细菌是怎样帮助砷进入地下水源的？

21世纪90年代初,孟加拉国和印度孟加拉邦恒河流域有上百万口水井被砷污染,世界卫生组织在一份报告中将其称人类历史上最严重的集体中毒事件饮用水和灌溉水被砷污染的风险仍然是对全世界数百万生命的一种威胁,所以更好地了解砷释放进地下水的机制至关重要。对获得的新证据,将能够还原金属的细菌对有机碳的利用与从印度孟加拉邦一个被污染的蓄水层收集到的沉积物中砷的运动联系了起来。这一结果支持认为有机碳的引入(如通过灌溉)是增加恒河三角洲浅层地下水中砷流动性的一个因素的理论。该信息对于制订富含砷的地下水的治理战略可能会有价值.…     

铜、砷在水稻－土壤体系中的迁移及其对水稻影响的研究

通过盆栽试验和现场布点试验，研究了铜、砷在水稻－土壤体系中迁移的规律。结果表明，该体系对铜、砷污染具有相当大的缓解作用；土壤中水溶性可交换态铜、砷含量很低；铜、砷主要累积在水稻根部；土壤中铜、砷相互有拮抗作用，确定土壤铜、砷临界值应考虑多因素综合作用。     

含砷废水净化剂的制备及其应用研究

本文描述了用黄铁矿和还原铁粉或其代用品为原料制备含砷废水净化剂－硫化亚铁的新方法，获得了制备的最佳条件，探讨了其在含砷废水处理中的应用条件和影响因素，结果表明，该净化剂的生产及其处理含砷废水的工艺简单，经济高效，具有良好的开发应用前景。     

离子色谱测定三价砷和五价砷的研究

本文对抑制电导离子色谱法测定三价砷和五价砷进行考察,对测定的条件如标样的配制、淋洗液的选择、三价砷的氧化进行了讨论.并推荐了一种三价砷和五价砷的快速、分辨率好的方法,该方法可望对废水中的砷进行测定.     

土壤中二氧化锰对As（Ⅲ）的氧化及其意义

研究了土壤中δ-MnO_2对三价砷的氧化动力学及其在农业生产上的意义。结果表明,氧化动力学符合假一级速率方程,且土壤中氧化铁、氧化铝和碳酸钙与δ-MnO_2的包蔽能改变氧化反应速率;砷污染水稻田的排水搁田能显著减轻水稻砷害。     

铁改性赤泥吸附剂的制备及其除砷性能研究

以氧化铝生产废渣--赤泥为原料,采用铁盐改性处理制备了新型羟基铁包覆型赤泥除砷吸附剂.研究考察了吸附剂吸附砷效能、投加量、吸附时间和pH值对吸附除砷效果的影响;采用扫描电镜(SEM)、红外光谱(IR)、比表面积(BET)等仪器对吸附剂进行了表征,并探讨了吸附机制.结果表明,铁盐改性赤泥吸附剂对As(V)具有显著吸附效能,在pH为7,初始砷浓度为1 mg·L-1,铁盐改性赤泥吸附剂饱和吸附容量为50.6mg·g-1时,除砷率高达99.9%,吸附后出水砷含量可达到0.01 mg·L-1以下,吸附规律符合Langmuir等温方程式;溶液pH值显著影响砷去除效果,吸附机制主要为羟基铁的表面吸附机制;吸附后的吸附剂可通过NaOH溶液再生,脱附率达到92.1%.     

Arsenic and major cation hydrogeochemistry of the Central Victorian (Australia) surface waters

This paper reports on the major cations（Ca, Mg, Na and K） and arsenic（As） compositions of surface waters collected from major creeks, rivers and lakes in Central Victoria （Australia）. The surface waters were found to be neutral to alkaline （pH 6.7-9.4）, oxidised （average redox potential （Eh） about 130 mV） and showed variable concentrations of dissolved ions （EC, about 51-4386 /μS/cm）. The concen- trations of dissolved major cations in surface waters were found to be in the order of Na〉〉Mg〉Ca〉K and in soils the contents of metals followed an order of abundance as： Ca〉Mg〉〉K〉Na. While Na was the least abundant in soils, it registered the highest dissolved cation in surface waters. Of the four major cations, the average concentration ofNa（98.7 mg/L） was attributed to the weathering of feldspars and atmospheric input. Relatively highly dissolved concentrations of Na and Mg compared with the world average values of rivers reflected the weathering of rock and soil minerals within the catchments. The As soil level is naturally high（linked to lithology） as reflected by high background soil values and mining operations are also considered to be a contributory factor. Under relatively alkaline-oxidative conditions low mobility of dissolved As （average about 7.9 μg/L） was observed in most of the surface waters with a few higher values（〉15 μg/L） around a sewage disposal site and mine railings. Arsenic in soils is slowly released into water under alkaline and/or lower Eh conditions. The efficient sink of Fe, AI and Mn oxides acts as a barrier against the As release under near neutral-oxidising conditions. High As content （average about 28.3 mg/kg） in soils was found to be associated with Fe-hydroxides as revealed by XRD and SEM analysis. The dissolved As concentration was found to be below the recommended maximum levels for recreational water in all surface waters（lakes and rivers） in the study area. Catchment lithology exerted the fundamental control on surface water chemistry. Sites impacted by mining waste dumps showed a decline in water quality.     

京杭运河（杭州段三堡船闸至塘栖大桥）底质砷污染分析

京杭运河（杭州段三堡船闸至塘栖大桥）的砷污染，污染源为杭州硫酸厂。该厂污水进入余杭塘河经勤丰桥汇入运河干流，底质砷污染自勤丰桥向两侧离散呈指数律递减。