臭氧+曝气生物滤池深度处理工艺试验研究

针对某污水厂出水不达标的情况,本研究采用臭氧(O3)和曝气生物滤池(BAF)组合工艺对其进行深度处理.结果表明,当采用两级臭氧+曝气生物滤池工艺时,出水COD在31～46 mg/L,色度在13～29倍,均达到一级A排放标准.在最佳运行条件下,臭氧氧化使相对分子质量大于50 000的有机物含量减少10％,小于1 000的有机物含量增加14％.曝气生物滤池工艺使相对分子质量小于1 000的有机物含量降低了24％.     

Carbon sequestration and soil microbes in purple paddy soil as affected by long-term fertilization

Soil organic carbon (SOC) sequestration impacts on food security and climate change and may be affected by soil microbes in fertilized croplands. A 12-year field experiment under the rice–wheat system was used to evaluate the effect of the long-term fertilization on the SOC accumulation, culturable soil microbes, and their interaction in purple paddy soil. Results showed that varied fertilizations resulted in a significant increase of the SOC content and stock in the plow layer, as well as rise in populations of major soil microbes, including bacteria, actinomycetes, and fungi compared with no fertilization. Soil with combined application of chemical NPK fertilizer and organic amendment (pig manure or rice straw return) on average had the highest organic carbon content and stock, amounts of bacteria, actinomycetes, and fungi, which were 7.8%, 5.8%, 75.8%, 130.5%, and 16.2% higher than the NPK fertilization alone. Fertilization differentially altered populations of the functional anaerobic bacteria in paddy soil. With the combined application of chemical NPK fertilizer and organic amendment, soil displayed higher amounts of anaerobic cellulolytic bacteria, anaerobic fermentative bacteria, hydrogen-producing acetogen, methanogenic bacteria, denitrifying bacteria, and sulphate-reducing bacteria than that with the NPK fertilization alone or no fertilization. Populations of all three major soil microbes showed significantly positive correlations with the SOC content, indicating their interaction was of mutual promotion. Data suggest that the combined application of the NPK fertilizer with organic amendment especially by the rice straw return is recommended to sustain the soil biological fertility and mitigate the emission of the greenhouse gas by the SOC sequestration in purple paddy soil.     

Contamination and vertical distribution of As,Cd, Cr,Cu, Pb,Tl, and Zn in paddy soil irrigated with untreated leachate from tailings retention ponds

The contamination and vertical distribution of As, Cd, Cr, Cu, Pb, Tl, and Zn in paddy soil irrigated with untreated leachate from the tailings retention pond were investigated. As, Cr, Cu, and Zn were slightly contaminated in the surface soil and hence their vertical distribution was not obvious. However, Cd and Pb were highly contaminated in the surface soil, while their concentrations decreased with depth, being negatively correlated with pH and positively with total organic matter. Tl was considerably contaminated in the surface soil and a V-shaped vertical distribution was observed where the concentration increased to a maximum at about 30 cm depth and decreased thereafter. The findings revealed that the regular irrigation with untreated leachate from the tailings retention ponds could cause considerable contamination of Cd, Pb, and Tl, and thus tailings should be stringently treated before disposal to minimize their potential environmental impacts on the surroundings.     

应用概率物种敏感度分布法研究太湖重金属水生生物水质基准

目前广泛使用的水质基准推导方法—物种敏感度分布法存在曲线拟合模型不确定、曲线拟合效果不佳、种内差异欠考虑、基准值不准确等诸多问题,概率物种敏感度分布法可有效解决上述问题。应用概率物种敏感度分布法构建了太湖水体中5种重金属Ag、Pb、Cd、Hg和Zn的概率物种敏感度分布曲线,在此基础上得到了保护水生生物的急性水质基准分别为1.079μg·L~(-1)、637.973μg·L~(-1)、19.465μg·L~(-1)、8.729μg·L~(-1)和105.506μg·L~(-1),慢性水质基准分别为0.108μg·L~(-1)、63.797μg·L~(-1)、1.947μg·L~(-1)、2.340μg·L~(-1)和52.753μg·L~(-1);不同类群间生物对重金属的敏感度存在差异,不同重金属对同一类群生物的毒性也存在差异;通过与国内外已有的重金属水质基准值比较,发现水质基准具有明显的区域性,目前基于国外水质基准或我国整体水域特点来制定的太湖水质标准,往往造成对太湖水生生物欠保护或过保护的状况。     

