重庆秀山锰矿区土壤和植物锰污染调查与评价

文章通过现场取样对重庆秀山锰矿区锰污染状况进行了调查分析。应用地积累指数法对锰矿区矿渣堆以及农田土壤Mn污染进行评价,结果表明矿区土壤及部分农田土壤Mn污染极其严重。矿区植物对Mn的吸收表现为富集型植物(如垂序商陆Phytolacca americana Linn.)、根部囤积型植物(如紫花香薷Elsholfizia argyi Levl.)、规避型植物(如长波叶山蚂蝗Desmodium sequax Wall.),可根据其特点通过制定合理的植被恢复措施修复Mn污染土壤。采用单项污染指数法对矿区种植蔬菜的Mn污染水平进行评价,发现辣椒、萝卜的食用部分受Mn污染极严重,长期食用这些蔬菜对人体健康存在很大风险。     

五种挺水植物对矿山废水中锰的去除效能比较

以水葱、香蒲、芦苇、灯芯草和野茭白五种挺水植物为研究对象,通过实验室模拟人工湿地系统,研究在投加不同浓度梯度人工拟合酸性矿山废水条件下各植物对重金属锰的去除效能以及植物各部位对锰的富集能力。结果表明,野茭白和水葱的去除效能最显著,第七天的去除率达到90%和76%以上,香蒲的相对较差,为56%以上。五种植物各部位对重金属锰的富集能力均遵循同一规律:对于无茎植物,根富集浓度大于叶富集浓度;对于有茎植物,则为根大于茎大于叶。     

义乌市TSP中3种重金属元素的沉降

测定了义乌市TSP及其中的重金属Fe,Mn和Cu的浓度,通过扫描电镜和降雨冲洗效果分析了含有这3种重金属的颗粒物的粒径,计算了3种重金属的沉降通量。结果表明相对于世界其他城市,义乌市TSP中这3种重金属浓度偏高;绝大部分TSP的半径小于4.5μm;Fe和Mn的湿沉降量大于干沉降量,而Cu以干沉降为主。     

锰砂人工湿地对污染物的强化去除

锰砂由于其具有强氧化和吸附作用已被广泛应用于净水领域中,而在人工湿地中以锰砂为填料的相关研究较少.根据前期研究推测,在人工湿地的基质中加入锰砂,其能通过氧化吸附强化去除水中的污染物,而还原生成的Mn （Ⅱ）又能被土壤及根系锰氧化微生物氧化为Mn （Ⅲ/Ⅳ）,进而防止Mn （Ⅱ）在水中的释放.为验证该推测,本研究探讨了加入锰砂的芦苇人工湿地对污染物的强化去除能力及微生物学机制.通过比较加入和未加入锰砂（对照组）的人工湿地的运行效果,发现锰砂人工湿地对溶解性有机碳（DOC）、TN和冬季时期NH₄⁺-N的去除具有显著的提升作用.16S rRNA测序结果表明,锰砂基质能显著提升冬季芦苇根系微生物的丰富度和多样性,但对人工湿地整体的群落结构影响较小,这可能与锰砂湿地强化污染物去除能力有关.本研究为人工湿地工艺优化提供了一种新思路.     

原子吸收光度法测定树叶中的重金属

用浓硝酸与高氯酸消解树叶,Ｃｕ、Ｚｎ、Ｍｎ含量较高,可直接用火焰原子吸收法测定,含量较低的Ｐｄ、Ｃｄ,Ｃｒ则用石墨炉法测定。Ｐｂ及Ｃｄ含量甚微,受基体及共存元素干扰严重用标准加入法可消除干扰,结果令人满意。     

Nutrient status and pollution levels in five areas around a manganese mine in southern China

