Selenium Pollution Around the World

Abstract

Selenium is a naturally occurring trace element that can be concentrated and released in the waste materials from certain mining, agricultural, petrochemical, and industrial manufacturing operations. Once in the aquatic environment, it can rapidly bioaccumulate and reach levels that are toxic to fish and wildlife. Selenium pollution is a worldwide phenomenon and is associated with a broad spectrum of human activities ranging from the most basic agricultural practices to the most high-tech industrial processes. Consequently, selenium contamination of aquatic habitats can take place in urban, suburban, and rural settings alike—from mountains to plains, from deserts to rainforests, and from the Arctic to the tropics. Few environmental contaminants have the potential to affect aquatic resources on such a broad scale, and still fewer exhibit the complex aquatic cycling pathways and range of toxic effects that are characteristic of selenium. This places additional importance on the need for techniques to identify, diagnose, and respond to aquatic selenium problems before they become widespread toxic episodes. For many years, selenium has been a largely unrecognized pollutant, particularly in developing nations, and it has been overshadowed by issues involving contaminants such as industrial chemicals, heavy metals, pesticides, and air pollutants among many others.