Effect of reclaimed water effluent on bacterial community structure in the Typha angustifolia L. rhizosphere soil of urbanized riverside wetland, China

In order to evaluate the impact of reclaimed water on the ecology of bacterial communities in the Typha angustifolia L. rhizosphere soil,bacterial community structure was investigated using a combination of terminal restriction fragment length polymorphism and 16S rRNA gene clone library. The results revealed significant spatial variation of bacterial communities along the river from upstream and downstream. For example,a higher relative abundance of γ-Proteobacteria,Firmicutes,Chloroflexi and a lower proportion ofβ-Proteobacteria and ε-Proteobacteria was detected at the downstream site compared to the upstream site. Additionally,with an increase of the reclaimed water interference intensity,the rhizosphere bacterial community showed a decrease in taxon richness,evenness and diversity. The relative abundance of bacteria closely related to the resistant of heavy-metal was markedly increased,while the bacteria related for carbon/nitrogen/phosphorus/sulfur cycling wasn't strikingly changed. Besides that,the pathogenic bacteria markedly increased in the downstream rhizosphere soil since reclaimed water supplement,while the possible plant growth-promoting rhizobacteria obviously reduced in the downstream sediment.Together these data suggest cause and effect between reclaimed water input into the wetland,shift in bacterial communities through habitat change,and alteration of capacity for biogeochemical cycling of contaminants.     

利川市生活垃圾卫生填埋场场址的比选

选址是卫生填埋场建设和运行的关键。以利川市实际情况为前提和依据，筐选出7个预选场址，经实地踏勘和从填坦容量、运输距离、搬迁户数量等方面分析，遴选出其中3个；分别从工程学、环境学、经济学、社会与法律等方面中如交通状况、服务年限、占地面积、基岩类型、渗透系数、地下水位、覆盖土来源等13项具体条件上对3个备选场址进行了详细的分析比较，确定杨柳村大天井为最终选定场址。利川垃圾填埋场的选址工作也可以为同类型的城市或地区提供参考和借鉴。     

Partitioning of water soluble organic carbon in three sediment size fractions： Effect of the humic substances

Water soluble organic carbon (WSOC) in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect the partitioning coeffcient (k) of WSOC. Influences of NaOH extracted humic substances were particularly focused on. Sediments were sampled from two cross-sections of the middle Yellow River and sieved into three size fractions (< 63 μm, 63-100 μm, and 100--300 μm). The total concentration of WSOC in sediments (CWSOC) and k were estimated using multiple water-sediment ratio experiments. Results show that CWSOC ranges from 0.012 to 0.022 mg/g, while k ranges from 0.8 to 3.9 L/kg. Correlations between the spectrum characteristics of NaOH extracted humic substances and k were analyzed. Strong positive correlations are determined between k and the aromaticity indicators of NaOH extracted humic substances in different sediment size fractions. Comparing with finer fractions (< 63 μm), k is higher in larger size fractions (63--100 and 100--300 μm) related to higher aromaticity degree of NaOH extracted humic substances mostly. While negative relationship between k and the area ratio of fourier transform infrared spectroscopy (FT-IR) at 3400 and 1430 cm-1 implied that the lowest k was related to the highest concentration of the acidic humic groups in particles < 63 μm. WSOC in finer fractions (< 63 μm) is likely to enter into pore water, which may further accelerate the transportation of aquatic contaminants from sediment to water.     

江西定南县离子型稀土尾矿周边水体氮污染状况与分布特征

为探究"稀土王国"江西省赣南地区离子型稀土矿对周边水体环境的影响,以离子型稀土矿分布密集区定南县濂江月子河流域和龙迳河龙头流域为研究对象,综合分析研究区特征污染物ρ（NH₄+-N）空间分布特征,采用相关性分析和主成分分析揭示其主要污染来源及影响因素.结果表明:①离子型稀土矿停产整顿半年后,濂江月子河流域和龙迳河龙头流域ρ（NH₄+-N）超过1.00和2.00 mg/L的采样点分别达72%和68%;pH范围为2.95~7.66,平均值分别为6.23和5.53,水体总体上偏酸性;ρ（TN）、ρ（NH₄+-N）、EC与ρ（NO₃--N）变异系数较大,均介于0.80~1.50之间.②相关性分析结果显示,ρ（NH₄+-N）与ρ（TN）、EC均呈极显著正相关（P < 0.01）;ρ（NH₄+-N）与pH呈显著负相关（P < 0.05）.③流经稀土尾矿区的水体中ρ（NH₄+-N）随距离增加呈现明显的空间梯度分布特征,即距稀土矿区边界200 m处水体中ρ（NH₄+-N）最高（12.20~200.00 mg/L）,其次为1.15 km内（3.69~11.80 mg/L）及3.5 km以上水体（0.80~1.51 mg/L）,矿区周边未受到采矿活动影响的水体中ρ（NH₄+-N）最低（0.03~0.15 mg/L）.④PCA结果表明,2条河流的主要环境影响因子为ρ（TN）、ρ（NH₄+-N）、pH和EC,主要受到周边稀土矿山尾矿的强烈影响.研究显示,离子型稀土矿原位浸矿开采停产半年后,重点小流域水体中ρ（NH₄+-N）高概率超标的现状仍然存在,受稀土开采活动影响较大.建议进一步开展重点小流域NH₄+-N剩余"库容"精算和矿山周边地表水定期监测.      

