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1.
The transfer 137Cs, 238Pu, 239/240Pu and 241Am to sheep which graze a saltmarsh in the Esk estuary, 7 km south of the sellafield reprocessing plant in west Cumbria (UK), has been estimated.The concentrations of gamma-emitting radionuclides and of 238Pu, 239/240Pu and 241Am were measured in liver, lung, muscle, kidney and bone from saltmarsh ewes and lambs. 137Cs concentrations in the soft tissues were similar in liver, lung and muscle but were consistently higher in kidney and much lower in bone. The highest concentration of the transuranics was found in liver.Transfer coefficients and concentration factors were calculated for both ewes and lambs. The concentration of 137Cs in the tissues of 5-month old lambs was higher than in those of their mothers. Therefore, a higher transfer coefficient was obtained for lamb muscle (1·8 × 10?1 d kg?1) than for ewe muscle (6·4 × 10?2 d kg?1). Concentration factors were consistently higher for 137Cs than for the transuranics.  相似文献   

2.
Radionuclides released into the Irish Sea by the Sellafield reprocessing plant are deposited onto tide-washed pastures along the western coast of the United Kingdom. Many of these pastures are grazed by sheep or cattle. This paper describes a controlled feeding study, in which saltmarsh vegetation harvested from close to the Sellafield plant, was fed to lambs and adult female sheep for a period of 8 weeks. Activity concentrations of (60)Co, (95)Nb, (106)Ru, (134)Cs, (137)Cs, (238)Pu, (239,240)Pu and (241)Am were determined in edible tissues and transfer parameters estimated. The activity concentrations of some of the radionuclides will not have been in equilibrium with those in the diet. Nevertheless, the study was reasonably realistic in terms of agricultural management as the period of the study was similar to that for which lambs graze on the saltmarshes. A field study to determine the activity concentrations of (137)Cs and (239,240)Pu in the milk of ewes grazing a saltmarsh close to Sellafield is also described.  相似文献   

3.
This paper reviews the published literature that describes the phenological development of above and below ground organs of temperate fruit trees (top fruit), particularly with respect to apple (Malus domestica). Critical information is presented which is considered appropriate in developing an understanding of the potential for top fruit species to take up radionuclide contaminants from the atmosphere and the soil. Information is cited on how climatic and edaphic factors influence the growth and development of temperate fruit trees, the phenological production of their leaf area and the development and growth of their fruit and hence the potential for foliar and fruit uptake of radionuclides from the atmosphere. The study also reports on the importance of the distribution and phenological development of roots in the soil and the potential for their uptake of radionuclides from the soil. The effects of above and below ground management procedures, within temperate fruit orchards, on potential radionuclide uptake are also considered. It is concluded that the potential for the uptake of radionuclides by temperate fruit tree species will depend on a number of phenological and physiological factors. For uptake from the soil these factors include; root distribution and density in the soil profile, seasonal changes in the production and distribution of roots, and the presence and amount of water in the soil. These factors are themselves influenced by rootstock type and its growth vigour, scion type and its growth vigour, tree age, spacing of trees in the orchard, orchard management practices (presence or absence of weeds or grass under the trees) and soil type and depth. Direct uptake by the shoot, however, will be influenced by the climatic conditions at the time of exposure and the presence of foliage. Deposition and uptake are likely to change with leaf area development and the ability of radionuclides to penetrate the cuticle of the leaf changes with seasonal development. Transport of radionuclides to the fruit may also depend on the time of season, as the importance of the xylem and phloem transport routes can change with the growth and development of the fruit.  相似文献   

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The selection of priority APIs (Active Pharmaceutical Ingredients) can benefit from a spatially explicit approach, since an API might exceed the threshold of environmental concern in one location, while staying below that same threshold in another. However, such a spatially explicit approach is relatively data intensive and subject to parameter uncertainty due to limited data. This raises the question to what extent a spatially explicit approach for the environmental prioritisation of APIs remains worthwhile when accounting for uncertainty in parameter settings. We show here that the inclusion of spatially explicit information enables a more efficient environmental prioritisation of APIs in Europe, compared with a non-spatial EU-wide approach, also under uncertain conditions. In a case study with nine antibiotics, uncertainty distributions of the PAF (Potentially Affected Fraction) of aquatic species were calculated in 100 1 100 km2 environmental grid cells throughout Europe, and used for the selection of priority APIs. Two APIs have median PAF values that exceed a threshold PAF of 1% in at least one environmental grid cell in Europe, i.e., oxytetracycline and erythromycin. At a tenfold lower threshold PAF (i.e., 0.1%), two additional APIs would be selected, i.e., cefuroxime and ciprofloxacin. However, in 94% of the environmental grid cells in Europe, no APIs exceed either of the thresholds. This illustrates the advantage of following a location-specific approach in the prioritisation of APIs. This added value remains when accounting for uncertainty in parameter settings, i.e., if the 95th percentile of the PAF instead of its median value is compared with the threshold. In 96% of the environmental grid cells, the location-specific approach still enables a reduction of the selection of priority APIs of at least 50%, compared with a EU-wide prioritisation.  相似文献   

