2018～2021年广元市饮用水源地总放射性水平及健康风险评价

为了解广元市集中饮用水源地的放射性水平，对居民通过饮水途径摄入放射性物质导致的健康风险进行评估。调查了广元市四县三区的集中饮用水源地2018年～2021年期间的总α、总β放射性水平，使用克鲁斯卡尔-沃利斯检验对检测数据进行了组间比较和分析；根据不用年龄段公众饮水的情况计算饮水途径导致的辐射吸收剂量，再应用健康风险模型评估导致的居民健康风险。调查结果显示总α放射性浓度范围为0.0045～0.1610Bq/L,总β放射性浓度范围为：0.0103～0.1560Bq/L;不同年度、不同水源地、不同水源地类型的总α、总β放射性水平间比较，差异均无统计学意义(P>0.05);不同水期的总α、总β放射性水平间比较，差异有统计学意义(P<0.05)。各年龄组通过饮水途径摄入总α、总β放射性所导致的年均总待积有效剂量均低于0.1mSv,总α和总β放射性对各年龄段居民所致的总致癌风险处于1.80×10^-8～3.74×10^-7,低于WHO和ICRP发布的最严格控制限值。广元市四县三区的集中饮用水源地的总α和总β放射性水平均符合《生活饮用水卫生标准》(G...     

咸阳常用装饰石材及釉面砖天然放射性水平

报道了咸阳市常用装饰石材及彩釉砖样品中天然放射性核素含量的调查分析结果,并据国家建筑材料放射性核素含量最新标准进行分类分析。分析结果表明,所调查的装饰石材样品中天然放射性核素^226Ra、^232Th、^40K的比活度范围分别为9.92～330.21 Bq/kg,12.86～300.20 Bq/kg,41.57～1830.64 Bq/kg。依据国家最新标准,24个装饰石材样品中1个样品属于B类、2个样品属于C类,这些样品不能用于住宅的内装饰;其余21个属于A类,使用范围不受限制。4个彩釉砖样品均属A类。     

关于水中总α总β放射性测量监测方法改进的探讨

目前国内关于水中总α、总β放射性测量相关标准还不够细化,操作规程在一些细节方面还存在部分问题,为减小实验误差,提高实验准确度,对监测方法进行了改进.对前期水中总α、总β放射性监测的实验过程进行经验总结,对实验条件进行优化改进,通过回收率和准确度对实验结果进行验证.对水中总α、总β放射性监测实验过程中的水样放置时间、蒸发...     

新疆伊犁煤中放射性核素铀、钍、镭、钾比活度

新疆伊犁州直地区燃煤放射性调查的157个有效燃煤样品的放射性核素238U、232Th、226Ra和40K比活度结果表明,数据离散,大小顺序为238U＞40K＞ 226Ra＞ 232Th；放射性比活度在各煤田的分布不均,伊北煤田煤中的放射性比活度小于其它煤田；各煤种238U和226Ra比活度为长焰煤＞不粘煤＞焦煤,232Th与40K为焦煤＞长焰煤＞不粘煤；伊犁州直地区燃煤中238U、226Ra和232Th比活度低于全国煤炭的平均比活度,而与美国和世界的相当,但40K高于全国煤炭的平均比活度.     

成都市土壤中天然放射性核素含量调查研究

本文报告1986至1987年成都市土壤中天然放射性核素含量的调查方法和结果。全市共采集19个土壤样品,样品采集与分析按国家环保局《环境天然放射性水平调查规定》进行。结果表明,成都市土壤中放射性核素含量各测点平均值与面积加权平均值相吻合,其中总β为786.5Bq/Kg;1 m高处空气中的γ吸收剂量率为5.78×10-8Gy/h;238U,29.5Bq/Kg;232Th,45.7Bq/Kg;226Ra,36.0 Bq/Kg;40K,525.2Bq/Kg;137Cs,14.2Bq/Kg。成都市土壤中天然放射性核素含量比四川省和全国略低,但总体上处于同一水平。     

高纯锗γ谱仪快速分析固体样品中~(226)Ra活度的方法研究

受测试样品中~(226)Ra-~(222)Rn平衡影响,通常高纯锗γ谱仪测量~(226)Ra需先将样品密封20天以上。在分析~(226)Ra-222Rn级联放射性衰变基础上,经过公式推导,提出用二次测量法快速预测固体样品中~(226)Ra活度,即在样品中~(226)Ra-~(222)Rn平衡前对样品进行两次测量,利用测量结果预测~(226)Ra-~(222)Rn平衡后样品中~(226)Ra活度。经实验验证,该方法分析固体样品中~(226)Ra活度,既可大大减少样品测试时间,又能得到较为可靠的测试结果,为应急监测节约宝贵时间。     