• The soil TP level was high or extremely high in all areas. • TN, OM and available Cu were insufficient in EA, TA and RA. • All areas reached the heavily polluted level and had high ecological risk levels. • Mn and Cd were the dominant pollutants. Nutrient status and pollution levels are the main factors affecting soil restoration. The nutrient status and pollution levels in five areas, an unexplored mine area (UA), an explored mine area (EA), a tailings area (TA), a reclamation area (RA) and an agricultural area (AA), around the Pingle manganese mine in Guangxi, China, were assessed in this study. The results showed that the average total phosphorus in these five areas ranged from 1.05 to 1.57 mg/kg, corresponding to grades of extremely high and high. The average total nitrogen values were 0.19, 0.69, 0.93, 1.24 and 1.67 mg/kg in EA, TA, RA, UA and AA, corresponding to grades of very low, low, medium-low, medium-high and medium-high, respectively. The average organic matter values were 12.78, 8.92, 22.77, 21.29 and 29.11 mg/kg in EA, TA, RA, UA and AA, which corresponded to grades of medium-low, low, medium-high, medium-high and medium-high, respectively. All these results indicated that the total phosphorus was sufficient in these areas, while the total nitrogen and organic matter were insufficient in EA, TA and RA. The available concentrations of Mn and Zn corresponded to the intermediate grade, while the values for Cu corresponded to the very low grade; these might be another factor restricting ecological reclamation. Contamination and ecological risk assessments based on the single contamination index, Nemerow multi-factor index and potential ecological risk index showed that the five tested areas around the Mn mine were considered heavily polluted and presented high ecological risk. Mn and Cd were the dominant pollutants.     

Mn的氧化价态对Mn/γ-Al2O3催化剂催化臭氧氧化气相低浓度甲苯的影响

采用共沉淀法,以Al₂O₃为载体制备Mn/γ-Al₂O₃和Mn-Ce/γ-Al₂O₃催化剂,并分别在N₂气氛和O₂气氛下焙烧。采用固定床连续流动反应器,研究所制备催化剂在室温条件下催化臭氧氧化甲苯的性能。通过XRD、XPS和FTIR等手段对催化剂的结构和组成进行表征。结果表明,Mn/γ-Al₂O₃催化剂具有良好的催化臭氧氧化甲苯和催化臭氧自身分解的性能,共沉淀法制备催化剂的最佳Mn负载量为20%。O₂气氛焙烧和Ce的加入,可以有效提高催化剂的活性和寿命。原因是O₂气氛焙烧和Ce的加入可以提高Mn的氧化价态。催化剂失活的主要原因是有机副产物在催化剂表面吸附堆积,失活催化剂在550℃、空气气氛下焙烧可恢复催化性能。     

电感耦合等离子体发射光谱法（ICP-AES)与火焰原子吸收法（AAS）测定水中铁、锰方法对比

采用电感耦合等离子体发射光谱法、火焰原子吸收法测定水中的铁、锰,优化了测定条件。结果表明,两种方法检Ⅲ限均较低,准确度高,精密度好,具有很强的可比性。     

Hydrochemistry of urban groundwater, Seoul, Korea: the impact of subway tunnels on groundwater quality

Hydrogeologic and hydrochemical data for subway tunnel seepage waters in Seoul (Republic of Korea) were examined to understand the effect of underground tunnels on the degradation of urban groundwater. A very large quantity of groundwater (up to 63 million m³ year^− 1) is discharged into subway tunnels with a total length of 287 km, resulting in a significant drop of the local groundwater table and the abandonment of groundwater wells. For the tunnel seepage water samples (n = 72) collected from 43 subway stations, at least one parameter among pathogenic microbes (total coliform, heterotrophic bacteria), dissolved Mn and Fe, NH₄⁺, NO₃⁻, turbidity, and color exceeded the Korean Drinking Water Standards. Locally, tunnel seepage water was enriched in dissolved Mn (avg. 0.70 mg L^− 1, max. 5.58 mg L^− 1), in addition to dissolved Fe, NH₄⁺, and pathogenic microbes, likely due to significant inflow of sewage water from broken or leaking sewer pipes.Geochemical modeling of redox reactions was conducted to simulate the characteristic hydrochemistry of subway tunnel seepage. The results show that variations in the reducing conditions occur in urban groundwater, dependent upon the amount of organic matter-rich municipal sewage contaminating the aquifer. The organic matter facilitates the reduction and dissolution of Mn- and Fe-bearing solids in aquifers and/or tunnel construction materials, resulting in the successive increase of dissolved Mn and Fe. The present study clearly demonstrates that locally significant deterioration of urban groundwater is caused by a series of interlinked hydrogeologic and hydrochemical changes induced by underground tunnels.     

伊犁河水质中CODCr和CODMn的相关性探讨

对伊犁河水质中CODCr与CODMn的相关性进行了讨论。