Geographic range size and extinction risk assessment in nomadic species

Geographic range size is often conceptualized as a fixed attribute of a species and treated as such for the purposes of quantification of extinction risk; species occupying smaller geographic ranges are assumed to have a higher risk of extinction, all else being equal. However many species are mobile, and their movements range from relatively predictable to‐and‐fro migrations to complex irregular movements shown by nomadic species. These movements can lead to substantial temporary expansion and contraction of geographic ranges, potentially to levels which may pose an extinction risk. By linking occurrence data with environmental conditions at the time of observations of nomadic species, we modeled the dynamic distributions of 43 arid‐zone nomadic bird species across the Australian continent for each month over 11 years and calculated minimum range size and extent of fluctuation in geographic range size from these models. There was enormous variability in predicted spatial distribution over time; 10 species varied in estimated geographic range size by more than an order of magnitude, and 2 species varied by >2 orders of magnitude. During times of poor environmental conditions, several species not currently classified as globally threatened contracted their ranges to very small areas, despite their normally large geographic range size. This finding raises questions about the adequacy of conventional assessments of extinction risk based on static geographic range size (e.g., IUCN Red Listing). Climate change is predicted to affect the pattern of resource fluctuations across much of the southern hemisphere, where nomadism is the dominant form of animal movement, so it is critical we begin to understand the consequences of this for accurate threat assessment of nomadic species. Our approach provides a tool for discovering spatial dynamics in highly mobile species and can be used to unlock valuable information for improved extinction risk assessment and conservation planning.     

黔中黄壤坡耕地区域降水及其氮磷输入特征

黄壤坡耕地不仅具有“黏、酸、瘦”的特点,而且水土、养分流失普遍严重,引起一系列农业面源污染环境问题。以黔中黄壤坡耕地氮磷流失长期定位监测基地为平台,于2008─2012年连续5年进行观测,研究了降水及氮磷湿沉降浓度、总量及季节性变化等特征,探明了降雨带入的氮磷养分对黄壤坡耕地养分流失的贡献,为农业生产、农业面源污染防治对策提供科学依据。结果表明：2008─2012年间,年降雨次数变幅为46~109次,年均64次;年降雨量变幅为558.4~901.5 mm,年均695.7 mm;频次降雨量变幅为6.5~15.5 mm,平均10.9 mm。5年湿沉降TN、NO3--N、NH4+-N、TP浓度变幅,分别为1.57~3.31、0.17~0.79、0.10~0.94和0.06~0.48 mol·L-1,平均值分别为1.91、0.42、0.28、0.14 mol·L-1,均与降水量呈负相关,但未达到显著水平;5年湿沉降TN、NO3--N、NH4+-N、TP输入量变幅,分别为11.19~18.47、0.96~5.47、1.22~6.65和0.42~1.34 kg·hm-2·a-1,平均值分别为14.32、3.37、2.77、1.09 kg·hm-2·a-1,TN、TP输入量与降雨量呈正相关(相关系数分别为0.774、0.707,P值分别为0.0003、0.0015)。输入量季节性变化5─8月最为集中,5─7月TN输入量为6.95 kg·hm-2,占全年TN输入量的比例高达51.1%;6─8月TP输入量为0.49 kg·hm-2,占全年TP输入量的比例高达47.4%,即冬、春季较低,夏、秋季较高。湿沉降TN、TP输入量相当于当地施肥投入的氮、磷素总量的7.54%、1.14%,因此在农业生产中制定施肥方案时,可考虑坡耕地湿沉降养分的输入,尤其是氮养分的输入。     

