华南某金矿下游河道砷镉分布特征

对华南某金矿下游河道砷、镉分布特征进行了初步研究,在金矿下游河道沿程布设7个沉积物采样点及两个河道断面,分析了沉积物及断面土壤的砷、镉、铬、铜、镍、铅、锌含量。采用Tessier连续提取法分析沉积物中砷、镉等重金属的形态。砷含量高达10 208⁷0 621 mg/kg,镉含量达2.870 621 mg/kg,镉含量达2.8¹0.2 mg/kg。沉积物中砷、铅元素含量沿水流方向总体呈现减少趋势,铬、铜元素含量沿水流方向呈现增加趋势,镉元素含量沿水流方向先增加后减少。上游断面沉积物砷、镉等重金属浓度由河流中泓线向河岸方向增加,砷含量由16 617 mg/kg增加至53 197 mg/kg;下游断面则反之,砷含量由16 860 mg/kg减少至384mg/kg。沉积物中砷、镉等重金属元素主要以铁锰氧化态、有机结合态和残渣态的形式存在。     

Vulcan_(42)消解—原子荧光测定土壤和沉积物中的砷汞

建立了全自动样品处理系统Vulcan 42-原子荧光光度法测定土壤和沉积物中砷和汞的方法。准确称取0.2500 g样品,经Vulcan42全自动消解系统消解后,采用原子荧光光度计测定砷和汞的含量。运用该方法砷的检出限为0.11 mg/kg,回收率在96%¹01%之间,相对标准偏差(n=6)在1.3%101%之间,相对标准偏差(n=6)在1.3%⁴.5%之间;汞的检出限为0.003 mg/kg,回收率在90%4.5%之间;汞的检出限为0.003 mg/kg,回收率在90%¹08%之间,相对标准偏差(n=6)在0.5%108%之间,相对标准偏差(n=6)在0.5%⁴.7%之间。     

漓江沉积柱重金属垂向分布特征及污染评价

对桂林漓江3个采样点沉积柱状沉积物中主要重金属元素(Cd、Cr、Cu、Zn、Pb、As和Ni)的垂向分布进行了测定。结果表明:7种重金属元素具有相似的垂向变化特征;横向上表现为靠近市区的含量高远离,市区的含量低。地积累指数评价结果显示,远离市区的沉积柱7种金属污染程度较轻,仅有Cd和Ni属于无～中污染程度。临近市区的沉积柱形成污染的元素为Cd、Cu、Zn、Pb和As,主要集中在底层和次表层。     

神东矿区矿井水悬浮物处理技术

煤矿矿井水伴随煤炭开采过程产生,不同程度受煤粉、岩粉等悬浮物污染,有效降低悬浮物浓度是矿井水处理技术核心之一,本文以神东矿区含悬浮物矿井水为例对悬浮物处理技术进行说明,并进一步探讨工程应用中存在的常见问题。     

Fish mercury increase in Lago Manso, a new hydroelectric reservoir in tropical Brazil

It has been frequently demonstrated that mercury (Hg) concentrations in fish rise in newly constructed hydroelectric reservoirs in the Northern Hemisphere. In the present work, we studied whether similar effects take place also in a tropical upland reservoir during impoundment and discuss possible causes and implications. Total Hg concentrations in fish and several soil and water parameters were determined before and after flooding at Rio Manso hydroelectric power plant in western Brazil. The Hg concentrations in soil and sediment were within the background levels in the region (22-35 ng g(-1) dry weight). There was a strong positive correlation between Hg and carbon and sulphur in sediment. Predatory fish had total Hg concentrations ranging between 70 and 210 ng g(-1) f.w. 7 years before flooding and between 72 and 755 ng g(-1) f.w. during flooding, but increased to between 216 and 938 ng g(-1) f.w. in the piscivorous and carnivorous species Pseudoplatystoma fasciatum, cachara, and Salminus brasiliensis, dourado, 3 years after flooding. At the same time, concentrations of organic carbon in the water increased and oxygen concentrations decreased, indicating increased decomposition and anoxia as contributing to the increased Hg concentrations in fish. The present fish Hg concentrations in commonly consumed piscivorous species are a threat to the health of the population dependent on fishing in the dam and downstream river for sustenance. Mercury exposure can be reduced by following fish consumption recommendations until fish Hg concentrations decrease to a safe level.     

巢湖污染现状与水质恢复措施

巢湖是属于国家"三河三湖"重点水污染防治流域之一。近年来,湖体营养过程加剧,生态环境受到明显损害,制约了流域社会经济的可持续发展。巢湖湖区水中高锰酸钾、总氮、总磷含量分别为4.9、2.48、0.227mg/L,水质类别为劣ⅴ类(重度污染);表层沉积物中总氮、总磷含量平均值为1065、587 mg/kg。要实现流域水资源的可持续利用,必须加快水污染综合治理。文章分析了巢湖污染现状,结合实际情况提出了治理对策。     

玄武湖沉积物中磷的形态分布特征

利用分级提取法分析了玄武湖的沉积磷形态,在玄武湖沉积物中,铝结合态磷的含量较低,平均值为64 mg/kg,其余形态磷中,铁结合态磷为241 mg/kg,有机磷为335 mg/kg,钙结合态磷为394 mg/kg.在环境变化的条件下,铁结合态磷可以释放到间隙水和上层水体中,是湖泊产生富营养化的重要因素;铝结合态磷由于含量少,对湖泊富营养化影响很小;钙结合态磷相对稳定且很难被生物利用,对湖泊富营养化影响不大;有机磷对水体有机负荷影响较大,并影响水体富营养化程度.     

In situ removal of copper from sediments by a galvanic cell

This study dealt with in situ removal of copper from sediments through an electrokinetic (EK) process driven by a galvanic cell. Iron (Fe) and carbon (C) were placed separately and connected with a conductive wire. Polluted sediments were put between them and water was filled above the sediments. The galvanic cell was thus formed due to the different electrode potentials of Fe and C. The cell could remove the pollutants in the sediments by electromigration and/or electroosmosis. Results showed that a weak voltage less than 1V was formed by the galvanic cell. The voltage decreased with the increase of time. A slight increase of sediment pH from the anode (Fe) to the cathode (C) was observed. The presence of supernatant water inhibited the variation of sediment pH because H(+) and OH(-) could diffuse into the water. The removal of copper was affected by the sediment pH and the distribution of electrolyte in sediment and supernatant water. Lower pH led to higher removal efficiency. More electrolyte in the sediment and/or less electrolyte in the supernatant water favored the removal of copper. The major removal mechanism was proposed on the basis of the desorption of copper from sediment to pore solution and the subsequent electromigration of copper from the anode to the cathode. The diffusion of copper from sediment to supernatant water was negligible.     

Origin and transport of U and Ra in riverine,estuarine and marine sediments of the Krka River,Croatia

Spatial distribution of ²³⁸U and ²²⁶Ra activities in sediment columns along the Krka River and estuary, were studied using gamma spectrometry. Markedly different ²³⁸U and ²²⁶Ra activities between riverine, estuarine and marine sediments were observed. Distribution of these radionuclides, as well as their anthropogenic and natural origin, was evaluated by activity measurements, taking into account sedimentation rates estimated by ¹³⁷Cs distribution in sediment columns.