The effect of sulphate on selenium bioaccumulation in two freshwater primary producers and a primary consumer

Site-specific conditions (e.g. presence of sulphate), may be linked to the variability in the uptake of selenium in organisms at the base of a food chain, potentially affecting the risk of adverse effects in higher trophic-level organisms. In this project, the effect of sulphate on selenate bioaccumulation in two primary producers (Lemna minor and Pseudokirchneriella subcapitata) and a primary consumer (Daphnia magna) was explored. When exposed to selenate, all three species exhibited a decrease in selenium tissue concentration with increasing sulphate. When D. magna were exposed to sulphate and dietary selenium, sulphate did not affect selenium tissue concentrations. The results were used to develop equations estimating selenium tissue concentrations when exposed to selenate and sulphate. The strong predictive ability of the equations suggests that selenate, sulphate, and dietary selenium (applicable to D. magna) are important for describing the relationship between selenate and selenium tissue concentrations.