紫色土丘陵坡地土壤微生物群落的季节变化

采用稀释平板法和Biolog-ECO微平板技术,以剌槐（Robinia pseudoacacia）天然次生林为研究对象,研究湖南省衡阳市紫色土丘陵坡地表层（0~10 cm）土壤微生物群落的季节变化特征。结果表明：1）夏季,土壤微生物总数,细菌数量、真菌数量和放线菌数量最高,分别为16.34×106、16.09×106、10.43×104和14.64×104 cfu·g-1干土,春季次之：11.61×106、11.45×106、5.00×104和10.65×104 cfu·g-1干土,秋季最低：5.87×106、5.78×106、4.67×104和4.08×104 cfu·g-1干土,春、夏和秋3季的差异达显著水平（P<0.05）;2）在培养168 h时,土壤微生物C源平均颜色变化率（Average well color development, AWCD）以夏季最高（1.20）,春季次之（0.88）,秋季最低（0.83）;3）土壤微生物功能多样性表现为夏季明显高于春、秋2季（P<0.05）,夏季的Patrick丰富度指数（R）（28）、Shannon-Wiener指数（H）（3.22）、Simpson指数（D）（0.96）和McIntosh指数（U）（8.20）显著高于春、秋2季（P<0.05）,而春、秋2季的R（23,24）、H（3.06,3.08）、D（0.95,0.95）和U（5.90,5.91）无显著差异（P>0.05）;4）氨基酸类、聚合物类和羧酸C源类是衡阳紫色土丘陵坡地土壤微生物偏好且利用率较高的C源类型;5）主成分分析表明,土壤微生物群落的C源利用可分为2类,一类在夏季,另一类在春、秋2季,其得分系数的分布范围分别为（2.59~6.00,2.43~5.09）和（-7.65~-1.90,-6.38~-3.43）。研究结果为科学评价湖南省衡阳市紫色土丘陵坡地土壤生境质量退化和恢复过程中微生物特征的变化提供了本底值参考。     

药品和个人护理用品在固体基底中的检测方法和分布现状

药品和个人护理用品(Pharmaceuticals and personal care products,PPCPs)在环境中广泛存在,威胁生态环境和人类健康,受到越来越多的关注.本文综述了固体基底中PPCPs的检测方法,总结了国内外污泥、土壤、沉积物等基底中PPCPs的污染现状,并对PPCPs的进一步研究进行了展望.结果表明,PPCPs的检测方法朝多样化和趋优化的方向发展.污泥样品中PPCPs种类多、浓度高(μg·kg-1—mg·kg-1),土壤和沉积物中虽然浓度不高,但是总量不可小觑.目前,固体基底中的PPCPs还需要更全面和更广泛的研究.     

长江重庆段表层水体中多环芳烃的分布及来源分析

采集了长江重庆段干流以及重要支流共7个断面的表层水样,采用液相色谱法分析15种优先控制的多环芳烃(PAHs).结果表明,水体中总PAHs浓度范围为6.44—109.39 ng·L-1,平均值为41.83 ng·L-1.在5个断面水体中检出苯并(a)芘,浓度为0.05—1.32 ng·L-1,低于我国地表水标准限值(2.8 ng·L-1).长江重庆段的PAHs浓度水平低于大部分国内其他河流,与国外一些河流的浓度水平相当.PAHs组成以中低环PAHs(3环和4环)为主,平均比例分别为55.7%和38.8%,高环PAHs(5环和6环)含量较低,分别占3.6%和1.9%.示踪PAHs比值法结果显示长江重庆段表层水体PAHs主要来源于石化产品的泄漏污染.     

江西钨矿周边土壤重金属生态风险评价:不同评价方法的比较

对江西省大余县某钨矿区周边的农田土壤进行调查分析,并采用不同的方法对土壤进行评价,结果表明,土壤As、Pb、Zn、Cu和Ni的含量范围分别为15.33—154.65 mg·kg-1、156.29—346.98 mg·kg-1、47.73—277.72 mg·kg-1、19.06—210.24 mg·kg-1和12.00—35.11 mg·kg-1,一些土壤样点的As、Pb、Zn和Cu含量已超过国家土壤环境质量二级标准.利用地累积指数法对土壤进行评价,结果表明土壤均受到As、Pb、Zn、Cu和Ni不同程度的污染;根据CPI(综合污染指数)评价标准,65.7%的土壤处于污染状态;利用TCLP法对土壤生态风险进行评价,结果显示所有土壤并未受到重金属的污染,以内梅罗综合污染指数法对土壤进行综合评价,结果表明该农田土壤重金属生态风险处于安全范围;以潜在生态危害指数法评价,发现Pb、As和Cu达到或超过中等生态风险的样点分别占37.14%、25.72%和2.86%,其他重金属污染风险均属轻微以下.不同评价方法得出的评价结果有差异,人们在评价重金属污染土壤时要根据评价的目的慎重选择合适的评价方法.