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1.
三峡工程与长江中游沿江产业带建设   总被引:3,自引:0,他引:3  
讨论了长江中游沿江产业带发展条件、限制因素和未来发展,指出三峡工程的建设将对长江中游产业的布局和经济发展带来深刻的变化;防洪作用促进中游两岸大型工业项目的兴建,调整现有沿江城镇的布局,使之结构趋于合理化;电力供应经解能源的紧张状态,改善航运条件,发挥长江黄金水道的综合效益。当然,由于坝下河道冲刷,对现有的码头带来一定的影响,由于冬季水位抬升引起两岸低湖田地下水位上升,加剧两岸土壤潜育化和沼泽化。  相似文献   
2.
Ligustrum lucidum Ait. f. tricolor (Rehd.) Rehd. in relation to atmospheric pollutants in Córdoba city, Argentina. The study area receives regional pollutants and was categorized taking into account traffic level, industrial density, type of industry, location of the sample point in relation to the street corner, treeless condition, and topographic level. Dried weight/fresh weight ratio (DW/FW) and specific leaf area (SLA) were calculated, and concentrations of chlorophylls, carotenoids, total sulfur, soluble proteins, malondialdehyde (MDA), and hydroperoxy conjugated dienes (HPCD) were determined in leaf samples. Sulfur content correlates positively with traffic density and SLA correlates negatively with some combinations of the categorical variables; MDA correlates positively with topographic level and total protein concentration correlates negatively with treeless condition. On the basis of our results, traffic, location of trees, type of industry, situation of a tree with respect to others, and topographic level are the environmental variables to bear in mind when selecting analogous sampling points in a passive monitoring program. An approximation to predict tree injury may be obtained by measuring DW/FW ratio, proteins, pigments, HPCD, and MDA as they are responsible for the major variability of data.  相似文献   
3.
Background, Aims and Scope Sediments of the Spittelwasser creek are highly polluted with organic compounds and heavy metals due to the discharge of untreated waste waters from the industrial region of Bitterfeld-Wolfen, Germany over the course of more than one century. However, relatively few data have been published about the chloroorganic contamination of the sediment. This paper reports on the content of different (chloro)organic compounds with special emphasis on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), and chlorobenzenes. Existing concepts for the remediation of Spittelwasser sediment include the investigation of natural attenuation processes, which largely depend on the presence of an intact microbial food web. In order to gain more insight in terms of biological activity, we analyzed the capacity of sediment microflora to degrade organic matter by measuring the activities of extracellular hydrolytic enzymes involved in the biogeochemical cycling of carbon, nitrogen, phosphorus and sulfur. Furthermore, the detection of physiologically active bacteria in the sediment, particularly of those known for their capability to reductively dehalogenate organochlorine compounds, illustrates the potential for intrinsic bioremediation processes. Methods PCDD/F and chlorobenzenes were analyzed by gas chromatography(GC)/mass spectrometry and GC/flame ionization detection, respectively. The activities of hydrolytic enzymes were determined from freshly sampled sediment layers using 4-methylumbelliferyl (MUF) or 7-amino-4-methylcoumarin-conjugated model compounds and kinetic fluorescence measurements. Physiologically active bacteria from different sediment layers were microscopically visualized by fluorescence in situ hybridization (FISH). Specific bacteria were identified by 16S rRNA gene amplification and sequencing. Results and Discussion The PCDD/F congener profile was dominated by dibenzofurans. In addition, the presence of specific tetra and pentachlorinated dibenzofurans supported the assumption that extensive magnesium production was one possible source for the high contamination. A range of other chloroorganic compounds, including several isomers of chlorobenzenes, hexachlorocyclohexane and 1,1,1-trichloro-2,2-bis (p-chloro-phenyl)ethane (DDT), was present in the sediment. Activities of extracellular hydrolytic enzymes showed a strong decrease in those sediment layers that were characterized by high contents of absorbable organic halogen (AOX), indicating disturbed organic matter decay. Interestingly, an abnormal increase of cellulolytic enzyme activities below the organochlorine-rich layers was observed, possibly caused by residual cellulose from discharges of sulfite pulping wastes. FISH revealed physiologically active bacteria in most sediment layers from the surface down to the depth of about 60 cm, including members of Desulfitobacterium (D.) and Sulfurospirillum. The presence of D. dehalogenans was confirmed by its partial 16S rRNA gene sequence. Conclusions Results of chemical sediment analyses demonstrated high loads of organochlorine compounds, particularly of PCDD/F. Several years after stopping the waste water discharge to Spittelwasser creek, this sediment remains a main source for pollution of the downstream river system by way of the ongoing mobilization of sediment during high floods. As indicated by our enzyme activity measurements, the decomposition potential for organic matter is low in organochlorine-rich sediment layers. In contrast, the comparably higher enzyme activities in less organochlorine-polluted sediment layers as well as the presence of physiologically active bacteria suggest a considerable potential for natural attenuation. Recommendations and Perspectives From our data we strongly recommend to explore the degradative capacity of sediment microorganisms and the limits for in situ activity towards specific sediment pollutants in more detail. This will give a sound basis for the integration of bioremediation approaches into general concepts to reduce the risk that permanently radiates from this highly contaminated sediment. Submission Editor: Dr. Henner Hollert (Henner.Hollert@urz.uniheidelberg.de)  相似文献   
4.
