Development of a bioaccumulation model for selenium oxyanions and organoselenium in stream biota.

This article focuses on the relationship between selenium (Se) speciation and bioaccumulation in aquatic food webs near coal mining operations in southeast British Columbia, Canada. Over five years and 142 sites, the study quantified inorganic (selenate and selenite) and organic selenium species, finding that methylseleninic acid (MeSe(IV)) and dimethylselenoxide (DMSeO) are the most bioaccumulative forms, with MeSe(IV) showing particularly high bioavailability. These organoselenium species primarily originate from biological metabolism in mine sedimentation ponds and contribute significantly to elevated selenium levels in benthic macroinvertebrates downstream, with concentrations declining with distance from the ponds. The findings suggest that managing biological productivity in mine ponds could be a key strategy for controlling selenium bioaccumulation and associated ecological risks in receiving lotic environments.