德阳市道路环境γ辐射剂量水平

本文在德阳市环境天然放射性水平调查基础上,对市辖5953.75平方公里范围内的五种不同材料路面,47个测点的道路γ辐射剂量率进行了分析研究,其结果是:(1)陆地γ辐射剂量率为5.54×10~(-8)Gyh~(-1);(2)贯空辐射剂量率为8.71×10~(-8)Gyh~(-1);(3)不同材料路面γ辐射剂量率的大小顺序是:泥土>碎石>水泥>柏油>石块路面。     

高海拔地区累积剂量法测量环境地表γ辐射剂量水平方法探讨

介绍了在西藏自治区自海拔1 500m~4 500m高度范围内,利用累积剂量方法测量环境地表γ辐射剂量的相关情况。考虑到不同海拔高度宇宙射线强度相差较大,本文对不同点位测量数据扣除了宇宙射线响应值,并与地表环境γ辐射剂量率瞬时测量值进行比对,结果表明:在高海拔地区累积剂量法测量环境地表γ辐射剂量率时,监测设备对宇宙射线的响应值可能远大于环境地表γ辐射剂量率值,在数据分析中需重点考虑;累积剂量法与瞬时剂量测量数据相对偏差在15%内,符合较好。     

HFETR周围环境γ剂量率变化趋势分析

环境γ剂量率测量辐射环境监测的重要监测项目之一,直接反映了核设施的运行状态。分析研究环境γ剂量率的变化趋势及影响因素,对于判别核设施的异常排放,制定核设施应急行动水平具有重要意义。HFETR周围环境γ剂量率监测系统运行期间积累了大量的环境γ剂量率的数据,本文以HFETR周围某年度环境γ剂量率连续监测数据为对象,结合理论、厂址特征、厂址气象等要素,开展了γ剂量率变化趋势及其构成、影响因素研究。研究表明,总体上各监测点全年监测结果与实际相符,并无明显异常现象。HFETR周围环境γ剂量率主要是由宇宙射线、天然存在的核素贡献。环境γ剂量率受降雨、风速、风向、异常排放等因素影响明显,受气温、湿度因素等影响不明显。通过研究,初步掌握了HFETR周围环境γ剂量率的变化规律及趋势,可为HFETR的安全运行、环境监控、制定应急行动水平等提供依据。     

车载巡测谱仪实源实装校准测试方法研究

为解决车载Na I(Tl)大晶体γ巡测谱仪系统探测效率的刻度问题。利用"计量标准器具",使用不同γ射线能量、不同活度的γ放射源;以固定安装车载大晶体的巡测车整体作为校准测试对象,在同一环境下,用"计量标准器具"环境辐射监测仪和车载大晶体γ辐射剂量率仪实源实装进行测试。以计量标准器具γ辐射剂量率仪测量数据为准,获得两种设备数据的相对标准偏差和校准因子,得到的校准因子可用于被测对象开展辐射环境监测和应急监测。该测试方法可行、可靠。     

新疆某区域矿产资源开发放射性水平调查与评价

为加强对新疆某区域矿产资源开发过程中的辐射安全监管,通过对该区域52家矿产资源开发企业的γ辐射剂量率进行监测,对超出"当地本底水平+50 nGy/h"的2家企业进行了采样,调查和测量了固体样品中放射性核素含量和水中放射性核素含量,估算了矿产企业工作人员所受年有效剂量。监测结果表明:大部分企业的γ辐射剂量率处在新疆及全国环境本底水平,2家企业处于全疆范围内的γ辐射剂量率的波动范围之外;其中1家企业的固体样品中放射性核素含量异常;水中放射性核素含量均处于全国环境本底水平。2家企业的工作人员所受年有效剂量分别为0.35 mSv和0.75 mSv。评价结果表明:该区域2家矿产资源开发企业存在放射性问题,需加强该区域的辐射安全监管工作。     

西宁市2008年至2011年y辐射水平的调查监测

文章就青海省辐射环境管理站在西宁市市区设置18个监测点位,采用X-Y剂量率仪对所选点位的瞬时贯穿辐射剂量率进行了测量,并对测量结果进行了统计和分析。     

闪烁型外照射测量仪对宇宙射线响应值的实验修正

国产 FT—620型和 SG—102型闪烁型外照射测量仪,存在着对宇宙射线响应差的弱点,使得给出准确的地层(或室内建材)γ幅射剂量率等有困难。本文提出了测绘每台外照射仪对宇宙射线的响应值曲线的修正方法,使问题得以解决。     

新疆大学校园辐射环境水平初步调查

为了了解新疆大学本部校园内辐射环境水平状况,对校园环境γ辐射剂量率、氡浓度水平、土壤中核素含量及红湖水样等采用国家规定的技术规范和方法进行现场测量、采样与实验室分析工作。结果表明,新疆大学本部校园内辐射环境水平处于乌鲁木齐市本底值范围之内,未见放射性异常。     

井矿盐开发所致的辐射水平

本文报道了自贡市井矿盐开发所致的辐射水平。井矿盐开发的主要废弃物－卤泥中＾２３８Ｕ，＾２２６Ｒａ，＾２３２Ｔｈ的天然放射性核素比活度比四川省土壤中相应核素平均值高１－２个数量级，且造成卤泥堆积场和局部生产环境陆地γ辐射剂量率高出自贡市环境陆地γ辐射平均值的２．０－４８．３倍，最主超过１６５倍。部份卤泥和盐厂附近江河排放口底泥中天然放射性废物标准。     

广元市道路贯穿辐射剂量水平研究

本文在广元市环境天然放射性水平调查的基础　上，通过对全市范围道路贯穿辐射剂量水平进行分析和研究，得出：（１）道路陆地γ辐射剂　量率为（６．４３±１．２１）×１０－８Ｇｙｈ－１；（２）道路贯穿辐射剂量率为（９．６６±１．３　５）×１０－８Ｇｙｈ－１；（３）道路γ辐射剂量水平与道路贯穿辐射剂量水平的地理分布　相似。即：北部中山区最高，东南低山区和东部次之，中部河谷平坝区和西南低山区最低。　（４）依不同路面材料，其道路陆地γ辐射剂量率的排列顺序为：泥土路＞碎石路＞砖路＞柏　油路＞水泥路。     

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.