Contribution of marine and continental aerosols to the content of major ions in the precipitation of the central Mediterranean

The region of the investigated receptor is situated in the southern part of the Adriatic Sea in the Mediterranean. The measuring station is located on the seashore, which, being considered as a border area, is representative for the qualitative and quantitative estimation of the influence of marine and continental aerosols on the content of major ions in precipitation. In the sampling period, precipitation in the region of the investigated receptor was more abundant during the summer and autumn than during the winter and spring. The most frequent precipitation heights were up to 20 mm, while high precipitation came exclusively from the continental region. The results of the measurements of ions readily soluble in water were used for the differentiation of marine from continental contributions of primary and secondary aerosols to their content in the precipitation. Using PCA, it was shown that main contribution of Cl(-), Na(+) and Mg(2+) came from primary marine aerosols, while the contribution from continental sources was dominant for the content of SO(4)(2-), NO(3)(-), NH(4)(+) and Ca(2+) in the precipitation. The continental origin of Ca(2+) was from a primary source, while SO(4)(2-), NO(3)(-) and NH(4)(+) were representatives of secondary aerosols produced by reactions between acid oxides and alkaline species in the atmosphere, but SO(4)(2-) and NO(3)(-) also exist in the precipitation as free acids. The origin of the trace elements Cd, Cu, Pb and Zn in the precipitation came from anthropogenic emission sources. The results obtained in this work are based on experimental data from 609 samples collected during the period 1995-2000.     

The effects of land use on fluvial sediment chemistry for the conterminous U.S. - results from the first cycle of the NAWQA Program: trace and major elements, phosphorus, carbon, and sulfur

In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S. The basins represented a variety of hydrologic settings, rock types (geology), land-use categories, and population densities. One aspect of the first cycle included bed sediment sampling; sites were chosen to represent baseline and important land-use categories (e.g., agriculture, urban) in each basin. In total, over 1200 bed sediment samples were collected. All samples were size-limited (< 63 µm) to facilitate spatial and/or temporal comparisons, and subsequently analyzed for a variety of chemical constituents including major (e.g., Fe, Al,) and trace elements (e.g., Cu, Zn, Cd), nutrients (e.g., P), and carbon. The analyses yielded total (≥ 95% of the concentrations present), rather than total-recoverable chemical data.Land-use percentages, upstream underlying geology, and population density were determined for each site and evaluated to asses their relative influence on sediment chemistry. Baseline concentrations for the entire U.S. also were generated from a subset of all the samples, and are based on material collected from low population (≤ 27 p km^− 2) density, low percent urban (≤ 5%), agricultural or undeveloped areas. The NAWQA baseline values are similar to those found in other national and global datasets. Further, it appears that upstream/underlying rock type has only a limited effect (mostly major elements) on sediment chemistry. The only land-use category that appears to substantially affect sediment chemistry is percent urban, and this result is mirrored by population density; in fact, the latter appears more consistent than the former.     

Hydrochemical characteristics and water quality assessment of surface water and groundwater in Songnen plain, Northeast China

Water quality is the critical factor that influence on human health and quantity and quality of grain production in semi-humid and semi-arid area. Songnen plain is one of the grain bases in China, as well as one of the three major distribution regions of soda saline-alkali soil in the world. To assess the water quality, surface water and groundwater were sampled and analyzed by fuzzy membership analysis and multivariate statistics. The surface water were gather into class I, IV and V, while groundwater were grouped as class I, II, III and V by fuzzy membership analysis. The water samples were grouped into four categories according to irrigation water quality assessment diagrams of USDA. Most water samples distributed in category C1-S1, C2-S2 and C3-S3. Three groups were generated from hierarchical cluster analysis. Four principal components were extracted from principal component analysis. The indicators to water quality assessment were Na, HCO₃, NO₃, Fe, Mn and EC from principal component analysis. We conclude that surface water and shallow groundwater are suitable for irrigation, the reservoir and deep groundwater in upstream are the resources for drinking. The water for drinking should remove of the naturally occurring ions of Fe and Mn. The control of sodium and salinity hazard is required for irrigation. The integrated management of surface water and groundwater for drinking and irrigation is to solve the water issues.     

