Module 2: Quality Control Requirements, Selection of Analytical Methods, and Review of Data

Data Quality Objectives (DQO) and Associated QA/QC Requirements..........................................1 Quality Control and Quality Assurance to Identify Sampling and Analysis Problems ...............................1 Use of Blanks to Minimize and to Identify Errors ..................................................................................2 Quality Control........................................................................................................................................2 Checking Results.....................................................................................................................................5 The Need for Quality Control Review of Data to Identify Corrupt Data and to Identify Unusual Conditions ........................................................................................................................................6 Importance of Identifying Corrupt Data......................................................................................................6 Basic Steps in Identifying Suspect Data..................................................................................................6 The Effects of Unusual High and Low Values on Probability Distribution Parameters..........................8 Examples of Methods used to Identify Corrupt Data ................................................................................11 Probability Distributions of Data...........................................................................................................13 Analysis of Log-normality of Stormwater Constituents Parameters .....................................................14 Identification of Unusual Monitoring Locations using Xbar and S Charts ...............................................22 Identifying the Needed Detection Limits and Selecting the Appropriate Analytical Method ..........25 Use of Field Methods for Water Quality Evaluations ...............................................................................28 Field Test Kits .......................................................................................................................................31 Selection of Appropriate Field Test Kits ...............................................................................................36 Conventional Laboratory Analyses ...........................................................................................................38 Reporting Results Affected by Detection Limits.............................................................................40 References.....................................................................................................................................41