Uncertainty in watershed response predictions induced by spatial variability of precipitation

Negligence to consider the spatial variability of rainfall could result in serious errors in model outputs. The objective of this study was to examine the uncertainty of both runoff and pollutant transport predictions due to the input errors of rainfall. This study used synthetic data to represent the “true” rainfall pattern, instead of interpolated precipitation. It was conducted on a synthetic case area having a total area of 20 km² with ten subbasins. Each subbasin has one rainfall gauge with synthetic precipitation records. Six rainfall storms with varied spatial distribution were generated. The average rainfall was obtained from all of the ten gauges by the arithmetic average method. The input errors of rainfall were induced by the difference between the actual rainfall pattern and estimated average rainfall. The results show that spatial variability of rainfall can cause uncertainty in modeling outputs of hydrologic, which would be transport to pollutant export predictions, when uniformity of rainfall is assumed. Since rainfall is essential information for predicting watershed responses, it is important to consider the properties of rainfall, particularly spatial rainfall variability, in the application of hydrologic and water quality models.     

Development of a multi-criteria index ranking system for urban runoff best management practices (BMPs) selection

Low impact development best management practices (LID-BMPs) are considered to be cost-effective measures for mitigating the water quantity and quality impact of urban runoff. Currently, there are many types of LID-BMPs, and each type has its own intrinsic technical and/or economical characteristics and limitations for implementation. The selection of the most appropriate BMP type(s) for a specific installation site is therefore a very important planning step. In the present study, a multi-criteria selection index system (MCIS) for LID-BMP planning was developed. The selection indexes include 12 first-level indices and 26 second-level indices which reflect the specific installation site characteristics pertaining to site suitability, runoff control performance, and economics of implementation. A mechanism for ranking the BMPs was devised. First, each individual second-level index was assigned a numeric value that was based on site characteristics and information on LID-BMPs. The quantified indices were normalized and then integrated to obtain the score for each of the first-level index. The final evaluation scores of each LID-BMP were then calculated based on the scores for the first-level indices. Finally, the appropriate BMP types for a specific installation site were determined according to the rank of the final evaluation scores. In order to facilitate the application of the MCIS BMP ranking system, the computational process has been coded into a software program, BMPSELEC. A case study demonstrating the MCIS methodology, using an LID-BMP implementation planning at a college campus in Foshan, Guangdong Province, is presented.     

The impact of stormwater treatment areas and agricultural best management practices on water quality in the Everglades Protection Area

Half of the original Everglades system has been lost to drainage and development. What remains is included within the boundaries of the Everglades Protection Area (EPA), comprised of three Water Conservation Areas (WCAs) and Everglades National Park (Park). Inflows to the EPA contain elevated nutrient concentrations. Best management practices (BMPs) were implemented and six large wetlands called stormwater treatment areas (STAs) were constructed to improve water quality. We analyzed water quality in the WCAs and Park and performed an economic analysis of the STAs to remove nutrients from EPA inflows. In general, nutrient concentrations in all WCAs were higher during the pre-STA period than after the STAs became operational. In WCA2 and the Park, total phosphorus (TP) trends showed more negative slopes prior, as compared to after, the STAs became operational. These results suggest that BMPs lead to large initial decreases in nutrient export resulting in improved downstream water quality. A preliminary economic analysis shows that operation and management of the STAs are complicated and cost intensive. Comparing the cost of phosphorus (P) removal from water entering the EPA using BMPs and STAs may not currently be viable. BMPs prevent P from being applied to, or leaving from agricultural fields while STAs remove P from stormwater. We expect nutrient concentrations in water flowing into and out of the STAs to decline as both BMPs and STAs become more effective. We suggest an economic analysis of BMPs, STAs, and other potential approaches to determine the most cost-effective methods to reduce nutrient concentrations and related stressors affecting the Everglades.     