岩溶地下河污染物运移模型对比研究   总被引:4,自引:0,他引:4  
两区模型(TRM)和暂时存储模型(TSM)为两种常用的岩溶地下河(管道)污染物运移模型,为了更好表征岩溶地下河污染物运移过程,开展模型对比研究.采用两种模型拟合室内管道示踪实验穿透曲线,从概念模型框架、模型优缺点、参数校正过程和物理意义、参数敏感性等方面对比分析两种模型的异同.结果表明,OTIS软件提供TSM的数值解,而CXTFIT软件提供TRM的解析解,但两者均能通过下游不同位置的穿透曲线分段表征地下河不同阶段的污染物运移过程.两种模型的物理意义相近,均可近似描述岩溶地下河中溶质的暂时性存储现象,较好地拟合溶质运移曲线.采用TSM可校正得到暂时存储区的横截面积,但采用TRM只能获得非流动区所占的比例.两种模型中弥散系数和传质/交换系数的敏感度较低,并且弥散系数的变化对穿透曲线拖尾无显著影响.研究结果为岩溶地下河污染物运移模型的选取与应用提供了依据.  相似文献   
5.
以北部湾独流入海河流南流江流域为研究对象,基于研究区2000年和2015年遥感数据解译的土地利用数据以及社会经济等数据,采用CLUE-S模型对未来2030年生态保护情景、自然增长情景以及粮食安全情景的土地利用格局进行了模拟预测,在此基础上采用InVEST模型对流域过去和未来不同情景的生物多样性进行了评估,探讨了流域生物多样性的生境质量和生境退化程度.结果表明:2000~2015年南流江流域建设用地、园地、水域和未利用地呈现出增加趋势,其中建设用地的增幅最大,而耕地和林地减幅最大.流域土地系统中共存在着34种土地网络转移流关系,上游存在24种,中游20种,下游28种,耕地与建设用地、耕地与林地以及林地与园地之间的转换占到流域总土地利用变化的70.74%.CLUE-S模型模拟未来土地利用的Kappa系数达到0.86,表明模型模拟未来情景的土地利用精度满足要求.2000年、2015年、2030年生态保护情景、2030年自然增长情景以及2030年粮食安全情景流域生境质量总得分和平均得分分别为866630,900357,921055,876231,865370和0.7457,0.7747,0.7925,0.7539,0.7466.2030年3种情景的中上游和下游地区生物多样性都呈现出不同程度的改善趋势,而中游地区则表现出退化趋势.  相似文献   
6.
Air pollution causes deleterious effects on human health with aerosols being among the most polluting agents.The objective of this work is the characterization of the PM_(2.5) and PM_(10) aerosol mass in the atmosphere.The methods of analysis include WD-XRF and EDS.Data were correlated with meteorological information and air mass trajectories(model HYSPLIT)by multivariate analysis.A morphological structural analysis was also carried out to identify the probable sources of atmospheric aerosols in the city of Sao Jose do Rio Preto,Brazil.The mean mass concentration values obtained were 24.54 μg/m~3 for PM_(10),above the WHO annual standard value of 20 μg/m~3 and 10.88 μg/m~3 for PM_(2.5) whose WHO recommended limit is10 μg/m~3.WD-XRF analysis of the samples revealed Si and Al as major components of the coarse fraction.In the fine fraction,the major elements were Al and S.The SEM-FEG characterization allowed identifying the morphology of the particles in agglomerates,ellipsoids and filaments in the PM_(10),besides spherical in the PM_(2.5).The analysis by EDS corroborated WD-XRF results,identifying the crustal elements,aluminosilicates and elements of anthropogenic origin in the coarse fraction.For the fine fraction crustal elements were also identified;aluminosilicates,black carbon and spherical particles(C and O) originating from combustion processes were predominant.The use of multivariate analysis to correlate air mass trajectories with the results of the morpho-structural characterization of the particulate matter allowed confirmation of the complex composition of the particles resulting from the combination of both local and long-distance sources.  相似文献   
7.
