Influence of environmental factors on the response of a natural population of Daphnia magna (Crustacea: Cladocera) to spinosad and Bacillus thuringiensis israelensis in Mediterranean coastal wetlands

The present study was undertaken to assess the impact of a candidate mosquito larvicide, spinosad (8, 17 and 33 μg L⁻¹) on a field population of Daphnia magna under natural variations of water temperature and salinity, using Bti (0.16 and 0.50 μL L⁻¹) as the reference larvicide. Microcosms (125 L) were placed in a shallow temporary marsh where D. magna was naturally present. The peak of salinity observed during the 21-day observation period may have been partly responsible for the decrease of daphnid population density in all the microcosms. It is also probably responsible for the absence of recovery in the microcosms treated with spinosad which caused a sharp decrease of D. magna abundance within the first two days following treatment whereas Bti had no effect. These results suggest that it may be difficult for a field population of daphnids to cope simultaneously with natural (water salinity and temperature) and anthropogenic (larvicides) stressors.     

A multicriteria model for planning agricultural regions within a context of groundwater rational management

Current international research focuses on topics like sustainable development, regional planning, environmental decision making and implementation, biodiversity conservation plus a number of other relevant issues, especially at times of economic crisis as today. Economic growth and environmental protection can go hand in hand, provided that decision makers develop and use tools and insights targeting in the implementation of successful and robust long term policies. This paper was developed in the framework of a European research project and implements a Multicriteria Mathematical Programming model that optimises the sustainable management of agricultural regions taking in account the available resources (land, labour, capital) and environmental parameters (agrochemicals, water consumption). The model achieves the optimum farm plan in the area combining different criteria to a utility function under a set of constraints and the spatial integration of the vulnerability maps of the regions into the model enables the regional authorities to design policies for the optimal agricultural development and the groundwater protection from the agricultural land uses. Furthermore, the model is used to simulate different scenarios and policies by the local stakeholders, due to changes on different social, economic and environmental parameters. In this way the decision makers can achieve alternative farm plans and agricultural land uses as well as to estimate economic, social and environmental impacts of different policies. The model has been applied to an agricultural region in Northern Greece and proved to be a valuable tool in the implementation of environmental policies and actions, especially in agricultural regions in a delicate balance as the study area.     

MULTICOMPONENT GEOCHEMICAL TRANSPORT MODELING USING HYDRUS-1D AND HP11

Abstract: The transport of reactive contaminants in the subsurface is generally affected by a large number of nonlinear and often interactive physical, chemical, and biological processes. Simulating these processes requires a comprehensive reactive transport code that couples the physical processes of water flow and advective-dispersive transport with a range of biogeochemical processes. Two recently developed coupled geochemical models that are both based on the HYDRUS-1D software package for variably saturated flow and transport are summarized in this paper. One model resulted from coupling HYDRUS-1D with the UNSATCHEM module. While restricted to major ion chemistry, this program enables quantitative predictions of such problems as analyzing the effects of salinity on plant growth and the amount of water and amendments required to reclaim salt-affected soil profiles. The second model, HPI, resulted from coupling HYDRUS-1D with the PHREEQC biogeochemical code. The latter program accounts for a wide range of instantaneous or kinetic chemical and biological reactions, including complexation, cation exchange, surface complexation, precipitation dissolution and/or redox reactions. The versatility of HP1 is illustrated in this paper by means of two examples: the leaching of toxic trace elements and the transport of the explosive TNT and its degradation products.     

尿中氚水和总氚的对比分析测定研究

用蒸馏液闪法测量尿中氚水浓度 ,用氧化蒸馏液闪法测量尿中总氚 (氚水和有机氚 )浓度。同时测量了 1999年核设施退役时接触氚人员的高于本底水平的尿中氚水和总氚浓度 72个样品。比较氚水和有机氚浓度 ,得到有机氚浓度占氚水浓度的平均值为 (5 4± 3 7) % ,其值与理论值和动物实验值基本相符     

基于小波包分析的爆破振动危害评价初探

结合振动主频的质点振速判据是对单一质点振速判据的补充和完善.但该判据的振动主频是通过FFT变换的频谱分析的方法获得的,不能体现爆破振动波形的多主振频带特征,而且由于方法本身的局限性使得主振频率发生的时间段不能确定.小波包分析法则克服了FFT频谱分析的局限,有效地分解和重构原始信号中的细节信号,并将其作为评价不同频率细节信号的爆破振动危害效果的基础.本文针对爆破振动的小波包分析法进行了研究,对各小波包细节信号加载条件下的不同危害效果进行了讨论,得到了相应的质点振速判据,并将该方法所得到的判据与FFT变换的频谱分析方法所得到的判据进行了对比.结果表明,基于小波包分析法的质点振速判据更加符合爆破振动危害的真实情况.     

PM2.5 assessment in 21 European study centers of ECRHS II: Method and first winter results

The follow-up of a cohort of adults from 29 European centers of the former European Community Respiratory Health Survey (ECRHS) I (1989-1992) will examine the long-term effects of exposure to ambient air pollution on the incidence, course, and prognosis of respiratory diseases, in particular asthma and decline in lung function. The purpose of this article is to describe the methodology and the European-wide quality control program for the collection of particles with 50% cut-off size of 2.5 microm aerodynamic diameter (PM2.5) in the ECRHS II and to present the PM2.5 results from the winter period 2000-2001. Because PM2.5 is not routinely monitored in Europe, we measured PM2.5 mass concentrations in 21 participating centers to estimate background exposure in these cities. A standardized protocol was developed using identical equipment in each center (U.S. Environmental Protection Agency Well Impactor Ninety-Six [WINS] and PQ167 from BGI, Inc.). Filters were weighed in a single central laboratory. Sampling was conducted for 7 days per month for a year. Winter mean PM2.5 mass concentrations (November 2000-February 2001) varied substantially, with Iceland reporting the lowest value (5 microg/m3) and northern Italy the highest (69 microg/m3). A standardized procedure appropriate for PM2.5 exposure assessment in a multicenter study was developed. We expect ECRHS II to have sufficient variation in exposure to assess long-term effects of air pollution in this cohort. Any bias caused by variation in the characteristics of the chosen monitoring location (e.g., proximity to traffic sources) will be addressed in later analyses. Given the homogenous spatial distribution of PM2.5, however, concentrations measured near traffic are not expected to differ substantially from those measured at urban background sites.     

Vegetation as an indicator of environmental changes

Composition of the vegetation and the properties of its environment are related, as was shown by research. In these, mostly statistical-correlative studies, both the vegetation and some growth factors, such as plant nutrients and moisture supply were analyzed and studied on interdependence. At present the environmental conditions can be estimated in the field from the floristic composition with regard to differences both in the combination of plant species and in their relative biomass production. With a vegetation survey the spatial pattern of the different environmental conditions can be indicated. For instance, the places where moisture supply gradients occur can be detected, also a better understanding is obtained of the environmental equalization and the decreasing number of plant species and spatial diversity. Conclusions can be drawn about changes in the vegetation to be expected, from the combined occurrence of, a terrestrial vegetation indicating an eutrofied environment and a water vegetation indicating a relatively oligotrophic environment. By comparing vegetation recordings of the past and present, environmental changes that have occurred in the same place can be indicated. By vegetations situated in different places in relation with soil profile properties the consequences of environmental changes can be predicted. For instance, lowering of the ground water table and intensifying the agricultural use. On the other hand, measures can be suggested to increase the biological value of land and water, for instance, indication of seepage areas and floristically rich areas in the field.     

填料在自由水面人工湿地中的应用

本文通过对深圳市某橡胶厂自行设计造的自由水面人工湿地的调查研究，分析了在人工湿地中采用填料代替植物的工作特性，并论证了土壤－植物－微笑一这样一个生态系统是传统自由水面湿地处理系统实现其处理污水功能的核心。