水体底泥对污染物的吸附-解吸机理的研究

水体底泥污染已经成为世界范围内的一个重要的环境问题,其污染物主要通过大气沉降、废水排放、雨水淋溶冲刷等进入水体,最后沉积到底泥中并逐渐富集,使底泥受到严重污染。吸附-解吸是底泥污染的重要过程,为了控制水体底泥污染,对底泥对各种污染物的吸附-解吸机理及其影响因素的研究显得极其重要。本文总结了底泥中氮、磷和重金属等的吸附-解吸的影响因素及机理,对今后水体底泥污染方面的研究具有重要意义。     

自然水体多相体系中重金属离子在生物膜上的竞争吸附

在实验室中模拟松花江水体,研究了在表层沉积物和悬浮颗粒物存在的条件下,铅、镉和铜3种重金属离子在生物膜上竞争吸附的热力学规律。对重金属在自然水体多相体系中的迁移规律进行了探究,以期为重金属污染的治理提供理论依据。     

有机菌肥对铅、镉、锌污染土壤和水体联合修复研究

为了研究液体有机菌肥在矿区周边农田污染土壤重金属去除效果，以重金属污染为研究对象，开展液体有机菌肥吸附混合液重金属试验和土壤重金属浸出毒性吸附实验，分析液体有机菌肥对重金属离子去除作用。结果表明：随着液体有机菌肥用量的增加，水体重金属铅、镉和锌含量浓度呈显著下降，液体有机菌肥容易吸附铅，吸附量高达到1667mg/kg,其次是镉和锌。在1%质量比添加量下，经过液体有机菌肥修复后的土壤镉、锌和铅含量下降率分别是29.62%、23.94%和11.66%,土壤重金属TCLP浸出毒性去除率效果显著。有机菌肥处理可改善土壤环境，对土壤和水体的铅、镉、锌重金属有一定修复作用。     

pH值对土壤吸附铜的影响分析

随着社会经济的不断进步,土壤中重金属污染问题日趋严峻,土壤中重金属污染已经受到政府相关部门和一些研究人员的高度重视。本文运用化学分析的方法研究了土壤对金属铜的吸附作用。研究土壤吸附铜的速率的方法是根据所做实验的数据进而绘制吸附量与时间之间的变化曲线,通过所得到的曲线斜率来探讨吸附动力学过程。通过实验分析我们得知:pH对土壤吸附铜的影响达到了显著水平,当其他的条件相同、土壤自身的pH增加时,土壤对铜的吸附量也随着增加,加入液pH为5.5时的吸附量显著高于pH为2.5的吸附量。表明土壤对铜的吸附作用受酸度影响较为明显,在酸度增加的情况下,土壤对铜的吸附降低,使得铜从土壤中解吸出来,进入水体对环境造成危害。因此,我们要提高预防酸雨等环境问题,防止酸雨使得土壤中重金属进入到水体。     

水体重金属污染的生态效应及生物监测

重金属污染是水体污染的一个重要方面,随着工业的发展和人口的不断增加,水体重金属污染已经成为全球的环境问题。本文主要介绍了水体重金属的污染现状以及对水生植物、水生动物和人体健康的危害,并探讨运用生物的敏感性来监测水体重金属污染的可行性,生物监测水体重金属污染有很好的发展前景。     

生物吸附法处理水体中的重金属的现状与展望

对生物吸附法处理水体中的重金属进行了综述，得出微生物对重金属表现出良好的吸附性能，吸附机理比较复杂，与离子交换有密切关系，常用吸附等温线评价微生物对重金属的吸附能力。由于该研究历史比较短，生物吸附的工艺应用、机理分析、生物固定化等研究还不够深入，有待进一步的研究探索，使其应用于工业生产。     

水体重金属污染治理技术研究进展

随着工业的发展和人口的不断增加,重金属废水排放量增加。有毒重金属对环境的严重威胁正逐渐成为全球性问题,不仅对环境造成危害,还威胁着人类的健康。介绍了水体重金属污染现状及危害,综述了目前国内外治理水体重金属污染主要技术的研究进展,指出了微生物治理重金属污染水体的良好应用前景。     

