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41.
Based on the theory of the politics of international law and the hermeneutic theory for international relations, this paper aims to demonstrate how the history and contextual changes within the Columbia River Basin have affected the underlying principles of the Columbia River Treaty with those of international water law.  相似文献   
42.
Radon is a radioactive gas, abundant in granitic areas, such as in the city of Porto at the north-east of Portugal. This gas is a recognized carcinogenic agent, being appointed by the World Health Organization as the leading cause of lung cancer after smoking. The aim of this preliminary survey was to determine indoor radon concentrations in public primary schools, to analyse the main factors influencing their indoor concentration levels and to estimate the effective dose in students and teachers in primary schools. Radon concentrations were measured in 45 classrooms from 13 public primary schools located in Porto, using CR-39 passive radon detectors for about 2-month period. In all schools, radon concentrations ranged from 56 to 889 Bq/m3 (mean = 197 Bq/m3). The results showed that the limit of 100 Bq/m3 established by WHO IAQ guidelines was exceeded in 92 % of the measurements, as well as 8 % of the measurements exceeded the limit of 400 Bq/m3 established by the national legislation. Moreover, the mean annual effective dose was calculated as 1.25 mSv/y (ranging between 0.58 and 3.07 mSv/y), which is below the action level (3–10 mSv). The considerable variability of radon concentration observed between and within floors indicates a need to monitor concentrations in several rooms for each floor. A single radon detector for each room can be used, provided that the measurement error is considerably lower than variability of radon concentration between rooms. The results of the present survey will provide useful baseline data for adopting safety measures and dealing effectively with radiation emergencies. In particular, radon remediation techniques should be used in buildings located in the highest radon risk areas of Portugal. The results obtained in the current study concerning radon levels and their variations will be useful to optimize the design of future research surveys.  相似文献   
43.
A study was performed in a Protected Area (Natural Reserve of Sado Estuary) in 1996, to evaluate the acute toxicity for aquatic life of surface water from rice fields treated with pesticides, particularly with molinate and quinclorac. As a preliminary assessment, the following rapid toxicity tests were used: “Rotoxkit F”;, “Thamnotoxkit F”; and the recently introduced “Daphtoxkit F magna”; and “Algaltoxkit F”;. Water samples were collected from: a water source for irrigating the rice fields, two rice plots, a drainage channel and from Sado river in which the water is discharged. The results showed that samples from the rice plot treated with molinate were more toxic than those obtained from rice plot treated with quinclorac. Water samples from the river were the most toxic, causing 100% of immobility in all organisms and a substantial inhibition in the algal growth. Water collected from the drainage channel in late July, was also found to be quite toxic. The results obtained until now indicate that some characteristics of these microbiotests, like their rapidity, simplicity and relatively low cost, make them a practical tool to evaluate acute effects of pesticides in freshwater ecosystems. They may also contribute to suggest some changes in pesticides use to promote agricultural practices with lower impact to aquatic life.  相似文献   
44.
The focus of this study, carried out on mudflat and mangrove sediments of Ulhas Estuary and Thane Creek in Mumbai, India, documents how sediment analysis in different ecosystems can help in understanding metal behaviour and pollution status of the region. Based on the the geoaccumulation index (I geo ), the study shows that the estuarine and creek regions, being recipients of industrial and domestic wastes, display moderate pollution. Ulhas Estuary with higher clay and organic matter contents, exhibits higher amounts of metals than Thane Creek. Furthermore, using correlation and cluster analyses, the creek projects stable subenvironments with similar types of metal associations, with Fe and total organic carbon as the dominant metal carriers. By contrast, in the estuarine subenvironments, the metal associations do not reveal any distinct trend, which may be attributed to the disturbance caused by dredging activities routinely carried out in the region. Factor analysis carried out on I geo data in both regions further helped in identifying polluted metal groups.  相似文献   
45.
In irrigated maize areas of an important Portuguese agricultural area, Ribatejo and Oeste Region, alachlor, atrazine and metolachlor were detected in ground water.

During the study performed from 1996 to 1998 atrazine was the herbicide that showed the highest frequency of detection. In the 177 ground water samples collected 62% were contaminated with atrazine, 30% with alachlor and 12% with metolachlor. All these herbicides were detected both in ground water for human consumption and for irrigation, in some cases above 0.1 ug/L. The maximum levels quantified were 13μg/L for alachlor, 30μg/L for atrazine and 56 μg/L for metolachlor.

Seasonal variation of residues in ground water it is also presented through several examples of studies performed during the period 1991–1999.  相似文献   
46.
ABSTRACT

