Quality Assurance

Introduction

Quality Assurance/ Control Manual, click to download PDF fileThe Water Quality Laboratory (WQL), located in Newport Beach, California, is an adjunct laboratory of Orange County Public Health Laboratory (OCPHL), Santa Ana. Microbiological water analyses are performed at the WQL. The Chemistry department of the OCPHL performs chemistry testing on water samples.

OCPHL is committed to ensure data accuracy and quality. The laboratory has been performing indicator bacterial testing according to an established quality assurance program approved by the Environmental Laboratory Accreditation Programs (ELAP) of the California Department of Health Services (DHS) (certificate number 2545). Accreditation is required of an environmental laboratory for producing analytical data for California regulatory agencies. The data may be used to demonstrate compliance with applicable requirements of drinking water and wastewater sections of the California Health and Safety and Water codes. The accreditation process includes completion of: (1) verification of a quality assurance program, (2) successful analysis of performance evaluation samples, (3) successful completion of a site visit by an ELAP auditor.

Microbiological water analyses are performed using testing methods in the Standard Methods for the Examination of Water and Wastewater, 20th edition and USEPA Improved Enumeration Methods for the Recreational Water Quality Indicators: Enterococci and Escherichia coli. Laboratory personnel follow standard operational procedures (SOPs) for media preparation, sample collection and log-in, analytical methods (including references), data reduction, validation and reporting and QA/QC procedures as established by the OCPHL. Laboratory personnel are required to follow safe laboratory practices and encouraged to participate in continuing education classes. Laboratory instruments and equipment are maintained on a regular basis to verify operation to manufacturer's and laboratory specifications. Instruction manuals and maintenance records for laboratory equipment are kept on file.

Laboratory facility

The WQL is currently located on Shellmaker Island in the City of Newport Beach, adjacent to the Newport Bay. The lab area includes office space and work areas. It is equipped with refrigerators, incubators, freezers, water baths, microscopes and other instruments used in research projects and routine water analyses.

Data management, analysis, validation and reporting

Field data samples include the following information: bottle number, time collected, and station number/location of sampling, which are tabulated on sample worksheets at time of sample collection. The date and time of receipt and time that the samples are processed are recorded on the sample worksheet. The results are recorded on the data sheets and reported as CFU/100 ml. Sample worksheets are reviewed and signed by senior staff prior to reporting the results. Hard copies of the worksheets are maintained in binders and archived for 5 years from the time they are completed. Copies of the data are available upon request. The data is also recorded into an electronic database and maintained on a separate disk.

Internal quality control checks to validate laboratory personnel performance are conducted on a routine basis. The type and frequency of internal quality control checks are detailed in the SOP. Microbiological media and reagents must meet acceptable criteria based on Standard Methods of manufacturer recommendations prior to use. Control samples are included during water analyses. Laboratory instruments and equipment are checked prior to use. Proficiency samples obtained from commercial sources are used to validate analyst techniques and practices.

The precision and accuracy of data for water samples is determined following procedures outlined in Standard Methods (SM) and by testing replicate samples. The measurement of precision criteria (SM 9020B) is used to determine analyst method precision.