7.
The tendency towards a homogenous mode of development modelled on that of Western countries means that sustainable development has become increasingly urgent. It is necessary to thoroughly redefine products and their expected performances in such a way that the consequences are compatible with sustainable development. In the domain of product design, this means that it is no longer sufficient to use assessment tools “after the fact” to check the impact of products whose functional unit (FU) was defined prior to production; it is now necessary to rethink the definition of the FU itself. This article aims to present an approach based on a combination of life cycle analysis methods and problem-solving by constraint satisfaction. This original approach makes it possible to vary the design of the different dimensions of the FUs of a complex system and thus to make it easier to identify the best architecture along with the best functional definition of the system. In this study, the EcoCSP approach is applied to define the functional performances of an ecological passenger ferry. The complexity of couplings between subsystems and the sheer number of those subsystems mean that the designer has to use “intelligent” tools. These simulate a great number of scenarios and help him/her to fine-tune the system and make the right technological choices with regard to the right functional specifications.  相似文献   

8.
Land-cover change is the result of complex multi-scale interactions between socioeconomic, demographic, and environmental factors. Demographic change, in particular, is thought to be a major driver of forest change. Most studies have evaluated these interactions at the regional or the national level, but few studies have evaluated these dynamics across multiple spatial scales within a country. In this study, we evaluated the effect of demographic, environmental, and socioeconomic variables on land-cover change between 2001 and 2010 for all Mexican municipalities (n?=?2,443) as well as by biome (n?=?4). We used a land-cover classification based on 250-m MODIS data to examine the change in cover classes (i.e., woody, mixed woody, and agriculture/herbaceous vegetation). We evaluated the trends of land-cover change and identified the major factors correlated with woody vegetation change in Mexico. At the national scale, the variation in woody vegetation was best explained by environmental variables, particularly precipitation; municipalities where woody cover increased tended to be in areas with low average annual precipitation (i.e., desert and dry forest biomes). Demographic variables did not contribute much to the model at the national scale. Elevation, temperature, and population density explained the change in woody cover when municipalities were grouped by biome (i.e., moist forest, dry forest, coniferous forest, and deserts). Land-cover change at the biome level showed two main trends: (1) the tropical moist biome lost woody vegetation to agriculture and herbaceous vegetation, and (2) the desert biome increased in woody vegetation within more open-canopy shrublands.  相似文献   

9.
It is widely acknowledged that the implementation of the majority of agri-environmental measures (AEMs) does not allow for the quantification of expected environmental benefits, thereby undermining the possibilities to assess both their effectiveness and efficiency. The objective of this paper is to show how an approach to develop agri-environmental measures based on the multifunctional character of agro-ecosystem is useful to overcome the difficulties in assessing expected environmental benefits. In the following sections, the main theoretical concepts underlying the actual European model of multifunctional agriculture are introduced. Following a critique of some aspects of the current analysis of the joint production of environmental non-commodities, the rationale to operate a shift of focus from multifunctionality of agriculture to that of agro-ecosystems is proposed. Finally the methodology developed by the AEMBAC project, based on the assessment of impacts exerted by agriculture on the capacity of local agro-ecosystem to perform environmental functions, is presented to explain how this shift of focus facilitates the assessment of the delivering of multiple environmental goods and services.  相似文献   

10.
The intensity of environmental regulation (ERI) affects the short-term effect of the level of green mining (GML), and which structure determines the long-term mechanism. Based on the panel data from 2001 to 2015, with the dynamic panel model and system GMM estimation method were employed to test the influence of heterogeneous environmental regulation on green mining and its transmission mechanism. The results show that, there is a “U” type nonlinear relationship between the ERI and GML. The direct effect of command-control-based (CAC) and the market incentive-based (MBI) environmental regulation on green development of mining shows the characteristics of inhibition and promotion. There is a “U” type of indirectly moderating effect between technological innovation and the energy consumption structure on the GML. The technological innovation promotes the green development of the mining industry only after pass the inflection point of MBI, while the CAC plays a significant guiding role in upgrading of the energy consumption structure. There is an inhibition and promotion effect of MBI on the GML in the southeast coastal area, and the CAC is not significantly. Meanwhile, both of the ERI shows no positive effects in the central and western inland region.  相似文献   

