Drahota Petr, Paces Tomás, Pertold Zdenek, Mihaljevic Martin, Skrivan Petr
Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, Prague 2, 128 43, Czech Republic.
Sci Total Environ. 2006 Dec 15;372(1):306-16. doi: 10.1016/j.scitotenv.2006.09.002. Epub 2006 Oct 24.
Arsenic in natural waters and in soils represents a serious health hazard. Natural sources of this element in soil are the subject of this communication. Weathering mass balance of As and rates of weathering in soils are evaluated from monitored inputs and outputs in two small watersheds. These watersheds are located within the Celina-Mokrsko gold district, Czech Republic. Annual chemical weathering fluxes of As are calculated from the monthly weighted means of stream water and groundwater. The fluxes are corrected for atmospheric precipitation, agrochemical inputs, and biological uptake. Mechanical and chemical weathering rates of the arsenopyrite-bearing rocks in the watersheds were estimated from mass balance data on sodium and silica. The input of As due to total weathering of bedrock was estimated to be 1369 g ha(-1)yr(-1) in the Mokrsko watershed (MW) and 81 g ha(-1)yr(-1) in the Celina watershed (CW). These results indicate that the annual weathering rate of As in the watersheds represents more than 95% of the total As input to the soil. Accumulation rate of As in the soil was estimated at 311 g ha(-1)yr(-1) in MW and 69 g ha(-1)yr(-1) in CW. The mass balance method for calculation of weathering rate of As was used, and the results suggest that weathering could be the most important process in the As biogeochemistry of the areas with elevated As content in the bedrock. Simple model of weathering and erosion can be used successfully in estimating their role in As pollution on the scale of small watershed. The method is also useful for indicating the mass balance of As in soils that is controlled by both the natural and anthropogenic inputs and outputs of As.
天然水体和土壤中的砷会对健康构成严重危害。本文探讨了土壤中该元素的天然来源。通过监测两个小流域的输入和输出，评估了土壤中砷的风化质量平衡和风化速率。这些流域位于捷克共和国的塞利纳 - 莫尔斯科金矿区内。根据溪水和地下水的月加权平均值计算出砷的年化学风化通量。对大气降水、农用化学品输入和生物吸收进行了校正。根据钠和硅的质量平衡数据估算了流域内含砷黄铁矿岩石的机械和化学风化速率。据估计，莫尔斯科流域（MW）基岩总风化导致的砷输入量为1369 g·ha⁻¹·yr⁻¹，塞利纳流域（CW）为81 g·ha⁻¹·yr⁻¹。这些结果表明，流域内砷的年风化速率占土壤总砷输入量的95%以上。MW流域土壤中砷的积累速率估计为311 g·ha⁻¹·yr⁻¹，CW流域为69 g·ha⁻¹·yr⁻¹。采用质量平衡法计算了砷的风化速率，结果表明风化可能是基岩砷含量较高地区砷生物地球化学中最重要的过程。简单的风化和侵蚀模型可成功用于估算其在小流域尺度上对砷污染的作用。该方法也有助于指示受砷的自然和人为输入与输出控制的土壤中砷的质量平衡。
