Section 811. Air testing: negative and positive controls

A. Negative controls.

1. Method blanks shall be performed at a frequency of at least one per batch of 20 environmental samples or less per sample preparation method. The results of the method blank analysis shall be used to evaluate the contribution of the laboratory provided sampling media and analytical sample preparation procedures to the amount of analyte found in each sample. If the method blank result is greater than the limit of quantitation and contributes greater than 10% of the total amount of analyte found in the sample, the source of the contamination shall be investigated and measures taken to eliminate the source of contamination. If contamination is found, the data shall be qualified in the report.

2. Collection efficiency. Sampling trains consisting of multiple sections (e.g., filters, sorbent tubes, impingers) that are received intact by the laboratory shall be separated into "front" and "back" sections if required by the client. Each section shall be processed and analyzed separately and the analytical results reported separately.

B. Positive controls. Laboratory control sample (LCS) shall be analyzed at a rate of at least one per batch of 20 or fewer samples per sample preparation method for each analyte. If a spiking solution is not available, a calibration solution whose concentration approximates that of the samples shall be included in each batch and with each lot of media. The concentration of the LCS shall be relevant to the intended use of the data and either at a regulatory limit or below it.

C. Surrogates shall be used as required by the test method.

D. Matrix spike shall be used as required by the test method.

Historical Notes

Derived from Volume 25, Issue 07, eff. January 1, 2009; amended, Virginia Register Volume 32, Issue 22, eff. September 1, 2016.

Statutory Authority

§ 2.2-1105 of the Code of Virginia.