城市生活垃圾焚烧飞灰熔融处理的进展

针对城市生活垃圾焚烧产生飞灰的处理以及由此引发的二次污染问题,阐述了飞灰的污染特性,讨论了各种飞灰处理技术的优缺点,分析了熔融处理技术在降低飞灰中重金属浸出毒性和彻底分解其中的二恶英所具有的优越性,为飞灰的无害化和资源化处理提供参考。     

武威绿洲农业水足迹变化及其驱动机制研究

农业活动通过改变绿洲赖以生存的水生态系统而影响着绿洲的稳定性。1950-2007年武威绿洲农业水足迹上涨了近7倍,而农业水足迹效率仅提高1.75倍;粮食作物水足迹比例过大,57 a间平均达74.32%,其中,2002年以前粮食作物水足迹比例呈下降趋势,但在2002年达到最低点58.63%之后开始出现反弹。人口增长和人民生活需求所驱动的以粮食生产为主体的农业规模扩大和农业开发强度加大,是农业水足迹增长的主要原因。适当压缩农业规模,加快农业内部结构调整,加大政府对农业节水灌溉工程的投入和农业节水技术的推广,是控制武威绿洲农业水足迹增长过快,维护绿洲生态系统稳定的有效方式。     

三里洞矸石废弃地人工植被群落构建初探

对矸石土样及植被材料进行采样测定,研究分析矸石的供肥能力、微量有毒元素含量、矿区植物中微量有毒元素的含量。研究结果表明:刺槐(Robinia pseudoacacia)对Cu、As元素吸收能力大于其它植物;荠菜(Capsella bursapastrois)对Zn元素的吸收能力较其他植物强;狗尾草(Setaria viridis)对Cr元素具有较强的吸收能力。依据矸石废弃地立地类型特点,矸石废弃地人工植被景观恢复过程中应选择臭椿(Ailanthus altissima)、刺槐(Robinia pseudoacacia)作为先锋树种,宜优先选用刺槐×沙棘×荠菜(Robinia pseudoacacia×Hippophae rhamnoides×Capsella)、刺槐×沙棘×狗尾草(Robinia pseudoacacia×Hippophae rhamnoides×Setariaviridis)、臭椿×沙棘×狗尾草(Ailanthusaltissima×Hippophae rhamnoides×Setaria viridis)群落与刺槐林、臭椿林配植模式。运用生态恢复的方法对矸石废弃地进行人工植被景观恢复与重建,恢复其受损伤的生态系统,这对矸石废弃地植被恢复有一定的理论指导意义。     

北京市城市生活垃圾处理现状与对策

介绍了北京市近几年来生活垃圾的产量及其变化趋势,对北京市近年来生活垃圾处理状况,垃圾处理场建设情况作了简要介绍。最后针对北京市生活垃圾处理面临的问题提出了建议,为北京市垃圾处理可持续发展提供理论依据。     

GIS在城市生活垃圾回收方案规划研究中的应用——以重庆市主城区为例

以重庆市主城区中的三个区为例,演示了GIS在城市生活垃圾回收方案规划研究中的应用:利用GIS的分类、计算和重叠功能,模拟各垃圾回收方案的运行,预测运行结果;利用GIS的可视化功能,将回收行为的空间分布以形象直观的地图形式表现出来,能为管理部门决策制定规划方案和管理措施提供有力的支持与依据。     

源分类家庭有机垃圾及其堆肥产品中的PAHs

将源分类家庭生物有机垃圾同秸秆按质量比10:1混合后进行堆肥处理,应用气相色谱-质谱联用仪(GC-MS)按照U.S.EPA 8270方法对生物有机垃圾及其堆肥产品中16种PAHs进行分析测试,比较生物有机垃圾及其堆肥产品中16种PAHs含量、分布及生物降解率,评估堆肥产品PAHs农田风险,综合论述影响家庭有机垃圾堆肥过程中PAHs降解因素,为生物有机垃圾堆肥农田利用提供依据.结果表明,源分类家庭生物有机垃圾及其堆肥产品中∑PAH16化合物含量分别为2.19和1.96mg/ks(以干重计,下同),其中萘、芴、菲、荧蒽含量相对较高,占总量的79.76%和81.76%,这4种有机物的苯环在2-3之间,属于易降解非致癌物质,在农田施用中易被降解;在生物垃圾堆肥过程中∑PAH16的生物降解率为25.88%,堆肥后产品PAHs含量符合农田使用标准.