寒冷地区人工湿地保温措施及运行方式优化研究

通过对垂直流人工湿地冬季运行保温效果的研究,得出这种湿地类型在冬季没有保温措施的情况下,也不会造成布水管道的冻结,有机物去除率在70%以上;在进行简单保温措施后,处理效果显著提高,有机物去除率普遍在80%以上,说明垂直流人工湿地在西北寒冷地区的应用没有问题。另外,冬季低温运行时可通过优化运行方式提高湿地的除污和抗冻能力。     

人工湿地对模拟煤矿废水铁、锰的去除效果研究

针对贵州省煤矿酸性废水的危害日益加剧的现状,通过建立人工湿地系统对模拟煤矿废水中铁、锰的去除效果研究,结果表明在进水浓度总铁:200 mg/L,总锰:12 mg/L,停留时间为24 h的条件下,对Fe的去除率达99.7%,对Mn的去除率达88.5%,均远低于煤炭工业污染物排放标准,为进行人工湿地系统处理煤矿酸性废水的可行性提供理论依据。     

湖北网湖自然保护区生态质量评价

湖北网湖自然保护区属于内陆湿地和水域生态系统类型的自然保护区。根据网湖自然保护区的特征,通过选取自然性、多样性、稀有性、代表性、面积适应性、人类干扰、稳定性7个评价指标,运用指标赋分法和加权平均分法进行生态质量综合评价。结果表明,该保护区生态质量很好,气候适宜,动植物种类丰富,并且由于该区域目前经济处于初步发展中,人为干扰对其影响较小,因此短期内其生态环境质量会相对稳定,具有很高的保护和研究价值。同时针对网湖湿地目前所存在的威胁以及国家在治理和恢复其他湿地保护区的经验,提出了几点关于网湖湿地建设和远景开发规划的建议。     

扎龙国家级自然保护区内滨洲铁路沿线植物资源调查

扎龙自然保护区始建于1979年,是黑龙江省生物多样性最丰富的重要湿地,也是丹顶鹤等多种珍稀濒危野生动物重要的繁殖栖息地;滨州铁路于1903年建成,铁路在保护区范围纵向24.4 km,横向线位离保护区北边界59 km,南边界28 km,由于铁路两侧地形和铁路分割等特点,多年来探索铁路运营与湿地保护协调发展,本次对铁路两侧保护区范围内典型植被进行了实地调查,为扎龙湿地保护区管理和规划以及铁路环境保护现状管理和建设规划提供科学依据。     

Featured Collection Introduction: Connectivity of Streams and Wetlands to Downstream Waters

Connectivity is a fundamental but highly dynamic property of watersheds. Variability in the types and degrees of aquatic ecosystem connectivity presents challenges for researchers and managers seeking to accurately quantify its effects on critical hydrologic, biogeochemical, and biological processes. However, protecting natural gradients of connectivity is key to protecting the range of ecosystem services that aquatic ecosystems provide. In this featured collection, we review the available evidence on connections and functions by which streams and wetlands affect the integrity of downstream waters such as large rivers, lakes, reservoirs, and estuaries. The reviews in this collection focus on the types of waters whose protections under the U.S. Clean Water Act have been called into question by U.S. Supreme Court cases. We synthesize 40+ years of research on longitudinal, lateral, and vertical fluxes of energy, material, and biota between aquatic ecosystems included within the Act's frame of reference. Many questions about the roles of streams and wetlands in sustaining downstream water integrity can be answered from currently available literature, and emerging research is rapidly closing data gaps with exciting new insights into aquatic connectivity and function at local, watershed, and regional scales. Synthesis of foundational and emerging research is needed to support science‐based efforts to provide safe, reliable sources of fresh water for present and future generations.     

Contamination status of arsenic,lead, and cadmium of different wetland waters

The present investigation was conducted to determine the contamination status of arsenic (As), cadmium (Cd), and lead (Pb) in the wetland waters of Bhaluka in Bangladesh. Water samples were collected from 15 selected wetlands of Bhaluka region and analyzed using an atomic absorption spectrophotometer. Estimated results of three metals detected were As (7–80?µg?L^?1), Pb (0–86?µg?L^?1) and Cd (0–70?µg?L^?1) in water samples in all wetlands. The level of As in all investigated wetlands (93%) was higher than that of WHO recommended permissible limit of drinking water except Alanga wetland. However, As levels were higher than that recommended for livestock water quality levels. Eighty-seven percent of the investigated wetlands showed lower content of Pb than WHO recommended permissible limit of drinking water, but two wetland waters (Dohuria-1 and Chowdhuri) were polluted with higher Pb levels. Sixty-seven percent of the investigated wetlands displayed higher levels of Cd than WHO recommended permissible limit in drinking water. Dissolved organic material showed no significant difference among the 15 investigated wetlands water, but total dissolved solids was significantly greater. The condition of the water of all wetlands was basic pH. All water samples were applied to linear regression equation and correlation coefficients where values showed no significant differences. Data demonstrate that the estimated high metal concentrations of these ponds may contribute to bioaccumulation within plants, food grains and shrimp.     

