Shipboard techniques based on flow injection analysis for measuring dissolved Fe, Mn and Al in seawater

An overview is presented of sampling techniques and flow injection analysis (FIA) methods for low concentrations of Fe, Mn and Al in filtered seawater. On the basis of sampling procedures, filtration techniques, accuracy, blanks, detection limits, intercalibration results and oceanographic consistency, the feasibility of these FIA methods was evaluated. It was found that these metals could be measured on board with a minimum risk of contamination and with good accuracy even at low subnanomolar levels (<0.5 nM). Results for reference seawater were in the case of Fe-FIA and Mn-FIA in excellent agreement with the certified values. Data from samples analyzed by Fe-FIA and by cathodic stripping voltametry (CSV) compared well, as did Mn-FIA and GFAAS. All three methods gave results that were mostly in good agreement with data from the same ocean regions published by other research groups. Two different types of surface water sampling were also tested and compared, namely conventional hand filling of a sample bottle from a rubber dinghy away from the ship, and underway pumping of seawater using a 'tow fish'. The latter method gave the best results. Also, conventional membrane filtration and cartridge filtration for large volume filtration were compared using Fe and Al data from water column samples. Good agreement was found for both filter types, although for defining dissolved metal species the latter filter type was preferred.     

基于X射线荧光分析原理的大气重金属在线分析仪的维护与质控

近年来大气细颗粒物中重金属元素成分的监测是细颗粒物化学成分监测的热点之一,这一类物质的在线监测在国内应用越来越多,笔者研究和探讨了影响X射线荧光法大气重金属在线分析仪器运行质量的主要运维工作和质量控制方法,提出了该仪器在线监测中的运维及质控要求,为环境监测工作者提供参考,以获得更加准确的监测数据。     

Assessment of spatial distribution of soil loss over the upper basin of Miyun reservoir in China based on RS and GIS techniques

Soil conservation planning often requires estimates of the spatial distribution of soil erosion at a catchment or regional scale. This paper applied the Revised Universal Soil Loss Equation (RUSLE) to investigate the spatial distribution of annual soil loss over the upper basin of Miyun reservoir in China. Among the soil erosion factors, which are rainfall erosivity (R), soil erodibility (K), slope length (L), slope steepness (S), vegetation cover (C), and support practice factor (P), the vegetative cover or C factor, which represents the effects of vegetation canopy and ground covers in reducing soil loss, has been one of the most difficult to estimate over broad geographic areas. In this paper, the C factor was estimated based on back propagation neural network and the results were compared with the values measured in the field. The correlation coefficient (r) obtained was 0.929. Then the C factor and the other factors were used as the input to RUSLE model. By integrating the six factor maps in geographical information system (GIS) through pixel-based computing, the spatial distribution of soil loss over the upper basin of Miyun reservoir was obtained. The results showed that the annual average soil loss for the upper basin of Miyun reservoir was 9.86 t ha(-1) ya(-1) in 2005, and the area of 46.61 km(2) (0.3%) experiences extremely severe erosion risk, which needs suitable conservation measures to be adopted on a priority basis. The spatial distribution of erosion risk classes was 66.9% very low, 21.89% low, 6.18% moderate, 2.89% severe, and 1.84% very severe. Thus, by using RUSLE in a GIS environment, the spatial distribution of water erosion can be obtained and the regions which susceptible to water erosion and need immediate soil conservation planning and application over the upper watershed of Miyun reservoir in China can be identified.     

Some comments on analysis techniques for censored water quality data

When investigating trace substances in ambient water, a proportion of water sample concentrations is usually below limits of detection. In medical and industrial reliability studies, comparisons are often made of time to event data which includes right censored observations indicating only that an observation is greater than a specified value. In this paper consideration is given to the application of non-parametric procedures, widely used in the analysis of time to event data, to water quality data which is left censored.A non-parametric estimate of the cumulative distribution function for left censored water quality data can be generated quite easily. For the comparison of levels of trace substances it is necessary to combine an unconditional likelihood for the proportion of observations below a detection limit with a partial likelihood for the portion of the distribution above the detection limit in order to make use of regression methodology. The details of this are outlined and an example is given which compares levels of toxic substances at the head and mouth of the Niagara river.When comparisons are based on matched pair data, further modifications are necessary. A development paralleling that for time to event data is given. Consideration is also given to model extensions which allow for a dependence between observations at the same location over a period of time.The presentation is introductory and designed to illustrate the potential of some available methodology for use in the analysis of water quality data.     

