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161.
We analyzed polychlorobiphenyls (PCBs), perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) in the edible part of farmed sea bass reared in two fish farms in Liguria (Northern Italy). The aim was to determine the contamination levels and human exposure to these chemicals through fish consumption. Concentrations of “dioxin-like” PCBs (DL-PCBs) ranged from 0.033 to 0.759 pg ΣTEQ-PCB g−1 whole weight (w.w.) in fish farm 1 and from 0.032 to 1.60 pg ΣTEQ-PCB g−1 w.w. in fish farm 2, and the six indicators of “non-dioxin-like” (NDL-PCBs) from 0.538 to 9.33 ng Σ6PCB g−1 w.w. and from 1.62 to 27.6 ng Σ6PCB g−1 w.w. Concentrations were generally lower in farm 1 than in farm 2. One reason for this difference might be the proximity of farm 2 to the seaport of La Spezia, which could be a punctual source of pollutants influencing the contamination of the water in the farm. Principal component analysis (PCA) showed differences also in the congeners profiles for the two sites, with higher-chlorinated PCBs more abundant in farm 1, and lower-chlorinated PCBs were more abundant in farm 2. Most of the concentrations of PFOS and PFOA were below the limit of detection (LOD 0.05 ng g−1 w.w.). Only about 10% of the samples analyzed had levels slightly higher than the LOD. Assessments of exposure using these data showed that consumption of farmed fish may contribute significantly to PCBs through the diet, whereas the contribution of PFOS and PFOA seems to be low.  相似文献   
162.
On the basis of a recent epidemiological study it is hypothesized that pyrite content in coal is an important factor in coal workers’ pneumoconiosis (CWP) pathogenesis. While the role of pyrite in pathogenesis remains to be resolved, the ability of the mineral to generate reactive oxygen species (ROS) through various mechanisms is likely a contributing factor. The aim of this study was to elucidate the importance of the pyrite content of coal in generating an inflammatory stress response (ISR), which is defined as the upregulation of ROS normalized by cell viability. The ISR of A549 human lung epithelial cells in the presence of natural coal samples with variable pyrite contents was measured. Normalized to surface area, five particle loadings for each coal reference standard were analyzed systematically for a total of 24 h. The ISR generated by coals containing 0.00, 0.01, and 0.49 wt.% pyritic sulfur is comparable to,though less than, the ISR generated by inert glass beads (299% of the control). The coals containing 0.52 and 1.15 wt.% pyritic sulfur generated the greatest ISR (798% and 1426% of the control, respectively).  相似文献   
163.
Ambient air samples were collected in five locations around a polychlorobiphenyl (PCB) production plant in a highly industrialized city in the north of Italy, for the analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) and PCBs.PCDD/F atmospheric concentrations were lower than those generally detected in urban areas, while PCB concentrations were higher than in urban and industrialized areas in other countries, especially in the locations closest to the plant. To identify source emissions responsible for air pollution we used principal component analysis (PCA) to compare the “fingerprint” of the air in Brescia with some source-related experimental and published data. This analysis showed that the PCDD/F fingerprints were more similar to steel plant emission data, while none of the PCB air patterns were comparable to emission profiles, indicating that different sources are responsible for the concentration of these two pollutants. The highest PCB concentrations detected in the areas closest to the chemical plant are indicative of its impact on the surrounding environment.  相似文献   
164.
A factor analytic model has been applied to resolve and apportion particles based on submicron particle size distributions downwind of a United States-Canada bridge in Buffalo, NY. The sites chosen for this study were located at gradually increasing distances downwind of the bridge complex. Seven independent factors were resolved, including four factors that were common to all of the five sites considered. The common factors were generally characterized by the existence of two or more number and surface area modes. The seven factors resolved were identified as follows: fresh tail-pipe diesel exhaust, local/street diesel traffic, aged/evolved diesel particles, spark-ignition gasoline emissions, background urban emissions, heavy-duty diesel agglomerates, and secondary/transported material. Submicron (<0.5 microm) and ultrafine (<0.1 microm) particle emissions downwind of the bridge were dominated by commercial diesel truck emissions. Thus, this study obtained size distinction between fresh versus aged vehicle exhaust and spark-ignition versus diesel emissions based on the measured high time-resolution particle number concentrations. Because this study mainly used particles <300 nm in diameter, some sources that would usually exhibit number modes >100 nm were not resolved. Also, the resolved profiles suggested that the major number mode for fresh tailpipe diesel exhaust might exist below the detection limit of the spectrometer used. The average particle number contributions from the resolved factors were highest closest to the bridge.  相似文献   
165.
Analysis of short-chain chlorinated paraffins: a discussion paper   总被引:1,自引:0,他引:1  
Short-chain chlorinated paraffins are a class of organic compounds widely used in many industrial applications, extensively diffused into the environment, persistent, bioaccumulative, and toxic towards aquatic organisms. However, their study and monitoring in the environment are still limited. Because of the enormous number of positional isomers that characterise their mixtures, the analysis of this class of pollutants is very difficult to perform. Beside this, the lack of certified reference materials poses a problem for the assessment of the quality assurance/quality control of any analytical procedure. At present, the scientific community does not agree on any analytical reference method, although the monitoring of short-chain chlorinated paraffins has already started in order to comply with the Water Framework Directive of the European Union on water quality. In this paper the regulatory framework, in which chlorinated paraffins are included, and the status concerning their determination are summarized. The main analytical difficulties still existing are discussed, and the definition of a method-defined parameter as well as the development of a standardised method are suggested as a way to obtain comparable monitoring data.  相似文献   
166.
