Grants and Contributions:

Grant or Award spanning more than one fiscal year (2017-2018 to 2018-2019).

Several different types of mining operations in Canada inadvertently mobilize selenium (Se) from the naturalx000D
resources they're processing. In some cases, selenium may cause adverse effects on aquatic organisms, sox000D
mining operations affected by Se issues remove most of the mobilized Se from their process waters prior tox000D
discharge. However, as a result of historic emissions and/or current low level emissions, some receivingx000D
environments have elevated Se concentrations in their sediments. It is known that microbes in sediments mayx000D
convert some of the deposited Se into more bioavailable organic forms ("species"), but it is unknown whetherx000D
these organic Se species are released from the sediments back into the overlying waters, where they might thenx000D
be available to organisms in the water column. We have recently developed analytical methods to measurex000D
discrete organic Se species in waters at the ng/L concentration level, and are now able to study suchx000D
compounds in environmental waters.x000D
If such organic Se species occur in mining-impacted aquatic systems, one primary open research question isx000D
their stability in these waters. In laboratory experiments, it has been shown previously that these organic Sex000D
species are susceptible to oxidation, e.g. by oxygen or UV-radiation, but there are to date no field data thatx000D
quantify the rates of these degradation processes in actual receiving waters. In this project, we will collectx000D
water samples from several sites within a Se-impacted ecosystem, and follow the degradation of organic Sex000D
species (native or spiked) in these waters under controlled laboratory conditions over time. The goal of thisx000D
project is to determine the degradation rates of discrete organic Se species in environmental waters, in order tox000D
assess for how long they might be available for bioaccumulation. As a useful side aspect, this study will alsox000D
determine the short term stability of the studied organic Se species in these waters, to check if significantx000D
degradation occurs during transport from sampling site to analytical laboratory.