Vacuum sampling techniques for industrial hygienists, with emphasis on beryllium dust sampling

The U.S. Department of Energy (DOE) Chronic Beryllium Disease Prevention Program Rule, 10 CFR Part 850 became effective in 2000 in response to the prevalence of Chronic Beryllium Disease (CBD) in workers. The rule requires surface and air monitoring for beryllium to determine exposure levels and the evaluation of the effectiveness of controls used to minimize or eliminate that risk. The most common methods for surface sampling use wet or dry wipes. Wipe sampling techniques may be impractical for many surfaces common to most buildings such as cinder block, textured wall surfaces, fabric and carpet. Vacuum sampling methods have been developed for the evaluation of lead or pesticides on residential surfaces such as carpets, bare floors and window sills. However, the current vacuum methods may be impractical for many workplace situations such as sampling of protective clothing, complex facility structures, or equipment surfaces. Recent work using vacuum sampling for potential bio-terrorism agents such as anthrax spores may have significant application to industrial hygiene evaluations of the workplace and may be extendable for use in sampling of metals such as beryllium. Validated vacuum sampling methods that provide meaningful data would be of great value to industrial hygienists in identifying areas having surface contamination, evaluating existing controls and work practices and determining the potential of toxic material on surfaces to become airborne and present a potential risk to workers and the public. This article discusses various vacuum sampling methodologies and recommends harmonization of sampling methods.     

The influence of two culturing techniques on toxicity of four chemicals in Arabidopsis

Plots of Arabidopsis thaliana L. (Heynh.) plants were grown in two hydroponic systems, one using a solid rooting support media (vermiculite) and the other a flowing solution culture. Both were tested with various concentrations of bromacil (5-bromo-3-sec-butyl-6-methyluracil), dichlobenil (2,6-dichlorobenzonitrile), copper sulfate (CuSO₄·5H₂O) and 3-aminotriazole. The effects on biomass production were compared. Plants treated with bromacil at concentrations up to 0.05 mg l^–1 were similarly reduced in growth in both culture methods. However, the toxic effects of dichlobenil, copper sulfate and 3-aminotriazole were different for both culture methods. Dichlobenil decreased plant growth in the solution culture at lower concentrations than in the vermiculite system. All aspects of growth were suppressed in the solution culture while the vegetative weight was unaffected in the vermiculite culture. Plants treated with 20 mg l^–1 copper sulfate in solution culture yielded mean seed weight of 1.2 g/plot compared to 3.1 g/plot when treated with the same concentration in the double-plot system. Plants treated with 0.5 mg l^–1 3-aminotriazole in solution culture produced no seed, while plants with the same nominal concentration in the double-pot method produced a mean seed weight of 6.5 g/plot. Solution culture testing was generally more sensitive and since roots were bathed directly in a solution of known pH, nutrient level and chemical concentration, the test conditions were more accurately defined.     

A comparative study on various statistical techniques predicting ozone concentrations: implications to environmental management

The objective of the present work is to compare various techniques for modeling the dependence of the tropospheric ozone concentrations on several meteorological and pollutant parameters. The study focuses on two different sites in the metropolitan area of Athens, Greece; one in the city centre and another one in the suburbs. It is found that although simple Linear Regression Analysis fails to construct accurate equations due to the existence of multicollinearity among the independent variables, still various combinations of a Multivariate Method (PCA) and Stepwise Regression Analysis manage to produce equations free of the multicollinearity issue. The derived formulas are validated and prove to have R(2) values in the order of 0.8 approximately. However, the equations are found to be unsuccessful in case of severe episodes. For this reason, a new procedure is followed for estimating the ozone values in case of episodes exclusively. The new R(2) value is estimated to be 0.9, approximately.     

