Greenhouse gas dynamics in an urbanized river system: influence of water quality and land use

Environmental Science and Pollution Research - Rivers act as a natural source of greenhouse gases (GHGs). However, anthropogenic activities can largely alter the chemical composition and microbial...     

Occurrence of perfluorooctanoate and perfluorooctanesulfonate in the Korean water system: implication to water intake exposure

Perfluorinated compounds (PFCs) measured in surface running waters indicated the existence of different emission sources in eight main city basins. The tap water reflected the contamination pattern and levels in their corresponding source water basins. The daily intakes through tap water consumption ranged from <0.01 to 0.73 ng kg⁻¹ d⁻¹ for perfluorooctanoate (PFOA) and <0.01 to 0.08 ng kg⁻¹ d⁻¹ for perfluorooctanesulfonate (PFOS). Tap water intake-derived exposure accounted for 8.6%-101% (for PFOA) and while <10% (for PFOS) of total daily exposure, which was estimated from Korean serum concentrations using a pharmacokinetic model. Our findings indicate that tap water intake could be an important contributor to PFOA exposure in Korean populations; accordingly, additional efforts are necessary to improve the removal efficiency of perfluorinated compounds (PFCs) in the water purification process. However, more fundamentally the aim would be to reduce the discharge of PFCs from potential sources within the basin.     

城市河流水质常规评价技术研究

运用综合水质标识指数法,对我国河流水质评价面临的关键技术问题,包括水质评价方法、水质评价项目,水质级别评价,水环境功能区达标评价、水质定性评价、河流及水系整体水质比较、水质随时间和空间变化等作了明确界定,并介绍了在上海河流水质评价中的应用。     

Importance of water level management for peatland outflow water quality in the face of climate change and drought

Environmental Science and Pollution Research - The impact of different climate scenarios, drought, and water level management on the outflow water quality of peatlands has been investigated. A...     

Impact of anthropogenic activities on urban stream water quality: a case study in Guangzhou,China

Anthropogenic activities are increasingly impacting the quality of urban surface water, particularly in regions undergoing intensive urbanization, such as Guangzhou of South China with a large urban stream network. To examine such impacts, we conducted field sampling on December 24, 2010, May 24, 2011, and August 28, 2011, representative of the low-, normal-, and high-flow periods, respectively. The first sampling was timed immediately after the closing of the 16th Asian Games (November 12–27, 2010) and the 10th Asian Para Games (December 12–19, 2010) held in Guangzhou. Assessments based on a pollution index method showed that the urban streams under investigation were extremely polluted, with direct discharge of untreated domestic sewage identified as the main pollution contributor. In addition, stream water quality around urban villages with high population densities was worse than that within business districts away from the urban villages. Pollution control measures implemented in preparation for the Asian Games were effective for urban streams within the business districts, but less effective for those adjacent to the urban villages. However, short-term efforts may not be able to achieve sustainable urban water quality improvements. In the case of Guangzhou, minimizing or even eliminating direct point-source inputs to the urban streams is perhaps the best option.     

Assessments of natural and anthropogenic influences on water chemistry in the upper Nakdong River,South Korea

Abstract

The purpose of this study is to evaluate what sources principally affect the chemical compositions in the catchment of the upper Nakdong River, South Korea where bedrock mostly consists of silicates as a natural factor. From October 7^th to 9^th, 2015, thirty-three water samples were collected, including samples from tributaries which run alongside mines. We analyzed the major anions, cations, trace elements and water isotopes of the samples and the analyzed data are divided into four groups by principle component analysis (PCA). We determined that most of the water samples are influenced by water-rock interactions when we consider the PCA results and the chemical weathering equation line. However, six samples have excess concentrations of sulfate and plot below the equation line. These samples were mostly from streams beside a zinc-cadmium smelter, which was also consistent with the PCA results. Samples near populated area could also be separated into a group via domestic pollution. Based on the PCA and chemical results, the chemical compositions of the river can be affected by two anthropogenic inputs: mine wastes and domestic contaminants.     