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Encapsulation technology involves entrapping a chemical active ingredient (a.i.) inside a hollow polymeric shell and has been applied to commercial pesticide manufacturing for years to produce capsule suspension (CS) formulations with average particle sizes in the micron-scale. The few literature sources that investigate the environmental fate and toxicity to non-target organisms of encapsulated commercially available pesticide products with regard to capsule size report on average sizes between 20 and 50 μm. Here, we have identified a CS formulation with an average capsule size of approximately 2 μm with some capsules extending into the nanometer scale (~ 200 nm). Determining how carrier size influences toxicity is important to understanding if current pesticide risk assessments are sufficient to protect against products that incorporate encapsulation technology. Here, a commercial pyrethroid CS pesticide with lambda-cyhalothrin (λ-Cy) as the a.i. was separated into two suspensions, a fraction consisting of nano-sized capsules (~ 250 nm) and a fraction of micron-sized capsules (~ 2200 nm) in order to investigate the influence of capsule size on toxicity to embryonic zebrafish, Danio rerio. Toxicity was evaluated 24 h after exposure to equivalent amounts of a.i. by the presence and severity of pyrethroid-specific tremors, 14 sublethal developmental impacts and mortality. Fish exposed to greater than 20 μg a.i. L 1 technical λ-Cy or formulated product experienced curvature of the body axis, pericardial edema, craniofacial malformations, and mortality. Exposure to the unfractionated formulation, micro fraction, nano fraction and technical a.i. resulted in no significant differences in the occurrence of sublethal impacts or mortality; however, the technical a.i. exposure resulted in significantly less fish experiencing tremors and shorter tremors compared to any of the formulated product exposures. This suggests that the capsule size does not influence the toxic response of the entrapped λ-Cy, but the presence or absence of the capsules does. Testing across other encapsulated products is needed to determine if size does not have influence on toxicity regardless of encapsulation technology.  相似文献   

13.
Eastern Austrian forest-steppe remnants are extremey important both from conservation and a scientific perspective, yet case studies integrating the examination of the grassland and the forest components are relatively scarce. Consequently, the knowledge on how the pattern of forested vs. non-forested patches influences species composition and diversity remains rather limited. In this study, we compared three sites with different forest/grassland proportions: grassland with a low canopy cover, a mosaic area with alternating forest and grassland habitats, and a forest with some canopy gaps. Our aim was to find out which one of them is the best for conservation purposes. We found that the grassland and the mosaic area had a similar composition, while the forested one was distinct from them. The mosaic vegetation seemed to be the most species rich, also hosting a high number of red-listed species. Beside forest-related and grassland-related species, the mosaic plot also supported some edge-related plants. We conclude that the preservation of mosaic-like forest- grassland habitats is the most favorable for conservation aims. Nevertheless, several species, among them some red-listed ones, were clearly linked either to the forest or to the grassland plot. Therefore, even though mosaics deserve a special attention, open grasslands and xeric forests should also be preserved.  相似文献   

14.
The effects of exposure to synthetic groundwater at elevated temperature gradients on the sorption properties of bentonite were investigated using the Mock-Up-Cz experiment. This experiment simulated the vertical placement of a container of radioactive waste according to the Swedish KBS-3 system for a period of more than 3 years. The mineralogical composition, as well as its chemical and physico-chemical properties, including the uptake of (99)TcO(4)(-) and (134)Cs(+), was used to evaluate the chemical changes caused by the long-term exposure of bentonite buffer to thermal and hydration gradients. It was found that the bentonite material was predominantly stable. No more than 2% of the montmorillonite was transformed due to thermal and moisture gradients. It was concluded that the new-formed mineral phases have no significant influence on the ion exchange and sorption properties of bulk bentonite samples.  相似文献   