The present study is focused on the implementation of a novel, low cost, urban grid of nanostructured chemresistor gas sensors for ammonia concentration ([NH(3)]) monitoring, with NH(3) being one of the main precursors of secondary fine particulate. Low-cost chemresistor gas sensors based on carbon nanotubes have been developed, their response to [NH(3)] in the 0.17-5.0 ppm range has been tested, and the devices have been properly calibrated under different relative humidity conditions in the 33-63% range. In order to improve the chemresistor selectivity towards [NH(3)], an Expert System, based on fuzzy logic and genetic algorithms, has been developed to extract the atmospheric [NH(3)] (with a sensitivity of a few ppb) from the output signal of a model chemresistor gas sensor exposed to an NO(2), NO(X) and O(3) gas mixture. The concentration of these pollutants that are known to be the most significant interfering compounds during ammonia detection with carbon nanotube gas sensors has been tracked by the ARPA monitoring network in the city of Milan and the historical dataset collected over one year has been used to train the Expert System.  相似文献   
167.
This study was performed to elucidate the distribution, concentration trend and possible source of polycyclic aromatic hydrocarbons (PAHs) in surface water and bed sediments of the Hungarian upper section of the Danube River and the Moson Danube branch. A total of 217 samples (water and sediments) were collected from four different sampling sites in the period of 2001–2010 and analysed for the 16 priority US Environmental Protection Agency PAHs. Concentrations of total 16 PAHs (∑PAHs) in water samples ranged from 25 to 1,208 ng/L, which were predominated by two- and three-ring PAHs. The ∑PAH concentrations in sediments ranged from 8.3 to 1,202.5 ng/g dry weight. Four-ring PAHs including fluoranthene and pyrene were the dominant species in sediment samples. A selected number of concentration ratios of specific PAH compounds were calculated to evaluate the possible sources of PAH contamination. The ratios reflected a pattern of pyrogenic input as a major source of PAHs. The levels of PAHs determined were compared with other sections of the Danube and other regions of the world.  相似文献   
168.
The aim of this study is to summarise the determination of concentrations of microcystins (MCs) in muscle and liver of freshwater fish species caught in stagnant waters of the Czech Republic. Within the years 2007–2009, 351 muscle samples and 291 liver samples of 16 freshwater fish species derived from four fishponds, and four water reservoirs were analysed. MCs were detected in 53 liver samples. The highest concentrations of microcystins were determined in liver samples of carnivorous fish species; 50.3 ng/g of fresh weight (FW) in perch (Perca fluviatilis) and 22.7 ng/g FW in pikeperch (Sander lucioperca). MCs in liver were detected in other five fish species; asp (Aspius aspius), pike (Esox lucius), common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idella) and European eel (Anguilla anguilla). Concentrations of MCs in liver of nine fish species (European bream, whitefish, tench, silver carp, European catfish, roach, chub, crucian carp and rudd) were below the detection limit of 1.2–5.4 ng/g FW for different MC congeners. However, the concentrations of MCs in all muscle samples were below the detection limit. The assessment of MCs concentrations might be influenced by the detection method used. Due to the concentrations of MCs being below the detection limit in muscle samples of all fish species analysed, it seems that there might be a low potential threat for human health in case of fish muscle consumption.  相似文献   
169.
Emissions of reduced sulphur compounds (RSCs) from the primary and secondary clarifiers at a Kraft mill were measured for respectively 8 and 22 days using a floating flux chamber. In the primary clarifier, dimethyl disulphide (DMDS) had the highest mean flux (0.83 microg s(-1) m(-2)) among all RSCs, and the mean flux of total reduced sulphur (TRS) was 1.53 microg s(-1) m(-2). At the secondary clarifier, dimethyl sulphide (DMS) had the highest mean flux (0.024 microg s(-1) m(-2)), and the mean flux of total reduced sulphur (TRS) was 0.025 microg s(-1) m(-2). Large variations in fluxes as a function of sampling date were observed in both clarifiers. Emission fluxes of DMS from the secondary clarifier were correlated with temperature in the flux chamber and with the biological and chemical oxygen demands (BOD and COD) of the wastewater. Emission rates of RSCs from the clarifiers were found to be insignificant by comparison with other mill sources.  相似文献   
170.
Cape Fear is an outdoor 7 × 7 m2 hillslope laboratory located at the University of Tuscia, Viterbo, Italy, and is equipped with real-time monitoring sensors used to analyse runoff generation. In this paper, hydrological phenomena that occurred during Cape Fear’s first 2 years of operation are reported to provide insight into the basic dynamics underlying the hydrological response at the hillslope scale. Based on our findings, surface and subsurface runoff are likely driven by rainfall-threshold phenomena, and evapotranspiration phenomena account for more than 70% of rainfall water input. Future studies will investigate the threshold relationship between rainfall and runoff.  相似文献   
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