Hillslope terracing effects on the spatial variability of plant development as assessed by NDVI in vineyards of the Priorat region (NE Spain)

The availability of heavy machinery and the vineyard restructuring and conversion plans of the European Union Common Agricultural Policy (Commission Regulation EC no. 1227/2000 of 31 May 2000) have encouraged the restructuring of many vineyards on hillslopes of Mediterranean Europe, through the creation of terraces to favor the mechanization of agricultural work. Terrace construction requires cutting and filling operations that create soil spatial variability, which affects soil properties and plant development. In the present paper, we study the effects of hillslope terracing on the spatial variability of the normalized difference vegetation index (NDVI) in fields of the Priorat region (NE Spain) during 2004, 2005, and 2006. This index was computed from high-resolution remote sensing data (Quickbird-2). Detailed digital terrain models before and after terrace construction were used to assess the earth movements. The results indicate that terracing by heavy machinery induced high variability on the NDVI values over the years, showing significant differences as effect of the cut and fill operations.     

滆湖大型底栖动物群落分布和氮磷因子的相关分析

于2012年12月—2013年11月对滆湖水体进行了调查,分析了水体氮、磷及大型底栖动物的时空分布,初步探讨大型底栖动物群落结构与氮、磷环境因子的关系。结果表明,滆湖水体的ρ(TN)在冬春季较高,ρ(TP)四季的差异不大,在空间分布上,北部湖区的ρ(TN)、ρ(TP)均高于南部湖区;大型底栖动物出现频率最高的为霍甫水丝蚓和中国长足摇蚊,其丰度在时间上均表现为秋季夏季冬季春季,在空间上的规律性不明显;CCA分析表明滆湖大型底栖动物群落结构随季节变化规律显著,且氮含量是滆湖底栖动物群落结构的重要影响因子;对优势种的丰度与氮磷的相关性分析结果显示,滆湖底栖动物优势种与TN和NO_3~--N有显著的负相关关系。     

Influence of spatial resolution on assessing channelization impacts on fish and macroinvertebrate communities in a warmwater stream in the southeastern United States

The choice of spatial and temporal scale used in environmental assessments may influence the observed results. One method of assessing the impact of stream habitat alterations involves the comparison of response variables among treatment categories (i.e., impacted and unimpacted sites). The influence of spatial resolution on patterns of response variables among treatment categories in assessments of stream channelization and other types of habitat alterations has not been evaluated. We examined how patterns of 10 community response variables among channel types and our interpretations of channelization impacts on fish and macroinvertebrate communities differed among three spatial resolutions in a warmwater stream in Mississippi and Alabama. Four fish and three macroinvertebrate community response variables exhibited different patterns among channel types at different spatial resolutions. Our interpretations of the impacts of channelization on fish and macroinvertebrate communities differed among spatial resolutions. Channelization had a negative influence on fish communities either with or without evidence of potential community recovery in one channel type. Channelization impacts on macroinvertebrate communities ranged from a negative influence to no effect. Our results suggest that spatial resolution can influence the observed results and interpretations derived from assessments of stream habitat alterations.     

水磨河污染调查与综合治理研究

在对水磨河水文现状、污染源数量及分布、废水及污染物排放情况、河流水质、流域内排水管网等情况进行认真调查的基础上,对其存在的环境问题进行详细分析,并提出了具体的综合治理建议.     

谈监测仪器的质量控制标准与维护管理

监测仪器是从事环境监测工作必不可少的工具。我国环保事业对监测仪器的需求量越来越大,仪器也越来越复杂。本文就监测仪器的质量控制标准与管理问题进行了探讨,以求最大限度地发挥监测仪器设备的效能,使我国监测科研工作提高到一个新水平。     

Impact of intensive agricultural practices on drinking water quality in the EVROS Region (NE GREECE) by GIS analysis