Impact of atmospheric deposition of anthropogenic and natural trace metals on Northwestern Mediterranean surface waters: a box model assessment

Under stratified oligotrophic conditions (May-November), the surface mixed layer of the Northwestern Mediterranean constitutes a homogeneous water volume of 10-30 m depth. In other respects, the mean residence time of Ligurian surface waters (0-200 m) is 102 days. It is therefore possible to quantify the extent to which atmospheric deposition of trace metals affects surface waters. On the basis of literature data on anthropogenic and natural trace metals, we demonstrate that the ratios between total seawater labile atmospheric deposition during 102 days (Δc) and dissolved TM concentrations in Ligurian surface waters (c) illustrate the impact of atmospheric deposition on surface seawater (Δc/c). High ratios indicate surface TM enrichments, while low ratios indicate surface TM depletion, due to the quasi-complete sorption and removal of TMs by plankton during spring bloom. The simple box model proposed here may be used for other marine regions where hydrodynamical and physico-chemical constraints are well defined.     

不同模糊评价方法在水环境质量评价中的应用比较

近年来,运用模糊评价方法对水质和水体营养化程度进行评价逐渐受到重视。目前,对模糊评价方法的研究多集中在实测数据标准化、权重的确定和模糊模式识别模型研究几个方面。以滇池历年营养物质数据为实测数据,通过对几种实测数据标准化方法、权重确定方法和模糊模式识别方法的组合应用,获得水环境质量模糊评价最优组合方法。结果表明,在评价方法中,实测数据标准化方法采用线性内插法,权重的确定采用超标倍数法,模糊模式识别模型采用广义海明距离和加权海明距离法,即采用超标倍数法的广义海明距离和加权海明距离法能够更真实反映水环境质量的实际情况。     

Coexistence of Cr and Ni in anthropogenic soils and their chemistry: implication to proper management and remediation

Environmental Science and Pollution Research - In anthropogenic soils, there have been relatively limited studies focusing on Cr and Ni contaminants because they exhibit less toxic effects to...     

Environmental risk assessment of airborne trichloroacetic acid--a contribution to the discussion on the significance of anthropogenic and natural sources

In environmental risk assessments the question has to be answered, whether risk reduction measures are necessary in order to protect the environment. If the combination of natural and anthropogenic sources of a chemical substance leads to an unacceptable risk, the man-made emissions have to be reduced. In this case the proportions of the anthropogenic and natural emissions have to be quantified. Difficulties and possible solutions are discussed in the scope of the OECD- and EU-risk assessments of trichloroacetic acid (TCA) and tetrachloroethylene.In the atmosphere, TCA is formed by photo-oxidative degradation of tetrachloroethylene (PER) and 1,1,1-trichloroethane. The available data on atmospheric chemistry indicate that tetrachloroethylene is the more important pre-cursor. With its high water solubility and low volatility, TCA is adsorbed onto aerosol particles and precipitated during rainfalls. Extended monitoring in rainwater confirmed the global distribution of airborne TCA. TCA reaches soils by dry and wet deposition. In addition formation of TCA from tetrachloroethylene in plants was observed. Consequently, high concentrations were detected in needles, leaves and in forest soil especially in mountain regions.The effect assessment revealed that plants exposed via soil are the most sensitive species compared to other terrestrial organisms. A PNECsoil of 2.4 microg/kg dw was derived from a long-term study with pine and spruce seedlings. When this PNEC is compared with the measured concentrations of TCA in soil, in certain regions a PEC/PNEC ratio >1 is obtained. This clearly indicates a risk to the terrestrial ecosystem, with the consequence that risk reduction measures are deemed necessary.To quantify the causes of the high levels of TCA in certain soils, and to investigate the geographical extent of the problem, intensive and widespread monitoring of soil, air and rainwater for TCA and tetrachloroethylene would be necessary to be able to perform a full mass balance study at an appropriate number of sites. In addition, measurements of the 14C content in TCA isolated from soil could clarify whether a significant proportion of the TCA occurs from natural sources. The possible formation of TCA in soil can also be tested by incubation of isotope enriched inorganic chloride with subsequent mass spectrometry of TCA.     

Modelling photochemical reactions in atmospheric water droplets: An assessment of the importance of surface processes

The relative importance of surface versus bulk processes was computed in spherical water drops, based on the model photochemical reaction yielding phenol from benzene via the ^•OH radicals, formed on UV photolysis of nitrate. The coadsorption of benzene and nitrate at the droplet surface was taken into account by means of the Wagner–Onsager–Samaras interaction model. The results indicate that the surface accumulation of benzene and the coadsorption of benzene and nitrate, which substantially increase the value of the concentration product of the model species at the droplet surface compared to the bulk, would cause surface processes to play a very significant role, in particular in small drops (1 μm radius, as can be found in haze and mist). Under such circumstances, over 15% of phenol photoformation would take place in just 0.1% of the drop volume. Similar results are expected in the case of benzene hydroxylation and nitration on nitrite photolysis.     

