环境监测技术1

环境监测技术Environmental Monitoring Technology,Contents,Chapter 1 Definition, Procedure and Standard,1.1 Definition Definition of Environmental MonitoringMonitoring and determining of different environmental indicators, using modern chemical, physical, medicinal, remote sensing and computer technologies. On the base of monitoring data, giving the comprehensive evaluation on environmental quality.就是运用化学、物理、生物、医学、遥测、遥感和计算机等现代化科技手段监视、测定、监控反映环境质量及其变化趋势的各种标志数据，从而对环境质量做出综合评价的学科。,Chapter 1 Definition, Procedure and Standard,Objectives of Environmental MonitoringMonitoring environmental indexes as wall as their variation trends timely, accurately and comprehensively, providing basic data for environmental layout, environmental assessment, pollution control and macroscopical decision-making for government departments. 环境监测的目的是及时、准确、全面地反映环境质量及发展趋势，为环境规划与管理、环境影响与评价、污染控制及政府宏观决策提供科学依据。,1.2 Procedure of Environmental Monitoring,Sampling (the number of sampling locations and their distribution)Analysis (item, method)Data processing (quality control, statistical analysis)Environmental assessment (assessment method, report),1.1 SamplingTaking atmosphere sampling for an example,Concentric Circle method,Gridding method,Functional Area method,Sampling time and frequency,采样时间：指每次采样所需时间的长短；采样频率：指一定时间范围内的采样次数；,Direct method被测组分浓度高分析方法灵敏度高,Concentrated method 被测组分浓度高分析方法灵敏度不够高,Sampling method,Direct sampling method,1.Syringe2.Plastic bag3.Gas container,4.High-vacuum jar,采样体积V：,V0-真空采气瓶容积，L；P-大气压力，kPa； PB-闭管压力计读数， kPa；,Cold trap method,1.2 Analysis,Analytical method,Specphototrometry,Determination of SO2,Tetrachloromercurate (TCM)-Pararosaniline method,Formaldehyde-Pararosaniline method,Conduction method,Thorin method,原理,用氯化钾和氯化汞配制成四氯汞钾吸收液，吸收大气中SO2，生成稳定的二氯亚硫酸盐络合物，该络合物再与甲醛和盐酸副玫瑰苯胺作用，生成紫色络合物，其颜色深浅与SO2含量成正比，用分光光度法测定。,反应式如下: HgCl2+2KC1=K2HgCl4 HgCl42-+SO2+H2O=HgCl2SO32-+2H+2Cl- HgCl2SO32-+HCHO十 2H+=HgCl2+HOCH2SO3H 羟甲基磺酸,紫色络合物,盐酸副玫瑰苯胺,原理,溶液电导法测定SO2,钍试剂分光光度法,1.3 Data processing,监测数据的五性： 代表性 (representation)； 准确性 (accuracy)； 精密性 (precision)； 可比性 (compatibility)； 完整性 (completeness)。,Data quality indicators1. Precision2. Accuracy3. Completeness4. Method detection limit5. Representativeness6. Comparability,1. PrecisionPrecision is a measure of agreement among two more determinations of the same parameter under similar conditions.Two terms used to describe precision are relative percent difference (RPD) and relative standard deviation (RSD), depending on whether two or more than two replicates are used.,For two replicates, RPD=100(X1-X2)/(X1+X2)/2 X1=larger of the two values X2=smaller of the two values For three or more replicates, RSD=100(S/X平均值） S= standard deviation,2. Accuracy Accuracy is the degree of agreement between a measured value and the true expected, or accepted. It is frequently expressed in terms of percent recovery (%R) whether standard reference materials (SRM) or spiked samples are used.,For SRMs are used, accuracy is expressed as follows:%R=100(CM/CSRM)CM=measured concentration of SRMCSRM=actual concentration of SRM,3. Completeness Completeness is a measure of the amount of valid data obtained compared with that expected to be obtained under normal operating conditions. %C=100(nv/n),4. Representativeness Representativeness express how closely a sample reflects the characteristics of the substance for which it is a surrogate. Ideally, the representativeness of the sample is 100%.,5.Comparability Comparability refers to how confidently one data set can be compared with another. Ideally, it would be 100%.Practically, because the data were collected under different conditions and for different purposes, comparing data sets must be done very cautiously.,1.4 Data processing,1.4.1 校准曲线（calibration curve）：用于描述待测物质的浓度（量）与相应的测量信号间定量关系的曲线。 