Search results for " sediments"

Mercury levels in sediments of central Mediterranean Sea: a 150+ year record from box-cores recovered in the Strait of Sicily.

2006

To evaluate the degree of anthropogenic mercury pollution, Hg contents have been measured for box-core sediments sampled along three nearshore-offshore transects in the Strait of Sicily and well constrained for their mineralogy, bulk geochemistry and TOC%. Hg values are generally low (from 15 to 70 microg kg(-1)); however, depth profiles clearly display upcore rising concentrations (up to 202 microg kg(-1) near the SE Sicily coast) that are attributed to anthropogenic load. Based on (210)Pb chronology, these trends are more dramatic across the last 20-30 years. Geogenic influence is thought to explain some anomalies related to volcanic emission and geothermal activity. Combined effects due …

Perfluoroalkyl substance contamination of the Llobregat River ecosystem (Mediterranean area, NE Spain).

2014

The occurrence and sources of 21 perfluoroalkyl substances (PFASs: C4-C14, C16, C18 carboxylate, C4, C6-C8 and C10 sulfonates and C8 sulfonamide) were determined in water, sediment, and biota of the Llobregat River basin (NE Spain). Analytes were extracted by solid phase extraction (SPE) and determined by liquid chromatography triple quadrupole mass spectrometer (LC-QqQ-MS). All samples were contaminated with at least one PFAS, being the most frequently found perfluorobutanoate (PFBA), perfluorooctanoate (PFOA) and perfluorooctane sulfonate (L-PFOS). In general, mean PFAS concentrations measured in sediments (0.01-3.67 ng g(-1)) and biota (0.79-431 μg kg(-1)) samples were higher than those …

Heavy metals in rivers of Latvia☆

2000

Abstract Total heavy metal concentrations in waters and sediments (HNO 3 digestible Pb, Cu, Co, Ni, Mn, Zn) and their speciation forms in sediments (exchangeable, carbonate bound, iron–manganese oxide bound, organic matter bound and residual) in major and common small watercourses (31 sampling stations) along their flow in Latvia were determined. The metal loads entering the Baltic Sea from Latvia were calculated. Increased metal concentrations were found only in lower reaches of the largest rivers and locally around known industrial pollution sources. Differences in metal concentrations and loads in rivers from different regions of Latvia were related to natural geochemical processes. Meta…

Assessment of polycyclic aromatic hydrocarbons (PAHs) in soil of a Natural Reserve (Isola delle Femmine) (Italy) located in front of a plant for the …

2009

Isola delle Femmine Natural Reserve is a very little isle about 15 km from the centre of Palermo, in front of a plant for the production of cement and about 600 m from coast. In the present research, profiles soil PAHs were obtained for 16 sites within the reserve and for 8 stations on the rural soil taken as reference. summation Sigma PAHs, in the soil of investigated area, ranged from 35 to 545 microg/kg. With the aim to find the origin of PAHs in the soil of Isola delle Femmine, we compare the distribution of single analytes in the investigated area with those of the reference rural area (Monte Raffo Rosso), with those of atmospheric urban particulate collected at Palermo along with repo…

Electrochemical characterization of mangrove sediments: A proposal of new proxies for organic matter oxidation

2019

Abstract The voltammetric response of microparticulate deposits resulting from solvent evaporation of ethanolic extracts of mangrove sediments in contact with aqueous acetate buffer is hereby described. Dated sediment cores sampled from the Peruvian mangrove system (“Manglares de Tumbes” National Sanctuary) presented voltammetric responses dominated by oxidative signals of organic components that exhibit significant variations depending on the depth. Voltammetric data allowed for the definition of electrochemical indexes representative of the electrochemically oxidable organic matter fraction. These electrochemical indexes were fEAOM (for the total amount of organic matter being electrochem…

On-line extraction coupled to liquid chromatographic analysis of hydrophobic organic compounds from complex solid samples-Application to the analysis…

2019

This work investigates the applicability of on-line extraction (OLE) directly coupled to liquid chromatography (LC) for the dynamic extraction of hydrophobic organic compounds from complex solid samples. The method operates within the existing apparatus of the LC by replacing the valve loop with an extraction vessel comprised of an empty guard column loaded with the sample. In this manner, extraction is accomplished by the mobile phase as it flows through the extraction vessel under high pressure without the need for additional apparatus other than those comprising the LC system or additional sample pretreatment steps. The experimental parameters affecting the extraction efficiency of the m…

Large-scale glaciotectonically-deformed Pleistocene sediments with deformed layers sandwiched between undeformed layers, Baltmuiža site, Western Latv…

2018

Sequential window acquisition of all theoretical fragments versus information dependent acquisition for suspected-screening of pharmaceuticals in sed…

2019

The aquatic ecosystems are dynamic environments often affected directly or indirectly by a myriad of anthropogenic contaminants that need to be properly identified. In this study, liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QqTOF-MS) suspected-screening was applied to mussels and riverine sediment both, non-spiked and spiked with a mixture of 32 pharmaceuticals. Three data acquisition methods –sequential window acquisition of all theoretical fragment-ion spectra (SWATH), in fix (FSWATH) and variable (VSWATH) window modes and Information Dependent Acquisition (IDA)– were compared to determine the most suitable acquisition technique. The results obtained in the spike…

Photochemical sample treatment for extracts clean up in PCB analysis from sediments.

2013

Sample purification can be considered the most polluting step of the whole analytical process for PCBs determination in sediment samples. The use of photochemical sample treatment represents an alternative methodology for extracts clean up allowing for a reduction of the used amount of organic solvents. The first application of a photochemical sample treatment for the selective removal or reduction of organic substances interfering with PCBs analyses in sediments is reported. The method's efficiency and robustness were compared with currently used chromatographic purification. Quality parameters such as recovery, linearity and reproducibility were studied. The entire procedure was validated…

The integration of surface and subsurface stratigraphic data with HVSR measures for studies of seismic microzonation: the case of Oliveri (ME)

2013

Because of its high seismic hazard the urban area of Oliveri has been subject of a study on seismic microzonation at first level (OPCM 3907/2010). The urban area develops on a large coastal plain made of Late Pleistocene and Holocene mixed fluvial/marine sediments, that mainly consist of silty sands and gravels. The eastern part of this plain is dominated by the alluvial deposits of the Elicona torrent. The coastal and alluvial sediments overlap a complexly deformed substrate made of Hercynian metamorphites (Aspromonte unit), the Capo d’Orlando Flysch, the Antisicilide Argille Scagliose and Pleistocene clays and calcarenites. This area is affected by high uplift rates as recently estimated …