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91.
This paper reports the results of indoor radon measurements carried out in the Lombard plain. The aim of this study, which is based on the geological context, was to identify radon high-risk areas. The underlying geology has been established by means of the available stratigraphies giving a schematic representation of the sites in which either occurrence of gravel or silt and clay predominate with depths ranging from 0 to 50 m. Radon measurements were performed in a sample of 411 one-family houses in seven villages located in the southern area of Bergamo and Brescia. The findings indicate that when the substrate is dominated by clay, radon concentration for dwellings on the ground floor are low, whereas a strong predominance of underlying gravel mixed up in sand gives in winter months high radon flux from underground.  相似文献   
92.
The Biobio River basin, located in central Chile, is one of the most important freshwater resources for a population of 1 million inhabitants. The river receives discharges of pulp mills, sewage treatment plants and there is a diffuse input of materials coming from the drainage basin. Previous studies reported high levels of etoxyresorufin-O-deethylase (EROD) induction in fish from the lower stretch of the river, mainly due to polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) exposure. The present study investigates polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-furans (PCDFs) levels as well as EROD induction in fish livers from Central Chile's Biobio River. Dioxin and furan levels in fish livers are reported for the first time in three areas of the Basin. In all samples the highest concentrations were found for the octachlorodibenzo-p-dioxin (OCDD) and PCDD/F TEQ concentrations ranged from 2.83 to 6.33 ppt (wet weight). The results indicate a clear induction of EROD activity in different fish species as the river mouth is approached, although this induction is not clearly related with dioxin and furan levels found in the fish livers. Our results clearly show that other pollutants might be acting as EROD inductors in the Biobio Basin.  相似文献   
93.
94.
The introduction of genetically modified plants into the environment has been marked by different positions, either in favor of or against their release. However, the problem goes well beyond such contradictory positions; it is necessary to take into account the legislation, ethics, biosafety, and the environment in the considerations related to the release of genetically modified organisms (GMOs). To this end, the Brazilian Committee of Biosafety (CTNBio), a consultative and deliberative multidisciplinary collegiate, provides technical and advisory support to the Brazilian Federal Government. This committee consists of scientists and non-scientists who participate in evaluating the dossiers of companies that are requesting approval by the Brazilian Government; consequently, the aim of this study was to investigate whether commercial approvals of GMOs were associated with the profile of the CTNBio members. Research was based on the minutes taken at CTNBio meetings carried out from 2006 up to 2009, considering law 11.105/2005 and the Constitution of 1988 as legal frameworks, to determine the number of voters in favor of or against releasing genetically modified Bt-maize, Bt-cotton, and herbicide resistant soybeans to be used in Brazilian agriculture. Via the internet, we had access to the curriculum vitae of the CTNBio members through the Plataforma Lattes database of the National Council for Scientific and Technological Development (CNPq), where we found their area of expertise. CTNBio members were divided into expert-for, expert-against, non-expert-for, and non-expert-against. Results showed that CTNBio decisions could be based on technical criteria as well as on the policy of the institution that expert-members were representing.  相似文献   
95.
In this work the feasibility of using woody agricultural biomass wastes as grapes and cherries seeds, sawdust, as pore forming agent, and sugar cane ash, as silica precursor, in bricks, were reported.Sawdust and grapes and cherries seeds, thanks to their organic substances content, during their combustion, bring an energetic support in the bricks firing phase and act as pore forming agent. Usually the addition of this kind of waste is limited to 10 wt.% in order to reach an equilibrium between positive (weight and shrinkage decrease and porosity increase) and negative (increase of water absorption and mechanical resistance decrease) effects. The results show that grapes and cherries seeds, added in a percentage of 5 wt.% to a brick formulation, have better influence with respect to the sawdust, maintaining the mechanical properties of the fired brick (950 °C), showing modulus of rupture around 21–23 MPa with a weight reduction of 3–10% (respect to the standard one). Regarding the sugar cane ash, the addition of 5 wt.% improves the mechanical properties (modulus of rupture around 27 MPa) and no weight decrease is observed. These results confirmed the role played by this kind of agricultural waste, which thanks to its high silica content (61 wt.%) is capable to demonstrate a filler and plasticity reducing effect on the brick bodies. Tests carried out highlighted that the addition of these by-products (5 wt.%) do not change negatively the main technological properties measured (water absorption, linear shrinkage, flexural resistance, etc.) and permit to hypothesize their use to obtain bricks with both insulating and higher mechanical properties using a pore agent forming or silica carrier alternative raw materials, respectively.  相似文献   
96.