This article aims to list the main sustainable practices developed in the processes of metal forming, casting, heat treatment, welding and electrostatic painting. When analysed the literature about sustainable manufacturing, a predominance of studies about machining is observed and the processes mentioned are few explored in academic studies. The research strategy used to reach the objective was systematic literature review, conducted for each process cited. Many sustainable practices were identified with prominence of better materials use and energy efficiency. The authors of this article believe that the information presented here can be useful for researches in their future studies and for industry professionals interested in improving manufacturing processes.  相似文献   
47.
Planning in sustainable development is believed to be an important element in allowing higher education institutions to set their goals and to commit themselves towards undertaking concrete actions and measures at all levels in order to implement sustainability. Yet, there is a paucity of research that has looked at the extent to which planning can support institutions of higher education to assess their performances and to determine whether the set aims have been met. This research gap needs to be met to allow a better understanding of how planning can help to promote the integration of the three components of sustainable development – economic development, social development and environmental protection in higher education. This paper explores the challenges for planning the sustainable development in higher education, also outlining the potentials lessons learned that could assist in improving Education for Sustainable Development efforts in Higher Education Institutions. Among its main results are the fact that many universities wish to pursue sustainable development, but their efforts are hindered by lack of institutional support and planning and limited emphasis on approaches, such as problem-based learning. The universities that are engaged in the field have to face many problems, varying from limited resources to lack of trained staff. As a result, integrated approaches to sustainability become difficult to implement. Finally, the paper has identified the fact that many opportunities offered mainstream developments, such as the UN Declaration ‘The World we Want’ or the UN Sustainable Development Goals are not being put to full use.  相似文献   
48.
This study quantifies metal concentrations in washed and unwashed feathers of feral pigeons (Columba livia). The material was collected in two different sites: Goiania (capital of Goiás State), with high anthropic activities, and Jataí (a city in Goiás), with low anthropic activities. Results revealed that metals such as Pb, Cr, and Cd were deposited in the feathers originating from air and soil (exogenous process). Other metals such as Cu, Fe, Mn, and Zn, which are part of the tissue constitution of a living being, were absorbed through the pigeons' diet (endogenous process). There was a statistically significant difference between mean values of Cd, Pb, and Cr in the three collection sites. The order of metal concentrations were Civic Square > Zoo > Jataí, which shows highest levels of metal contamination in anthropic environments. Significant differences between Cd, Pb, and Cr in washed and unwashed feathers suggest that metal concentrations are directly related to exposure time due to exogenous sources. We concluded that it is possible to quantify and monitor metal levels in the environment by analyzing the feathers of urban feral pigeons. Furthermore, unwashed feathers were especially efficient to investigate endogenous and exogenous absorption of the metals in our study.  相似文献   
49.
The condition factor and blood variables, including erythrocyte lipid peroxidation (LPO) and the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), in two ecologically distinct fish species (Astyanax fasciatus and Pimelodus maculatus) were evaluated at five sites in the Furnas Hydroelectric Power Station reservoir (Brazil) to assess water quality. Aldrin/dieldrin, endosulfan, heptachlor epoxide, and metolachlor were detected at different concentrations in four of the sites. Condition factor was not directly affected by such contaminants. A negative correlation between hematocrit and heptachlor was detected in P. maculatus. Positive correlations between red blood cells and heptachlor as well as an interactive effect of metolachlor and aldrin/dieldrin were detected in A. fasciatus. The erythrocytes of both species collected from the contaminated sites showed high levels of LPO, an increase in SOD and GPx activities and a decrease in CAT activity. Although the leukocyte number and the differential percentage of leukocytes varied among the sites, the hematological variables, the LPO levels, and the antioxidant enzyme activities could be used to assess water quality, regardless of the differences in the responses of the fish species.  相似文献   
50.
With large influx of freshwater that decreases sea-surface salinities, weak wind forcing of <10 m s−1 and almost always warm (>28°C) sea-surface temperature that stratifies and shallows the mixed layer leading to low or no nutrient injections into the surface, primary production in Bay of Bengal is reportedly low. As a consequence, the Bay of Bengal is considered as a region of low biological productivity. Along with many biological parameters, bacterioplankton abundance and production were measured in the Bay of Bengal during post monsoon (September–October 2002) along an open ocean transect, in the central Bay (CB, 88°E) and the other transect in the western Bay (WB). The latter representing the coastal influenced shelf/slope waters. Bacterioplankton abundances (<2 × 109cells l−1) were similar to those reported from the HNLC equatorial Pacific and the highly productive northern Arabian Sea. Yet, the thymidine uptake rates along CB (average of 1.46 pM h−1) and WB (average of 1.40 pM h−1) were less than those from the northwestern Indian Ocean. These abundances and uptake rates were higher than those in the oligotrophic northwestern Sargasso Sea (<7 × 108 cells l−1; av 1.0 pM h−1). Concentrations of chlorophyll a (chl a), primary production rates and total organic carbon (TOC) were also measured for a comparison of heterotrophic and autotrophic production. In the WB, bacterioplankton carbon biomass equaled ∼ 95% of chl a carbon than just 31% in the CB. Average bacterial:primary production (BP:PP) ratios accounted for 29% in the CB and 31% in the WB. This is mainly due to lower primary productivity (PP) in the WB (281 mg C m−2 d−1) than in the CB (306 mg C m−2 day−1). This study indicates that bacteria–phytoplankton relationship differs in the open (CB) and coastal waters (WB). Higher abundance and contrastingly low bacterial production (BP) in WB may be because of the riverine bacteria, brought in through discharges, becoming dormant and unable to reproduce in salinities of 28 or more psu. Heterotrophic bacteria appear to utilize in situ DOC rather rapidly and their carbon demand is ∼50% of daily primary production. It is also apparent that allochthonous organic matter, in particular in the western Bay, is important for meeting their carbon demand.  相似文献   
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