Heavy metals in the surficial sediments of Fontana Lake, North Carolina

Concern about the possible contamination by heavy metals of Fontana Lake (reservoir) and potential sources of such materials led to a study of surficial sediments. Samples of sediment were collected in the main body of the lake and near the mouths of its major tributaries and analayzed for magnesium, iron, aluminum, manganese, zinc, copper and mercury. Although the drainage area of the reservoir is primarily forested and rural without major industrial developments, the results indicated that manganese, copper and zinc were present in concentrations similar to areas receiving industrial pollution. Chemical analyses of pyritic materials in the watershed (e.g. schists or Anakeesta formation) showed relatively high concentrations of many of the same metals present in Fontana sediments. It appears, therefore, that the metals in the lake sediments represent materials derived from geological sources, although airborne contributions of certain metals cannot be ruled out.     

Potential source contributions and risk assessment of PAHs in sediments from Taihu Lake, China: comparison of three receptor models

In this work, three receptor models (Principal Component Analysis-Multiple Linear Regression (PCA-MLR) model, Unmix model and Positive Matrix Factorization (PMF) model) were employed to investigate potential source apportionment of PAHs in sediments from Taihu Lake, China. A total of 15 priority PAHs in 29 sediments from Taihu Lake were measured, with ∑PAHs (sum of 15 PAHs) concentrations ranging from 209 to 1003 ng g⁻¹ dw. Source apportionment results derived from three different models were similar, indicating that the highest contribution to ∑PAHs was from vehicular emission (53.6-54.3%), followed by coal combustion (23.8-28.8%) and wood combustion (11.9-16.0%). The contribution of mixed wood and coal combustion source identified by PCA-MLR was 41.3%. For the first time the risk assessment for each identified source category was quantitatively calculated by combining the BaP equivalents (BaPE) values with estimated source contributions. The results showed that vehicular emission posed the highest toxic risk, with BaPE values of 26.9-31.5 ng g⁻¹ dw, and the BaPE values for coal combustion and wood combustion were 6.56-15.6 ng g⁻¹ dw and 2.94-6.11 ng g⁻¹ dw, respectively. The distributions of contribution and BaPE for each identified source category were studied as well, and showed similar trends among the sampling sites, for each source category.     

Trace element analysis in the serum and hair of Antarctic leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii

Leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii, occupy an upper trophic level within the Antarctic ecosystem and are useful indicator species in the Southern Ocean of trace element concentrations. Reference values for the concentration of 19 trace elements were determined in the serum and hair of leopard and Weddell seals sampled in Eastern Antarctica. These reference values can be used as 'baseline' levels for monitoring trace element concentrations in these species. Greater trace element concentrations were determined in hair compared to serum, indicating different time scales of trace element accumulation in these samples. For the majority of trace elements, except for Se in the leopard seal samples and Cr in the Weddell seal samples, significant regression relationships for trace element concentrations in hair and serum were not elucidated. Significant differences were determined in the concentrations of seven out of 15 elements with hair type, moult and new, in the leopard seal; concentrations in moult hair were determined to be greater than in new hair for all elements except Zn. Hair analysis was determined to be useful for monitoring exposure to trace elements and when collected off the ice from moulting seals, hair can be employed as a non-invasive sample for trace element analysis in leopard and Weddell seals.     

