Selenium in Chinese coals: Distribution, occurrence, and health impact

Selenium (Se) is one of the volatile elements in coal. During mining and utilization of coal, Se is largely released into the environment, which influences environmental quality, and consequently impacts on human health. This paper is a review of current knowledge on the distribution, occurrence and environmental impact of Se in Chinese coals. This study includes the following aspects: distribution and abundance of Se in coals of different provinces of China, different coal-forming periods, modes of occurrence of Se in coals, formation mechanism of Se in coals, migration processes and transformation of Se during coal combustion and leaching and their environmental effects. The available data show that Se content in Chinese coals is highly variable in different coalfields, different coal-forming periods, and different coal seams from individual coalfields. The average Se content in Chinese coal is 3.91 mg/kg.