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This investigation was under taken to evaluate the groundwater resources contamination due to intensive agricultural practices (particularly greenhouses). The study-area is located in the coastal area of the Ragusa province (South-East Sicily), where numerous existing greenhouses may cause the contamination of groundwater systems (unconfined and confined aquifers) beneath the cropped land. The pollution risk is mainly related with the seepage process of macro-elements nitrogen (N), phosphorus (P), potassium (K), held in the irrigation water and the massive use of fertilizers and pesticides, that may pass through the unsaturated zone of the soil profile. Moreover, the area is characterized by the presence of several wells (about 15 wells/km2) for agricultural use that cause the aquifer overexploitation and the consequent risk of seawater intrusion. The agriculture practices adopted in the study area (irrigation volumes, fertilizer concentrations, use of pesticides…) were monitored since February 2009; moreover, the pollution risk of the aquifers was evaluated through the analysis of groundwater water samples collected (monthly) in the monitoring wells; in particular, nitrogen compounds, soluble phosphorous (PO?2?), potassium, as well as the main pesticides commonly used in the study area, were measured.The results show that electrical conductivity and chloride concentration values can cause reduction of production and leaf damage problems, respectively, for most of the monitored farm systems. The high nitrogen compounds concentrations observed in the monitored wells can cause health and environmental problems. Moreover high pesticide contamination of groundwater was found in two of the five monitored wells.  相似文献   
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Distribution in Portugal of some pollutants in the lichen Parmelia sulcata   总被引:2,自引:0,他引:2  
During the months of July and August 1993 a lichen (Parmelia sulcata Taylor) collection campaign was held in Portugal where samples were obtained from olive tree bark at 228 sites, following a grid of 10 x 10 km along the Atlantic coast and 50 x 50 km in the interior of the country. The samples were analysed by instrumental neutron activation analysis and proton induced X-ray emission techniques. Concentration data patterns for the pollutants As, Cr, Hg, Ni, Pb, S, Sb, Se, and V were obtained for the whole country surface by making use of an extinction rule of 1/r(3), preventing any cut-off distance from being artificially introduced. Some pollution sources were identified: (1) oil-powered plants on the Lisbon-Setúbal axis (V, Ni), (2) coal-power plants in Porto and Sines (S, Se), (3) traffic in the northern area and the Lisbon-Setúbal axis (Pb), (4) a chemical industry south of Porto (Hg, As), and (5) soil influence (Cr, Sb). Arsenic and chromium results largely exceed, in a few areas, the concentrations acceptable to plants, and in a few spots also Hg, Ni, and Pb data.  相似文献   
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As resource conservation is an imperative for sustainable development, it is crucial to achieve a deeper understanding of the factors involved in people's decisions to recycle. This is even more so because the level of environmental concern is usually higher than the level of ecological behaviours. In this paper we take this fact as indicating that decision-making regarding conservation behaviours happens in the context of an internal debate where contradictory ideas are weighed up and the possibility of ambivalence arises. The main aim of this paper is therefore to explore how contradiction and ambivalence impact upon the attitudes, intentions and pro-ecological behaviours of the private sphere. The paper focuses specifically on the separation and deposition of metal cans, and compares the predictive capacity of beliefs, attitudes and intentions for two groups of respondents – one with a high and another with a low level of ambivalence, as assessed with a direct measure. The role of personal identity and the influence of structural constraints are also explored. Results demonstrate a clear moderating effect of experienced ambivalence, and show how beliefs, particularly negative ones, present a higher predictive capacity of the attitude in the high-ambivalence group, and personal identity plays a relevant role in predicting behaviour in both groups. We discuss the importance of pursuing the study of ambivalence when analysing decision-making in the conservation area.  相似文献   
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Offspring quality of decapod crustaceans has been widely studied, with special emphasis on the sources of variability determining embryonic and larval quality. Nevertheless, maternal provisioning has commonly been overlooked as a potential source of offspring within-brood variability. In the present study, the existence of variable maternal provisioning was assessed through the analysis of the fatty acid (FA) profile of newly extruded embryos from different regions of the brooding chamber of Homarus gammarus. Significant differences in the FA profile of embryos sampled from different pleopods and sides of the brooding chamber were recorded. Significant deviations of the overall mean of each surveyed female were also observed for essential FA, particularly 20:4n-6, 20:5n-3 and 22:6n-3. Lipid energy available to fuel embryogenesis also varied among embryos sampled from different regions of the brooding chamber. Results suggest variable female investment at oocyte production, which may be amplified during the incubation period of developing embryos by differential lipid catabolism. For the first time, maternal provisioning is evidenced as an additional source for within-brood variability in the FA profile of embryos.  相似文献   
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