Trace element differentiation in ferruginous accumulation soil patterns under tropical rainforest of southern Cameroon,the role of climatic change

Regions under tropical rainforest cover, such as central Africa and Brazil are characterised by degradation and dismantling of old ferricrete structures. In southern Cameroon, these processes are relayed by present-day ferruginous accumulation soil facies, situated on the middle and the lower part of hill slopes. These facies become progressively harder towards the surface, containing from bottom to top, mainly kaolinite, kaolinite-goethite and Al-rich goethite-hematite, and are discontinuous to the relictic hematite-dominated ferricrete that exist in the upper part of the hill slope. These features were investigated in terms of geochemical differentiation of trace elements. It appears that, in contrast to the old ferricrete facies, the current ferruginous accumulations are enriched in transitional trace elements (V, Cr, Co, Y, Sc) and Pb, while alkali-earth elements are less differentiated. This recent chemical accumulation is controlled both by intense weathering of the granodiorite bedrock and by mobilisation of elements previously accumulated in the old ferricrete. The observed processes are clearly linked to the present-day humid climate with rising groundwater tables. They slowly replace the old ferricretes formed during Cretaceous time under more seasonal climatic conditions, representing an instructive case of continuos global change.     

Long-term water quality monitoring of the Sejnane reservoir in northeast Tunisia

The Sejnane reservoir in northeast Tunisia provides drinking and irrigation water. Long-term water quality monitoring data including precipitation, evaporation, temperature, pH, conductivity, dissolved oxygen, turbidity, total suspended solids, major anions and cations, fluoride, BOD₅, NO₃ ⁻, NO₂ ⁻, NH₄ ⁺, P _tot, fecal coliform bacteria, boron and heavy metals (Fe, Zn, Cu, Ni, Pb, Cr and Cd) are reported. The appropriateness for irrigation was estimated by the SAR and Na percentage and the water quality assessed using the Canadian Water Quality Index as good to excellent, which confirmed its suitability for drinking, aquatic life and irrigation purposes.      

Evaluation of distribution, mobility and binding behaviour of heavy metals in surficial sediments of Louro River (Galicia, Spain) using chemometric analysis: a case study

Contents of total and extractable heavy metals, carbonates, MnO and Fe₂O₃, organic matter, and matrix components such as SiO₂, Al₂O₃, CaO, Na₂O, MgO, TiO₂, K₂O and P₂O₅ are used along with principal component analysis (PCA) for studying distribution, mobility and binding behaviour of Cd, Cr, Cu, Ni and Pb in the Louro River (Galicia, Spain). Eleven surficial sediment samples were taken along the beds of the river course. Total metal concentrations were obtained after microwave-assisted digestion whilst extractable metal contents were obtained following a three-stage sequential extraction scheme (i.e. soluble, reducible and oxidisable fractions). Loading plots of heavy metals bound to carbonates, Fe–Mn oxides, organic matter and aluminosilicates allowed determination of binding behaviour. Correlations found indicate that Pb and Cu are mainly discharged from urban wastes, whereas Cr and Ni are from electroplating and galvanizing industries. The occurrence of diffuse pollution sources along the river can account for the binding behaviour of Cd. Metal mobility decreased in the order: Cd>Pb>Cu>Ni>Cr. Despite total contents indicating moderate-to-high heavy metal pollution in this river, metals are mostly distributed in the residual fraction, hence showing a low risk of mobility.     

Influence of acid volatile sulfides and simultaneously extracted metals on the bioavailability and toxicity of a mixture of sediment-associated Cd, Ni, and Zn to polychaetes Neanthes arenaceodentata

Laboratory microcosm experiments were conducted to investigate the influence of acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) in sediments on the bioavailability and toxicity of Cd, Ni, and Zn in sediments to polychaete worms Neanthes arenaceodentata. Cohorts of juvenile N. arenaceodentata were exposed to sediments spiked with metal mixtures containing Cd, Ni, and Zn (0.5-15 micromol x g(-1) of total SEM) with Low- (approximately 1 micromol x g(-1)), Medium- (approximately 5 micromol x g(-1)), and High-AVS concentrations (approximately 10 micromol x g(-1)) for 20 days to determine mortality, growth rate, and metal bioaccumulation. Tissue Cd and Zn concentrations at the end of the exposure were significantly higher in sediments with the low-AVS concentration at a given SEM concentration due to the increased dissolved metal concentrations in overlying water (OW). However, tissue Ni concentrations were not related to dissolved Ni in the OW. AVS concentrations also influenced the toxicity of metals to the worms. Significant mortality was observed only at the highest SEM treatments at Low-AVS series. Most individuals survived at the highest SEM treatments at Medium- and High-AVS series. Similarly, the growth rates of worms were reduced in treatments having higher molar differences between SEM and AVS ([SEM-AVS]). Overall, the bioavailability and toxicity of metals in sediments was not well predicted by sediment metal concentrations only, but considering the influence of geochemical factors (AVS) on the metal bioavailability improved the prediction of toxicity. Also, the relationship between tissue metal concentration and toxicity was used to determine which contaminant was most responsible for the observed toxicity of the metal mixture.     

