat. In the BMR lead (Pb) is a contaminant of interest due to potential bio-magnification and subsequent uptake by migratory waterfowl in OWWE. This study focuses on the relationships between constructed OWWE, autochthonous productivity and lead accumulation. Eleven sites were selected to represent the spectrum of the OWWE environments in the BMR. Sites were characterized by measuring salinity (0%- 2.83%), pH (6.6-9.1) and specific limnological and physical parameters. Variability at each site was defined through weekly determination of water pH, temperature, dissolved oxygen (DO), salinity and total dissolved solids (TDS). Top-of-core and bottom-of-core OWWE sediment samples were collected for each site and analyzed for loss on ignition (LOI), carbon-nitrogen (C:N) stable isotopes and elemental concentrations of Pb and other environmental proxies (Ti, Fe, Mn) using an X-ray fluorescence spectrometer (XRF). C:N data indicates variable productivity (6.73 - 17.62) and that the organic sediment in all environments is dominantly autochthonous. Till and salt marsh sediment had variable concentrations of lead (salt marsh sediment 8ppm; till 20 ppm). The variation in sediment lead concentrations is likely due to a combination of factors including variable shoreline erosion, variable autochthonous productivity and, in some cases point source pollution. OWWE have lower lead concentrations (0-28 ppm) in both modern and older sediment samples than natural lake sites (18-95 ppm; White, 2012). There was little evidence to indicate that lead sequestration correlates with salinity or pH. Results suggest xii constructed OWWE have higher autochthonous productivity and lower lead in surface sediments than natural OWWE or natural lakes in the BMR1
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