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11.
The Po valley in northern Italy is renowned for its high air pollutant concentrations. Measurements of air pollutants from a background site in Modena, a town of 200 thousand inhabitants within the Po valley, are analysed. These comprise hourly data for CO, NO, NO(2), NO(x), and O(3), and daily gravimetric equivalent data for PM(10) from 1998-2010. The data are analysed in terms of long-term trends, annual, weekly and diurnal cycles, and auto-correlation and cross-correlation functions. CO, NO and NO(2) exhibit a strongly traffic-related pattern, with daily peaks at morning and evening rush hour and lower concentrations over the weekend. Ozone shows an annual cycle with a peak in July due to local production; notwithstanding the diurnal cycle dominated by titration by nitrogen oxide, the decreasing long term trend in NO concentration did not affect the long term trend in O(3), whose mean concentration remained steady over the sampling period. PM(10) shows a strong seasonality with higher concentration in winter and lower concentration in summer and spring. Both PM(10) and ozone show a marked weekly cycle in summer and winter respectively. Regressions of PM(10) upon NO(x) show a consistently greater intercept in winter, representing higher secondary PM(10) in the cooler months of the year. There is a seasonal pattern in primary PM(10) to NO(x) ratios, with lower values in winter and higher values in summer, but the reasons are unclear.  相似文献   
12.
In this paper, in an attempt to reveal possible changes connected to natural or anthropogenic causes, the main results of hydrogeochemical monitoring carried out at Mount Etna are evaluated. We report on the salinity contents of the groundwaters that flow in fractured volcanics, which make up the flanks of the volcano. These waters, analyzed for major ion chemistry, were sampled regularly from 1994 to 2004. Basing on nonparametric Sen??s slope estimator, time series of groundwater composition reveal that the salinity of most of the Etnean aquifers increased by 0.5% to 3.5% each year during this period. This change in the water chemistry is clearly referable to the overexploitation of the aquifers. This increasing trend needs to be inverted urgently; otherwise, it will cause a shortage of water in the near future, because the maximum admissible concentration of salinity for drinking water will be exceeded.  相似文献   
13.
Dioxins and furans (PCDD/Fs), polychlorobiphenyls (PCBs) and hexachlorobenzene (HCB) in the ecosystem of the Lagoon of Venice were studied, in order to provide a general picture of conditions in the lagoon in terms of contamination by persistent organic pollutants (POPs). We present here novel data on atmospheric deposition, water, sediment and clam samples collected in the lagoon during the period January 2001-December 2004. Atmospheric deposition was sampled monthly at six sites located both close and far from large industrial and urban sources. Water samples were collected monthly from fifteen stations, and twenty-five samples of sediments and clams (Tapes philippinarum) were collected in four areas where clams are farmed and harvested inside the lagoon. All samples were analysed for PCDD/Fs, PCBs and HCB by HRGC/HRMS in the same laboratory. All samples examined (atmospheric deposition and water) substantially confirmed the spatial pattern reported in previously published data on sediments and atmospheric deposition: the zone surrounding the Porto Marghera petrochemical plant always had the highest levels of POPs (i.e., PCDD/Fs: atmosphere approximately 6 pg of 2,3,7,8-TCDD equivalents (I-TE) m(-2)d(-1); water 0.37 pg I-TEl(-1); sediment: 300 ng kg(-1); clam 2.8 pg I-TE g(-1)), and the minima were found at points on the margins of the lagoon (PCDD/Fs: atmosphere approximately 1 pg I-TEm(-2)d(-1); water 0.05 pg I-TEl(-1); sediment: approximately 5 ng kg(-1); clam approximately 0.2 pg I-TE g(-1)). Intermediate values were often encountered in the historical city centre of Venice and in the central part of the lagoon. To confirm this, new data on correlation between levels of PCDD/F in sediments and clams are reported, both for absolute values and for the PCDD/F "fingerprint". There is always a clear fingerprinting signature (PCDF/PCDD>1) for samples collected near Porto Marghera, and the opposite (PCDF/PCDD<1) in the rest of the lagoon.  相似文献   
14.
The aim of these trials was to study the distribution of dieldrin in soil and its translocation to roots and the aerial parts of vegetable crops grown in greenhouses and fields. The main objectives were to characterize dieldrin accumulation in plant tissues in relation to the levels of soil contamination; uptake capability among plants belonging to different species, varieties and cultivars. The presence of the contaminant was quantified by gas chromatography-electron capture detector (GC-ECD) and confirmed by gas chromatography-mass spectrometer (GC-MS). The results showed a translocation of residues in cucurbitaceous fruits and flowers confirming that zucchini, cucumber and melon are crops with high uptake capability. The maximum level of dieldrin residue at 0.01 mg/kg was found to be a threshold value to safeguard the quality production of cucurbits. Tomato, lettuce and celery were identified as substitute crops to grow in contaminated fields.  相似文献   
15.
