EFFECTS OF ADJACENT AGRICULTURAL ACTIVITIES AND WATERSHED CHARACTERISTICS ON STREAM MACROINVERTEBRATE COMMUNITIES1

Benthic macroinvertebrate communities in streams adjacent to cornfields, streams where cows had unrestricted access, and reference locations without agriculture were compared to examine the effects of local land use and land use/land cover in the watershed. At each local site, macroinvertebrates and a variety of habitat parameters were measured upstream, adjacent, downstream, and farther downstream of the local land use. A geographic information system (GIS) was used to calculate drainage basin area, land use/land cover percentages in each basin, and the distance from sample sites to the stream source. Three‐way analysis of covariance (ANCOVA) tests with date, site type, and sampling location as main effects were used to explore differences in macroinvertebrate metrics using median substrate size, percent hay/pasture area, and stream depth as covariates. The covariates significantly improved model fit and showed that multiple contributing factors influence community composition. Local impacts were greatest at sites where cows had access, probably because of sedimentation and embeddedness in the substrate. Differences between the upstream and the adjacent and downstream locations were not as great as expected, perhaps because upstream recolonization was reduced by agricultural impacts or because of differences in the intensity or proximity of agriculture to riparian areas in the watershed. The results underscore the importance of both local and watershed factors in controlling stream community composition.     

基于时序NDVI数据的鄱阳湖流域常绿覆被季节性变化特征

选择位于红壤丘陵区的鄱阳湖流域作为研究对象，利用1 km×1 km分辨率的时序SPOT4 VEGETATION数据，对流域内典型土地覆被--常绿覆被的绿度值、峰值、谷值、年均NDVI(NDVI-I)和NDVI年内极差(NDVI MM)等特征值进行了提取。在此基础上，探讨了不同常绿覆被类型的NDVI指数年内季节变化规律。结果表明：时序NDVI指数基本上能够较好地刻画不同常绿覆被类型之间的差异性，植被指数NDVI特征值随覆被的类型及其生长状态有规律地变化，即NDVI年均值和最小值基本上按“常绿阔叶林＞常绿针阔叶混交林＞常绿针叶林＞常绿针叶-落叶混交林”的顺序变化；典型常绿阔叶林的NDVI指数年内变化曲线基本上没有大的起伏波动；常绿针叶林以及常绿针阔叶混交林占主导地位的常绿混交林NDVI指数年内变化比较和缓，但常在8月和11月有所波动；以常绿针叶林为主、但有较多落〖JP2〗叶林混杂其中的常绿混交林，其NDVI指数年内变化曲线基本上呈和缓的单峰型波动。     

基于Landsat影像的赤峰市生态环境状况评估

根据国家生态环境状况评价技术规范,基于1990,2000,2010和2015年四期的遥感和地理信息数据对赤峰市生态环境状况进行评估.结果表明：赤峰市的生态环境变化状况可以分为3个阶段,即退化期（1990~2000年）,恢复期（2000~2010年）和平稳期（2010~2015年）.4a生态环境状况指数（EI）分别为70.58、61.21、67.63和68.35,生态环境状况整体为良.赤峰市1990~2015年生态环境状况变化度（△EI）为-2.23,略微变差.从退化时期到恢复时期,△EI由负变正,表明赤峰市生态环境状况在2000~2010年期间有所改善;从恢复时期到平稳时期,｜△EI｜变小,表明2010~2015年间生态环境状况变好趋势减缓.城市化进程和水资源短缺是赤峰市生态环境状况转好趋势减缓的主要原因,因此需要进一步开展生态保护工程,并合理利用地下水资源.     

铁碳促进O3/H2O2体系深度处理准好氧矿化垃圾床渗滤液尾水中难降解有机物

构建了铁碳-O_3/H_2O_2体系降解矿化垃圾床渗滤液尾水中有机物,并考察了体系O_3、铁碳及H_2O_2投加量、初始pH值和反应时间对铁碳-O_3/H_2O_2体系处理渗滤液尾水的影响.结果表明,在铁碳投加量为3 g·L~(-1),O_3投加量为9.798 mg·min~(-1),H_2O_2投加量为2 mL·L~(-1),初始pH值为3的条件下,反应10 min后,渗滤液尾水的COD和UV_(245)分别从711.96 mg·L~(-1)、0.19下降至295.04 mg·L~(-1)、0.10.类比实验结果表明,铁碳-O_3/H_2O_2体系对渗滤液尾水有机物具有较高的去除率,且可生化性得到提高(BOD/COD从0.04增加至0.40).紫外-可见和三维荧光光谱显示,废水中难降解有机物转化为小分子有机化合物且腐殖质的分子缩合度降低.最后,采用SEM-EDS、XRD和XPS技术对铁碳-O_3/H_2O_2体系的反应机理进行了解析,发现铁碳-O_3/H_2O_2反应的机理为铁碳微电解反应、铁氧化物-H_2O_2非均相芬顿反应、O_3/H_2O_2、铁碳-O_3非均相的高级氧化作用和铁基胶体对有机物的吸附沉淀作用.研究表明,铁碳-O_3/H_2O_2体系是一种能够有效去除矿化垃圾床渗滤液尾水中难降解有机物的方法.     