高寒高海拔地区降雨入渗对排土场边坡稳定性影响研究

为分析高寒高海拔地区降雨条件下渗流作用对露天矿山排土场边坡稳定性影响,本文选取西藏某露天矿山排土场为研究对象,通过室内实验获得岩土体的渗透系数和物理力学参数,采用数值模拟的方式,利用极限平衡计算方法,计算排土场边坡在降雨时长为24 h,降雨量分别为20 mm/d、30 mm/d和40 mm/d条件下排土场的安全系数变化特征,对该矿排土场边坡稳定性进行分析计算。研究结果表明：水是影响排土场稳定的重要因素之一,降雨入渗降低排土场内部软弱结构面的强度,造成排土场边坡不稳定,安全系数随降雨量增大而减小,降雨量达到一定程度之后,岩土体充水接近饱和,边坡易发生破坏。研究成果可为高寒高海拔地区排土场边坡稳定性工程提供参考。     

River water quality of the River Cherwell: an agricultural clay-dominated catchment in the upper Thames Basin, southeastern England

The water quality of the River Cherwell and a tributary of it, the Ray, are described in terms of point and diffuse sources of pollution, for this rural area of the upper Thames Basin. Point sources of pollution dominate at the critical ecological low flow periods of high biological activity. Although the surface geology is predominantly clay, base flow is partly supplied from springs in underlying carbonate-bearing strata, which influences the water quality particularly with regards to calcium and alkalinity. The hydrogeochemistry of the river is outlined and the overall importance of urban point sources even in what would normally be considered to be rural catchments is stressed in relation to the European Unions Water Framework Directive. Issues of phosphorus stripping at sewage treatment works are also considered: such stripping on the Cherwell has reduced phosphorus concentrations by about a factor of two, but this is insufficient for the needs of the Water Framework Directive.     

Multivariate statistical techniques for the evaluation of spatial and temporal variations in water quality of Gomti River (India)--a case study

This case study reports different multivariate statistical techniques applied for evaluation of temporal/spatial variations and interpretation of a large complex water-quality data set obtained during monitoring of Gomti River in Northern part of India. Water quality of the Gomti River, a major tributary of the Ganga River was monitored at eight different sites selected in relatively low, moderate and high pollution regions, regularly over a period of 5 years (1994-1998) for 24 parameters. The complex data matrix (17,790 observations) was treated with different multivariate techniques such as cluster analysis, factor analysis/principal component analysis (FA/PCA) and discriminant analysis (DA). Cluster analysis (CA) showed good results rendering three different groups of similarity between the sampling sites reflecting the different water-quality parameters of the river system. FA/PCA identified six factors, which are responsible for the data structure explaining 71% of the total variance of the data set and allowed to group the selected parameters according to common features as well as to evaluate the incidence of each group on the overall variation in water quality. However, significant data reduction was not achieved, as it needed 14 parameters to explain 71% of both the temporal and spatial changes in water quality. Discriminant analysis showed the best results for data reduction and pattern recognition during both temporal and spatial analysis. Discriminant analysis showed five parameters (pH, temperature, conductivity, total alkalinity and magnesium) affording more than 88% right assignations in temporal analysis, while nine parameters (pH, temperature, alkalinity, Ca-hardness, DO, BOD, chloride, sulfate and TKN) to afford 91% right assignations in spatial analysis of three different regions in the basin. Thus, DA allowed reduction in dimensionality of the large data set, delineating a few indicator parameters responsible for large variations in water quality. This study presents necessity and usefulness of multivariate statistical techniques for evaluation and interpretation of large complex data sets with a view to get better information about the water quality and design of monitoring network for effective management of water resources.     