Chorionic villus sampling was performed between 7 and 12 weeks gestation in 1000 patients, 935 of whom intended to continue after fetal diagnosis. Transcervical and Transabdominal aspiration techniques were used providing a sampling success rate of 99 per cent. Anatomical and clinical contraindications to transcervical aspiration were pointed out, and the complementary role of the transabdominal approach evaluated. In the 615 concluded pregnancies an overall abortion rate of 4.1 per cent was observed. A significant association between fetal loss and number of catheter insertions was demonstrated. Bacterial inoculation by catheter insertion and colonization of uterine cavity was suspected as the cause of chorionamnionitis diagnosed in two cases (0.2 per cent) after CVS. Bleeding was the most frequent early complication (12.0 per cent) following chorionic aspiration, but was not significantly related to pregnancy wastage. Late complications, i.e. premature rupture of membranes (0.8 per cent), preterm delivery (6.3 per cent), perinatal losses (1.2 per cent), placental disorders (1.6 per cent), and congenital defects (2.6 per cent) did not exceed the expected values. Normal intrauterine growth patterns were ultrasonically estimated by cross-sectional and longitudinal studies, while the weight at birth was normally distributed in the range of the general population.  相似文献   
16.
Sustainable remediation is the elimination and/or control of unacceptable risks in a safe and timely manner while optimizing the environmental, social, and economic value of the work. Forthcoming International Organization for Standardization (ISO) Standard on Sustainable Remediation will allow countries without the capacity to develop their own guidance to benefit from work done over the past decade by various groups around the world. The ISO standard has progressed through the committee draft (ISO/CD 18504) and draft international standard (ISO/DIS 18504) stages. The risk‐based approach to managing the legacy of historically contaminated soil and groundwater has been incorporated into policy, legislation, and practice around the world. It helps determine the need for remediation and the end point of such remediation. Remediation begins with an options appraisal that short lists strategies that could deliver the required reduction in risk. A remediation strategy comprises one or more remediation technologies that will deliver the safe and timely elimination and/or control of unacceptable risks. The ISO standard will help assessors identify the most sustainable among the shortlisted, valid alternative remediation strategies. Practitioners presenting case studies claiming to constitute sustainable remediation should now report how they have aligned their work with the new standard. Indicators are used to compare alternative remediation strategies. The simplest metric that allows a characteristic to act as an indicator should be chosen. Weightings indicators can become a contested exercise and should only be undertaken where there is a clear desire for it by stakeholders and a clear need for it in identifying a preferred strategy. The simplest means of ranking alternative remediation strategies should be adopted.  相似文献   
17.
18.
The routes of five satellite-tracked loggerhead turtles (Caretta caretta), subjected to an experimental translocation away from their usual migratory routes, have been analysed in relation to the concurrent oceanographic conditions. Remote sensing data on sea surface temperature and height anomalies, as well as trajectories of surface drifters were used, to get simultaneous information on the currents encountered by the turtles during their long-range oceanic movements. Turtles mostly turned out to move in the same direction as the main currents, and their routes were often influenced by circulation features they encountered. A comparison between turtle ground speeds with that of drifters shows that in several instances, the turtles did not drift passively with the currents but contributed actively to the overall movement. Two turtles embarked on an oceanic crossing, probably induced by seasonal changes in surface temperatures, a crossing that was largely determined by the main currents existing in the area.  相似文献   
19.
Widespread alteration of natural hydrologic patterns by large dams combined with peak demands for power and water delivery during summer months have resulted in frequent aseasonal flow pulses in rivers of western North America. Native species in these ecosystems have evolved with predictable annual flood-drought cycles; thus, their likelihood of persistence may decrease in response to disruption of the seasonal synchrony between stable low-flow conditions and reproduction. We evaluated whether altered flow regimes affected 2 native frogs in California and Oregon (U.S.A.) at 4 spatial and temporal extents. We examined changes in species distribution over approximately 50 years, current population density in 11 regulated and 16 unregulated rivers, temporal trends in abundance among populations occupying rivers with different hydrologic histories, and within-year patterns of survival relative to seasonal hydrology. The foothill yellow-legged frog (Rana boylii), which breeds only in flowing water, is more likely to be absent downstream of large dams than in free-flowing rivers, and breeding populations are on average 5 times smaller in regulated rivers than in unregulated rivers. Time series data (range = 8 - 19 years) from 5 populations of yellow-legged frogs and 2 populations of California red-legged frogs (R. draytonii) across a gradient of natural to highly artificial timing and magnitude of flooding indicate that variability of flows in spring and summer is strongly correlated with high mortality of early life stages and subsequent decreases in densities of adult females. Flow management that better mimics natural flow timing is likely to promote persistence of these species and others with similar phenology.  相似文献   
20.
Land capability classification systems define and communicate biophysical limitations on land use, including climate, soils and topography. They can therefore provide an accessible format for both scientists and decision-makers to share knowledge on climate change impacts and adaptation. Underlying such classifications are complex interactions that require dynamic spatial analysis, particularly between soil and climate. These relationships are investigated using a case study on drought risk for agriculture in Scotland, which is currently considered less significant than wetness-related issues. The impact of drought risk is assessed using an established empirical system for land capability linking indicator crops with water availability. This procedure is facilitated by spatial interpolation of climate and soil profile data to provide soil moisture deficits and plant available water on a regular 1-km grid. To evaluate potential impacts of future climate change, land capability classes are estimated using both large-scale ensemble (multi-simulation) data from the HadRM3 regional climate model and local-scale weather generator data (UKCP09) derived from multiple climate models. Results for the case study suggest that drought risk is likely to have a much more significant influence on land use in the future. This could potentially act to restrict the range of crops grown and hence reduce land capability in some areas unless strategic-level adaptation measures are developed that also integrate land use systems and water resources with the wider environment.  相似文献   
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