Louisiana Administrative Code
Title 48 - PUBLIC HEALTH-GENERAL
Part V - Preventive Health Services
Subpart 28 - Drinking Water Laboratories
Chapter 80 - Certification of Laboratories Performing Drinking Water Analyses
Subchapter C - Criteria and Procedures for Chemical Testing and Analysis
Section V-8057 - Quality Assurance for Environmental Testing

A. Laboratories which have received certification or are seeking certification to perform any of the required chemical analyses, shall have established quality control procedures pursuant to Chapter IV of the USEPA Manual for the Certification of Laboratories Analyzing Drinking Water.

B. The laboratory shall implement the essential quality control procedures in Chapter IV of the USEPA Manual for the Certification of Laboratories Analyzing Drinking Water.

C. The laboratory shall perform all quality control procedures at the frequency required in the approved reference method(s) specified in 40 CFR Parts 141 and 143 in the analysis of drinking water parameters. In addition, the laboratory shall meet the acceptance criteria specified in the applicable, approved reference method(s) specified in 40 CFR Parts 141 and 143 in the analysis of drinking water parameters.

D. Control charts, generated from the laboratory's control sample (however named), shall be maintained by the laboratory. Until sufficient data are available from the laboratory, usually a minimum of 20 to 30 test results on a specific analysis, the laboratory shall use the control limits (if specified) in the method. When sufficient data becomes available, the laboratory shall develop control charts from the mean percent recovery (X_) and the standard deviation (S) of the percent recovery for the Quality Control (QC) checks specified in the above Subsections of this Section (also, see Chapter VI of the Handbook for Analytical QC in Water and Wastewater Laboratories, EPA-600/4-79-019 or Standard Methods for the Examination of Water and Wastewater, 20th edition, Part 1020B, or similar laboratory analytical QC reference texts for further information). These data are used to establish upper and lower control limits as follows:

E. After each five to ten new recovery measurements, new control limits should be calculated using the most recent 20-30 data points. These calculated control limits shall not exceed those established in the method. If any of these calculated control limits are tighter than the control limits specified within the method, the laboratory shall use the tighter criteria.