Evaluation of hydrogeochemical processes and groundwater quality for suitability of drinking and irrigation purposes: a case study in the Aosta Valley region,Italy     

Ashwani Kumar Tiwari  Raffaella Ghione  Marina De Maio  Muriel Lavy 《Arabian Journal of Geosciences》2017,10(12):264

The present study aims to discuss the hydrogeochemical processes in the Aosta Valley region and assess the quality of its groundwater for suitability of drinking and irrigation purposes. One hundred twenty-two samples were collected from the Aosta Valley region in the years 2007 and 2008 (61 per year), and analysed for pH, electrical conductivity, total dissolved solids (TDS), total hardness, major cations and anions. The pH of the samples in both years indicated a near-neutral to alkaline nature of the groundwater. The cation and anion chemistry showed the general ionic abundance as: Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and HCO₃ ^?>SO₄ ^2?>Cl^?>NO₃ ^?>F^? in both years. Ca²⁺-Mg²⁺-HCO₃ ^? and Ca²⁺-Mg²⁺-Cl^?-SO₄ ^2? were the dominant hydrogeochemical facies. The computed saturation indices demonstrated that the groundwater was supersaturated with respect to dolomite and calcite in both years. The groundwater chemistry of the study area was mainly controlled by the dissolution of carbonate, sulphate and silicate minerals, as well as ion exchange processes. A comparison of the groundwater quality in relation to drinking water standards showed that most of the water samples were suitable for drinking and domestic uses. The computed water quality index (WQI) values of the study area groundwater ranged from 24 to 84 in the year 2007 and from 22 to 82 in the year 2008, and all the location fell under the Excellent to Good category. Quality assessment for irrigation uses revealed that the groundwater was good to permissible quality for irrigation; however, locally higher salinity, residual sodium carbonate (RSC) and magnesium hazard (MH) restricted its suitability for irrigation at a few sites. These results will be useful in implementing future measures in groundwater resource management at regional and national level.  相似文献   

Effect of agrochemicals on macroinvertebrate assemblages in Pampasic streams,Buenos Aires,Argentina     

Marina Solis  Hernán Mugni  Silvia Fanelli  Carlos Bonetto 《Environmental Earth Sciences》2017,76(4):180

Agricultural practices have been intensified in recent decades in Argentina. The Pampa plain is the main agricultural region of the country. The effect of increased application of agrochemicals on the invertebrate fauna of the Pampasic streams remains unreported. In the present study, we compared the abundance and composition of invertebrate assemblages in seven Pampasic streams with contrasting soil use in their basins. Two streams run through intensively cropped plots, two drain basins with livestock fields, while the other three are located within a biosphere Reserve. Higher nutrient and insecticide concentrations were measured in the streams draining cropped basins, related with pesticide applications and crop fertilization. The invertebrate assemblage composition of the cropped streams differed significantly from the others and between the two. Present evidence suggests that the impact of agrochemicals results in a change in composition with decreased abundance or absence of sensitive species such as Hyalellidae, Caenidae, Baetidae and Curculionidae and increased abundance of more tolerant taxa: Ostracoda, Glossiphoniidae (Hirudinea), Ancylidae (Gundlanchia), Ampullariidae (Pomacea canaliculata), Sphaeriidae and Dugesiidae. Available information suggests that macrophyte cover and composition also influence the invertebrate assemblages of the Pampasic streams.  相似文献   

LiDAR-based digital terrain analysis of an area exposed to the risk of lava flow invasion: the Zafferana Etnea territory, Mt. Etna (Italy)     

Marina Bisson  Boris Behncke  Alessandro Fornaciai  Marco Neri 《Natural Hazards》2009,50(2):321-334