生物吸附法处理水体中的重金属的现状与展望

对生物吸附法处理水体中的重金属进行了综述,得出微生物对重金属表现出良好的吸附性能。吸附机理比较复杂,与离子交换有密切关系,常用吸附等温线评价微生物对重金属的吸附能力。由于研究的历史比较短,生物吸附的工艺应用、机理分析、生物固定化方面的研究还不够深入,有待进一步的研究,使其应用于工业生产。     

生物吸附法处理水体中的重金属的现状与展望

对生物吸附法处理水体中的重金属进行了分析，得出微生物对重金属表现出良好的吸附性能；吸附机理比较复杂，与离子交换有密切关系；常用吸附等温线评价微生物对重金属的吸附能力。由于研究的历史比较短，生物吸附的工艺应用、机理分析、生物粒化方面的研究还不够深入，有待进一步的研究，使其应用于工业生产。     

广元市嘉陵江干流重金属特征研究

为了解嘉陵江干流(广元段)水体中重金属污染状况,对其水中重金属含量变化进行分析,并探讨了水体温度、pH及DO对重金属(Pb、Zn、Cd、Cu)含量变化相关性和重金属之间的相互关系。结果表明:2012年到2015年重金属Pb、Zn、Cd、Cu总含量变化整体呈现下降趋势,Hg含量呈上升趋势;枯水期重金属含量低于平水期和丰水期;不同水文时期对水体温度、pH及DO对重金属含量变化影响不同;重金属含量之间存在一定的显著相关性,可能具有一定的同源性。     

Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.     

AN APPLICATION RUNOFF MODEL STRATEGY FOR UNGAGED WATERSHEDS1

ABSTRACT: Mathematical models for predicting watershed surface flow responses are available, most of which are elaborate nonlinear numerical surface and channel flow models linked with infiltration models. Such models may be used to make predictions for ungaged areas, assuming an acceptable fitting of the model to the topography and roughness of the real system. For some application purposes, these models are impractical because of their complexity and expensive computer solutions. A procedure is developed that uses a complex model of an ungaged area to derive a simpler parametric nonlinear system model for repetitious simulation with input sequences. The predicted flow outputs are obtained with the simpler model at significant savings of money and time. The procedures for constructing a complex kinematic model of a 40 acre (161,880 m²) reference watershed and deriving the simpler system model are outlined. The results of predictions from both models are compared with a selected set of measured events, all having essentially the same initial conditions. Peak discharges ranged from 3 to 118 ft³/sec (0.085 to 3.34 m³/sec), which includes the largest event of record. The inherent limitations of lumped systems models are demonstrated, including the bias caused by their inability to model infiltration losses after rainfall ceases. Computer costs and times for the models were compared. The derived simple model has a cost advantage when repeated use of a model is required. Such an applications hydrologic model has an engineering tradeoff of reduced accuracy, and lumping bias, but is more economical for certain design purposes.     

Urban ecological systems: scientific foundations and a decade of progress

Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.     

Neighbourhood characteristics and urban gardens in the Toledo metropolitan area: staffing and voluntarism,food production,infrastructure, and sustainability practices

Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.     

Using Paleo Reconstructions to Improve Streamflow Forecast Lead Time in the Western United States

In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.     

Predicting deer-vehicle collisions in an urban area

Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.     

MANGANESE CYCLE IN IMPOUNDMENT WATER

Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.     

Biodiversity and biotechnology

The maintenance of biodiversity is urged from many quarters and on grounds ranging from aesthetic considerations to its usefulness, particularly for biotechnology. But regardless of the grounds for preserving biodiversity, writers are generally in agreement that it should be preserved. But, in examining the various references biodiversity, such as species diversity, genetic diversity, and habitat diversity, it is apparent that we cannot aim to preserve biodiversityas such, since there are a number of conflicts in any such undertaking. In preserving one aspect of biodiversity, we damage another aspect. Five arguments which attempt to ground our moral concern for biodiversity are reviewed and critiqued, not only for their consistency but also for their power to move us to action. The final section of the paper shows how conflicts in the values of personal and environmental health can impair ethical action and especially policy formation.An earlier version of this paper was read at the conference on Agriculture, Food, and Human Values: Tradition and Change, Orlando, Florida, October 7–9, 1987.     

Surface applied water treatment residuals affect bioavailable phosphorus losses in Florida sands

Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.     

Sources and Transport of Phosphorus to Rivers in California and Adjacent States,U.S., as Determined by SPARROW Modeling

The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de‐trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small‐ and intermediate‐sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams.