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131.
In semi-arid areas like the Kairouan region, salinization has become an increasing concern because of the constant irrigation with saline water and over use of groundwater resources, soils, and aquifers. In this study, a methodology has been developed to evaluate groundwater contamination risk based on the unsaturated zone hydraulic properties. Two soil profiles with different ranges of salinity, one located in the north of the plain and another one in the south of plain (each 30 m deep) and both characterized by direct recharge of the aquifer, were chosen. Simulations were conducted with Hydrus-1D code using measured precipitation data for the period 1998–2003 and calculated evapotranspiration for both chosen profiles. Four combinations of initial conditions of water content and salt concentration were used for the simulation process in order to find the best match between simulated and measured values. The success of the calibration of Hydrus-1D allowed the investigation of some scenarios in order to assess the contamination risk under different natural conditions. The aquifer risk contamination is related to the natural conditions where it increased while facing climate change and temperature increase and decreased in the presence of a clay layer. Hydrus-1D was a useful tool to predict the groundwater level and quality in the case of a direct recharge and in the absence of any information related to the soil layers except for the texture. 相似文献
132.
Tong Wu Charles Perrings Chenwei Shang James P. Collins Peter Daszak Ann Kinzig Ben A. Minteer 《Ambio》2020,49(4):939-949
Highly pathogenic avian influenza (HPAI) H5N1 has led to the death or destruction of millions of domesticated and wild birds and caused hundreds of human deaths worldwide. As with other HPAIs, H5N1 outbreaks among poultry have generally been caused by contact with infected migratory waterfowl at the interface of wildlands and human-dominated landscapes. Using a case–control epidemiological approach, we analyzed the relation between habitat protection and H5N1 outbreaks in China from 2004 to 2017. We found that while proximity to unprotected waterfowl habitats and rice paddy generally increased outbreak risk, proximity to the most highly protected habitats (e.g., Ramsar-designated lakes and wetlands) had the opposite effect. Protection likely involves two mechanisms: the separation of wild waterfowl and poultry populations and the diversion of wild waterfowl from human-dominated landscapes toward protected natural habitats. Wetland protection could therefore be an effective means to control avian influenza while also contributing to avian conservation. 相似文献
133.
Methneni Nosra Anthonissen Roel Van de Maele Jolien Trifa Fatma Verschaeve Luc Mansour Hedi Ben Mertens Birgit 《Environmental science and pollution research international》2020,27(32):40088-40100
Environmental Science and Pollution Research - Due to the complexity and variability of textile wastewater composition, a constant search for new treatment strategies that are efficient,... 相似文献
134.
多效膜蒸馏技术浓缩回收废水中的二甲基亚砜 总被引:1,自引:0,他引:1
利用具有内部潜热回收功能的气隙式多效膜蒸馏(MEMD)组件对含二甲基亚砜(DMSO)的化纤废水进行了浓缩回收研究,考察了料液中DMSO浓度、进料流量、进料温度和膜侧进口温度对膜通量、造水比、分离因子和回收率的影响。结果表明,多效膜蒸馏可以将DMSO废水浓缩至200~300 g/L;初始浓度为6.2 g/L时,造水比和分离因子最高值分别为12.4和76.0;虽然膜通量、造水比和分离因子均随料液浓度增大而下降,但是当DMSO浓度达到200 g/L时,膜通量、造水比、分离因子仍分别高达3.74 L/(m2·h)、7.1、32.1;在整个浓缩过程中,回收率维持在99.6%以上;当DMSO废水浓缩达到150 g/L以上时,含有少量DMSO的渗透液可作为二次料液继续用MEMD过程浓缩。膜组件在连续运行的1个月内保持了良好的操作性能。该实验研究表明,多效膜蒸馏过程可以高效节能地浓缩回收化纤废水中的DMSO。 相似文献
135.
Mounir Ben Mbarek Nadia Ben Ali Rochdi Feki 《Environment, Development and Sustainability》2014,16(6):1253-1262
This article analyzes the causality between the economic growth, the energy and the environment, measured by CO2 emissions. Our empirical study is based on a series of annual data from 1980 to 2010 in Tunisia. Our study was conducted using the Granger causality test and variance decomposition. The empirical results confirm the presence of a positive effect between the energy consumption and the economic growth measured by gross domestic product (GDP). Thus, there is a unidirectional relationship between GDP and CO2 emissions in the short term. This analysis shows, as is common to relatively fast-growing economies in Tunisia, that the biggest contributor to the rise is CO2 emissions. Hence, in congruence with the result of variance decomposition, the GDP affects CO2 emissions in the short and medium term at an almost constant level (10 %). The non-renewable energy intensity in Tunisian economy is responsible for a modest reduction in CO2 emissions, which suggests the implementation of conservation policies aimed at energy efficiency and the orientation toward renewable energy. 相似文献
136.