基于产生来源的固体废物鉴别研究

通过对美国、欧盟和日本的固体废物定义和范围,以及已完成的固体废物鉴别实例的研究,指出固体废物鉴别的关键点在于产生来源分析。提出依据产生来源,固体废物可以分为丧失原有使用价值的物质、生产过程中产生的副产物类物质、环境治理和污染控制过程中产生的物质、其他类物质4大类。如果待鉴别物质的产生来源属于该4大产生来源中的任何一类,则其属于固体废物。     

Study of the variation and the effect of geo-chemical composition on the external background radiation level

The study to generate the baseline of natural radiation and radioactivity in East and West Khasi Hills District of Meghalaya, India was conducted to determine the different radiation dose in selected stations. Twenty stations were selected in both the district, which include Shillong the capital of Meghalaya and the Domiasiat area, which has been identified as one with a Uranium ore deposit. The dose was measured using a Micro-R-Survey meter and from the measurement it was found out that the absorbed dose in both the districts ranges from 0.04 to 1.66 microGy h(-1). The maximum dose was observed in Kylleng (0.72 microGy h(-1)) and the minimum in Mawphlang (0.06 microGy h(-1)). Average absorbed dose and equivalent dose were found to be higher than the Indian and world average values by several orders. The radiation levels distribution was found to be non-uniform through out the selected study area.     

Traffic noise assessment based on mobile measurements

Continuous noise monitoring based on mobile systems could provide a quick feedback to assess the effect of policies implemented by authorities to mitigate noise pollution. The present research verifies that mobile measurements taken along a main street and aggregated in time and space can accurately estimate noise levels at static points. As a consequence, mobile sensors would be suitable to build, and continuously update, noise maps. Furthermore, the experiment computes the optimum aggregation distance of the mobile measurements.To perform the mobile noise measurements, a low-cost noise sensor with an integrated GPS was mounted on a bicycle. One hour worth of measurements was taken along a main avenue with the mobile receiver simultaneously to 6 static measurement points. For the mobile receiver, the L_Aeq was computed aggregating samples within a radius from 1 m to 100 m around the static measurement points. Then, the error between the aggregated L_Aeq of the mobile and the static receivers for the same time period was computed. It is observed that the RMSE and the measurement uncertainties decrease as the aggregation distance increases, having a minimum at an aggregation radius of 33 m and reaching a stabilization due to the constant traffic of the studied street.     

Effects of sampling techniques on physical parameters and concentrations of selected persistent organic pollutants in suspended matter

This study focusses on the effect of sampling techniques for suspended matter in stream water on subsequent particle-size distribution and concentrations of total organic carbon and selected persistent organic pollutants. The key questions are whether differences between the sampling techniques are due to the separation principle of the devices or due to the difference between time-proportional versus integral sampling. Several multivariate homogeneity tests were conducted on an extensive set of field-data that covers the period from 2002 to 2007, when up to three different sampling techniques were deployed in parallel at four monitoring stations of the River Rhine. The results indicate homogeneity for polychlorinated biphenyls, but significant effects due to the sampling techniques on particle-size, organic carbon and hexachlorobenzene. The effects can be amplified depending on the site characteristics of the monitoring stations.     

基于健康的环境监测技术规范研究

阐述了环境与健康监测的现状,根据江苏省典型区域环境与健康调查取得的成果和经验,对开展环境与健康监测的基本原则和技术思路作分析。提出环境与健康监测内容包括污染物排放监测、环境质量监测、外暴露监测、内暴露监测和健康效应监测,探讨了属于环保部门职责范畴的前3项监测技术内容及相关要求。     

Upstream flood pattern recognition based on downstream events

Reverse stream flood routing determines the upstream hydrograph in a stream reach given the downstream hydrograph. The Muskingum model of flood routing involves parameters that govern the routed hydrograph. These parameters are herein estimated using simulation methods coupled with optimization tools to achieve optimized parameters. Different simulation methods are shown to perform unequally in the estimation of nonlinear Muskingum parameters. This paper presents two simulation methods for nonlinear Muskingum reverse flood routing: (1) Euler equations and (2) Runge-Kutta 4th order equations. Moreover, the generalized reduced gradient (GRG) is used as the optimization tool that minimized the sum of the squared deviations (SSQ) between observed and routed inflows in a benchmark flood routing problem. Results show the Runge-Kutta 4th order equations yield better routed hydrographs with smaller SSQ than obtained in previous research and with the first simulation method (Euler equations).     

