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1.
Aristolochic acids (AAs) are carcinogenic and nephrotoxic plant alkaloids present in Aristolochia species, used in traditional medicine. Recent biomolecular and environmental studies have incriminated these toxins as an etiological agent in Balkan endemic nephropathy (BEN), a severe kidney disease occurring in the Balkan Peninsula. The questions on how the susceptible populations are exposed to these toxins have not yet been clearly answered. Exposure to AAs through the food chain, and environmental pollution (soil/dust), could provide an explanation for the presence of BEN in the countries where no folkloric use of the plant has been documented (Bulgaria, Croatia). Additional exposure pathways are likely to occur, and we have shown previously that AAs can contaminate crop plants through absorption from soil, under controlled laboratory environment. Here, we attempt to provide additional support to this potential exposure pathway, by revealing the presence of AAI in soil and soil organic matter samples collected from BEN and non-BEN areas. The samples were processed in order to be analyzed by high-pressure liquid chromatography, and ion trap mass spectrometry. Our results showed the presence of AAI in small concentrations, both in BEN and non-BEN soils, especially where Aristolochia plants and seeds were present.  相似文献   

2.
• The boron concentration in diluted DS can satisfy the irrigation water standard. • The boron concentration in diluted DS equaled that in two-pass RO permeate. • FDFO process SEC was slightly lower than the 2nd pass RO SEC. • FDFO has potential as an alternative to 2nd pass RO for irrigation water production. Agriculture is the largest consumer of freshwater. Desalinated seawater is an important alternative water source for sustainable irrigation. However, some issues of the current desalination technology hinder its use for agriculture irrigation, including low boron removal and high energy consumption. This study systematically explored the feasibility of employing fertilizer drawn forward osmosis (FDFO) as an alternative to 2nd pass reverse osmosis (RO) by considering the boron removal performance and specific energy consumption (SEC). Different operating conditions were investigated, such as the boron and NaCl concentrations in feed solution (FS), draw solution (DS) concentration, pH, the volume ratio of FS to DS, membrane orientation, flow rate, and operating temperature. The results indicated that a low boron concentration in FS and high pH DS (pH= 11.0) decreased the boron solute flux, and led to low final boron concentration in the DS. The other operating conditions had negligible influence on the final DS boron concentration. Also, a lower flow rate and higher specific water flux with certain permeate water volumes were conducive to reducing the SEC of the FDFO process. Overall, our study paves a new way of using FDFO in irrigation, which avoids the phytotoxicity and human health risk of boron. The results show the potential of FDFO as an alternative to 2nd pass RO for irrigation water production.  相似文献   

3.
ABSTRACT

This paper interprets aspects of the implementation of environmental education in a Higher Education Institution, situated in a developing country, to promote Education for Sustainable Development (ESD). The paper will allow educators to categorise the multiplicity of ESD programmes and projects in higher education institutions, determine their limitations and acceptability, and benefit from the theoretical framework of affective learning in designing new ESD interventions. The paper will also provide an overview of the processes required to establish ESD in developing and developed countries. This paper will further help universities to develop a better understanding of how integration of the three components of sustainable development – economic development, social development and environmental protection – can be incorporated in higher education. The paper explores the challenges for planning the implementation of ESD in an education faculty, outlining the potential lessons learned that could assist in improving ESD efforts in Faculties of Education.  相似文献   

4.
5.
An individual-based model was developed to predict the population dynamics of Daphnia magna at laboratory conditions from individual life-history traits observed in experiments with different feeding conditions. Within the model, each daphnid passes its individual life cycle including feeding on algae, aging, growing, developing and – when maturity is reached – reproducing. The modelled life cycle is driven by the amount of ingested algae and the density of the Daphnia population. At low algae densities the population dynamics is mainly driven by food supply, when the densities of algae are high, the limiting factor is “crowding” (a density-dependent mechanism due to chemical substances released by the organisms or physical contact, but independent of food competition).  相似文献   

6.
This study documents the event chronology and causes of land-use change in a deltaic region of the Philippines since the beginnings of aquaculture in the late nineteenth century. Satellite images and topographic maps spanning the period 1972–2013 were processed to map fishponds and the natural habitats over which they have encroached. Historical archives were consulted and interviews were conducted to understand the historical exploitation of local natural resources and the reasons behind the recorded land changes. Results showed that aquaculture developed in the late nineteenth century and expanded subsequently across the landscape under a succession of forcing factors. The global market, for example, played an early role but a number of land-use changes were also a direct response to changing environmental constraints and natural hazards. These cumulative events have promoted continuous gain in favor of aquaculture, to the detriment of other land-use options.  相似文献   

7.
The dechlorination of OCDD, OCDF and 1,2,3,4,7,8‐H6CDD is studies on an alumina support impregnated with activated carbon, copper chloride and potassium chloride. There is a high correlation between the isomer pattern found after dechlorination and molecular structure properties. We also found a substantial correlation between the isomer pattern and the Gibbs free energy of formation of the individual isomers. This suggests a thermodynamically controlled process.  相似文献   

8.
Soil moisture variability in natural landscapes has been widely studied; however, less attention has been paid to its variability in the urban landscapes with respect to the possible influence of texture stratification and irrigation management. Therefore, a case study was carried out in the Beijing Olympic Forest Park to continuously monitor the soil in three typical profiles from 26 April to 11 November 2010. The texture stratification significantly affected the vertical distribution of moisture in the non-irrigated profile where moisture was mostly below field capacity. In the profile where irrigation was sufficient to maintain moisture above field capacity, gravity flow led to increased moisture with depth and thus eliminated the influence of texture. In the non-irrigated sites, the upper layer (above 80 cm) exhibited long-term moisture persistence with the time scale approximating the average rainfall interval. However, a coarse-textured layer weakened the influence of rainfall, and a fine-textured layer weakened the influence of evapotranspiration, both of which resulted in random noise-like moisture series in the deeper layers. At the irrigated site, frequent irrigation neutralized the influence of evapotranspiration in the upper layer (above 60 cm) and overshadowed the influence of rainfall in the deeper layer. As a result, the moisture level in the upper layer also behaved as a random noise-like series; whereas due to deep transpiration, the moisture of the deep layer had a persistence time-scale longer than a month, consistent with characteristic time-scales found for deep transpiration.  相似文献   

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