Assessment of Temporal and Spatial Variation of Nitrate Removal in Riparian Zones

The aim of this study was to monitor long-term temporal and spatial groundwater NO₃^- removal efficiencies in different riparian zones via a limited number of sampling wells. Groundwater NO₃^- concentrations were measured fortnightly or monthly over a period of two years using transects of ground water sampling wells. Depending on the level of the NO₃^- load (up to 120mgNL^-1 at the input side of the riparian zone a distance of 10 to 30m was needed to remove NO₃^- from the groundwater below 11.3mgNL^-1. Considering all seasons, the mixed vegetation and grass riparian site succeeded to remove groundwater NO₃^- efficiently (92—100% within a distance of 30m. The forested riparian zone removed 72—90% of the total NO₃^- input within a distance of 30m. Evidence emerged that NO₃^- could also be removed actively at depths up to 2m, due to the presence of organically enriched layers of alluvial deposits or roots. Our four dimensional approach (three dimensional space and time), in combination with a limited number of sampling wells, was shown to be a useful monitoring tool to assess the variability of NO₃^- removal in riparian zones.     

三峡水库消落带典型主动与被动修复策略对土壤饱和导水率的影响

人工造林的主动修复与退耕还林还草的被动修复是退化生态系统典型的生态修复策略.以三峡水库运行后形成的消落带为研究对象,研究不同生态修复策略对消落带土壤饱和导水率的影响,对生态脆弱带的水土保持效应具有重要意义.选取桑树+水杉复合林(主动修复)、自然草地(被动修复)、农田(对照)为研究样地,探究了两种不同生态修复策略下三峡水...     

选矿废水中醚胺的某些环境化学特性研究

通过降解,吸附及土柱淋滤试验等手段,对选矿废水中醚胺的降解规律,降解能力,吸附能力,分配特征以及在土壤中的垂直迁移规律等环境化学特性进行了试验研究。结果表明：（１）醚胺在水体中的降解规律服从一级生物化学反应方程ｃ－ｃｏｅｓｐ（－Ｋｔ）,温度和ｐＨ值是影响降解系数Ｋ的两个主要因素;（２）土壤对醚胺的吸率在９２％以上,吸附方程为ｑ＝５．３３５＋６３．３ｇｃ;（３）醚胺在土壤中的垂直迁移规律为ｃ＝ａｅｘ     

稳定塘污泥降解的静态模拟研究

通过人工控制下的实验室内静态模拟,研究了稳定塘污泥降解过程中的pH值变化趋势?有机物浓度?淤积时间?温度对污泥降解速率的影响以及污泥降解的数学模型?结果表明:污泥降解过程的pH值先降低?后回升,继而趋于稳定;有机物浓度对污泥降解速率无影响,污泥降解速率与降解时间的关系为r∝t-α;温度对降解速率常数的影响符合Arhenius指数关系式;实验室内的污泥降解符合零级反应规律?      

城市绿化法初论:概念与立法目的

城市绿化法是指调整人们在城市绿化活动中产生的社会关系的法律规范总和。它应以保障人的健康和福利、促进城市可持续发展、保障和促进城市绿化事业的发展、保护和改善生态环境、美化生活环境为立法目的。城市绿化法的立法目的既是城市绿化法创制和适用的前提和根本,也是研究城市绿化法的逻辑起点。     

Water Quality Functions of a 15-Year-Old Riparian Forest Buffer System1

Newbold, J. Denis, Susan Herbert, Bernard W. Sweeney, Paul Kiry, and Stephen J. Alberts, 2010. Water Quality Functions of a 15-Year-Old Riparian Forest Buffer System. Journal of the American Water Resources Association (JAWRA) 46(2):299-310. DOI: 10.1111/j.1752-1688.2010.00421.x Abstract: We monitored long-term water quality responses to the implementation of a three-zone Riparian Forest Buffer System (RFBS) in southeastern Pennsylvania. The RFBS, established in 1992 in a 15-ha agricultural (row crop) watershed, consists of: Zone 1, a streamside strip (∼10 m wide) of permanent woody vegetation for stream habitat protection; Zone 2, an 18- to 20-m-wide strip reforested in hardwoods upslope from Zone 2; and Zone 3, a 6- to 10-m-wide grass filter strip in which a level lip spreader was constructed. The monitoring design used paired watersheds supplemented by mass balance estimates of nutrient and sediment removal within the treated watershed. Tree growth was initially delayed by drought and deer damage, but increased after more aggressive deer protection (1.5 m polypropylene shelters or wire mesh protectors) was instituted. Basal tree area increased ∼20-fold between 1998 and 2006, and canopy cover reached 59% in 2006. For streamwater nitrate, the paired watershed comparison was complicated by variations in both the reference stream concentrations and in upslope groundwater nitrate concentrations, but did show that streamwater nitrate concentrations in the RFBS watershed declined relative to the reference stream from 2002 through the end of the study in early 2007. A subsurface nitrate budget yielded an average nitrate removal by the RFBS of 90 kg/ha/year, or 26% of upslope subsurface inputs, for the years 1997 through 2006. There was no evidence from the paired watershed comparison that the RFBS affected streamwater phosphorus concentration. However, groundwater phosphorus did decline within the buffer. Overland flow sampling of 23 storms between 1997 and 2006 showed that total suspended solids concentration in water exiting the RFBS to the stream was on average 43% lower than in water entering the RFBS from the tilled field. Particulate phosphorus concentration was lower by 22%, but this removal was balanced by a 26% increase in soluble reactive phosphorus so that there was no net effect on total phosphorus.     