Occurrence of polycyclic aromatic hydrocarbons in surface sediments of a highly urbanized river system with special reference to energy consumption patterns

Sediment samples collected from downstream of the Dongjiang River, a highly urbanized river network within the Pearl River Delta of South China, were analyzed for 28 polycyclic aromatic hydrocarbons (PAHs). Total concentrations of 28 PAHs, 16 priority PAHs designated by the United States Environmental Protection Agency (USEPA) and the seven carcinogenic PAHs classified by the USEPA ranged from 480 to 4600, 100 to 3400 and 10 to 1700 ng/g dry weight, respectively. Principal component analysis-based stepwise multivariate linear regression showed that sediment PAHs were predominantly derived from coal combustion, refined fossil fuel combustion and oil spills, accounting for 37%, 32% and 23%, respectively, of the total loading. The levels of sediment PAHs remained steady from 2002 to 2008, during which fossil fuel consumption had doubled, probably reflecting efforts to control PAH emissions from fossil fuel combustion. Finally, use of natural gas and liquefied petroleum gas in automobiles should be encouraged to improve environmental quality.     

Integrated biological responses of zebrafish (Danio rerio) to analyze water quality in regions under anthropogenic influence

This study analyzed water quality in regions around Patos lagoon (Southern Brazil) that are under anthropogenic pressure. Water samples were collected from five different sites, including one used as a source for human consumption (COR) and others known to be influenced by human activities (IP). Danio rerio (Teleostei, Cyprinidae) organisms were exposed for 24 h to these water samples, plus a control group. It was observed that: (1) reactive oxygen species levels were lower in COR and IP than in the control group; (2) glutamate-cysteine ligase (catalytic subunit) expression was higher in COR than in other sites; (3) exposure to all water samples affected long-term memory (LTM) when compared to control group. Thus, some water samples possess the ability to modulate the antioxidant system and to induce a decline in cognitive functions, as measured by LTM. The obtained results indicate that a combination of variables of different organization level (molecular, biochemical and behavioral) can be employed to analyze water quality in impacted regions.     

Stationary and non-stationary autoregressive processes with external inputs for predicting trends in water quality

An autoregressive approach for the prediction of water quality trends in systems subject to varying meteorological conditions and short observation periods is discussed. Under these conditions, the dynamics of the system can be reliably forecast, provided their internal processes are understood and characterized independently of the external inputs. A methodology based on stationary and non-stationary autoregressive processes with external inputs (ARX) is proposed to assess and predict trends in hydrosystems which are at risk of contamination by organic and inorganic pollutants, such as pesticides or nutrients. The procedures are exemplified for the transport of atrazine and its main metabolite deethylatrazine in a small agricultural catchment in France. The approach is expected to be of particular value to assess current and future trends in water quality as part of the European Water Framework Directive and Groundwater Directives.     

River water quality assessment using environmentric techniques: case study of Jakara River Basin

Jakara River Basin has been extensively studied to assess the overall water quality and to identify the major variables responsible for water quality variations in the basin. A total of 27 sampling points were selected in the riverine network of the Upper Jakara River Basin. Water samples were collected in triplicate and analyzed for physicochemical variables. Pearson product-moment correlation analysis was conducted to evaluate the relationship of water quality parameters and revealed a significant relationship between salinity, conductivity with dissolved solids (DS) and 5-day biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), and nitrogen in form of ammonia (NH₄). Partial correlation analysis (r _p) results showed that there is a strong relationship between salinity and turbidity (r _p?=?0.930, p?=?0.001) and BOD₅ and COD (r _p?=?0.839, p?=?0.001) controlling for the linear effects of conductivity and NH₄, respectively. Principal component analysis and or factor analysis was used to investigate the origin of each water quality parameter in the Jakara Basin and identified three major factors explaining 68.11 % of the total variance in water quality. The major variations are related to anthropogenic activities (irrigation agricultural, construction activities, clearing of land, and domestic waste disposal) and natural processes (erosion of river bank and runoff). Discriminant analysis (DA) was applied on the dataset to maximize the similarities between group relative to within-group variance of the parameters. DA provided better results with great discriminatory ability using eight variables (DO, BOD₅, COD, SS, NH₄, conductivity, salinity, and DS) as the most statistically significantly responsible for surface water quality variation in the area. The present study, however, makes several noteworthy contributions to the existing knowledge on the spatial variations of surface water quality and is believed to serve as a baseline data for further studies. Future research should therefore concentrate on the investigation of temporal variations of water quality in the basin.     

