应用Dot—ABC法检测植物镉金属污染

用不同浓度的氯化镉诱导黄瓜幼叶Cd—MT的产生，并应用Dot—ABC法检测了30种来自天水不同区域植物的MT含量，初步确定它们的重金属污染情况。结果表明，CA—MT浓度与环境诱导浓度呈显著正相关，Dot—ABC法检测的植物金属硫蛋白的最低含量为16mg，并初步估测了其中10种植物可能存在不同程度的重金属污染。本法具有特异、简便和灵敏的特点，可用于农产品镉金属污染的检测。     

我国重金属污染土壤的利用研究

检测了重金属污染地区粮食、蔬菜、水果等不同作物的重金属含量。结果表明,这3类作物对高背景值耕地土壤中有害元素吸收能力的顺序为:蔬菜粮食水果。同一地区不同地块采样点土样中重的金属含量有所差异,同一有害元素在不同作物中的积累特性不同,不同作物种类对高背景值元素的吸收差异较大,为合理开发利用被重金属污染的土地资源提供了理论依据。     

西溪湿地底泥质量现状与生态风险初步评价

为了解西溪湿地底泥质量现状,2012年9月采集保护区内不同干扰类型的底泥样本,测试了底泥中重金属和POPs中PCBs、OCPs和PAHs的含量,并对湿地底泥污染进行了生态风险初步评价。结果表明,底泥中未检出PCBs和OCPs,但检测出14种EPA优控PAHs,总PAHs的浓度范围为115.9～217.8 ng·g^-1,低于潜在生态风险的效应区间低值ERL,其中列入中国＂水中优先控制污染黑名单＂的7种PAHs均有检出并且其总量占∑PAHs 1/2左右（平均为50.08%）;底泥中8种重金属含量平均值低于《土壤环境质量标准》（GB 15618—1995）的二级标准,但Hg、Zn、Pb、Ni含量在多个位点已超过一级标准;分别采用土壤背景值和国家一级标准为参比值对湿地底泥中重金属进行单因子污染风险指数评价,发现分别有7种和4种元素的污染指数大于1;综合分析不同干扰类型的底泥质量,发现底泥疏浚能有效降低有机质含量、全氮和PAHs含量,但对全磷、重金属含量则无明显效果,封闭水体的干塘措施能显著减少污泥量和有机物含量。研究结果表明,西溪湿地底泥中高环PAHs和重金属污染水平可能对西溪湿地生物具有潜在的生物毒性作用及不利的生态影响效应,其疏浚底泥农用则无生态风险。     

长沙水利枢纽工程蓄水后的湘江长沙段重金属污染评价

2014年8月~2015年5月对工程蓄水后的湘江长沙段水体中砷、汞、铅、镉4种主要重金属的污染状况进行了水质监测,并运用改进后的内梅罗指数法进行水体中的重金属污染综合评价。评价计算结果显示,同为饮用水源一级保护水域的黑石铺和杜甫江阁断面水体中汞含量超标率均达到100%,所有断面总超标率为66.7%。多个断面重金属镉监测浓度超过1ug/L,最高浓度为1.469ug/L。工程蓄水前后,水体重金属镉含量基本持平,砷、汞、铅含量均出现不同程度的上升,汞为湘江长沙段污染最严重的重金属。在各个监测断面中,坪塘、黑石铺和杜甫阁断面水质重金属污染严重,其余断面分时段出现轻度污染。     

重金属污染土壤的修复方法及其在几类典型土壤修复中的应用

文中首先阐述了重金属污染土壤的途径与特点。介绍了当前几类主要的重金属污染土壤修复方法:物理化学方法、植物修复法、微生物修复法、动物修复法等的技术要点,详述了各自的技术特点及机理,并对它们的修复效能、环境友好性等进行了比较。从土壤的特性出发,区分出了3种典型的遭受重金属污染的土壤:农业土壤、城市土壤、矿区土壤,并从国内外最新的重金属污染修复实践中选取了适合各自土壤类型的修复方法进行了重金属污染土壤的治理探讨。最后,对土壤重金属污染修复技术的发展进行了展望。     

邯郸市某冶炼厂周边小麦体内重金属含量研究

分析邯郸市某冶炼厂周边小麦重金属污染情况,为当地农作物的科学种植提供参考。以邯郸市某冶炼厂周边的小麦为研究对象,研究了距离冶炼厂不同距离5个采样点小麦体内重金属含量,并采用单因子污染指数法和内梅罗综合污染指数法评价小麦中3种重金属的污染状况。结果表明,小麦中Cd和Pb含量均出现了不同程度的超现象,Cu含量没有超标。由单因子指数法可知,距冶炼厂400m内,小麦体内Pb重度污染,Cd轻、中度污染;距冶炼厂400~1 600m之间,小麦未被Cd污染;距冶炼厂800~1 600m之间,小麦体内Pb中度污染。由内梅罗综合污染指数可知,综合污染指数在1.5~4.5之间,距冶炼厂400m内,为重度污染;400~1 600m之间,为轻度污染。小麦体内重金属污染程度与距冶炼厂的距离有明显的相关性,污染指数随着距离增加而降低。冶炼厂周边农田的小麦均受到不同程度的重金属污染,不适合于研究区种植。     

株洲市清水塘工业区地表水底泥重金属污染评价

对株洲市清水塘工业区地表水底泥重金属含量进行了检测,并采用地积累指数法进行了评价.结果表明,该区底泥受到重金属极强污染,各溪港污染程度为老霞湾港铜塘港>霞湾港,各元素污染程度为CAHgPbAs;霞湾港由于底泥量最大,其重金属含量最大,Cd、Hg、Pb、As分别占总量的69.45%、80.62%、66.46%和86.56%;霞湾港中污水厂～河口段重金属含量最大,CA、Hg、Pb、As分别占该港总量的98.50%、56.06%、18.14%和52.09%.     

