Yutangba is one of the most typical high-Se areas in Enshi Prefecture in China.Comprehensive studies were conducted in order to better understand distribution and variation of selenium in soils.plants and water bodies of Yutangba.The results show that high-Se plants and soils are mainly distributed in the northwestern part,Shangba and Xiaba of Yutangba,where exposure of Se-rich carbonaceous strata is found.No significantly positive relationship between soil Se and plant Se was found,which indicates Se uptake by plants is not always controlled by concentration of total Se in the soil.In the past 30 years,selenium content in the soil has remained almost unchanged whereas plant Se has showed a significant declining trend,indicating that in the soil Se available to plants has obviously decreased.Although water samples high in Se can be collected from streams flowing through the Se-rich carbonaceous strata or abandoned stone coal spoils,no obvious variation of Se content in water was observed,demonstrating that the release of Se has reached a geochemical equilibrium.The distribution of Se in Yutangba,apart from topographic and geological factors with regard to Se-rich rocks,is also related to pathways of Se transportation.The exposed Se-rich carbonaceous strata in the northwestern part of Yutangba is a necessary condition for developing high-Se areas,but the high-Se soil in Shangba and Xiaba of Yutangba is attributed to human activities such as cultivation and mining.Local farmers often use Se-rich "stone coals" as fertilizer or soil amendment,thus leading to Se further accumulation in food chain,of which the impact is long term.Therefore should the local government not take adequate measures or make reasonable planning for the exploitation of the Se resources in Enshi Prefecture,the risk of Se poisoning is still very high in Yutangba and some other high-Se places in Enshi Prefecture.