Acosta Jose A, Arocena Joselito M, Faz Angel
Sustainable Use, Management, and Reclamation of Soil and Water Research Group, Department of Agrarian Science and Technology, Technical University of Cartagena, Paseo Alfonso XIII, 52, 30203 Cartagena, Spain.
Environmental Science Program, University of Northern British Columbia, Prince George, BC V2N 4Z9, Canada.
Chemosphere. 2015 Nov;138:1014-20. doi: 10.1016/j.chemosphere.2014.12.050. Epub 2015 Jan 7.
Soils near artisanal and small-scale gold mines (ASGM) have high arsenic (As) contents due to the presence of arsenopyrite in gold ores and accelerated accumulations due to mine wastes disposal practices and other mining activities. We determined the content and speciation to understand the fate and environmental risks of As accumulations in 24 bulk and 12 rhizosphere soil samples collected in the Virgen Del Rosario and the Rayo Rojo cooperative mines in the highlands of Bolivia. Mean total As contents in bulk and rhizosphere soils ranged from 13 to 64 mg kg(-1) and exceeded the soil environmental quality guidelines of Canada. Rhizosphere soils always contained at least twice the As contents in the bulk soil. Elemental mapping using 4×5 μm synchrotron-generated X-ray micro-beam revealed As accumulations in areas enriched with Fe. Results of As-X-ray Absorption Near Edge Spectroscopy (As-XANES) showed that only As(V) species was detectable in all samples regardless of As contents, size fractions and types of vegetation. Although the toxicity of As(V) is less than As(III), we suggest that As uptake of commonly-grazed vegetation by alpaca and llama must be determined to fully understand the environmental risks of high As in soils near ASGM in Bolivia. In addition, knowledge on the speciation of the As bio-accessible fraction will provide another useful information to better understand the fate and transfer of As from soils into the food chain in environments associated with the ASGM in Bolivia and other parts of the world.
手工和小规模金矿（ASGM）附近的土壤由于金矿中存在毒砂以及矿山废弃物处理做法和其他采矿活动导致的加速积累而含有高浓度的砷（As）。我们测定了在玻利维亚高地的维根德尔罗萨里奥和雷约罗霍合作矿山采集的24个表层土壤和12个根际土壤样品中砷的含量和形态，以了解砷积累的归宿和环境风险。表层土壤和根际土壤中的平均总砷含量范围为13至64毫克/千克（-1），超过了加拿大的土壤环境质量标准。根际土壤中的砷含量始终至少是表层土壤的两倍。使用4×5微米同步加速器产生的X射线微束进行的元素映射显示，砷在富含铁的区域积累。砷-X射线吸收近边光谱（As-XANES）结果表明，无论砷含量、粒径分数和植被类型如何，所有样品中仅可检测到As（V）形态。尽管As（V）的毒性小于As（III），但我们建议必须确定羊驼和美洲驼对常见放牧植被的砷吸收情况，以全面了解玻利维亚ASGM附近土壤中高砷的环境风险。此外，关于砷生物可利用部分形态的知识将提供另一个有用信息，以更好地了解在玻利维亚和世界其他地区与ASGM相关的环境中砷从土壤进入食物链的归宿和转移情况。