The La Antigua watershed drains into the Gulf of Mexico and can be considered as one of the most important areas in Mexico because of its high productivity, history, and biodiversity, although poverty remains high in the area in spite of these positive attributes. In this study, we performed an integrated assessment of the watershed to recommend a better direction toward a sustainable management in which the four capitals (natural, human, social, and built) are balanced. We contrasted these four capitals in the municipalities of the upper, middle and lower watershed and found that natural capital (natural ecosystems and ecosystem services) was higher in the upper and middle watershed, while human and social capitals (literacy, health, education and income) were generally higher downstream. Overall, Human Development Index was negatively correlated with the percentage of natural ecosystems in the watershed, especially in the upper and lower watershed regions. Our results indicate that natural capital must be fully considered in projections for increasing human development, so that natural resources can be preserved and managed adequately while sustaining intergenerational well-being.  相似文献   
97.
Environmental Science and Pollution Research - Atmospheric pollutants, such as NOx, SO2, and particulate matter, together with water percolation inside the stone pores, represent the main causes of...  相似文献   
98.
Environmental Science and Pollution Research - In this study we propose, a multi-step strategy of selection and characterization of long-term dataset of contaminant concentrations in different...  相似文献   
99.
Contamination of industrial sites by wood preservatives such as chromated copper arsenate (CCA) may pose a serious threat to groundwater quality. The objective of this study was to characterise the spatial variability of As and Cr concentrations in the solid phase and in the soil water at a former wood impregnation plant and to reveal the fundamental transport processes. The soil was sampled down to a depth of 2m. The soil water was extracted in situ from the vadose zone over a period of 10 months at depths of 1 and 1.5m, using large horizontally installed suction tubes. Groundwater was sampled from a depth of 4.5m. Results showed that arsenic and chromium had accumulated in the upper region of the profile and exhibited a high spatial variability (As: 21-621 mg kg(-1); Cr: 74-2872 mg kg(-1)). Concentrations in the soil water were high (mean As 167 microg L(-1); Cr: 62 microg L(-1)) and also showed a distinct spatial variability, covering concentration ranges up to three orders of magnitude. The variability was caused by the severe water-repellency of the surface soil, induced by the concurrent application of creosote wood preservatives, which leads to strong preferential flow as evident from a dye experiment. In contrast to soil water concentrations, only low As concentrations (<12 microg L(-1)) were detected in the groundwater. High Cr concentrations in the groundwater (approx. 300 microg L(-1)), however, illustrated the pronounced mobility of chromium. Our study shows that at sites with a heterogeneous flow system in the vadose zone a disparity between flux-averaged and volume-averaged concentrations may occur, and sampling of soil water might not be adequate for assessing groundwater concentrations. In these cases long-term monitoring of the groundwater appears to be the best strategy for a groundwater risk assessment.  相似文献   
100.
The capability of Scirpus maritimus and of Juncus maritimus to accumulate metals and the role of each plant on the physico-chemical composition of sediments, from Douro river estuary (NW Portugal), were investigated through a year of plants' life. The contents of Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined (by atomic absorption spectrophotometry) in sediment, rhizosediments (those in contact with each plant roots and rhizomes) and different tissues of S. maritimus and of J. maritimus. Both plants influenced the sediment composition (concentrating metals around its roots) and were able to bioaccumulate Cd, in spite of some seasonal variations in the metal levels in the system (both in rhizosediments and plants' roots). Therefore, both plants showed to have potential for Cd phytostabilization. S. maritimus could also concentrate Pb in its roots, probably by sorption on the root surface in (hydr)oxide forms, therefore, denoting capability for Pb phytostabilization.  相似文献   
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