浅谈国家环境监测网实验室能力考核(验证)工作的经验总结

为进一步做好国家环境监测网实验室能力考核(验证)工作,持续保持实验室体系运行的有效性,进一步保证监测数据的质量,从样品测定和质量管理体系两方面总结了近几年参加国家环境监测网实验室能力考核(验证)工作的一些经验,涵盖“人、机、料、法、环、测”,数据审核,报告审核,结果应用等环节,对实验室参加其他类型的外部考核也有较好的参考作用。     

突发水污染事件应急监测外部质量控制活动实例

<正>为确保某跨省突发水污染事件应急监测数据的准确可靠,安徽省环境监测系统在加强实验室内部质量控制的基础上,进一步强化外部质量控制措施,实现了应急监测的全过程质量控制。具体质量控制措施包括建立实施异常数据分析判断整改程序、进行外部质控样品分析以及现场平行双样和实验室平行双样分析、开展实验室间、实验室内比对监测和空白样的测定等。实施质控数据与每批监测数据的     

固定污染源排气中颗粒物测定的质量保证

固定污染源排气中颗粒物的监测是一个复杂的过程,它综合了实验室分析、现场采样及生产工艺等因素,是环保管理部门监控、考核企业污染物是否排放达标的重要因子之一。本文从滤筒的选择、实验室称量、采样仪器、采样点位置、运行工况等几方面提出了固定污染源排气中颗粒物测定中应注意的问题,并对实验室湿度和滤筒烘烤温度对滤筒称重的影响进行了测定,得出实验室的湿度应控制在两次称量±5%范围之内,同时应根据排气筒类型不同,选择不同的温度烘烤滤筒,否则会直接影响滤筒称量的准确度。只有做好固定污染源排气中颗粒物监测过程中各个环节的质量控制,才能获得科学、准确的监测数据。     

浅析实验室质量控制图的制作与应用

文章采用实例分析方法对实验室质量控制图的制作与应用作了较全面的研究与分析,阐述了空白试验值控制图、均数控制图、均数-极差控制图、准确度控制图的制作方法与技巧,并对其进行分析和判断,结果说明这四种质量控制图可有效控制实验室分析过程的稳定性和测定结果的准确度、精确度。     

环境监测质控技术考核及其数据分析(三) 实验室间测试数据的评价

在(一)、(二)篇文稿中,笔者借助质控考核的数据讨论了如何观察和分析实验数据的基本单元性概念。本文以四川省参加全国酸雨统考(85年10月)的数据为例,讨论实验室间数据的统计运算及其总体概念. 一、实验室间测试数     

化学需氧量_((COD))分析质量控制

分析质量控制是科学管理实验室、保证环境监测分析数据可靠性的行之有效的方法,也是保证实验空间数据具有可比性的关健。我们接受总站下达的考核任务,对于 COD 进行了一系列质控实验,本文仅以 COD 的质控方法做一总结,以供参考。     

电感耦合等离子体发射光谱法测定土壤中金属元素含量的不确定度评定

为提高土壤金属元素分析数据质量,采用微波消解-电感耦合等离子体发射光谱法(ICP-OES法)测定土壤中12种金属元素含量,对整个分析过程进行了不确定度评定.结果表明,土壤中金属元素的不确定度主要来源于样品消解、曲线拟合、重复测量及定容稀释过程,结论提出了有效降低不确定度的措施,为提高实验室数据质量及建立相关国家标准提供...     

环境监测质量管理实践与探讨

环境监测质量管理是环境监测实验室的重要工作之一,是保证环境监测数据“准确性、精密性、代表性、完整性、可比性”的重要手段。在总结环境监测实验室（二级站）环境监测质量管理实践经验的基础上,针对管理过程中存在的领导重视程度不够、体系文件宣贯不到位、技术人员上岗证考核不系统、现场采样和样品管理质控有缺陷等方面问题,提出了强化制度落实、加强技术培训、试行全过程质控等对策建议。     

提高水中BOD5测定质量的探讨

介绍了环境空气质量、分析用水、接种液加入量、曝气方法的选择等因素对BOD5测定的影响。提出测定过程中实验室空气质量、分析用水的选择、接种液的选择和加入量以及曝气方法应注意事项,以期得到较为准确的测定结果,提高废水中BOD5测定质量。     

