固相微萃取(SPME)技术在水质监测中的应用

固相微萃取技术(SPME)作为一种样品前处理技术,具有方便、快捷、不使用有机溶剂、灵敏度高、价格低廉等优点,已被广泛地应用于环境样品的分析.本文综合评述了采用SPME法预处理环境水体中的有机物、无机离子等污染物的监测情况,并对SPME法在环境水质监测中的应用以及对国外的研究进展进行了展望.     

C_8-SBA-15新型介孔涂层SPME-HPLC联用测定水样中的芘

以辛基键合SBA-15为固相微萃取（SPME）的吸附涂层,考察了吸附和解吸时间、萃取温度、搅拌速率对SPME效率的影响。该方法的线性范围为3.0—320μg/L,检出限为0.5μg/L,依据此方法测定了环境水样中芘,具有灵敏度高和精密度好的特点。     

C8-SBA-15新型介孔涂层SPME-HPLC联用测定水样中的芘

以辛基键合SBA- 15为固相微萃取(SPME)的吸附涂层,考察了吸附和解吸时间、萃取温度、搅拌速率对SPME效率的影响.该方法的线性范围为3.0-320μg/L,检出限为0.5μg/L,依据此方法测定了环境水样中芘,具有灵敏度高和精密度好的特点.     

水中阿特拉津及代谢物前处理和快速检测技术研究进展

查阅了近10年来针对环境样品中阿特拉津及代谢物检测的相关文献,综述了目前水中阿特拉津液液萃取、固相萃取、分散固相萃取、磁固相萃取、固相微萃取、直接进样等前处理技术,并就各种前处理方法的优缺点、适用水样类型及检测范围进行了介绍,并关注了基于免疫学、生物学、电化学、光学等为基础的快速检测方法的主要优缺点及应用现状,同时对水中阿特拉津及代谢物前处理及快速检测技术发展重点关注方向进行了展望。     

液相色谱—电感耦合等离子体质谱联用测定水质有机锡化合物的前处理方法研究

采用液液萃取前处理方法对水中的有机锡进行提取,并在一定的分析条件下用液相色谱—电感耦合等离子体质谱联用（HPLC-ICP-MS）分析法,测定水中的二苯基锡、二丁基锡、三苯基锡和三丁基锡4种有机锡化合物。为了提高前处理的萃取效率,研究了萃取溶剂、萃取次数和萃取酸度不同时对萃取效率的影响。     

介孔涂层SPME- HPLC联用测定水样中的多环芳烃

以辛基键合SBA- 15为固相微萃取(SPME)的吸附涂层,考察了吸附和解吸时间、萃取温度、搅拌速率对SPME效率的影响,该方法的线性范围分别为0.4-300μg/L、4.0-450μg/L,检出限为0.3μg/L、0.10μg/L,以此方法测定了环境水样中萘、蒽的含量.该方法具有灵敏度高和精密度好的特点.     

搅拌棒吸附萃取技术在环境样品分析中的应用

搅拌棒吸附萃取(SBSE)是继固相微萃取(SPME)之后的又一种无溶剂的用于痕量有机物分离和浓缩的技术,其萃取涂层体积大,具有灵敏度高、检出限低、重现性好、不使用有机溶剂等优点。适用于环境样品中挥发性及半挥发性有机物的痕量分析。本文综述了SBSE在环境样品分析中的应用,以及该技术的应用展望。     

土壤中半挥发性有机物前处理方法的比较研究

现阶段索氏萃取法、超声波萃取法、微波辅助萃取法和加压流体萃取法是主流的土壤样品前处理技术,每种方法有着各自的特点。以多环芳烃和有机氯农药为目标化合物,通过研究每种萃取方法的萃取效率,进行横向比较研究后发现,索氏萃取法的萃取效率较高,但是自动化程度不高;而加速溶剂萃取法和微波辅助萃取法在保证了样品萃取效率的前提下,具有节省溶剂、自动化程度高等特点,特别适合于大批量样品的前处理工作。     

ICP-MS联用色谱技术在环境领域元素形态分析的应用

ICP-MS联用色谱技术是元素形态分析的主流分析手段,围绕ICP-MS联用气相色谱(GC)或高效液相色谱技术(HPLC)在环境领域元素形态分析的应用,从联用接口、前处理方法、应用进展三个方面展开文献调研并进行综述:联用接口方面,主要关注近年联用商品化接口在实际应用中的性能改进优化研究;前处理方法方面,介绍了衍生化、毛细管吹扫捕集、固相微萃取、微波或超声波辅助萃取、液相微萃取、磁性固相萃取、酶解法等作为联用技术前处理方法的应用实例;应用进展方面,重点总结了近十年来国内外有关联用技术用于空气和废气、水和废水、土壤和沉积物、生物样品等不同环境样品元素形态分析的最新研究成果及前沿研究方向。最后在此基础上,探讨了联用技术未来的三个发展趋势。     

固相微萃取涂层的研究进展

固相微萃取是一种新型的样品前处理技术.萃取头涂层是固相微萃取的核心,涂层的性质对萃取的选择性和灵敏度起着决定性作用,综述了固相微萃取涂层的发展及其应用.     

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.