基于水体形态与环境定量分析的湖泊公园保护研究——以武汉中心城区为例

通江湖泊发挥着调节长江水文的重要作用,围绕湖泊修建的湖泊公园又是市民和游客游憩休闲的重要场所.以武汉市中心城区已建成的12个湖泊公园为研究对象,统计各湖泊水体的水质、营养状况等环境指标,利用岸线发育指数、形状率、近圆率等指标对水体形态进行分析,并建立各指标之间关系的数学模型.在此基础上,从生态和湖滨带修复、湖泊指标控制...     

Cycling and ecosystem impact of metals in contaminated calcareous dredged sediment-derived soils (Flanders, Belgium)

Significant areas in Flanders, Belgium exhibit moderate contamination with trace metals caused by disposal of contaminated dredged sediments. After disposal, the sediments develop into a soil-like material, on which vegetation is planted or develops spontaneously. Behaviour, cycling and ecosystem impacts of trace metals in calcareous dredged sediment disposal sites in Flanders is reviewed. Although soil physico-chemical properties favour a low metal bioavailability, pore water concentrations can be elevated compared to pore water in uncontaminated soils. While metal leaching is not considered to be of concern, several plants accumulate elevated levels of Cd and Zn in leaves. Also metal levels in soil dwelling organisms and small mammals, particularly Cd, are elevated compared to reference situations. This raises concern for an enhanced transfer of metals to the food chain. Future research should identify biological effects on organisms caused by the contamination. A comprehensive knowledge of metal behaviour in these sites is essential for developing appropriate management options for these sites.     

PAHs in sediments of the Black River and the Ashtabula River, Ohio: source apportionment by factor analysis

Sources of polycyclic aromatic hydrocarbons (PAHs) in the Black River and Ashtabula River sediments were apportioned using a factor analysis (FA) model with nonnegative constraints. Source profiles, contributions (microg/g) and percent contributions are determined with no prior knowledge of sources. The FA model includes scaling and backscaling of data with average PAH concentrations, without sample normalization. The present work is a follow-up to studies that used a chemical mass balance model to apportion sources to the same data sets. Literature source profiles, modified based on gas/particle partitioning of individual PAHs, from nine PAH sources were considered for comparison. FA results for a three-source solution indicate traffic (58%), coke oven (26%), and wood burning/coal tar (16%) are the primary PAH sources to Black River sediments. The primary PAH sources to the Ashtabula River sediments are traffic (51%), coke oven (44%), and wood burning (5%). This work supports the previous studies of Black River and Ashtabula River PAHs by CMB model. In addition, FA provides a more realistic fit to Ashtabula River model data by eliminating 100% contributions from one source.     

Influence of water quality on the presence of off-flavour compounds (geosmin and 2-methylisoborneol)

Geosmin and 2-methylisoborneol are off-flavour compounds related to poor organoleptics and a decrease in consumer satisfaction with drinking water. The relationship between these off-flavour compounds and 39 parameters of water quality (chemical, physical and biological) for three different surface waters from lotic systems that supply potable water to Quebec City and Lévis (Canada) was studied using principal component analysis. The objective of this study was to show that a multidimensional approach with principal component analysis using the component matrix serves to differentiate the processes involved in the appearance of the olfactory compounds from those not involved or little involved and to extract the most representative data of these processes. Our study shows that the presence of geosmin can be explained, in the case of the water studied, by a process associated primarily with the eutrophication of water and, to a lesser degree, by an allochthonous origin. However, the presence of 2-methylisoborneol may be linked to two processes with different origins, but of equal importance: a winter origin – most likely allochthonous – involving anthropic contributions and an autochthonous bacterial origin.     