Chemical fertilizers are used extensively in modern agriculture, in order to improve yield and productivity of agricultural products. However, nutrient leaching from agricultural soil into groundwater resources poses a major environmental and public health concern. The Evros region is one of the largest agricultural areas in Northern Greece, extending over 1.5 million acres of cultivated land. Many of its drinking water resources are of groundwater origin and lie within agricultural areas. In order to assess the impact of agricultural fertilizers on drinking water quality in this region, tap-water samples from 64 different locations were collected and analyzed for the presence of nitrates [Formula: see text], nitrites [Formula: see text], ammonium [Formula: see text], sulfate [Formula: see text] and phosphate [Formula: see text]. These chemicals were selected based on the information that ammonium nitrate, ammonium sulfate and inorganic phosphate were the primary fertilizers used in local crop production. [Formula: see text], [Formula: see text] and [Formula: see text] levels exceeding accepted values were recorded in 6.25, 4.70 and 9.38% of all sampling points, respectively. [Formula: see text] and [Formula: see text] concentrations, on the other hand, were inside the permitted range. The data generated were introduced into a geographic information system (GIS) program for computer analysis and projection maps representing afflicted areas were created. Our results indicate a profound geographic correlation in the surface distribution of primary contaminants in areas of intensified agricultural production. Thus, drinking water pollution in these areas can be attributed to excessive fertilizer use from agricultural sources.     

强化突发性环境污染事故应急监测管理

对建立健全突发性环境污染事故应急监测与处置技术支持系统、强化突发性环境污染事故应急监测管理方面进行的一系列研究和指导性工作进行了总结.     

The impact of disturbance and ensuing forestry practices on Collembola in monitored stands of windthrown forest in the Tatra National Park (Slovakia)

Soil Collembola communities were investigated in spruce forest stands of the High Tatra Mts that had been heavily damaged by a windstorm in November 2004 and subsequently by a wildfire in July 2005. The study focused on the impact of these disturbances and forestry practices on collembolan community distribution and structure 4 years after the disturbance. Four different treatments were selected for this study: intact forest stands (REF), non-extracted windthrown stands (NEX), clear-cut windthrown stands (EXT) and burnt windthrown stands (FIR). From a total of 7,820 individuals, 72 species were identified. The highest total abundance mean was recorded in FIR stands followed by NEX and EXT stands and, surprisingly, the lowest in REF stands. The highest total species richness was observed in REF stands, followed by NEX stands and FIR stands and the lowest in EXT stands. In REF and NEX stands, the most abundant species were Folsomia penicula and Tetracanthella fjellbergi, while in heavily damaged stands, the most abundant was Anurophorus laricis. The ordination method used demonstrated a significant influence of treatment on the abundance of Collembola. ANOVA used confirmed significant differences for all dominant species between treatments. The present study shows the negative impact of windthrow on Collembola communities as reflected in decreased species richness and abundance. However, disturbance by fire caused a considerable increase in collembolan abundance 3 years after the event. Moreover, we show that clearing of windthrown spruce forests after a windstorm is less favourable for communities of soil collembolans and slows down the recovery process.     

Pollution and Genetic Structure of North American Populations of the Common Dandelion (Taraxacum Officinale)

Assessing the genetic structure of natural populations differentially impacted by anthropogenic contaminants can be a useful tool for evaluating the population genetic consequences of exposure to pollution. In this study, measures of genetic diversity at variable-number-tandem-repeat loci in six dandelion populations (3 urban and 3 rural) showed patterns that may have been influenced by exposure to environmental contaminants. Mean genetic similarity among individuals within a population was significantly and positively correlated with increasing levels of airborne particulate matter ( 10 m, PM₁₀) and soil concentrations of four metals (Cd, Fe, Ni and Pb). In addition, mean genetic similarity was always significantly higher at the urban sites compared to rural sites. There was a significant negative correlation between the number of genotypes at a site and increasing amounts of PM₁₀, concentrations of five soil metals (Cd, Cu, Fe, Ni and Pb), leaf tissue levels of Fe and a significant positive correlation between the extent of clonality at a site and levels of PM₁₀ and soil concentrations of five metals (Cd, Cu, Fe, Ni and Pb). Although, this study does not directly establish a causal link between the specific contaminants detected at the study sites and differences in genetic diversity, our data are consistent with the hypothesis that pollution-induced selection has contributed in some fashion to the lower genetic diversity found at the urban sites.     

