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401.
建立模拟降雨装置,研究降雨条件下功能性材料与聚合物对降水土壤渗透性与地表径流污染负荷的影响.研究证实,沸石与PAM不仅能够促进降雨土壤水的入渗、延缓并减少地表径流,而且使土壤渗液和地表径流水质TSS、TN、TP、COD污染物负荷降低.以3 kg/hm2 PAM、3 kg PAM与7.5 t/hm2沸石、6 kg/hm2 PAM 3种方式处理,径流COD负荷为对照的39.12%~69.76%、26.14%~46.63%和20.60%~28.09%;TN、TP与TSS负荷较对照分别减少44.36%~96.47%、66.63%~98.99%、93.71%~99.62%和50.46%~98.40%、83.30%~99.31%、94.91%~99.72%和31.06%~77.23%、46.82%~86.22%、83.54%~95.33%.聚合物与功能性材料改良土壤是一种削减地表降雨径流非点源污染的有效手段. 相似文献
402.
Dynamic factor analysis of groundwater quality trends in an agricultural area adjacent to Everglades National Park 总被引:3,自引:0,他引:3
The extensive eastern boundary of Everglades National Park (ENP) in south Florida (USA) is subject to one of the most expensive and ambitious environmental restoration projects in history. Understanding and predicting the water quality interactions between the shallow aquifer and surface water is a key component in meeting current environmental regulations and fine-tuning ENP wetland restoration while still maintaining flood protection for the adjacent developed areas. Dynamic factor analysis (DFA), a recent technique for the study of multivariate non-stationary time-series, was applied to study fluctuations in groundwater quality in the area. More than two years of hydrological and water quality time series (rainfall; water table depth; and soil, ground and surface water concentrations of N-NO3-, N-NH4+, P-PO4(3-), Total P, F-and Cl-) from a small agricultural watershed adjacent to the ENP were selected for the study. The unexplained variability required for determining the concentration of each chemical in the 16 wells was greatly reduced by including in the analysis some of the observed time series as explanatory variables (rainfall, water table depth, and soil and canal water chemical concentration). DFA results showed that groundwater concentration of three of the agrochemical species studied (N-NO3-, P-PO4(3-)and Total P) were affected by the same explanatory variables (water table depth, enriched topsoil, and occurrence of a leaching rainfall event, in order of decreasing relative importance). This indicates that leaching by rainfall is the main mechanism explaining concentration peaks in groundwater. In the case of N-NH4+, in addition to leaching, groundwater concentration is governed by lateral exchange with canals. F-and Cl- are mainly affected by periods of dilution by rainfall recharge, and by exchange with the canals. The unstructured nature of the common trends found suggests that these are related to the complex spatially and temporally varying land use patterns in the watershed. The results indicate that peak concentrations of agrochemicals in groundwater could be reduced by improving fertilization practices (by splitting and modifying timing of applications) and by operating the regional canal system to maintain the water table low, especially during the rainy periods. 相似文献
403.
Cifuentes JM Becker PH Sommer U Pacheco P Schlatter R 《Environmental pollution (Barking, Essex : 1987)》2003,126(1):123-137
Seabird eggs were used as bioindicators of chemical contamination in Chile. Brown-hooded Gull (Larus maculipennis), Kelp Gull (Larus dominicanus), Trudeau's Tern (Sterna trudeaui), Neotropic Cormorant (Phalacrocorax brasilianus), and Pink-footed Shearwater (Puffinus creatopus) eggs were sampled at different breeding sites during the 1990s. Mercury and organochlorines (PCBs, DDT, HCB, HCH, and PCP) were quantified to reveal the interspecific differences, spatial and temporal trends in contamination levels. Trudeau's Tern displayed the highest levels of mercury (486 ng g(-1) wet weight). The highest sumDDT concentrations were measured in Brown-hooded Gulls (726 ng g(-1)). PCB levels were similar among the species (102-236 ng g(-1)), but the composition of the PCB mixture was different in Pink-footed Shearwaters. With the exception of the Brown-hooded Gull, all species studied presented similar and low levels of organochlorines (sumOHa). Residues of PCB and related compounds were not detected in any of the seabird eggs analyzed in Chile. Geographical variation was low, although levels of industrial chemicals were slightly higher in eggs from Concepción Bay, and agricultural chemicals in eggs from Valdivia. Also interannual variation was low, but some evidence was found of decreasing levels in gull eggs throughout the time of the study. The causes of the low levels and small variability in space and time of environmental chemicals in Chilean seabirds are discussed. We propose the use of seabirds in future monitoring of the development of chemical contamination in Chile. 相似文献
404.