Salwa Magdich Chedlia Ben Ahmed Raja Jarboui Béchir Ben Rouina Makki Boukhris Emna Ammar 《Chemosphere》2013
Olive mill wastewater (OMW) is a problematic by-product of olive oil production. While its high organic load and polyphenol concentrations are associated with troublesome environmental effects, its rich mineral and organic matter contents represent valuable nutrients. This study aimed to investigate the valorization of this waste biomass as a potential soil conditioner and fertilizer in agriculture. OMW was assayed at three doses 50, 100, and 200 m3 ha−1 year−1) over three successive years in olive fields. The effects of the effluent on the physico-chemical and microbial properties of soil-layers were assessed. The findings revealed that the pH of the soil decreased but electrical conductivity and organic matter, total nitrogen, sodium, and potassium soil contents increased in proportion with OMW concentration and frequency of application. While no variations were observed in phosphorus content, slow increases were recorded in calcium and magnesium soil contents. Compared to their control soil counterparts, aerobic bacteria and fungi increased in proportion with OMW spreading rates. The models expressing the correlation between progress parameters and OMW doses were fitted into a second degree polynomial model. Principal component analysis showed a strong correlation between soil mineral elements and microorganisms. These parameters were not related to phosphorus and pH. 相似文献
137.
城市环境质量多级模糊综合评价 总被引:40,自引:0,他引:40
文章将模糊聚类与层次分析相结合,提出了城市环境质量多级模糊综合评价法,并将该方法应用于宣州市环境质量综合评价,结果表明,该方法克服了综合指数法受人为因素影响大的缺点,较好地反映了环境质量分级界限的模糊性,并且较好地解决了权值分配问题,使评价结论更合理,可靠,是一种有价值的城市环境质量综合评价方法。 相似文献
138.
深圳市公路建设对生态环境的影响、治理及对策 总被引:7,自引:0,他引:7
公路建设曾经给深圳的生态环境造成了较为严重的危害 ,主要有 :严重的水土流失及其派生影响 ,对一些具有观赏价值的自然景观产生破坏 ,影响了部分区域动植物生存环境等。主要对这些环境影响及已进行的治理及其成效进行综述 ,对治理工作的不足及未来对策也进行了探讨。 相似文献
139.
Implications of differing input data sources and approaches upon forest carbon stock estimation 总被引:3,自引:0,他引:3
Michael A. Wulder Joanne C. White Graham Stinson Thomas Hilker Werner A. Kurz Nicholas C. Coops Ben?it St-Onge J. A. Trofymow 《Environmental monitoring and assessment》2010,166(1-4):543-561
Site index is an important forest inventory attribute that relates productivity and growth expectation of forests over time. In forest inventory programs, site index is used in conjunction with other forest inventory attributes (i.e., height, age) for the estimation of stand volume. In turn, stand volumes are used to estimate biomass (and biomass components) and enable conversion to carbon. In this research, we explore the implications and consequences of different estimates of site index on carbon stock characterization for a 2,500-ha Douglas-fir-dominated landscape located on Eastern Vancouver Island, British Columbia, Canada. We compared site index estimates from an existing forest inventory to estimates generated from a combination of forest inventory and light detection and ranging (LIDAR)-derived attributes and then examined the resultant differences in biomass estimates generated from a carbon budget model (Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3)). Significant differences were found between the original and LIDAR-derived site indices for all species types and for the resulting 5-m site classes (p?<?0.001). The LIDAR-derived site class was greater than the original site class for 42% of stands; however, 77% of stands were within ±1 site class of the original class. Differences in biomass estimates between the model scenarios were significant for both total stand biomass and biomass per hectare (p?<?0.001); differences for Douglas-fir-dominated stands (representing 85% of all stands) were not significant (p?=?0.288). Overall, the relationship between the two biomass estimates was strong (R 2?=?0.92, p?<?0.001), suggesting that in certain circumstances, LIDAR may have a role to play in site index estimation and biomass mapping. 相似文献
140.
Soil erosion and sediment fluxes analysis: a watershed study of the Ni Reservoir,Spotsylvania County,VA, USA 总被引:1,自引:0,他引:1
Anthropogenic forces that alter the physical landscape are known to cause significant soil erosion, which has negative impact on surface water bodies, such as rivers, lakes/reservoirs, and coastal zones, and thus sediment control has become one of the central aspects of catchment management planning. The revised universal soil loss equation empirical model, erosion pins, and isotopic sediment core analyses were used to evaluate watershed erosion, stream bank erosion, and reservoir sediment accumulation rates for Ni Reservoir, in central Virginia. Land-use and land cover seems to be dominant control in watershed soil erosion, with barren land and human-disturbed areas contributing the most sediment, and forest and herbaceous areas contributing the least. Results show a 7 % increase in human development from 2001 (14 %) to 2009 (21.6 %), corresponding to an increase in soil loss of 0.82 Mg ha-1 year-1 in the same time period. 210Pb-based sediment accumulation rates at three locations in Ni Reservoir were 1.020, 0.364, and 0.543 g cm-2 year-1 respectively, indicating that sediment accumulation and distribution in the reservoir is influenced by reservoir configuration and significant contributions from bedload. All three locations indicate an increase in modern sediment accumulation rates. Erosion pin results show variability in stream bank erosion with values ranging from 4.7 to 11.3 cm year-1. These results indicate that urban growth and the decline in vegetative cover has increased sediment fluxes from the watershed and poses a significant threat to the long-term sustainability of the Ni Reservoir as urbanization continues to increase. 相似文献