15.
Universal two-child policy has been implemented since the end of 2015 in China. This policy is anticipated to bring a significant increase in the total population, with profound influences on the resources and environment in the future. This paper analyzes the changing dynamics of urban and rural population, and forecasts urban and rural population from 2016 to 2030 at national and provincial scale using a double log linear regression model. Drawing upon the results of these two predictions, the impact of the population policy change on Chinese resources consumption and environmental pollution are predicted quantitatively. Given the future total population maintains current levels on resources consumption and environmental emission, the additional demand of resources and environment demand for the new population is forecasted and compared against the capacity on supply side. The findings are as follows: after implementing the universal two-child policy, China’s grain, energy consumption, domestic water demand, and pollutant emissions are projected to increase at different rates across provinces. To meet the needs arising from future population growth, food and energy self-sufficiency rate will be significantly reduced in the future, while relying more on imports. Stability of the water supply needs to be improved, especially in Beijing, Henan, Jiangsu, Qinghai, and Sichuan where the gap in future domestic water demand is comparatively larger. Environmental protection and associated governing capability are in urgent need of upgrade not least due to the increasing pressure of pollution.  相似文献   

16.
The accumulation of dust pollution on the photovoltaic (PV) module can have a significant effect on the productivity and efficiency of PV systems in different locations in the world. Dust which accumulated over time on the PV module and is based on weather conditions led to the reduction in the effectiveness of solar cells. The aim of this research was to experimentally investigate the effect of the natural dust and the effects of environmental parameters on PV performance. The experiments were conducted to propose a model for the current, voltage, power and efficiency and to simulate the effect of environmental parameters on PV performance. The natural dust investigated consisted of different compounds: SiO2 (45.53 %), CaO (24.62 %), Al2O3 (10.83 %), Fe2O3 (10.46 %), MgO (6.33 %), K2O (0.87 %), TiO2 (0.45 %), SO3 (0.24 %), MnO2 (0.21), Cr2O3 (0.23 %), SrO (0.13 %) and NiO (0.09 %). It was found that the most accurate correlation is a polynomial from seventh degree for current, voltage, power and efficiency, fourth degree for solar radiation and temperature, cubic degree for humidity and wind velocity. The coefficients of general model are 0.6343, 0.0110, 0.0 and 0.0001 for PV module, respectively, with 0.0011 fitting factor. The proposed model has been validated using models in the literature.  相似文献   

17.
Consideration is given to changes in the vegetation and climatic conditions on the eastern slope of the Northern Urals in the second half of the Holocene as reconstructed on the basis of integrated palynological, botanical, paleocarpological, and radiocarbon analysis of material from a peat bog section in the floodplain of the Loz’va River. The results show that the northern taiga zone of the study region in the period between approximately 5000 and 700 years BP was occupied by forests of southern taiga facies, as the climate was significantly warmer than it is today.  相似文献   

18.
The purpose of this work is to assess the impact on the Esteros del Ibera wetland ecosystem caused by the Yacyreta dam, a large hydroelectric power plant on the Parana River, Argentina, in comparison to other factors of environmental change. The project of the dam started around 1970. The power plant began operating in 1994. In 1989, the neighboring Ibera wetland ecosystem showed a substantial increase in the water level for which several different causes were conceivable, including climate change and the dam construction. We analyzed all existing hydrometeorological data and studied other changes that were observed in this ecosystem. A water balance model was used to analyze different scenarios. Increased groundwater inflow, generated since the construction of the dam, appears to be affecting the wetland more than any other factor. The study has implications for the assessment of global and regional consequences of building dams.
Graciela A. CanzianiEmail: Phone: +54-2292-447104Fax: +54-2293-446317
  相似文献   

19.
Corn seeds responded to soaking in aqueous solutions of benzo(a)pyrene with increased root growth. Growth stimulation decreased from 14% to 0 with increasing concentrations (0.0005–0.02 ppm), and with increasing soaking times (6 and 12 hr). Shoot growth and dry weights of shoots were not affected. Wheat did not respond as distinctly as corn to similar treatments. A decrease in the growth of shoots and roots with increasing BaP concentrations was not statistically significant.  相似文献   

20.
The influence of food change on the development of the mothArchips podana was studied. Larvae of a natural population were collected from an apple tree. Nevertheless, the minimal duration of development and the maximal weight of pupae in the next generation were observed in insects that developed on plum, pear, and currant, rather than on apple trees. Transfer has effect on larvae of late instars: transfer from the plum to other trees results in the deterioration of developmental parameters, while that from apple to plum and currant leads to their improvement. This procedure has an effect on the proportion of pupating larvae. The timing of egg laying influences the development and mortality of the larvae. The development of adults from older clutches on apple is comparable to that on plum.  相似文献   

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