Natural and anthropogenic factors affecting the groundwater quality in the Nandong karst underground river system in Yunan, China

The Nandong Underground River System (NURS) is located in a typical karst agriculture dominated area in the southeast Yunnan Province, China. Groundwater plays an important role for social and economical development in the area. However, with the rapid increase in population and expansion of farm land, groundwater quality has degraded. 42 groundwater samples collected from springs in the NURS showed great variation of chemical compositions across the study basin. With increased anthropogenic contamination in the area, the groundwater chemistry has changed from the typical Ca–HCO₃ or Ca (Mg)–HCO₃ type in karst groundwater to the Ca–Cl (+ NO₃) or Ca (Mg)–Cl (+ NO₃), and Ca–Cl (+ NO₃ + SO₄) or Ca (Mg)–Cl (+ NO₃ + SO₄) type, indicating increases in NO₃⁻, Cl⁻ and SO₄²⁻ concentrations that were caused most likely by human activities in the region. This study implemented the R-mode factor analysis to investigate the chemical characteristics of groundwater and to distinguish the natural and anthropogenic processes affecting groundwater quality in the system. The R-mode factor analysis together with geology and land uses revealed that: (a) contamination from human activities such as sewage effluents and agricultural fertilizers; (b) water–rock interaction in the limestone-dominated system; and (c) water–rock interaction in the dolomite-dominated system were the three major factors contributing to groundwater quality. Natural dissolution of carbonate rock (water–rock interaction) was the primary source of Ca²⁺ and HCO₃⁻ in groundwater, water–rock interaction in dolomite-dominated system resulted in higher Mg²⁺ in the groundwater, and human activities were likely others sources. Sewage effluents and fertilizers could be the main contributor of Cl⁻, NO₃⁻, SO₄²⁻, Na⁺ and K⁺ to the groundwater system in the area. This study suggested that both natural and anthropogenic processes contributed to chemical composition of groundwater in the NURS, human activities played the most important role, however.     

Biological water quality assessment of running waters based on macroinvertebrate communities: history and present status in Europe

This paper reviews the history and development of biological water quality assessment using macroinvertebrates in Europe, and critically evaluates each of the principal approaches used. As the biotic approach incorporates the most highly regarded features of the saprobic and diversity approaches, it has received the most attention in recent years. Most modern biotic index and score systems have evolved from the Trent Biotic Index, through a series of refinements and adaptations (i.e. the Extended Biotic Index, Chandler's Score, Indice Biotique) into the two modern systems. These methods are the Biological Monitoring Working Party System, used mainly in Great Britain, and the Belgian Biotic Index Method. The results of these techniques are now influencing policy decisions concerning surface water management in Europe, where macroinvertebrate community assessment are being used as a planning tool for managing water uses, for ambient monitoring, and for evaluating the effectiveness of pollution control measures. New research directions aimed at improving the performance of bioassessment techniques are being explored. These include defining reference communities based on stream typology which can then be used to set water quality objectives, and applying these methods to the assessment of toxic pollution.     

Groundwater quality assessment for different uses using various water quality indices in semi-arid region of central Tunisia

Environmental Science and Pollution Research - The Hajeb Layoun-Jelma basin, located in the central Tunisia, is the principal source of water supply for Sidi Bouzid and Sfax region. The...     

Multivariate statistics and entropy theory for irrigation water quality and entropy-weighted index development in a subtropical urban river,Bangladesh

Environmental Science and Pollution Research - Currently, a well-developed combination of irrigation water quality index (IWQIs) and entropy water quality index (EWQIs) for surface water appraisal...     

密云水库上游河流底栖动物群落结构与水质评价

于2013年5月至10月对密云水库上游河流中大型底栖无脊椎动物(以下简称底栖动物)进行了采样调查。结果表明,采集到的底栖动物隶属于4门10纲16目45科,其中以节肢动物种类最多,占总数的80%,且水生昆虫占总数的67%,出现频率最高的是节肢动物门蜉蝣目蜉蝣科的昆虫,出现频率达87%;从分布来看,白河流域采集到的底栖动物种类最多、密度最高,而潮河流域采集到的底栖动物生物量最大;以底栖动物为指示生物的水质评价结果显示,密云水库上游河流中50%采样点的水质为Ⅰ级(清洁),其余50%为Ⅱ级(轻微污染),水质整体较好,与现场生境调查和水质监测的结果相吻合。