Selenium: When a Good Nutrient Goes Bad

Selenium (Se) was an essential nutrient necessary for metabolic functions, preventing diseases like Keshan and Kashin-Beck, and potentially reducing cancer and diabetes risks. However, excessive Se could be toxic, causing symptoms like hair loss and cardiovascular issues, and even leading to fatal incidents, such as the accidental overdose that killed 21 polo horses in 2009. Human activities increased Se concentrations in the environment, impacting ecosystems and raising global concerns. While Se was extracted as a by-product of copper mining and used in various industries, its scarcity and environmental impact necessitated careful management. The dual nature of Se, beneficial in proper doses but harmful in excess, highlighted the need for integrated environmental assessment and management.