Search results for "drain"
showing 10 items of 417 documents
Pesticide monitoring in the basin of Llobregat River (Catalonia, Spain) and comparison with historical data.
2014
Through an extensive sampling in the Llobregat River basin, the presence of 50 currently used pesticides in water, sediment, and biota was assessed. Pesticides were detected primarily in water (up to 56% of the analytes), whereas their presence in sediments was more intermittent, and in biota was scarce. Those at high concentrations in water were the benzimidazoles (carbendazim in 22% of the samples up to 697ngL-1), the organophosphorus (malathion in 54% of the samples up to 320ngL-1), and the ureas (diuron in 54% of the samples up to 159ngL-1). However, this pattern differed in sediments and biota, which were contaminated primarily with organophosphorus (higher Kow) (chlorpyrifos 93% of se…
Boron and lithium behaviour in river waters under semiarid climatic conditions
2022
Boron (B) and Lithium (Li) concentrations were studied in the Platani river, one of the most important catchments of South-Central Sicily which is under semiarid climatic conditions for roughly eight months to a year. In this area, evaporites result in potential B and Li sources for surface waters. Results from river waters have measured ionic strength values between 0.1 and 4.54 M. B and Li distributions in these waters were studied in colloidal (CF, extracted by ultrafiltration from the 0.45 μm filtrate) and total dissolved (TDF) fractions and in fractions extracted from corresponding riverbed sediments, according to changes of the B/Li ratio. In river waters, CF and TDF showed very simil…
Screening of currently used pesticides in water, sediments and biota of the Guadalquivir River Basin (Spain)
2013
The occurrence of 50 currently used pesticides and their transformation products in surface and waste waters, sediment and fish in the Guadalquivir River Basin was determined in 2010 and 2011. After selective sample extraction, pesticides were identified and quantified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The contamination profile in water and sediments is marked by the presence of organophosphorus and triazines. Transformation products were even at higher concentrations than parent pesticides. A wider range of pesticides was present in water than in sediments but none of them were detected in fish. The mean concentrations ranged from 0.2 to 13.0 ng/L in …
Use of geomorphological units to improve drainage network extraction from a DEM
1999
Abstract Drainage networks are one of the main elements characterizing basins, and network topology and geometry form the basis of many hydrological and geomorphological models ( eg Geomorphological Unitary Hydrograph). The identification and manual delineation of channel networks from maps or aerial photographs requires much time and effort. In the last two decades, algorithms and procedures for automated extraction of drainage networks from digital elevation data have been developed and implemented in many specialized software applications. Nevertheless, automatically delineated channel networks do not always show close agreement with manually delineated networks. This paper describes a c…
Endoskopische ablative Verfahren bei Gallengangstumoren – Effektivität der photodynamischen Therapie und der Radiofrequenzablation
2015
Nur etwa 20–30 % der Patienten mit hilarem cholangiozellularen Karzinom (CCC) konnen bei Diagnosestellung kurativ operiert werden, da erst bei fortgeschrittenem Tumorstadium Symptome auftreten 3 . Daher konnen den meisten Patienten mit dieser Tumorentitat lediglich palliative Therapiekonzepte angeboten werden. Die Effektivitat der photodynamischen Therapie (PDT) wurde in 2 kontrolliert randomisierten sowie in weiteren kontrollierten Studien nachgewiesen. Eine endoskopische Drainage in Kombination mit einer intraluminalen PDT stellte bislang das beste palliative Therapiekonzept dar [1, 3]. Die Radiofrequenzablation (RFA) ist ein neues endoskopisches Verfahren im Rahmen des palliativen Therap…
Successive alkalinity producing system for the treatment of acid sulphate soil runoff: preliminary results of a field trial
2005
A successive alkalinity producing system (SAPS) has been investigated as a potential passive treatment option for acid, metal containing runoff from acid sulphate soil. A pilot-scale system was installed at an agricultural land site in Rintala embankment area in mid-western Finland. The experimental layout consists of three parallel treatment units: two different SAPS cells and one limestone-filled cell for comparison of performance. The SAPS cells are composed of a bottom layer of limestone and a top layer of compost supplemented with sand. One of the SAPS cells contains sulphate-rich, waste gypsum mixed with the compost layer in order to enhance the metal reduction by sulphate reducing-ba…
How to tackle the stringent sulfate removal requirements in mine water treatment-A review of potential methods.
2018
Abstract Sulfate (SO₄²⁻) is a ubiquitous anion in natural waters. It is not considered toxic, but it may be detrimental to freshwater species at elevated concentrations. Mining activities are one significant source of anthropogenic sulfate into natural waters, mainly due to the exposure of sulfide mineral ores to weathering. There are several strategies for mitigating sulfate release, starting from preventing sulfate formation in the first place and ending at several end-of-pipe treatment options. Currently, the most widely used sulfate-removal process is precipitation as gypsum (CaSO₄·2H₂O). However, the lowest reachable concentration is theoretically 1500 mg L⁻¹ SO₄²⁻ due to gypsum’s solu…
Pluvial flooding in urban areas: the role of surface drainage efficiency
2018
Pluvial flooding in urban areas may derive from the limited or temporarily reduced efficiency of surface drainage, even when the underlying storm sewers are properly designed. This study focuses on the impact of uncertainties in the operational condition of the surface drainage system on pluvial flood hazard. The flood propagation model FLURB-2D is implemented on a selected study area in the town of Genoa (Italy). Synthetic hyetographs based on the Chicago and bivariate copula methods with suitable return periods are used as input. While simulating the design rainfall, inlet operational conditions are varied stochastically using a Monte Carlo approach. Results confirm that microtopography h…
The formation of alluvial fans and young floodplain deposits in the Lieser catchment, Eifel Mountains, western German Uplands: A study of soil erosio…
2011
This study deals with the exploration and spatiotemporal quantification of the young Holocene, nearly skeleton-free floodplain sediments of the Lieser River, a tributary of the Mosel River in the Eifel Mts. The deposits are primarily a consequence of anthropogenic-triggered soil erosion in the catchment. To observe the phenomenon of corresponding soil erosion on multiple levels two small alluvial fans of tributary catchments were investigated. For comparison, one location in the neighboring Salm valley was described. The results were compared with those of other streams. With extensive fieldwork more than 100 drillings and pits were made at 12 locations. For dating the sediments OSL dating…
Arsenic Pollution in the Southwest of Tuscany: Monitoring of Cornia Catchment Basin
2006
The territory of Colline Metallifere, in SW Tuscany, is characterized by the presence of strong arsenic anomalies. Some hypotheses, formulated in the last 20 years, based on geological and mineralogical factors have failed to explain the peculiar distribution of this toxic element in soil, fluvial sediments and ground water. Our research group has been studying for four years the problem of arsenic pollution in this district to investigate the origin and the mechanism of As diffusion in the environment. In particular we started a comparative study based on the extensive sampling of the stream sediments of the main waterways of Colline Metallifere (Pecora, Bruna and Cornia and their tributar…