工作曲线（work curve)；标准溶液的分析步骤与样品分析步骤完全相同； 标准曲线（standard curve)；标准溶液的分析步骤与样品分析步骤相比有所省略，如省略部分前处理步骤。,1.4.2 检测限的概念,检出限(Detection Limit, DL或Limit of Detection, LOD)； 特定分析方法在给定的置信度内可从样品中检出待测物质的最小浓度或最小量。检出限是以一定的置信水平为基础的量值，并且随介质、被分析组分以及分析方法的不同而不同。,IUPAC于1975年推荐检出限的定义：检出限以浓度(或质量)表示，指由特定的分析方法能够合理地检测出的最小分析信号xL求得的最低浓度cL(或质量qL)，表达式为： cL(或qL)=(xL-b)/m=KSb/m 式中m为分析校准曲线在低浓度范围内的斜率；b为空白平均值；Sb为空白标准偏差。测定次数为20次，IUPAC建议K=3作为检出限计算标准。,仪器的检出限(Instrument Detection Limit, IDL)：是指分析仪器能够检测的被分析物的最低量或浓度，这个浓度与特定的仪器能够从背景噪音中辨别的最小响应信号相对应。比如色谱仪的检出限是产生至少2倍于基线噪音的进样量。仪器的检出限不考虑任何样品制备步骤的影响，因此，其值总是比方法的检出限要低。仪器的检出限一般不用于最终的数据报告，而主要用于数据的统计分析，以及不同仪器的性能比较。,方法检出限(Method Detection Limit, MDL)：是指在通过某一种分析方法的全部处理和测定过程之后(包括样品制备和样品测定)，被测定物质产生的信号能以99%置信度区别于空白样品而被测定出来的最低浓度方法的检出限与仪器的检出限相似，但考虑了样品分析前的所有制备过程的影响。方法的检出限是我们建立分析方法时最关心的一个参数。,定量限(Limit of Quantitation, LOQ)：被测组分的浓度能产生比空白足够大的信号，这个信号能够被良好实验室在常规操作条件下以指定的置信水平定量检出，这个浓度就是定量限。一般以产生10倍试剂空白的标准偏差的信号所对应的浓度作为定量限。LOQ随介质、分析方法和分析对象的不同而不同。,上述四个定义相应的数值有这样的近似关系， 即：IDL:LOD:MDL:LOQ=1:2:4:10。,Method detection limit (MDL),The minimum concentration of a substance that can be measured and reported with 99% confidence that the analyte concentration is greater than zero and is determined from analysis of a sample in a given matrix containing the analyte.,Scope and Application,This procedure is designed for applicability to a wide variety of sample types ranging from reagent (blank) water containing analytes to wastewater containing analytes.The MDL for an analytical procedure may vary as a function of sample type.,The procedure requires a complete, specific, and well defined analytical method. It is essential that all sample processing steps of the analytical method be included in the determination of the method detection limit.,Continues,Principles of data collection and handling,Know why the data must be collectedDocument everything thoroughlyCalibrate instruments and test softwarePreserve the original dataUse only validated dataUse tables or graphs to present summary statisticsBeware of using data collected for another purpose,Environmental evaluation (assessment method, report),问题1,1.3 Environmental Quality Standards,环境标准： 是关于控制污染、保护环境的各种标准的总称。 All criterions, standards and laws established by administration, aiming to pollution control and environment protection.环境标准的作用：应用于环境规划、环境评价、环境监督管理；环境标准是环境法规的重要组成部分，具有法律效力，具有社会导向作用。,我国的环境标准体系三级：国家环境标准(GB)、国家环境行业标准(HJ)、地方行业标准。六类：环境质量标准、污染物排放标准、环境基础标准、环境方法标准、环境标准物质标准、环保仪器设备标准。 GB/T: 国家推荐标准； GB/Z: 国家指导性技术文件；GHZB:国家环境质量标准；GWPB:国家污染物排放标准；HJ:国家环保总局标准；HJ/T:国家环保总局推荐标准。,水环境质量标准,地表水环境质量标准（GB 3838-2002）生活饮用水卫生标准（GB 5749-85）农业灌溉用水水质标准（GB 5084-92）海水水质标准（GB 3097-1997）渔业水质标准（GB 11607-89）地下水环境质量标准（GB/T 14848-1993）,地表水环境质量标准基本项目标准限值(mg/L),污水综合排放标准（GB8978-1996),第一类污染物，指能在环境和动植物内蓄积，对人体健康产生长远不良影响的污染物。,第二类污染物：指长远影响小于第一类的污染物。,空气质量标准,环境空气质量标准(GB 3095-1996)室内空气质量标准(GB/T 18883-2002)保护农作物的大气污染物最高允许浓度(GB 9137-88),空气污染指数的定义及分级限值 API（Air Pollution Index的英文缩写）是空气污染指数.,式中：C大与C小：在API分级限值表中最贴近C值的两个值，C大为大于C的限值，C小为小于C的限值。I大与I小：在API分级限值表（表1）中最贴近I值的两个值，I大为大于I的值，I小为小于I的值。,空气