The town of Zafferana Etnea, located on the southeastern slope of Mt. Etna volcano (Italy), has been repeatedly threatened by lava flows in recent centuries. The last serious threat occurred during the 1991–1993 eruption, when the lava front came to a halt only 1.7 km from the centre of town. Morphostructural data derived from light detection and ranging (LiDAR) surveys carried out on Etna in 2005 have enabled us to evaluate the risk of lava invasion in a section (16 km²) of the Zafferana Etnea territory. Qualitative and quantitative results are obtained combining the information derived from LiDAR analysis with geological, morphological and structural data using geographic information systems technology (GIS). The study quantifies in unprecedented detail the areal extent and volume of forested and urban areas and its degree of exposure to different levels of hazard from future lava invasion. Nearly 52% of the urban texture fall into areas of moderate to high risk from lava invasion. Future land use planning should take these findings into account and promote new development preferentially in areas of lower risk.  相似文献   

Investigating the molecular systematic relationships amongst selected Plesionika (Decapoda: Pandalidae) from the Northeast Atlantic and Mediterranean Sea     

Joana M da Silva  Antonina dos Santos  Marina R Cunha  Filipe O Costa  Simon Creer  Gary R Carvalho 《Marine Ecology》2013,34(2):157-170

Despite the high number of species and ecological diversity of pandalid shrimps, there has been no previous attempt to resolve evolutionary relationships of several genera using molecular tools. Although mitochondrial DNA cytochrome oxidase I (COI) is widely used in barcoding studies to delimit species boundaries, additional insights into phylogenetic affinities can be obtained, especially when used in combination with data from additional genes. The knowledge of molecular diversity is essential to understand phylogenetic relationships and will help systematic clarifications. Based on partial fragments of the 16S and COI genes, we have focused specifically on addressing the systematic relationships of the economically and ecologically important shrimp genus Plesionika within a framework of five genera from within the Pandalidae. Our results showed that species within Plesionika are substantially divergent when compared with other genera, exhibiting the highest average nucleotide divergence, with 0.1123 and 0.0846 in COI and 16S genes, respectively. In addition, sequence divergence was found to vary greatly within the genus Plesionika (COI/16S): 0.0247/0.0016 between Plesionika antigai and Plesionika heterocarpus and 0.1616/0.098 between Plesionika heterocarpus and Plesionika edwardsii. We did not find amino acid sequence divergence between P. heterocarpus and P. antigai compared with P. heterocarpus and P. edwardsii (8.10%, K2P distance). Three species of Plesionika (P. antigai, P. heterocarpus and Plesionika scopifera) appear well separated from other Plesionika species in both maximum likelihood and Bayesian analyses. The present study confirms the utility of COI over 16S as a genetic marker to resolve relationships between different species of Plesionika from the Northeast Atlantic and Mediterranean Sea, in addition to species delimitation. The findings highlight the need to further review paraphyly within Plesionika in an attempt to recognize a concordance in the evolutionary history of Plesionika with major ecological and geological events.  相似文献   

自动计算热带气旋位置和范围的方法研究     

LIU  Yong-lu SHAO  Li-min LANG  Feng-wang 《海洋通报(英文版)》2013,(2):37-45

本文以卫星云图的热带气旋云系为研究对象,基于Canny边缘检测、contour轮廓提取等方法,研究了通过图像的形状特征和范围大小对热带气旋云系进行自动识别,得到了较好的效果。这种方法有助于提高热带气旋云系识别的自动化程度,实现热带气旋的自动跟踪,从而为热带气旋的预报提供了便利。  相似文献   

基于卫星遥感数据的全球表层流场反演重构     

AN Yu-zhu  CHEN Yi-de  ZHANG Ren  WANG Hui-zan  CHEN Jian 《海洋通报(英文版)》2013,(2):46-58

利用2000~2008年的卫星高度计资料和QuikSCAT风场资料,反演了全球的海表的地转流和Ekman流,将两者合成后生成了0．5°×0．5°的逐周全球表层流产品。在计算Ekman流的时候,引入了权重函数,改进了Lagerloef方法中Ekman流在25°S和25°N上的不连续问题。分析表明：卫星资料反演的流产品能够反映出海表流场的特征,将其分别于TAO观测和SGUD流产品进行定量化的比较显示,所得流产品具有较高的反演精度和可信度,说明改进的方法是有效的。  相似文献   

