Undisturbed lake sediment records provide a robust natural archive of conditions within
waterbodies. They have been used successfully over a number of decades to determine
temporal trends of surface water acidification and to follow the effects of eutrophication.
However, lake sediments also provide an archive of changes occurring within lake catchments
and of atmospheric pollutants deposited onto lake and catchment surfaces. In August 2006,
parallel lake sediment cores were collected from 22 lakes in the Athabasca Oil Sands Region of
Alberta by UCL staff as part of the RAMP regional lakes survey. Twelve of these lakes were
selected for study covering a range of locations from around the Fort McMurray area to sites in
the Caribou Mountains and the Canadian Shield. The main aim of this initial study was to
assess the evidence for lake acidification in the region, but analysis also revealed changes in
nutrient input and, at one site, mercury (Hg) analysis showed an indication of industrial
contamination. This work was reported in Curtis et al. (2010).
The analysis undertaken in this initial project was focussed on single radiometrically dated
sediment cores (hereafter the ‘A’ cores) from each of the 12 selected lakes. The parallel cores
from each lake (the ‘B’ cores) were stored dark, at 4ºC, following their transfer to UCL and
hence were available for further analysis. Both sediment cores (A and B) from the remaining 10
lakes remain unstudied.
The aim of this current project was to use the stored ‘B’ sediment cores to assess temporal
trends and rates of change in trace element input to a subset of the lakes cored in the
Athabasca Oil Sands Region of Alberta and compare these with the sediment records of two
reference lakes in the Caribou Mountains.
This interim report contains details of progress on this work up to end March 2012 and a
summary of remaining work under this contract. As a consequence this report focusses on data
collected so far. Only limited interpretation is provided and will be undertaken fully when the
dataset is complete. A final report will be produced upon completion of the study