Search results for "Environmental engineering"
showing 10 items of 2674 documents
Total mercury and methyl-mercury contents and accumulation in polar microbial mats.
2014
Although polar regions are considered isolated and pristine areas, the organisms that inhabit these zones are exposed to global pollution. Heavy metals, such as mercury, are global pollutants and can reach almost any location on Earth. Mercury may come from natural, volcanic or geological sources, or result from anthropogenic sources, in particular industrial or mining activities. In this study, we have investigated one of the most prominent biological non-marine communities in both polar regions, microbial mats, in terms of their Hg and methyl-mercury (MeHg) concentrations and accumulation capacities. The main hypotheses posed argued on the importance of different factors, and to test them…
Quantification of diffuse and concentrated pollutant loads at the watershed-scale: an Italian case study
2009
In this study, diffuse and point source pollutant loads were evaluated using an Italian case study: the Nocella catchment, which has been subject to extensive monitoring. The Nocella catchment is located in Sicily (Italy) and has an area of about 60 km2. The river receives wastewater and stormwater from two urban areas drained by combined sewers. The two sewer systems, two wastewater treatment plants and a river reach were monitored during both dry and wet weather periods. Thereafter, an integrated catchment-scale model was applied to simulate point pollutant sources, i.e., pollution coming from the urban drainage system, and nonpoint pollutant sources, i.e., pollution coming from agricultu…
Trace elements in native and transplanted Fontinalis antipyretica and Platyhypnidium riparioides from rivers polluted by uranium mining.
2017
The past uranium/polymetallic mining activities in the Sudety (SW Poland) left abandoned mines, pits, and dumps of waste rocks with trace elements and radionuclides which may erode or leach out and create a potential risk for the aquatic ecosystem, among others. In the present work four rivers affected by effluents from such mines were selected to evaluate the application of aquatic mosses for the bioindication of 56 elements. Naturally growing F. antipyretica and P. riparioides were compared with transplanted samples of the same species. The results demonstrate serious pollution of the examined rivers, especially with As, Ba, Fe, Mn, Pb, Ti, U and Zn, reaching extremely high concentrations…
Chemical speciation of metals from marine sediments : assessment of potential pollution risk while dredging, a case study in southern Sweden
2020
Abstract Contamination associated with metals is a critical concern related to their toxicity, persistence, and bio-accumulation. Trace elements are partitioned into several chemical forms, which some are more labile during fluctuations in the environment. Studying the distribution of metals between the different chemical fractions contributes to assess their bioavailability and to identify their potential risk of contamination to surrounding environments. This study concerns the speciation of metals (Pb, Cr, Ni, Zn and Fe) from sediments coming out from Malmfjarden bay, Sweden. The aim was to assess the potential risk of metal pollution during present and future dredging as well as while u…
Assessment of toxicity hazards of dredged lake sediment contaminated by creosote.
2000
In order to predict the potential toxicity hazards of sediment remediation by dredging, an experimental laboratory simulation was made by investigating seven ratios of creosote-contaminated sediment (Lake Jamsanvesi, central Finland) and artificial lake water mixtures. Sediment was suspended in water at the ratios of 1:1, 1:2, 1:4, 1:8, 1:16, 1:32, 1:64, 1:128 v/v. The elutriates were analysed for the acute toxicity by photoluminescence bacterial and waterflea (Daphnia magna Straus) tests. The concentrations of polycyclic aromatic hydrocarbons (PAHs) are determined by gas chromatography (GC/FID). The elutriate of ratio 1:2 was most toxic to bacteria (EC50 = 4.5%), whereas the ratio 1:4 was …
POPs and organic polysufides in sediments of Lake Ladoga
2007
Abstract The study included one station close to a pollution source (depth 59 m) and another far from polluted areas (depth 40 m). Samples were analysed for organic chlorine, bromine and sulfur compounds. Samples taken with a corer were sliced to the layers of 0–1, 1–4, 4–7 cm etc. down to the depth of 34 cm. The dating was made with two independent methods, the 210Po method and with the soot particle counting method. The analyses were made with a multiresidue method. Gas chromatography was connected to low resolution mass spectrometry (LRMS) or to high resolution mass spectrometry (HRMS). A different extraction was applied to screen the possible occurrence of polysulfides. Typical chloroph…
Analytical method, pattern and sources of polycyclic aromatic hydrocarbons (PAHs) in the stone of the Temples of Agrigento (Italy)
2009
Abstract This study shows the extraction and analytical conditions for the determination of polycyclic aromatic hydrocarbons (PAHs) in the stone of archaeological and historical interest. The aim of this research was to determine the concentrations, distribution and the main sources of PAHs present in the surface layer of stone of the Temples of Agrigento. Together with PAHs, we analyzed sulphates and nitrates since it has been demonstrated that these are very destructive salts that play an important role in the deterioration of stones. Total PAHs at different sites of the Valley of Temples at Agrigento varied from 18 to 84 μg/kg. Analyses were performed by GC–MS. The relative abundance of …
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…