Selenium analysis in waters. Part 1: Regulations and standard methods

Selenium is released into the aquatic environment through anthropogenic activities such as agricultural irrigation, coal mining, and metallurgical activities, where it acts as a reproductive toxin with negative effects on predatory fish and water fowl. Waterborne selenium concentrations are closely regulated worldwide, and various standardized methods are implemented by regulatory bodies to allow for the monitoring of selenium concentrations in different types of waters. Here, we discuss worldwide regulations relating to concentration limits of selenium in drinking, natural, and industrial waters. Focusing specifically on North America, we look at some standardized analysis methods and discuss the fact that many of these methods are not adequately sensitive to measure selenium in the concentrations outlined by the associated regulations for natural waters. We look in detail at the limitations of these methods with regards to both detection limits and interfering sample matrix components and establish the need for more sensitive and robust methods of analysis for regulatory compliance. This review is complemented by a second part (LeBlanc et al., 2018) where we discuss the state of selenium speciation analysis and importance of speciation data for decision makers in industry and regulators.