四川原煤及其废渣与制品放射性的测试分析

本文介绍了四川原煤及其废渣与制品的γ辐射剂量率、附加γ辐射人均年有效剂量量。同时,用低本底Ge(Li)多道γ能谱仪测定了原煤、矸粉与矸砖,煤渣与煤渣砖、粉煤灰及粘土砖等样品中的天然放射性核素~(238)U,~(232)Th,~(226)Ra,~(40)K的比活度。经比较和研究,找出了这些物质的放射性水平及它们彼此之间的规律。     

基于HPGe水体在线伽马测量估计水体总α/β比活度

基于XTG-2000W型水体放射性实时在线监测系统,通过高纯锗探测器对水体γ射线能谱的测量间接计算水体中总α/β放射性活度。对成都郫县河水、某品牌矿泉水、东风渠水和成都理工大学内自来水进行了伽马能谱测量并计算对应水体的总α/β放射性活度,比较3种水样的计算结果与外检结果得出α比活度拟合值与测量值间的相对误差为8.65%、9.49%、121.87%,β比活度拟合值与测量值间的相对误差为6.73%、27.95%、16.96%,证明了该方法的可行性。     

日本福岛核事故后四川省部分生态系统和食物链的γ核素放射性水平调查

本文调查和掌握了四川省部分生态系统中放射性水平,分析了日本福岛核泄漏事故中放射性核素对四川省主要环境介质的影响和放射性核素的迁移和富集情况,了解此次事故对部分食物链和生态系统的影响程度。对气溶胶、沉降物、土壤、植物、动物、人类食物这一链条样品中的238U、232Th、226Ra、40K、137Cs、131I 6种放射性核素进行检测,结果表明,天然放射性核素238U、232Th、226Ra、40K的检测结果均属于环境正常水平,人工放射性核素137Cs、131I低于仪器检出限。所有样品的检测结果均符合相关国家标准,与环境背景值相当,日本福岛核事故在短时间内,未对四川省生态环境和食物链造成放射性影响。     

大庆地区土壤环境放射性本底及现状水平调查与评价

人工放射源在石油勘探、开采等方面得到广泛应用，放射性核素可通过多种途径污染土壤环境。大庆油田有13个单位应用放射性物质（非密封源或密封源）。为了对大庆油田地区的土壤放射性状况进行较全面的调查，因此对土壤放射性本底、现状水平及放射源周围土壤放射性强度进行了监测，采集样品200多个，总α的测定采用饱和厚度法，总β的测定采用有效厚度法，监测结果说明原油开采应用放射性物质对土壤环境未造成不良影响。     

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.     

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.     

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.     

Provincial development plans in Zimbabwe: an analysis of their content,structure and methodology

Zimbabwean provincial plans were instituted to help in the achievement of the national goal of the creation of an egalitarian, socialist and integrated society. The national goal itself was adopted as an antithesis to the dualist society characterised by spatial, economic, social, politican and technological inequalities that Zimbabwe inherited from colonialism. This meant that provincial plans had to play both a functional (or growth allocating/distribution) and a territorial (or redistribution) role.

This paper reviews their role in achieving the national goal by examining their functions, content, structure and methodology. The paper concludes that because of their nature, provincial plans are not suitable tools for the achievement of the national goal.     

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.     

Effect of Light on Biodegradation of Estrone, 17β‐Estradiol,and 17α‐Ethinylestradiol in Stream Sediment

Biodegradation of [A‐ring ¹⁴C] Estrone (E1), 17β‐estradiol (E2), and 17α‐ethinylestradiol (EE2) to ¹⁴CO₂ was investigated under light and dark conditions in microcosms containing epilithon or sediment collected from Boulder Creek, Colorado. Mineralization of the estrogen A‐ring was observed in all sediment treatments, but not epilithon treatments. No difference in net mineralization between light and dark treatments was observed for ¹⁴C‐E2. Net mineralization of ¹⁴C‐E1 and ¹⁴C‐EE2 was enhanced in light treatments. Extents of ¹⁴CO₂ accumulation and rates of mineralization were significantly greater for E2 than E1 under dark conditions, but were comparable under light conditions. These results indicate substantial differences in the uptake and metabolism of E1 and E2 in the environment and suggest biorecalcitrance of E1 relative to E2 in light‐limited environments. The extent of ¹⁴CO₂ accumulation and rate of mineralization for EE2 in dark treatments were less than half of that observed for E2 and generally lower than for E1, consistent with previous reports of EE2 biorecalcitrance. However, ¹⁴CO₂ accumulation and rates of mineralization were comparable for EE2, E2, and E1 under light conditions. These results indicate photoactivation and/or phototransformation/photodegradation processes can substantially enhance heterotrophic biodegradation of estrogens in sunlit environments and may play an important role in estrogen transport and attenuation.