Selenium bioaccumulation in Daphnia pulex via aqueous and dietary exposure

• Published in: Environmental monitoring and assessment 2024-07, Vol.196 (7), p.628-628, Article 628
• Main Authors: Davila-Arenas, Catherine Estefany, Doig, Lorne E., Ji, Xiaowen, Panigrahi, Banamali, Ezugba, Immanuela, Liu, Xia, Liber, Karsten
• Format: Article
• Language: English
• Subjects: Alberta; Algae; Animals; Aquatic organisms; Atmospheric Protection/Air Quality Control/Air Pollution; Bioaccumulation; Daphnia - metabolism; Daphnia pulex; Dietary Exposure; Dry weight; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental Management; Environmental Monitoring; Exposure; Freshwater crustaceans; guidelines; Lakes; Lakes - chemistry; Mine tailings; Monitoring/Environmental Analysis; Oil sands; oils; Regulatory mechanisms (biology); selenates; Selenium; Selenium - analysis; Selenium - metabolism; Static tests; summer; Surface water; Waste materials; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - metabolism; Water quality
• ISSN: 0167-6369; 1573-2959; 1573-2959
• DOI: 10.1007/s10661-024-12761-5

Pit lakes are currently being investigated as a way to store and reclaim waste materials in the Alberta Oil Sands (AOS) region, Canada. Lake Miwasin (LM) is a pilot-scale pit lake consisting of treated fine tailings overlayed with oil sands process-affected water (OSPW) blended with fresh surface water. In October 2021, the surface water contained a mean concentration of 1.33 ± 0.04 µg/L dissolved selenium (Se), slightly above the Canadian Council of Ministers of Environment water quality guideline for long-term protection of aquatic life (1 µg Se/L). This study assessed the bioaccumulation of Se by the cladoceran Daphnia pulex under laboratory conditions through both aqueous and dietary exposure routes for comparison to field-collected specimens. In 12-day semi-static tests, lab-cultured D. pulex were exposed to water, and algae grown in media spiked with selenate. Results showed that Se bioaccumulation by lab-cultured D. pulex increased in all exposure treatments from days 5 to 12, with maximum Se concentrations of 3.08–3.47 µg/g dry weight (dw) observed within the exposure range tested. Interestingly, lower Se bioaccumulation concentrations (1.26–1.58 µg/g dw) were observed in the highest dissolved Se and dietary Se treatments, suggesting potential internal regulatory mechanisms. In addition, native D. pulex (LM) collected from Lake Miwasin and cultured in-house were exposed in 8-day semi-static tests to Lake Miwasin surface water and algae cultured in Lake Miwasin surface water. Selenium bioaccumulation in native D. pulex (LM) ranged from 2.00 to 2.04 µg/g dw at day 8 and was not significantly different ( p  > 0.05) compared to Se concentrations in D. pulex collected from Lake Miwasin (2.15 ± 0.28 µg/g) in summer 2022.