Ability of Remnant Riparian Forests,With and Without Grass Filters,to Buffer Concentrated Surface Runoff1

Knight, Kris W., Richard C. Schultz, Cathy M. Mabry, and Thomas M. Isenhart, 2010. Ability of Remnant Riparian Forests, With and Without Grass Filters, to Buffer Concentrated Surface Runoff. Journal of the American Water Resources Association (JAWRA) 46(2):311-322. DOI: 10.1111/j.1752-1688.2010.00422.x Abstract: Riparian forest buffers established according to accepted conservation practice standards have been recommended as one of the most effective tools for mitigating nonpoint source pollution. The midwestern United States is characterized by many kilometers of narrow, naturally occurring forests along streams. However, little is known about the relative effectiveness of these remnant forests compared with these newly established buffers. This study compared the ability of naturally occurring remnant forests with and without adjacent planted grass filters to buffer concentrated flow paths (CFPs) originating in crop fields along first- and second-order streams in three northeast Missouri watersheds. Remnant forests breached by runoff through CFPs were narrower than those that dispersed 100% of the CFPs. Remnant forests with adjacent grass buffers were nearly twice the width as those without grass filters. We also found that CFPs, which developed within remnant forests and at the base of in-field grass waterways, were potential sources of sediments to streams. Methods to mitigate these CFPs warrant further investigation. Our study suggests that although these natural remnant forests provide substantial buffering capacity, both improved management and/or the addition of an adjacent grass filter would improve water quality by reducing sediment loss to streams. Inferences can be used to inform the design and management of similar conservation buffer systems within the region.     

Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil

Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, ρ(b), and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D(p)/D(o), ratio of gas diffusion coefficients in soil and free air) and air permeability (k(a)) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting ρ(b) values ranging from 1.40 to 2.10 g cm(-3). Results showed that D(p) and k(a) values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2mm) under variably-saturated conditions for a given soil-air content (ε), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D(p) and k(a) was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D(p)/D(f), the ratio of measured D(p) to D(p) in total porosity (f), (ii) for air permeability k(a)/k(a)(,pF4.1), the ratio of measured k(a) to k(a) at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content (ε) to total porosity (f) (air saturation). Based on the normalized parameters, predictive power-law models for D(p)(ε/f) and k(a)(ε/f) models were developed based on a single parameter (water blockage factor M for D(p) and P for k(a)). The water blockage factors, M and P, were found to be linearly correlated to ρ(b) values, and the effects of dry bulk density on D(p) and k(a) for both '+gravel' and '-gravel' fractions were well accounted for by the new models.     

Roles of environmental movement organisations in land-use planning: case studies of the Niagara Escarpment and Oak Ridges Moraine,Ontario, Canada

The paper explores the roles of environmental movement organisations (EMOs) in land-use planning, including domain creation (establishment of new or modified landscape planning boundaries) and regime change (adoption of new or modified legal and planning rules). The research involved two case studies of land-use planning processes: the Niagara Escarpment and Oak Ridges Moraine, Ontario, Canada. The two cases together reveal an evolution of land-use planning towards collaborative processes on mainly private lands in Southern Ontario during the period from 1960 to 2002. The results suggest that EMOs can create new planning domains through agenda setting activities, build landscape value and vision, educate governments and the public, and work to maintain and alter regimes. Collaborative planning has emerged as an important process in which some EMOs are now participating.     

Green Lawfare: Environmental Public Interest Litigation and Mediatized Environmental Conflict

Communication strategies involving news media and environmental groups are well documented and research into protest politics and other forms of environmental communication has made considerable progress in the analysis of the strategies that various actors use to influence environmental policy. There is less scholarship, however, on the journalistic representation of the legal strategies employed by environmental non-government organizations, such as the mediatized debates about the use of law by these groups and the laws themselves. Further, while legal scholarship observes the role of public interest litigation in environmental matters, the role of news media as an influential force in public opinion formation and mobilization in the context of environmental litigation as an activist strategy remains less understood. Using the 2015 “green lawfare” debate in Australia that followed a successful Australian Federal Court challenge to a coalmine, this paper argues that the “mediatized visibility” inherent in public interest litigation is an important, but mostly overlooked, element of mediatized environmental conflict.