Effect of vehicle exhaust on the quantity of polycyclic aromatic hydrocarbons (PAHs) in soil

PAHs are formed during the incomplete combustion of organic substances containing carbon and hydrogen and are one of the first atmospheric pollutants identified as carcinogens. Most of the PAH environmental burden is found in the soil (95%). Soil samples collected from different roadsides were analyzed for seven polycyclic aromatic hydrocarbons (PAHs). The quantitative and qualitative analysis was carried out by UV Spectrophotometer. The individual PAH value ranged from 0.1 to 18.0 mg/kg. Phenenthrene and Pyrene were found to be the most abundant compounds. Vehicle emissions are the principal source of PAH in the Roadside soils. The highest concentration was found at site S2 (Hasthtnagri Roadside) which shows the highest traffic density.     

Effect of temperature on single and competitive adsorptions of Cu(II) and Zn(II) onto natural clays

This study conducted a combined adsorption-sequential extractionanalysis (CASA), by which five phases (i.e., exchangeable, carbonate, Mn-Oxide, organic, and Fe-Oxide phases) of adsorbed heavy metals were analyzed, to investigate temperature effects on single and competitive adsorptions of Zn(II) and Cu(II) ontonatural clays. In the case of single adsorption of Zn, the exchangeable phase adsorption decreased from 65 to 40%, but thecarbonate phase adsorption increased from 30 to 40%, with an increase in temperature from 15 to 55 °C. However, in itscompetitive adsorption with Cu, Zn was mostly present in the exchangeable phase (over 90%), and with an increase in temperature, the exchangeable phase adsorption decreased only 10%. In the case of Cu, over 50% among the total amount of adsorption was present in the carbonate phase in both cases ofsingle and competitive adsorptions. The carbonate phaseadsorption of Cu increased from 56 to 61% and from 60 to 66% in single and competitive adsorptions, respectively, with atemperature increase. These results show that in the case of Zn,the major mechanism of retention in natural clay soils might beexchangeable phase adsorption, especially in the case of competitive adsorption with Cu. However, in the case of Cu, the major mechanism might be carbonate phase adsorption, which is known to be a more immobile phase than exchangeable phase adsorption. It seems that the adsorption of Zn and Cu onto natural clays is an endothermic reaction, which represents thatthe adsorption equilibrium constants and capacities increase with a temperature increase, with the exception of exchangeablephase adsorption.     

Effect of heavy metals (Cu, Pb, and As) on the ultrastructure of Sargassum pallidum in Daya Bay, China

Concentrations of Cu, Pb, and As were determined in seawater, surface sediment, Sargassum pallidum collected from the Daya Bay, China. The influence of metal contamination on the marine alga was investigated at chemical and ultrastructural level. Mean concentrations of Cu (19.44 mg kg^?1) and Pb (33.99 mg kg^?1) were found to be high in sediment, whereas concentration of As (122.29 mg kg^?1) in S. pallidum was higher than that in water and sediment. The ultrastructure of S. pallidum cells was anomalous and aberrant. Energy-dispersive x-ray spectroscopic analysis revealed that the nanometal particles in the form of comparatively high-electron density substance diffused in the cell structures constituted by Cu, Pb, As, etc. There is a remarkable similarity or correspondence in the anomalous elements between the geochemistry and the botanic cell, and the heavy metals have potential hazardous effect on the ocean ecology system in Daya Bay.     

土壤中邻苯二甲酸酯类检测空白研究

通过气质联机法检测六种主要的邻苯二甲酸酯类(PAEs),对土壤中PAEs检测过程中各个环节进行了空白影响的测定.实验表明,邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二(2-乙基己基)酯(DEHP)三种物质对空白造成的影响较大.试剂污染是土壤中PAEs检测空白偏高的主要原因.而在不同的前处理方法中,水浴浓缩对空白的污染最小.     