Thermal anomalies associated with shallow gas hydrates in the K-2 mud volcano, Lake Baikal     

Jeffrey Poort  Oleg M. Khlystov  Lieven Naudts  Albert D. Duchkov  Hitoshi Shoji  Shin’ya Nishio  Marc De Batist  Akihiro Hachikubo  Masato Kida  Hirotsugu Minami  Andrey Y. Manakov  Marina V. Kulikova  Alexey A. Krylov 《Geo-Marine Letters》2012,32(5-6):407-417

Thermal measurements and hydrate mapping in the vicinity of the K-2 mud volcano in Lake Baikal have revealed a particular type of association of thermal anomalies (29–121?mW?m^–2) near hydrate-forming layers. Detailed coring within K-2 showed that hydrates are restricted to two distinct zones at sub-bottom depths exceeding 70–300?cm. Temperature data from stations with hydrate recovery and degassing features all display low thermal gradients. Otherwise, the thermal gradients within the mud volcano are generally increased. These findings imply a more complicated thermal regime than often assumed for mud volcanoes, with important roles for both fluids and hydrates. The coexistence of neighbouring low and high thermal anomalies is interpreted to result from discharging and recharging fluid activity, rather than hydrate thermodynamics. It is suggested that hydrates play a key role in controlling the fluid circulation pattern at an early stage. At a later stage, the inflow of undersaturated lake water would favour the dissolution of structure I hydrates and the formation of structure II hydrates, the latter having been observed on top of structure I hydrates in the K-2 mud volcano.  相似文献   

Methane fluxes in the southeastern Baltic Sea   总被引：2，自引：2，他引：0  

Marina Ulyanova  Vadim Sivkov  Timur Kanapatskij  Pavel Sigalevich  Nikolay Pimenov 《Geo-Marine Letters》2012,32(5-6):535-544

New data from surveys of gas-bearing mud areas in the Gdansk Deep (southeastern Baltic Sea) were collected during four research cruises in 2009–2011. These revealed the presence of seven large pockmarks apart from the three already known, and enabled significant improvement of the existing digital map of gassy mud distribution. Based on geochemical sediment analyses, calculated diffusive methane fluxes from the upper (0–5?cm) seabed layer into near-bottom waters were highest—3.3?mmol/(m²?day)—in pockmark mud, contrasting strongly with the minimum value of 0.004?mmol/(m²?day) observed in typical, background mud. However, fluxes of less than 0.1?mmol/(m²?day) were observed in all sediment types, including pockmarks. In a newer attempt to roughly estimate budgets at a more regional scale, diffusive methane venting amounts to 280?×?10⁶?mmol/day for southeastern Baltic Sea muddy sediments. Elongated pockforms in the southern Gotland Deep, known since the end of the 1980s as pockmarks, had methane concentrations that were similar to those of gassy mud from the Gdansk Basin, and there was no geo-acoustic evidence of considerably increased gas levels.  相似文献   

Biotechnology of Metal Removal from Industrial Wastewater: Zinc Case Study          下载免费PDF全文

Inga Zinicovscaia  Gheorghe Duca  Liliana Cepoi  Tatiana Chiriac  Ludmila Rudi  Tatiana Mitina  Marina V. Frontasyeva  Sergey Pavlov  Svetlana F. Gundorina 《洁净——土壤、空气、水》2015,43(1):112-117

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Mineral systems and the thermodynamics of selenites and selenates in the oxidation zone of sulfide ores – a review     

Charykova  Marina V.  Krivovichev  Vladimir G. 《Mineralogy and Petrology》2017,111(1):121-134

Mineralogy and Petrology - Contemporary mineralogy and geochemistry are concerned with understanding and deciphering processes that occur near the surface of the Earth. These processes are...  相似文献