EPA review letter, 133-135 Greenwich Street

NYC 9/11 Public Portal Document

Part II - Environmental Community Monitoring Plan 133-135 Greenwich & 21-23 Thames Streets Airtek Project 05-0701— Rev 2 September 16, 2005

5.0 DATA VALIDATION AND QUALITY ASSURANCE AUDIT

This section outlines the procedures necessary for the data validation and quality assurance audit, which ensures the accuracy of the results.

5.1 Data Validation

Data validation is a systematic procedure of reviewing a body of data against a set of established criteria so as to provide a specified level of assurance of its validity prior to its intended use. The review of the data will include an audit of the quality control samples—the laboratory's method blanks, field blanks, spikes, and surrogate recoveries. These quality control samples allow a direct check on the variability in the methods of analysis and sampling and in the sample matrix itself. The data will be reviewed by the laboratory's QA Officer for compliance to the technical specifications and completeness. The laboratory will provide a non-conformance summary as appropriate for the analytes determined. Included in the non-conformance summary will be notification of sample receipts. This will include information regarding problems with sample packaging, Chain of Custody and sample preservation. A preliminary review for deviations from method protocols including holding times, surrogate recoveries, and spike recoveries will be reviewed.

The QA Officer will evaluate a number of criteria including the following: • Chain of Custody completeness; • Analyses completed versus analyses planned; • Time held versus holding times; • Laboratory blanks (method and instrument); • Laboratory Control Sample; • Trip and field blank results; and • Duplicate analyses precision.

Deficiencies discovered by the contracted laboratory QA Officer will be documented and communicated to the Airtek QA Officer, the Project Manager, and the Laboratory. The impact of deficiencies on use of the data will be evaluated by the Airtek QA Officer and the Project Manager.

5.2 Laboratory Audits

During the laboratory analyses, Airtek QA Officer will be in direct contact with the laboratory to check on the project status. Any technical concern will be discussed during these updates, and formalized in writing by the contracted laboratory. A telefax may be used. Any significant problems impacting either the holding times, or the analytical methodologies, or the deliverable package will be determined.

5.3 Fleld Audits

The purpose of QA field audits is to ensure compliance with the approved SAP and QAPP. During the performance of the sampling procedures, the QA Officer will make on site audits. Deviations from the approved plans will be brought to the attention of the Field Manager and the Project Manager. All deviations will be recorded in the QA Officer's log and field notebook of

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NYC-WTC 000134260