Study On Rare Earth Elements Enrichment Characteristics Of Bryophytes In The Bayan Obo Mining Area,China

Bryophytes are effective living organisms to monitor environmental quality,and now are widely accepted.In this paper,the content of 15 rare earth elements?REEs?and radioactive elements ²³²Th in bryophytes and its corresponding soil samples collected from Bayan Obo Mining Area and the Periphery was detected by ICP-MS.The enrichment ability of REEs was analyzed by means of Bioconcentration factor?BCF?.In order to select the species of bryophytes for indication rare earth elements existence in the substance soil and biology prospecting,the study on enrichment characteristics of bryophytes for REEs application was conducted.The experimental results showed as follows:In this study 569 bryophytes specimens had been collected from study area.A total of 63 species and varieties in 28 genera and 13 families of bryophytes were reported.The area of mosses communities were mainly concentrated respective under100 cm² and 200 cm² in Bayan Obo Mining Area and the Periphery.The total concentrations of rare earth elements of 9 mosses were sorted by Didymodon constrictus>Didymodon vinealis>Didymodon tectorum>Jaffueliobryum wrightii>Didymodon cordatus>Syntrichia sinensis>Didymodon fallax>Didymodon icmadophillus>Hypnum vaucheri.The concentrations of REEs indicated the following abundance order:Ce>La>Nd>Pr>Sm>Gd>Y>Eu>Dy>Tb>Er>Yb in soil and moss samples.REEs and every rare earth elements varied in same trend in mosses and corresponding substrate soils,with high consistency,and appeared significant positive correlation.the contents of REEs in three mining areas showed that MO>EO>WO>BLM>MDL>RTH>HSE.The rare earth elements were concentrated in Bayan Obo mining area,so far as the Periphery,the northeast was higher,while the southwest was lower.The concentrations of REEs in different soil layers were following soil-I>soil-U>soil-O.The mineral particles in the environment accumulated around the rhizoid in the community and then transform to the bryophytes.Precipitation and leaching also caused the rare earth elements to transform to the soil-U.When the bryophytes absorb and enrich rare earth elements,the most important factor that affects the total amount of rare earth elements was Ce.The La-Pr and La-Nd were always in synergistic effect.The absorption and enrichment capacity of REEs in mosses also make a significant difference in 9 moss species,the BCF in mosses are between 0.33⁰.72,with the order of D.cordatus>D.constrictus>S.sinensis>D.fallax>D.icmadophillus>D.vinealis>J.wrightii>D.tectorum>H.vaucheri.The BCF of mutual species in the Periphery showed S.sinensis>H.vaucheri,suggesting acrocarpous mosses>pleurocarpous ones.Considering various constraints,This paper believe that Syntrichia sinensis could be used as an effective biological indicator for environmental indicators and biology prospecting for rare earth elements.