仪器法测定水环境高锰酸盐指数的应用

高锰酸盐指数是表征水质污染程度的重要指标之一,按照GB 11892—1989《水质 高锰酸盐指数的测定》中的水浴温度、水浴时间、滴定终点颜色判断、滴定条件的要求,人为因素和实验环境因素对 高锰酸盐指数检测数据的准确性影响较大,传统手工容量法检测的弊端日益显现,因此按照环境监测标 准设计自动化检验分析设备,提高实验室检测水平尤为重要。文章对水质高锰酸盐指数全自动分析仪方 法的准确度和精密度进行了测定分析,并与国标容量法的操作过程和数据进行对比探讨,仪器法测定下限为0.05 mg/L,而国标容量法规定的测定下限为0.5 mg/L,仪器法在实际样品测定中的应用范围更 广,数据更可靠。     

THE EFFECT OF DATA INDEPENDENCE IN MODEL CALIBRATION AND MODEL TESTING1

ABSTRACT: With the increased use of models in hydrologic design, there is an immediate need for a comprehensive comparison of hydrologic models, especially those intended for use at ungaged locations (i.e., where measured data are either not available or inadequate for model calibration). But some past comparisons of hydrologic models have used the same data base for both calibration and testing of the different models or implied that the results of model calibration are indicative of the accuracy at ungaged locations. This practice was examined using both the regression equation approach to peak discharge estimation and a unit hydrograph model that was intended for use in urban areas. The results suggested that the lack of data independence in the calibration and testing of regression equations may lead to both biased results and misleading statements about prediction accuracy. Additionally, although split-sample testing is recognized as desirable, the split-samples should be selected using a systematic-random sampling scheme, rather than random sampling, because random sampling with small samples may lead to a testing sample that is not representative of the population. A systematic-random sampling technique should lead to more valid conclusions about model reliability. For models like a unit hydrograph model, which are more complex and for which calibration is a more involved process, data independence is not as critical because the data fitting error variation is not as dominant as the error variation due to the calibration process and the inability of the model structure to conform with data variability.     

NETWORK DESIGN FOR WATER SUPPLY FORECASTING IN THE WEST1

ABSTRACT: The objective is to develop techniques to evaluate how changes in basic data networks can improve accuracy of water supply forecasts for mountainous areas. The approach used was to first quantify how additional data would improve our knowledge of winter precipitation, and second to estimate how this knowledge translates, quantitatively, into improvement in forecast accuracy. A software system called DATANET was developed to analyze each specific gage network alternative. This system sets up a fine mesh of grid points over the basin. The long-term winter mean precipitation at each grid point is estimated using a simple atmospheric model of the orographic precipitation process. The mean runoff at each grid point is computed from the long-term mean precipitation estimate. The basic runoff model is calibrated to produce the observed long-term runoff. The error analysis is accomplished by comparing the error in forecasts based on the best possible estimate of precipitation using all available data with the error in the forecasts based on the best possible estimate of winter precipitation using only the gaged data. Different data network configurations of gage sites can be compared in terms of forecast errors.     

基于典型道路谱的模拟运输振动试验方法研究

针对深圳某一路段使用美国Lansmont公司开发的SAVER环境应力记录仪记录汽车运输过程中的环境应力，利用相关处理软件整理分析数据，最后在实验室中的通过电磁振动台的随机振动模式来进行模拟重现从而实现“Fieldtolab”。该方法用短时间的实验室内试验来代替长时间的实际运输过程，不仅绿色环保，而且省时省力，是一种值得推广的试验方法。     

TraK装置测定废水中的BOD_5

在对废水中的BOD5进行常规分析时,采用化学稀释法操作繁琐,对稀释倍数估计易发生错误。而利用TraK装置测试样品时,无须进行稀释和化学分析。用该装置对标准样品BOD5的测定结果表明:准确度相对误差为-3.3%～4.3%,精密度的相对误差为-3.5%～5.6%。该仪器测试性能可靠,数据准确度、精密度合格。与化学法对照分析表明,相对误差都在容许范围内,即在可接受范围内。     

