Assessment of Water Quality in the Elbe River at Flood Water Conditions Based on Cluster Analysis,Principle Components Analysis,and Source Apportionment

An assessment of water quality measurements during a spring flood in the Elbe River is presented. Daily samples were taken at a site in the middle Elbe, which is part of the network of the International Commission for the Protection of the Elbe River (IKSE/MKOL). Cluster analysis (CA), principal components analysis (PCA), and source apportionment (APCS apportioning) were used to assess the flood‐dependent matter transport. As a result, three main components could be extracted as important to the matter transport in the Elbe River basin during flood events: (i) re‐suspended contaminated sediments, which led to temporarily increased concentrations of suspended matter and of most of the investigated heavy metals; (ii) water discharge related concentrations of pedogenic dissolved organic matter (DOM) as well as preliminary diluted concentrations of uranium and chloride, parameters with stable pollution background in the river basin; and (iii) abandoned mines, i.e., their dewatering systems, with particular influence on nickel, manganese, and zinc concentrations.     

Volcanic tsunami: a review of source mechanisms, past events and hazards in Southeast Asia (Indonesia, Philippines, Papua New Guinea)

Southeast Asia has had both volcanic tsunamis and possesses some of the most densely populated, economically important and rapidly developing coastlines in the world. This contribution provides a review of volcanic tsunami hazard in Southeast Asia. Source mechanisms of tsunami related to eruptive and gravitational processes are presented, together with a history of past events in the region. A review of available data shows that many volcanoes are potentially tsunamigenic and present often neglected hazard to the rapidly developing coasts of the region. We highlight crucial volcanic provinces in Indonesia, the Philippines and Papua New Guinea and propose strategies for facing future events.     

Environmental impact assessment of structural flood mitigation measures: a case study in Šiba,Slovakia

The proposed flood mitigation measures in the Slovak Republic are subject of environmental impact assessment (EIA) process before its approval. The paper elaborates and demonstrates the application of the risk analysis method for evaluating alternatives, which is core in EIA. Risk analysis is an appropriate tool to determine the level of the risk of the proposed flood mitigation measures and through which it is possible to choose the alternative with the lowest level of risk for the environment. The article presents the application of the developed methodology based on universal matrix of risk analysis in ?iba village that is in existing flood risk. It analyses and discusses the results of the impact assessment from EIA practice in the Slovakia. The aim of the work is to improve existing qualitative and quantitative methods for assessing the impacts of proposed activities on the environment. Developed methodology stimulates creative approaches in searching of the best alternative to proposed activities (constructions) that are environmentally friendly. Innovation in this paper is presented by an implementation of universal matrix of risk analysis for flood mitigation measures (developed by the authors) for the purposes of EIA process.     

A Case Study of CO<Subscript>2</Subscript>, CO and Particles Content Evolution in the Suburban Atmospheric Boundary Layer Using a 2-μm Doppler DIAL,a 1-μm Backscatter Lidar and an Array of In-situ Sensors

A network of remote and in-situ sensors was deployed in a Paris suburb in order to evaluate the mesoscale evolution of the daily cycle of CO₂ and related tracers in the atmospheric boundary layer (ABL) and its relation to ABL dynamics and nearby natural and anthropogenic sources and sinks. A 2-μm heterodyne Doppler differential absorption lidar, which combines measurements of, (1) structure of the atmosphere, (2) radial velocity, and (3) CO₂ differential absorption was a particularly unique element of the observational array. We analyse the differences in the diurnal cycle of CO, CO₂, lidar reflectivity (a proxy for aerosol content) and H₂O using the lidar, airborne measurements in the free troposphere and ground-based measurements made at two sites located few kilometres apart. We demonstrate that vertical mixing dominates the early morning drawdown of CO and aerosol content trapped in the former nocturnal layer but not the H₂O and CO₂ mixing ratio variations. Surface fluxes, vertical mixing and advection all contribute to the ABL CO₂ mixing ratio decrease during the morning transition, with the relative importance depending on the rate and timing of ABL rise. We also show evidence that when the ABL is stable, small-scale (0.1-km vertical and 1-km horizontal) gradients of CO₂ and CO are large. The results illustrate the complexity of inferring surface fluxes of CO₂ from atmospheric budgets in the stable boundary layer.     

