The characteristics of accumulated sediments were investigated, with a focu
s on selected trace metals, in three stormwater management facilities and o
ne natural site, all located in the Regional Municipality of Ottawa-Carleto
n, in Ontario, Canada. This study was conducted in response to concerns exp
ressed by Environment Canada about possible ecosystem impacts by contaminan
ts accumulated in these commonly utilized, passive treatment systems. Also
of interest were the effects of facility configuration and operation and ma
intenance on particulate deposition patterns and resulting exposure risk Th
is was the first phase of a multidisciplinary study to quantify the risk of
ecosystem effects in these systems, and results indicate that there were s
ome significant potential risks present. In addition, results indicate that
a simple comparison with provincial sediment quality guidelines may not be
sufficient to alert facility owners and operators to these potential risks
.