COMBUSTIVE APPROACH FOR MEASURING TOTAL VOLATILE PHOSPHORUS CONTENT IN LANDFILL GAS

A technique was developed to measure the total gaseous phosphorus content in biogas. The amount of air needed for a neutral to oxidising flame was mixed with the biogas. The gas mixture was burnt in a closed quartz burner and the combustion gasses were bubbled through a nitric acid solution. The phosphate content in the bubbling liquid was determined with sector field ICP-MS. The technique was validated in the lab with phosphine. Afterwards the set-up was installed on a landfill. The total gaseous phosphorus content in the landfill gas, measured with the combustive technique, ranged from 1.65 to 4.44 g P/m³. At the same time the phosphine concentration in the landfill gas was determined gas chromatographically (GC). The phosphine (PH₃) content measured with GC ranged from 7.6 to 16.7 g PH₃-P/m³. Since the phosphine-P content (GC) was consistently higher than the total gaseous phosphorus content (burner/ICP-MS), the hypothesised presence of highly toxic gaseous phosphorus compounds other than phosphine could not be demonstrated.     

evaluation of a measurement method for forest vegetation in a large-scale ecological survey

We evaluate a field method for determining species richness andcanopy cover of vascular plants for the Forest Health MonitoringProgram (FHM), an ecological survey of U.S. forests. Measurementsare taken within 12 1-m² quadrats on 1/15 ha plots in FHM.Species richness and cover are determined for four height classes(strata) within each quadrat and aggregated by stratum over the entireplot. We estimated (1) the agreement between experienced trainers andinexperienced technicians who collected the data on this survey(accuracy) and (2) the agreement among the technicians (precision) forresults on species richness and cover from 3 test plots at 3 timeintervals. The methods appear to be highly precise, although somediscrepancies with the values obtained by the trainers were found.Trainers found significantly more species in the ground stratum (0–0.6 m) and measured significantly more cover in the uppermost stratum(>4.9 m). The proportion of variation due to measurement error andtemporal variability was less than 13% for species richness (all strata)and cover (all but one stratum). This indicates that the method issuitable for monitoring changes in species richness and canopy coverfor a large-scale synoptic monitoring project such as FHM.     

厌氧填埋垃圾降解阶段指标体系的建立

以厌氧填埋场中垃圾的降解过程为依托点,从渗滤液的水质特征和填埋气的组成两个方面筛选出判断指标,最后建立判断填埋垃圾降解阶段的指标体系.结果表明,ρ(BOD5)/ρ(COD)可以反映出渗滤液的可生化性,从而间接反映出填埋垃圾所处的降解阶段,是判断填埋垃圾降解阶段的重要定量指标.     

Removal of high concentrated ammonia nitrogen from landfill leachate by landfilled waste layer

The landfill of municipal solid waste(MSW) could be regarded as denitrification reactor and involved in ammonia nitrogen biological removal process. In this research, the process was applied to municipal solid waste collected in Shanghai, China, which was characterized by high food waste content. The NH4^ removal efficiency in the system of SBR nitrifying reactor followed by fresh and matured landfilled waste layer in series was studied. In the nitrifying reactor, above 90% of NH4^ in leachate was oxidized to NO2^- and NO3^- . Then high concentrated NO2^- and NO3^- were removed in the way of denitrification process in fresh landfilled waste layer. At the same time, degradation of fresh landfilled waste was accelerated. Up to the day 120, 136.5 gC/(kg dry waste) and 17.9 gN/(kg dry waste) were converted from waste layer. It accounted for 50.15 % and 86.89 % of the total carbon and nitrogen content of preliminary fresh waste, which was 4.42 times and 5.17 times higher than that of reference column respectively. After filtering through matured landfilled waste, BOD5 concentration in leachate dropped to below 100 mg/L, which would not affect following nitrification adversely. Because the matured landfilled waste acted as a well methanogenic reactor, 23% of carbon produced accumulatively from fresh landfilled waste degradation was converted into CH4.     

危险废物安全填埋场运行机制与收费标准

危险废物安全填埋场应探讨企业化经营模式。在单一处理模式、一体化经营模式和依托于大型企业模式中选择适宜的模式。填埋场建设资金筹集渠道中,由废物产生单位集资建设是可行办法。探讨了填埋场收费标准的计算方法,并给出计算公式。     

填埋处理场易发的各种环境问题及其对策

固体废弃物的填埋处理法在处理量和处理成本等方面比起其他方法有很强的优势，然而填埋处理场如果得不到正确的运转和管理，将成为新的污染源，易引发地表水和地面水污染、大气污染以及甲烷气体爆炸等环境问题。鉴于上述问题，文中针对上述事例介绍了排气设备、诱引气床等物理和化学方面的防止对策。