Improving the computation of the gravitational terrain effect close to ground stations in the GTE software

The precise computation of the vertical gravitational attraction of the topographic masses (terrain correction) is still being studied both for geodetic and geophysical applications. In fact, it is essential in high precision geoid estimation by means of the well-known remove-compute-restore technique, which is used to isolate the gravitational effects of anomalous masses in exploration geophysics. The terrain correction can be evaluated exploiting a Digital Terrain Model (DTM) in different ways, such as classical numerical integration, prisms, tesseroids, polyhedrons, and/or Fast Fourier Transform techniques. The increasing resolution of recently developed DTMs, the increasing number of observation points, and the increasing accuracy of gravity data represent, nowadays, major challenges for the terrain correction computation. Classical point mass approximation and prism based-algorithms are indeed too slow, while Fourier-based algorithms are usually too much approximate when compared to the required accuracy. In this work, we improve the Gravity Terrain Effects (GTE) algorithm, the innovative tool that exploits a combined prism-Fast Fourier Transform approach especially developed for airborne gravimetry, to compute the terrain correction on the surface of the DTM (i.e. corresponding to the ground stations and/or its vicinity). This required development of a proper adjustment of the algorithms implemented within the GTE software and also to define and implement a procedure to overcome the problems of the computation of the gravitational effects due to the actual slope of the terrain close to the stations. The latter problem is thoroughly discussed and solved by testing different solutions like concentric cylindrical rings, triangulated polyhedrons, or ultra-high resolution squared prisms. Finally, numerical tests to prove the temporal efficiency and the computational performances of the improved GTE software to compute terrain correction for ground stations are also presented.     

A standardized method for sampling and extraction methods for quantifying microplastics in beach sand

Microplastics are ubiquitous in the environment, are frequently ingested by organisms, and may potentially cause harm. A range of studies have found significant levels of microplastics in beach sand. However, there is a considerable amount of methodological variability among these studies. Methodological variation currently limits comparisons as there is no standard procedure for sampling or extraction of microplastics. We identify key sampling and extraction procedures across the literature through a detailed review. We find that sampling depth, sampling location, number of repeat extractions, and settling times are the critical parameters of variation. Next, using a case-study we determine whether and to what extent these differences impact study outcomes. By investigating the common practices identified in the literature with the case-study, we provide a standard operating procedure for sampling and extracting microplastics from beach sand.     

Alternative conceptual models and the robustness of groundwater management scenarios in the multi-aquifer system of the Central Veneto Basin, Italy

A three-dimensional (3D) groundwater flow model of the deep multi-aquifer Quaternary deposits of the Po plain sedimentary basin, within a 3,300-km² area (Veneto, Italy), is developed, tested and applied to aid sustainable large-scale water-resources management. Integrated mathematical modelling proves significantly successful, owing to an unusual wealth of available geological, geophysical, and hydrologic data and to state-of-the-art numerical tools. Of particular interest is the evaluation of the influence of alternative conceptual models; that is, of reconstructed representations of the 3D geological model of the structure of the aquifers. The reference conceptual model is set up by means of extended geological sections and stratigraphic records, and is used to create a large, unstructured 3D finite element grid. By analyzing the effects on piezometric surfaces and on the overall water budget of geometrical perturbations from the reference structure, alternative geo-structural models, obtained by systematically shifting the pinch-out of the aquitards, are compared. Interestingly, the impacts of aquitard pinch-out prove far from negligible. The results suggest the critical importance of reliable geological models even for large, complex 3D models. The good practice of iteratively testing numerically the impact of surprises on the conceptual model, as more field information is collected, is thus supported.     

Spatial and temporal variation of biomarkers in mussels (Mytilus galloprovincialis) from the Lagoon of Venice, Italy

A multiple biomarker approach was adopted in a seasonal study carried out in the Lagoon of Venice, with the double aim of evaluating the natural and anthropic stresses influencing the biological responses of mussel (Mytilus galloprovincialis) and of assessing the effects due to spatial rather than temporal variations. Biochemical (aldehyde dehydrogenase and catalase activities), cellular (neutral red retention time) and physiological (survival in air and condition index) biomarkers were determined in mussels collected in four differently impacted lagoon areas. Multivariate analysis showed that samples were distributed mainly according to temperature and four seasonal groups were identified. The combination of spatial and temporal information enabled us to distinguish physiological variations due to natural causes from those due to anthropic stress, and to identify the sampling period when several biomarkers are less influenced by both natural and endogenous factors.