洪泽湖不同入湖河流沉积物磷形态特征及生物有效性   总被引:1,自引:0,他引:1  
为揭示洪泽湖入湖河流沉积物磷形态空间差异性及影响因素,分析了洪泽湖自西北向西南7条入湖河流65个表层沉积物中不同磷(P)形态,并探讨了磷形态空间赋存特征的影响因素及环境意义.研究表明:沉积物总磷(TP)含量为488.90mg/kg~960.22mg/kg,无机磷(Pi)为主要形态,相对含量为65.81%~76.16%.西部入湖流域沉积物有机磷(Po)以非活性有机磷(NLOP)为主,汴河最高,相对含量约占Po的50.41%,生物有效态无机磷(BAP)相对含量最高,占Pi的66.84%,污染程度最高;西南和西北入湖流域Po则以中活性有机磷(MLOP)为主,Pi以钙结合态无机磷(HCl-Pi)为主.西北入湖流域由于受当地地质背景的影响,HCl-Pi所占Pi相对含量最高(43.02%),从而减缓了磷的移动能力,污染程度最低.随着沉积物污染程度的增加,生物有效态Po含量增加,但所占Po相对含量降低;HCl-Pi含量增加,所占Pi相对含量降低,这一现象和我国其它典型地区沉积物磷形态空间分布类似.西部和西南入湖流域主要受水土流失、有机面源污染及藻类生长的影响,有机质环境较高,水交换能力弱,可被有机质降解的Po组分高于可被矿化的Po组分,大部分难降解Po组分易沉积,导致西部和西南入湖流域较高的BAP和NLOP含量,富营养化程度较高.沉积物OM是各形态磷之间相互转化的关键因素,和沉积物内源磷地球生物化学循环密切相关.洪泽湖入湖流域沉积物磷形态空间差异性主要由农业面源污染物的输入而导致内源磷负荷加剧.洪泽湖西部和西南入湖流域应重点控制农田水土流失及养殖业面源污染,建设滨岸修复带,遵循少量多次增施有机肥原则,减少农用地水土流失.健全农村养殖业废水废渣处理;划定科学养殖区;提倡铜围网箱,增加水体交换率.而对于洪泽湖西北入湖流域则应重点防止过度城镇化带来的水土流失及对生态功能保护区过高的污染负荷.  相似文献   
8.
天津市河流生态完整性评价   总被引:1,自引:1,他引:0       下载免费PDF全文
对河流生态健康状况进行评价,可为河流治理和生态修复提供依据.基于2018年8—9月天津市河流现场调查获取的物理、化学和生物群落指标(浮游动物、浮游植物、底栖动物、鱼类、水生大型植物、陆生植物)数据,构建包含物理完整性、化学完整性和生物完整性在内的河流IEI(index of ecological integrity,生态完整性指数)评价体系,对天津市河流生态健康状况进行评价.根据生物栖息地评分和水质状况确定参照点位,采用标准化方法筛选候选指标,应用层次分析法计算三部分指标权重,最终得出天津市河流生态健康评价结果.结果表明:①IEI评价结果显示,天津市河流生态健康状况等级为“健康”的样点占18.8%,“较好”的样点占28.1%,“一般”的样点占40.6%,“较差”的样点占6.3%,“差”的样点占6.3%,天津市河流生态健康状况整体处于“一般”水平.②相关性分析表明,ρ(NH4+-N)和ρ(CODMn)超标是造成天津市水质达不到功能区标准的主要原因,同时也是影响河流生态健康的主要因素.研究显示,IEI评价法能够较为敏感地响应研究区面临的环境压力,适用于评价研究区河流生态健康.   相似文献   
9.
Several theoretical, analytical, and institutional difficulties have impeded the development and application of the assessment of cumulative environmental impacts. Watershed development on coastal wetlands offers an ideal context for evaluating the land disturbance target approach to cumulative impact assessment. A model land use planning system involving a time series approach was developed for Elkhorn Slough in California. The approach included four major components: evaluation of erosion susceptibility, measurement of land disturbance, establishment of a land disturbance target, and a comparison of existing and target land disturbance values. Further research is needed to test the transferability of the approach in a wide range of coastal watersheds and to verify the applicability of the methods to other cumulative impact problems.  相似文献   
10.
根据奎屯市区城市废水的排放量大、排污口多、污染物浓度高以及排污下水管道污水处理设施的建成现状等特点,提出了以污水处理厂为治理中心,市区排污管道网络化的改造设想、存在问题及对策。  相似文献   
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