SMC chemistry intercalibration to ensure consistency, quality of stormwater monitoring data

The SMC has launched the fourth cycle of a periodic intercalibration exercise intended to ensure that laboratories that perform routine chemistry analyses of Southern California runoff samples are capable of generating consistently high-quality monitoring data.

The SMC’s fourth chemistry laboratory intercalibration, which was launched last year, is evaluating seven laboratories’ ability to measure five different classes of chemical contaminants in wet- and dry-weather runoff.

The SMC previously hosted chemistry laboratory intercalibrations in 2004, 2007 and 2010, followed by a toxicity laboratory intercalibration in 2016. The SMC’s bioassessment and physical habitat assessment intercalibrations, meanwhile, take place through annual field audits.

The periodic SMC intercalibrations are a prime opportunity for the stormwater monitoring community to come together to directly evaluate the performance of laboratories that produce stormwater monitoring data under discharge permits and other programs.

Through these intercalibrations, SMC member agencies gain confidence that laboratories they contract with are producing comparable data – and moreover, that using a different laboratory will not produce different results.

Periodic intercalibration exercises like the SMC’s fourth chemistry laboratory intercalibration –launched last year – play a key role in ensuring that laboratories that generate stormwater monitoring data across Southern California are producing comparable results. SMC member agencies look favorably on laboratories that participate in the voluntary exercise as they make decisions about which laboratories to contract with for their monitoring needs.

Participating laboratories work in an iterative fashion through three rounds of analysis over a three-year period and are scored on both intra- and inter-laboratory variability. Participants help develop the study design, then collectively review and discuss results to optimize their processes in subsequent rounds.

SMC member agencies use participation in SMC intercalibration exercises as part of decision-making about which laboratories to contract with for their monitoring needs. Laboratories that participate and pass the intercalibration typically receive bonus points for proposals. Moreover, some SMC member agencies require laboratories they contract with for chemical analysis to have participated in this intercalibration.

The chemistry laboratory intercalibration is expected to be completed in 2024 and will include publication of an updated manual that provides best-practices guidance for how to ensure proficiency in chemistry analysis techniques, as well as the results of the SMC chemistry laboratory intercalibration.

Although the SMC has completed Round 1 of its three-year intercalibration cycle, additional laboratories are welcome to join in Rounds 2 and 3 as full participants. The Round 2 intercalibration is scheduled to start in fall 2022.

For more information about joining the study, contact Dr. Charles Wong with the Southern California Coastal Water Research Project (SCCWRP).

SMC Summer 2022 Newsletter
Volume 3, Issue 1

This newsletter is published three times a year by the Southern California Stormwater Monitoring Coalition (SMC). To subscribe to this newsletter, contact [email protected].