Department of Environmental Geochemistry, IRNASA (CSIC), C/ Cordel de Merinas 40-52, 37008 Salamanca, Spain.
Department of Environmental Geochemistry, IRNASA (CSIC), C/ Cordel de Merinas 40-52, 37008 Salamanca, Spain.
Sci Total Environ. 2016 Jan 15;542(Pt A):238-46. doi: 10.1016/j.scitotenv.2015.10.054. Epub 2015 Oct 28.
A mining impacted cropland was studied in order to assess its As pollution level and the derived environmental and health risks. Profile soil samples (0-50 cm) and rye plant samples were collected at different distances (0-150 m) from the near mine dump and analyzed for their As content and distribution. These cropland soils were sandy, acidic and poor in organic matter and Fe/Al oxides. The soil total As concentrations (38-177 mg kg(-1)) and, especially, the soil soluble As concentrations (0.48-4.1 mg kg(-1)) importantly exceeded their safe limits for agricultural use of soils. Moreover, the soil As contents more prone to be mobilized could rise up to 25-69% of total As levels as determined using (NH4)2SO4, NH4H2PO4 and (NH4)2C2O4·H2O as sequential extractants. Arsenic in rye plants was primarily distributed in roots (3.4-18.8 mg kg(-1)), with restricted translocation to shoots (TF=0.05-0.26) and grains (TF=<0.02-0.14). The mechanism for this excluder behavior should be likely related to arsenate reduction to arsenite in roots, followed by its complexation with thiols, as suggested by the high arsenite level in rye roots (up to 95% of the total As content) and the negative correlation between thiol concentrations in rye roots and As concentrations in rye shoots (|R|=0.770; p<0.01). Accordingly, in spite of the high mobile and mobilizable As contents in soils, As concentrations in rye above-ground tissues comply with the European regulation on undesirable substances in animal feed. Likewise, rye grain As concentrations were below its maximum tolerable concentration in cereals established by international legislation.
为评估采矿影响农田的砷污染水平及其衍生的环境和健康风险，对该农田进行了研究。在距离矿山最近的倾倒场 0-150 m 不同距离处采集了剖面土壤样品（0-50 cm）和黑麦植物样品，并对其砷含量和分布进行了分析。这些农田土壤为沙质、酸性、贫有机质和铁/铝氧化物。土壤总砷浓度（38-177 mg kg(-1)），尤其是土壤可溶性砷浓度（0.48-4.1 mg kg(-1)）远远超过了土壤农业利用的安全限值。此外，使用（NH4）2SO4、NH4H2PO4 和（NH4）2C2O4·H2O 作为连续提取剂时，土壤中更易被迁移的砷含量可能高达总砷水平的 25-69%。黑麦植物中的砷主要分布在根部（3.4-18.8 mg kg(-1)），向地上部分（TF=0.05-0.26）和谷粒（TF=<0.02-0.14）的转移受到限制。这种排除行为的机制可能与根中砷酸盐还原为亚砷酸盐有关，随后与硫醇络合，正如黑麦根中高亚砷酸盐水平（高达总砷含量的 95%）和黑麦根中硫醇浓度与黑麦地上部分砷浓度之间的负相关（|R|=0.770；p<0.01）所表明的那样。因此，尽管土壤中具有高的可移动和可迁移的砷含量，但黑麦地上部分组织中的砷浓度符合欧洲关于动物饲料中有害物质的法规。同样，黑麦谷物中的砷浓度低于国际法规规定的谷物中最大耐受浓度。