基于韦伯-费希纳拓广定律的环境空气质量标准

基于韦伯--费希纳(Weber-Fischna)定律并加以拓广,指出空气污染物浓度成等比变化时,其对人体和生态环境产生的危害程度成等差变化;应用‘等比赋值,等差分级'的指数标度法,确定出7项空气污染物的日平均浓度的环境空气质量标准,并与国家<环境空气质量标准(GB3095-1996)>进行了比较.结果表明,除NO2、CO和TSP在两种标准中各有一个级别的浓度限值差异稍大外,其余空气污染物的两种标准的相同级别浓度限值十分接近,从而为制订的国家<环境空气质量标准(GB3095-1996)>提供了理论依据.     

基于风险评估模型的环境风险地图研究

环境风险地图基于地理信息系统(GIS)对信息和数据的空间分析,通过各种风险评估或预测模型,将评估的结果以空间方式展示出来.由于环境风险地图直观、信息量大的优点,有助于环境风险管理以及突发事件的应急反应和实时决策.对风险地图种类作了概述,总结风险制图中需注意的问题以及国内外风险地图的应用研究以及发展情况.     

Recharge signal identification based on groundwater level observations

This study applied a method of the rotated empirical orthogonal functions to directly decompose the space-time groundwater level variations and determine the potential recharge zones by investigating the correlation between the identified groundwater signals and the observed local rainfall records. The approach is used to analyze the spatiotemporal process of piezometric heads estimated by Bayesian maximum entropy method from monthly observations of 45 wells in 1999-2007 located in the Pingtung Plain of Taiwan. From the results, the primary potential recharge area is located at the proximal fan areas where the recharge process accounts for 88% of the spatiotemporal variations of piezometric heads in the study area. The decomposition of groundwater levels associated with rainfall can provide information on the recharge process since rainfall is an important contributor to groundwater recharge in semi-arid regions. Correlation analysis shows that the identified recharge closely associates with the temporal variation of the local precipitation with a delay of 1-2 months in the study area.     

Ecosystem classifications based on summer and winter conditions

Ecosystem classifications map an area into relatively homogenous units for environmental research, monitoring, and management. However, their effectiveness is rarely tested. Here, three classifications are (1) defined and characterized for Canada along summertime productivity (moderate-resolution imaging spectrometer fraction of absorbed photosynthetically active radiation) and wintertime snow conditions (special sensor microwave/imager snow water equivalent), independently and in combination, and (2) comparatively evaluated to determine the ability of each classification to represent the spatial and environmental patterns of alternative schemes, including the Canadian ecozone framework. All classifications depicted similar patterns across Canada, but detailed class distributions differed. Class spatial characteristics varied with environmental conditions within classifications, but were comparable between classifications. There was moderate correspondence between classifications. The strongest association was between productivity classes and ecozones. The classification along both productivity and snow balanced these two sets of variables, yielding intermediate levels of association in all pairwise comparisons. Despite relatively low spatial agreement between classifications, they successfully captured patterns of the environmental conditions underlying alternate schemes (e.g., snow classes explained variation in productivity and vice versa). The performance of ecosystem classifications and the relevance of their input variables depend on the environmental patterns and processes used for applications and evaluation. Productivity or snow regimes, as constructed here, may be desirable when summarizing patterns controlled by summer- or wintertime conditions, respectively, or of climate change responses. General purpose ecosystem classifications should include both sets of drivers. Classifications should be carefully, quantitatively, and comparatively evaluated relative to a particular application prior to their implementation as monitoring and assessment frameworks.     

肿瘤病房医用直线加速器对周围环境电离辐射的调查分析

通过对医院肿瘤病房医用直线加速器机房周围环境的电离辐射监测调查 ,并计算分析各相关人群的年有效剂量当量 ,结果低于《辐射防护规定》(GB870 3- 88)中的标准限值。表明医用直线加速器机房的辐射防护设施设计是安全合理的 ,具有重要的现实意义 ,该辐射防护设施具有推广价值。     

光导纤维生物膜碘荧光传感器的研究

把荧光素固定在经处理的生物膜上,研制成光导纤维生物膜碘荧光传感器。Ｉ－的线性响应范围为３×１０－５ｍｏｌ／Ｌ—５×１０－３ｍｏｌ／Ｌ,相对标准偏差为０６５％,响应时间为２５～３５ｍｉｎ。