Application of autonomous sensor technology to estimate selenium exposure and a site‐specific selenium threshold in a Canadian boreal lake. (25th July 2022)

• Record Type: Journal Article
• Authors: Peixoto Mendes, Maíra; Cupe‐Flores, Beatriz; Panigrahi, Banamali; Liber, Karsten
• Is Part Of: Integrated environmental assessment and management. Volume 19:Number 2(2023)
• Page Start: 395
• Page End: 411
• Publication Date: 2022-07-25
• Subjects: Autonomous sensors -- Boreal lake -- Electrical conductivity -- Selenium -- Uranium mill; Environmental management -- Periodicals; Pollution -- Periodicals; Environmental toxicology -- Periodicals; Environmental risk assessment -- Periodicals; Environmental impact analysis -- Periodicals; 628
• DOI: 10.1002/ieam.4644
• Languages: English
• ISSNs: 1551-3777

Abstract

Abstract: There is an increasing trend in the use of real‐time sensor technology to remotely monitor aquatic ecosystems. Commercially available probes, however, are currently not able to measure aqueous selenium (Se) concentrations. Because of the well‐described bioaccumulation potential and associated toxicity of Se in oviparous vertebrates, it is crucial to monitor Se concentrations at sites receiving continuous effluent Se input. This study aimed to estimate Se concentrations in a boreal lake (McClean Lake) downstream from a Saskatchewan uranium mill using real‐time electrical conductivity (EC) data measured by autonomous sensors. Additionally, this study aimed to derive a site‐specific total aqueous Se (TSe) threshold based on Se concentrations in periphyton and benthic macroinvertebrates sampled from the same lake. To characterize effluent distribution within the lake, eight Smart Water (Libelium) sensor units were programmed to report EC and temperature for five and seven consecutive weeks in 2018 and 2019, respectively. In parallel, periphyton and benthic macroinvertebrates were sampled with Hester‐Dendy's artificial substrate samplers ( n = 4) at the same sites and subsequently analyzed for Se concentrations. Electrical conductivity was measured with a handheld field meter for sensor data validation and adjusted to the median lake water temperature (13 °C) registered for the deployment periods. Results demonstrated good accuracy of sensor readings relative to handheld field meter readings and the successful use of real‐time EC in estimating TSe exposure ( r = 0.87; r 2 = 0.84). Linear regression equations derived for Se in detritivores versus Se in periphyton and Se in periphyton versus sensor‐estimated TSe were used to estimate a site‐specific TSe threshold of 0.7 µg/L (±0.2). Moreover, mean Se concentrations in periphyton (16.7 ± 4.4 µg/g dry weight [d.w.]) and benthic detritivores (6.0 ± 0.4 µg/g d.w.) from one of the exposure sites helped identify an area with potential for high Se bioaccumulation and toxicity in aquatic organisms in McClean Lake. Integr Environ Assess Manag 2023;19:395–411. © 2022 SETAC Key Points: Electrical conductivity data from autonomous sensors were a good surrogate parameter for monitoring aqueous selenium concentrations on a real‐time scale in a Canadian boreal lake. The estimated site‐specific aqueous selenium threshold for this lake (0.7 ± 0.2 µg/L) is below current North American guideline values for total selenium in surface waters. Key environmental monitoring locations were identified based on the diluted effluent distribution in McClean Lake and selenium concentrations measured in periphyton and benthic macroinvertebrates.