The concentration of Mn,Cu, Zn,Co, B,Sr, Cd and Pb in alluvial soils of the Ob River (forest-steppe,southern taiga and central taiga)

Three areas of the Ob River floodplain (forest-steppe, southern taiga and central taiga) were investigated. The total amount of Mn, Cu, Zn, Co, B, Sr, Cd and Pb was identified. The same elements were identified in ammonium acetate buffer extract, 1N HCl extraction and Tamm’s and Grimm’s soil extracts. The basic amount of trace elements in the soils is in the potentially unstable form, in Tamm’s and 1N HCl extracts (up to 74% of the total amount). The geochemical spectra of the investigated elements’ concentration in the soils and meadow vegetation are given. The Ob floodplain is not polluted as it has not been affected by industry, and that is why natural mechanisms of these soils can be easily detected. The content reduction regularity of most of the trace elements and their unstable forms in the soils from the south to the north of the Ob floodplain is observed. The same regularity concerns plants in which Co, Mo, B, Sr and Cd contraction and Mn, Zn and Cu increase are detected.     

The analysis of PM2.5 and associated elements and their indoor/outdoor pollution status in an urban area

In this study, elemental composition of PM2.5 and the status of indoor/outdoor pollution were investigated in a commercial building near a roadside area in Daejeon, Korea. A total of 60 parallel PM2.5 samples were collected both on the roof (outdoor) and in an indoor office of a building near a highly congested road during the spring and fall of 2008. The concentrations of 23 elements were analysed from these PM2.5 samples using instrumental neutron activation analysis. PM2.5 levels in indoor environment (47.6 ± 16.5 μg/m(3)) were noticeably higher than the outdoor levels (37.7 ± 17.2 μg/m(3)) with the I/O concentration ratio of 1.37 ± 0.33 [correlation coefficient (r) = 0.89, P < 0.001]. Principal component analysis results coincidently showed the predominance of sources such as soil dust, traffic, oil/coal combustion and road dust for both indoor and outdoor microenvironments. An isolated source in the indoor environment was assigned to environmental tobacco smoke (ETS) with high factor loading of Ce, Cl, I, K, La and Zn. The overall results of our study indicate that the sources of indoor constituents were strongly dependent on outdoor processes except for the ones affected by independent sources such as ETS. PRACTICAL IMPLICATIONS: An improved understanding of the factors affecting the indoor PM2.5 concentration levels can lead to the development of an efficient management strategy to control health risks from exposure to indoor PM2.5 and related toxic components. A comparison of our comprehensive data sets indicated that most indoor PM2.5 and associated elemental species were strongly enriched by indoor source activities along with infiltration of ambient outdoor air for a naturally ventilated building.     

Application of multivariate statistical analyses in the differentiation between two phosphate ores from the Nuba Mountains,Sudan

In previously published research, uranium abundance and major and trace element content were determined in phosphate ore samples from the Kurun and Uro areas of the Nuba Mountains in Sudan. The current work aims to characterise and differentiate between the phosphate ores from these two areas by subjecting the obtained geochemical data to quantitative and qualitative statistical analyses. Multivariate statistical analyses and correlation studies show several geochemical differences in the occurrence of uranium in Kurun and Uro phosphate ores. Uranium in Uro phosphate ore shows a higher degree of mobility coefficient of variability (CV%?=?91) than that in Kurun phosphate ore (CV%?=?48). Kurun and Uro phosphate ores are found to be good sources of titanium and strontium. The average concentrations of Ti and Sr in Uro phosphate ore are 4880 and 2780?mg?kg^–1, respectively. The corresponding values in Kurun phosphate ore are 7300 and 2630?mg?kg^–1, respectively. A cluster analysis of trace elements demonstrates that both Ti and Sr, which are the most abundant trace elements, appear in individual groups or in sub-groups. Uranium behaves in the same manner in both phosphate ores in that it associates in groups containing all the transition metals except for the most abundant trace element, titanium.