Yu Li Zhiming Yu Xiuxian Song Qinglin Mu 《Environmental monitoring and assessment》2006,121(1-3):489-499
Suspended particulate matter (SPM), sediments and clams were collected at three sites in Jiaozhou Bay to assess the magnitude of trace metal pollution in the area. Metal concentrations in SPM (Cu: 40.11–203; Zn: 118–447; Pb: 50.1–132; Cd: 0.55–4.39; Cr: 147.6–288; Mn: 762−1670 μg/g), sediments (Cu: 17.64–34.26; Zn: 80.79–110; Pb: 24.57–49.59; Cd: 0.099–0.324; Cr: 41.6–88.1; Mn: 343−520μg/g) and bivalves (Cu: 6.41–19.76; Zn: 35.5–85.5; Pb: 0.31–1.01; Cd: 0.51–0.67; Mn: 27.45−67.6 μg/g) are comparable to those reported for other moderately polluted world environments. SPM showed a less clear pattern. Metal concentrations in sediments displayed a clear geographical trend with values increasing with proximity to major urban centers. The clams (on dry weight) showed a complex pattern due to the variability introduced by age-related factors. Cd showed an apparent reverse industrial trend with higher concentrations in clams collected at distant stations. Zn, Pb and Mn showed no clear geographical pattern, whereas Cu increased in the clams collected in the most industrialized area. In addition, the bioaccumulation factors (BAF) were calculated. The result indicated that the studied Ruditapes philippinarum in Jiaozhou Bay possessed different bioaccumulation capacities for Cd, Zn, Cu, Pb and Mn, and Cd, Zn had a relatively high assimilation of those metals from sediment particles. A significant relationship with clam age was observed for Zn (positive) and Cu (negative) suggesting different physiological requirements for both metals with age. Trace metal concentrations measured in the tissue of the investigated clam were in the range considered safe by the WHO for human use. 相似文献
405.
Vallejo B Muñoz R Izquierdo A Luque de Castro MD 《Journal of environmental monitoring : JEM》1999,1(6):563-568
A method aimed at decreasing the toxicity of heavy metals [namely, Zn(II) and Cr(III)] in real polluted residues by immobilisation has been developed. The residues were processed either with two cement-type stabilisers or lime. The cement-type stabilisers were Portland cement and Depocrete SM/2 at the self-generated pH (ca. 11) which afforded physical as well as chemical potential for the immobilisation of heavy metals. The other stabiliser, lime, reduced organic compounds, thus favouring the decrease of the chemical oxygen demand (COD) and endowing the residue with better mechanical properties for transport. After leaching the stabilised residues using the standard leaching test [Order 13/10/89, Boletín Oficial del Estado (BOE) 270 10/11/89], three ways for establishing the toxicity of the treated residues were used, namely: (1) the ecotoxicity test using Photobacterium phosphoreum (DIN 38 412); (2) determination of the concentration of heavy metals by atomic absorption spectrometry (AAS); (3) determination of the COD or oxygen required for complete chemical oxidation of a water sample. Portland cement (20%) blended with Depocrete SM/2 (3%) acted as an effective stabiliser for residues containing heavy metals as it increased the ecotoxicity index (EC50) by more than five times. Thus the heavy metal concentration in the leaching liquid was lowered to less than 0.1 mg l-1. The addition of 5% of lime afforded a residue easily transportable from the place of treatment to the landfill. The precision of the method was studied in terms of both repeatability and reproducibility. The values found with respect to EC50 and expressed as the relative standard deviation (RSD) were 1.6% and 5.1%, respectively. 相似文献
406.
我国城市污水处理厂的规模绝大多数在10万t/d以下(含10万t/d),由于10万t/d以下的城市污水处理的工艺繁多,且各有利弊,选择何种工艺对城市污水进行处理,是建设项目的业主、设计单位和主管政府部门较难解决但又必须解决的问题.本文从城市污水处理厂的处理工艺入手,根据国家的城市污水处理及污染防治技术政策,对10万t/d以下城市污水处理工艺进行排序和优选,并给出城市污水处理厂建设及运营的主要技术经济指标,供城市污水处理厂建设的相关方参考. 相似文献
407.
Influence of soil pH on the fractionation of Cr, Cu and Zn in solid phases from a landfill site 总被引:2,自引:0,他引:2
Muñoz-Meléndez G Korre A Parry SJ 《Environmental pollution (Barking, Essex : 1987)》2000,110(3):122-504
The spatial variability of soil pH for engineered Weathered Oxford Clay is described using 35 samples collected from the base of a new cell in an existing landfill. Soil pH variability influences the reactivity of Cr, Cu and Zn in the site. The reactivity of these metals as natural components was determined using a sequential extraction method. The total concentration of Cr, Cu and Zn and the mineralogical composition were also determined. The results showed that due to the presence of a layer rich in pyrite in the base, a natural acidification may occur which can produce a soil pH as low as 2.7. The spatial variability of soil pH in this area has been described with an anisotropical variogram model and the estimation of its values at unsampled locations was carried out using the ordinary kriging algorithm. From the spatial modelling of the soil pH, it was found that the metals in the soil solid phases follow a similar distribution. 相似文献
408.
物元分析在环境工程方案评标中的应用 总被引:2,自引:0,他引:2
根据物元分析理论,建立了环境工程方案评标的数学模型,并成功地应用于某废水治理工程的中标方案的优选工作中。 相似文献
409.
运用系统决策方法优选大气污染治理方案 总被引:2,自引:0,他引:2
本文运用层次分析和多目标决策技术来量化大气污染治理方案的综合效益,从而为最佳治理方案的选取提供了科学依据. 相似文献
410.