我国南方桉树人工林区水库沉积物重金属垂向分布及污染评价

为研究我国南方桉树人工林区水库沉积物中重金属污染程度及垂向分布特征,选取南宁市那降水库和天雹水库为研究对象,采用ICP-AES测定沉积物中Cr、Cu、Zn、As、Cd、Hg和Pb 7种重金属在垂向上的含量分布,并采用地累积指数法对重金属污染进行风险评价。结果表明,天雹水库沉积物中重金属污染较那降水库严重,且7种重金属平均含量远远高于南宁市土壤重金属元素背景值。重金属垂向分布特征显示,重金属Cu和Pb平均含量呈波动增长趋势,Zn和Cd呈持续增长趋势,而Cr、As和Hg呈波动下降趋势。由重金属含量变异系数垂向变化来看,重金属Hg含量变异系数最大,不同深度处均大于0.45,离散程度较高。地累积指数法评价结果表明,重金属污染程度由大到小顺序为:HgCdZnCuPbCrAs,重金属Hg累积最严重,属于中度污染程度,且有逐年加重趋势,两个水库的相似点是重金属Hg和Cd也有明显累积,处于中度污染水平。     

铜陵铜官山矿区土壤重金属污染状况研究

通过野外调查和室内分析,研究了铜陵铜官山铜矿区土壤重金属含量,并采用单因子指数法和内梅罗指数法对铜官山土壤污染程度进行评价.研究结果表明,研究区土壤Cu、Zn、As、Hg平均含量高于当地的土壤背景值,土壤已受Cu、Zn、As重污染,受Hg轻污染.不同样点土壤重金属含量存在较大差异,其中处于选矿厂附近的9到16号样点土壤重金属污染情况较其它样点相对较重,15和16号样点的重金属单项污染指数和综合污染指数都很高,污染状况在所有样点中最为严重.     

规模化农田土壤重金属污染修复的中试试验研究——以某镇土壤污染治理为例

农用地重金属污染长期以来一直是生态环境的热点和难点问题。2017年,对某镇农田土壤重金属污染开展详查,单项污染指数评价结果表明,镉超标率为67.60%(Pi>1),基于内梅罗污染指数法的评价结果显示,57.30%的点位受到不同程度的污染(PN≥1.0);2018年,分别选取钝化修复和植物修复进行中试试验,经钝化修复后土壤有效镉和总镉含量分别平均降低32.73%和5.64%。经超富集植物籽粒笕种植一季修复后,土壤总镉含量降低15%以上。本次中试试验修复效果良好,能为下一阶段的土壤镉污染修复方案的制定和优化提供科学的依据,为全国农用地重金属污染修复提供了有价值的借鉴意义。     

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.     

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.     

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.     

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.     

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.     

BIOLOGICAL INDICATORS AND BIOLOGICAL EFFECTS OF ESTUARINE/COASTAL POLLUTION1

ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish - their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species - probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.     

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.     

Journalists' views of advertiser pressures on agricultural news

All major journalism ethical codes explicitly state that journalists should protect editorial copy from undue influence by outside sources. However, much of the previous research on agricultural information has concentrated on what information various media communicate (gatekeeping studies) or communication's role in increasing innovation adoption (diffusion studies). Few studies have concentrated specifically on organizational and structural constraints that might adversely affect agricultural journalists' ethical standards; those that have, focus largely on farm magazines. A study of newspaper reporters who cover agricultural news found that the most pressing ethical concern is the effect of advertiser (agri-business) pressure on editorial copy, and that their concerns in general parallel those of farm magazine writers and editors. The majority reported being in situations in which they might be exposed to advertiser pressure, including pressures to change or withhold editorial copy. Large minorities suggested that advertising pressures affect the overall environment in which agricultural journalists work, and more than one in ten said they allow advertiser pressures to influence editorial decisions. The newspaper reporters who cover agricultural beats showed slightly more resistance to advertiser pressure than did farm magazine editors in a parallel study.     

Definition Procedures Have Little Effect on Performance of Environmental Classifications of Streams and Rivers

Mapped environmental classifications are defined using various procedures, but there has been little evaluation of the differences in their ability to discriminate variation in independent ecological characteristics. We tested the performance of environmental classifications of the streams and rivers of France that had been defined from the same environmental data using geographic regionalization and numerical classification of individual river valley segments. Test data comprised invertebrate assemblages, water chemistry, and hydrological indexes obtained from sites throughout France. Classification performance was measured by analysis of similarity (ANOSIM). Geometric regions defined by a regular grid and without regard to environmental variables and a posteriori classifications based on clustering the test datasets defined lower and upper bounds of performance for a given number of classes. Differences in classification performances were generally small. The ANOSIM statistics for the a posteriori classifications were around twice that of all environmental classifications, including geometrically defined regions. The hydro-ecoregions performed slightly better for the invertebrate data and the network classification performed slightly better for the chemistry and hydrological data. Our results indicate that environmental classifications that are defined using different procedures can be comparable in terms of their ability to discriminate variation of ecological characteristics and that alleged differences in performance arising from different classification procedures can be small relative to unexplained variation. We conclude that definition procedures might have little effect on the performance of large-scale environmental classifications and decisions over which procedures to use should be based primarily on pragmatic considerations.