Estimation of methane emitted by natural wetlands of Orissa: Based on case studies on three representative wetlands

The rapid increase in the concentration of greenhouse gases in our atmosphere has led to significant changes in global climate. Methane is second to carbon dioxide in terms of its contribution to global warming. The wetlands serve as a major natural source of methane. Orissa State, located on the east coast of India, has a number of natural wetlands. Three representative wetlands: Chilka – the largest semi-saline lake of Asia, Anshupa – a land-locked fresh water lake and Gahirmatha – a tidal flood plain of Bhitara Kanika region that has sprawling mangrove vegetation (extension of the Sunderbans of the Gangetic delta) were chosen for intensive monitoring of water and sediment quality, along with methane flux over a period of three years during 1997–2000. The average seasonal methane fluxes were integrated to arrive at the annual flux from each wetland category. Finally, those results were extended to other natural wetlands of Orissa to arrive at the average annual methane flux of Orissa State. This is useful in calculating the total budget of greenhouse gases of India.     

Estimating rate constants of contaminant removal in constructed wetlands treating winery effluent: A comparison of three different methods

In this paper we investigated the use of three different methods for determining the rate constants for degradation of winery effluent within a sub-surface flow constructed wetland (CW). These methods comprised of using a dispersed plug flow (the Peclet) equation; a tanks-in-series (TIS) equation; and analysing the residence time distribution (RTD) directly. The last of these is described by the convolution integral (CI). We demonstrated self-similarity of the RTDs, which meant that the system's hydraulics were similar throughout the CW. We therefore extrapolated the RTD data to develop a more complete understanding of the hydraulic properties of the CW and examine how they affected the kinetics of degradation. We found that whilst both the Peclet and the TIS equation were able to predict concentration within the CW, this required the optimisation of more than one variable at the same time rendering a result that was more of a modelling exercise than a useful design tool. The CI method could be applied to predict system parameters effectively. We used it to measure rate constants of removal for both ethanol and potassium (key species for tracking the degradation/treatment of the effluent). Acetic acid, however, did not degrade implying that the CW operated aerobically. The concentration of sodium increased very slightly, indicating that it is not bioremediated/removed and that there are some minor evapotranspirative effects. The rate constant found for the biodegradation of COD was found to have significantly more uncertainty associated with it than the measurement of the rate of degradation individual components and we therefore posit that it is better to describe the processes of degradation by tracking individual components rather than lumped parameters.     

海滨湿地景观过程模型与模拟研究——以江苏盐城保护区核心区为例

景观过程模型已经成为深化景观变化研究的重要手段并日益受到重视。海滨湿地是一种高度复杂和动态变化的景观系统,构建景观过程模型能够从机理上解释湿地景观时空动态演变过程。研究中,将盐城国家级自然保护区核心区划分为人工管理区和自然湿地区两种模式,根据2000、2006、2011 年3 个时相的景观资料以及野外生态监测数据,构建海滨湿地景观过程模型,结果如下：①利用空间代替时间并结合灰色关联分析,确定了海滨湿地景观演变的关键影响因素为土壤盐度和水分;②运用人工神经网络的方法,分析了土壤盐度和水分的空间分异,并通过图层叠加和分级统计,得出了土壤盐度和水分的阈值范围以及变化规律;③运用GIS-Matlab-CA技术构建了基于关键生态过程的海滨湿地景观过程模型,模型总体精度都在80%以上,Kappa 系数都在0.7 以上,一致性检验结果表明空间位置一致率决定了整个景观模拟的精度;④运用已构建好的模型对研究区2012-2020、2025 年的结果进行了模拟预测,预测结果表明,盐城海滨湿地芦苇沼泽和米草沼泽扩张、碱蓬沼泽面积减少的趋势将愈加明显。     

SEMIPERMEABLE MEMBRANE DEVICES USED TO ESTIMATE BIOCONCENTRATION OF POLYCHLORINATED BIPHENYLS1

ABSTRACT: Aquatic organisms passively accumulate hydrophobic organic compounds, such as polychlorinated biphenyls, even when ambient water concentrations of the contaminant are below analytical detection limits. However, contaminant concentrations in tissue samples are subject to an inherently high level of variability due to differences in species, life stage, and gender bioconcentration potentials. Semipermeable membrane devices (SPMDs) were used to sample Aroclor 1254, a mixture of readily bioconcentrated polychlorinated biphenyls (PCBs), in a contaminated wetland near Flat Top, WV. The devices consisted of triolein, a lipid found in fish, enclosed in a polyethylene membrane. SPMDs were deployed in the water column and in direct contact with wetland sediments along a previously identified concentration gradient of PCBs. The devices were retrieved after a 25-day exposure period. Analytes were recovered by dialyzing the devices in nanograde hexane. Hexane dialysates were condensed and analyzed by gas chromatography. All deployed devices sequestered quantifiable amounts of Aroclor 1254. Water-column SPMDs accumulated PCBs far in excess of ambient water concentrations. The devices contacting sediments accumulated PCBs at all sites, though accumulated concentrations did not exceed concentrations in sediment. Patterns of PCB concentration in the devices corresponded to the identified gradient at the site. Results from the water-column SPMDs were used to estimate the concentration of the dissolved, bioavailable fraction of PCBs present in the water column. These concentrations ranged from 0.01 to 0.09 μg/L of bioavailable Aroclor 1254.