分光光度法与离子色谱法测定空气中氯化氢的对比研究

通过对硫氰酸汞分光光度法和离子色谱法测定空气中氯化氢含量的对比发现，两种方法对实验室质控样和实际样品的分析测定均能达到要求，且F检验法分析表明实测结果没有显著性差异。然而，硫氰酸汞分光光度法的测试过程操作繁琐，误差较大，稳定时间较长，且硫氰酸汞具有剧毒，危害操作人员的健康，残液也难以处理。离子色谱法分析操作简单，过程安全可靠，能够有效降低样品受污染的可能性并保证分析质量。     

Estimation of daily sunshine duration using support vector machines

Although sunshine duration (SD) is one of the most frequently measured meteorological parameters, there is a lack of measurements in some parts of the world. Hence, it should be estimated accurately for areas where no reliable measurement is possible. The main objective of this study is to evaluate the potential of support vector machine (SVM) approach for estimating daily SD. For this purpose, three different kernels of SVM, such as linear, polynomial, and radial basis function (RBF), were used. Different combinations of five related meteorological parameters, namely cloud cover, maximum temperature (T_max), minimum temperature (T_min), relative humidity (RH), and wind speed (WS), and one astronomic parameter, day length, were considered as the inputs of the models, and the output was obtained as daily SD. Simulated values of the models were compared with ground measured values, and concluded that the usage of the SVM-RBF estimator with combination of all input attributes produced the best results. The coefficient of determination, root mean square error, and mean absolute error were found to be 0.8435, 1.5105 h, and 1.0771 h, respectively, for the pooled four-year daily data set of 14 stations in Turkey. It was also deduced that accuracy increased as the number of attributes increased and the major contribution to this came from RH as compared with T_max, T_min, and WS. This study has shown that the SVM methodology can be a good alternative for conventional and artificial neural network methods for estimating daily SD.     

"钼酸铵显色-离心分离光度法"测高悬浮物地表水中总磷的方法探讨

本文对高悬浮物地表水中总磷测定方法进行了探讨,提出了用“钼酸铵显色-离心分离法”解决由于高悬浮物所带来的分析误差。通过实验室大量样品分析实验,证明此方法的可行性。     

玻璃量器滴定管容量示值误差对分析结果的影响

介绍了玻璃量器滴定管的用途、分类和容量示值误差的检定,分析和探讨了容量示值误差和流液口最后一滴水珠示值的大小对分析结果的影响。容量示值误差的大小能够影响分析结果的准确性,使被测样品的含量偏离其真实结果,选择合格、合适的滴定管,可以减少分析过程带来的误差,提高分析结果的准确度。     

烟气测试中流速计算误差分析

本文通过对烟气测试中流速计算公式的比较分析，结合实际监测数据处理，认为烟气流速计算中，使用通用公式与简化公式的误差，虽然与Ｒｓ和Ｂｓ有关，但主要误差来源于Ｂｓ。而Ｒｓ不必用精密仪器测出烟气中各组份后求算。只要用简易仪器测得烟气中的Ｘｏ２和Ｘｓｗ的百分含量，即可求出Ｒｓ近似值，用于烟气流速计算。     

QUALITY ASSURANCE TECHNIQUES FOR ELECTRONIC DATA ACQUISITION1

ABSTRACT: Electronic instruments are increasingly being used to gather water quality data. Quality assurance protocols are needed which provide adequate documentation of the procedures followed in calibration, collection, and validation of electronically acquired data. The level of precision of many data loggers exceeds the technology which is commonly used to make field measurements. Overcoming this problem involves using laboratory quality equipment in the field or enhanced quality control at the time of instrument servicing. Time control procedures for data loggers are needed to allow direct comparisons of data between instruments. Electronic instruments provide a mechanism to study transient events in great detail, but, without time controls, multiple loggers produce data which contain artifacts due to timing errors. Individual sensors deployed with data loggers are subject to different degrees of drift over time. Certain measurements can be measured with defined precision and accuracy for long periods of time, while other sensors are subject to loss of both precision and accuracy with increasing time of use. Adequate quality assurance requires the levels of precision and accuracy be documented, particularly those which vary with increasing time deployment.