Selenium accumulation and speciation in soils along a climate gradient

Selenium (Se) is an essential element for humans and animals. Main intake routes are via food consumption such as grains, cereals, and meat. Although Se is not known to be essential for plants, it can promote the growth and quality of crops (Haug et al. 2007). Selenium deficiency was estimated to be a major health problem for 0.5 to 1 billion people worldwide, and even more people probably consume less Se than is required for optimal protection against cancer, cardiovascular, and severe infectious diseases, including HIV (Haug et al. 2007).