The Effect of Regulation Caused by a Dam on the Distribution of the Functional Feeding Groups of the Benthos in the Sub Basin of the Grande River (San Luis, Argentina)

The construction of small dams in principal streams is one of the most common forms of regulation in the province of San Luis since they cause changes of physical, chemical and biological nature downstream. The purpose of this study was to analyze the short-term modifications in the food organization of benthic macroinvertebrates communities due to the construction of a dam in the Grande River (San Luis, Argentina). Two sampling sites were established: one before the dam and another one after it. The samplings were carried out with Surber sampler and during an annual cycle extending from April 1997 to March 1998, and two complementary samplings were done in low and high waters. The field sampling design was stratified randomly, and 3 pseudo replicas were taken in a transect seasonally and monthly and were then averaged. Macroinvertebrates were classified in different functional feeding groups. The comparisons at the level of physical and chemical variables and absolute abundances of the functional groups were carried out by means of the Wilcoxon test for two related samples. The collector-filterers, scrapers and predators increase whereas the collector-gatherers and shredders decreased. There were significant differences at the level of gatherers and shredders.     

Effect of seasonal variation in seawater dissolved mercury concentrations on mercury accumulation in the muscle of red sea bream (Pagrus major) held in Minamata Bay, Japan

Japanese stingfish (Sebastiscus marmoratus) and Bambooleaf wrasse (Pseudolabrus japonicas) are monitored annually for mercury pollution in Minamata Bay, Japan. The average total mercury concentration in the muscle of these two species in Minamata Bay was 0.36 mg?kg^?1 wet weight and 0.20 kg^?1 wet weigh, respectively, between 2008 and 2010. This is higher than levels elsewhere in Japan (0.125 mg?kg^?1 wet weight and 0.038 mg?kg^?1 wet weight, respectively). The FDA (2001) and EPA (2004) suggested that a proportion of mercury accumulated in fish is derived from seawater. We reared young red sea bream (Pagrus major) over a 2-year period in Minamata Bay and Nagashima (control) to evaluate the uptake of mercury from seawater and dietary sources. Fish were fed a synthesized diet that did not contain mercury. There was no difference in mercury accumulation in the muscle of red sea bream between Minamata Bay and Nagashima. Thus, our results suggest that the majority of mercury accumulated in fish muscle is not from seawater.     

Effect of sugar industry spentwash (diluted) on the characteristics of soil and sugarcane (<Emphasis Type="Italic">Saccharum officinarum</Emphasis> L.) growth in the subtropical environment of Sindh,Pakistan

Spentwash is a rich source of organic matter and essential plant nutrients in addition to excess salts. Sugar mills in Pakistan discharge about 3.48 million tons of spentwash annually, with no proper procedures for its disposal or utilization. To test the effect of diluted spentwash on soil and the soil’s ability to support plant growth, sugarcane (Saccharum officinarum L.) variety CPF-237 was planted. The experiment was conducted in a randomized complete block design involving factorial combination of four concentrations of each spentwash (0, 10, 20, and 30%) and mineral fertilizers (0, 1/3, 2/3, and the full recommended rate of NP). The 10% spentwash plus 2/3 mineral fertilizer treatment substituted 33% each of N and P and 100% of K, saving mineral fertilizer cost (Rs. 48600 ～ US$458) in addition to 29.54% increase in yield over full NP fertilizer. The same treatment also improved the soil organic matter (65%), N (20%), P (25%), and K (230%) over full NP treatment alone. An increase in the salt content of the soil was detected within the prescribed limits, with the exception of HCO₃.     

阳极溶出伏安法中电极体系的安装与使用

电极是完成阳极溶出伏安法分析测试的关键。本文就其电极的选择、处理、使用、维护等作了较详细的说明,以保证获得准确的测定数据