Accumulation and speciation of selenium in Cardamine sp. in Yutangba Se Mining Field, Enshi, China

• Published in: Acta geochimica 2014-12, Vol.33 (4), p.357-364
• Main Authors: Shao, Shuxun, Deng, Guodong, Mi, Xiubo, Long, Shengqiao, Zhang, Jing, Tang, Jun
• Format: Article
• Language: English
• Subjects: Accumulation; Biomass; China; Contamination; Detoxification; Earth and Environmental Science; Earth Sciences; Fronds; Geochemistry; Human; Leaves; Liquid chromatography; Mines; Mining; Plants (organisms); Seedlings; Selenium; Speciation; 中国; 形态; 恩施地区; 渔塘坝; 硒矿; 碎米; 超积累
• ISSN: 1000-9426; 2096-0956; 1993-0364; 2365-7499
• DOI: 10.1007/s11631-014-0698-7

A naturally selenium-accumulating Cardamine sp. is growing in Yutangba Selenium Mining Field, Enshi area, Hubei Province, China, where the geochemical environment is selenium-enriched and endemic selenosis ever occurred in humans. The present study investigated the characteristics of accumulation, speciation and quantity of selenium in Cardamine sp. with HPLC-ICP-MS. Results show that Cardamine sp. can accumulate Se at most 1427 mg/kg in seedling leaves. Even after the biomass incensement of growing up, the plant still could accumulate Se up to several hundred of mg/kg in concentration. Moreover, the biomass enrichment coefficient （BEC） of Se is exceedingly high, in the seedling leaves mostly, higher than 50 mg/kg; in the range of 43.7-68 mg/kg; and the lowest value is higher than 3 mg/kg in mature fronds. Se is present in the plant predominantly in form of SeCys2 with the highest concentration in seeds; up to 1081 mg/kg as Se. In contrast, SeCysz levels are low during early growth period; they are 136.1 mg/kg as Se in seedling fronds and 39.4 mg/kg as Se in mature fronds, respectively. SeMet concentration is comparatively low; 10.6 mg/kg as Se in seedling frond and 5.3 mg/kg as Se in half mature fronds, respectively. This indicates that Cardamine sp. is extremely efficient in extracting Se from soil and translocating it into its above-ground biomass. Therefore, Cardamine sp., found in Yutangba Se Mining Field may be a new Se hyperaccumulator. It is still uncertain whether the Se-accumulation or detoxification of Cardamine sp. happens through the pathway of SeCys methylated to form Se-methylselenoCys or through the formation of Se-carboxymethyl- selenohomocysteine. Indeed, further study should be carried out on the determination of more Se species to explain the high Se hyperaccumulation in Cardamine sp.