Publication Summary

The Laboratory Guidance and Whole Effluent Toxicity (WET) Test Review Criteria document provides the regulatory context for WET testing and related services provided by labs. Having an understanding of the purpose of WET testing in Washington State can help labs provide better service to permittees and other clients. The document provides details on sample handling, test conditions for specific WET tests, acceptability of test results, and related activities such as treatment chemical or ballast water biocide evaluation.

The Laboratory Guidance and Whole Effluent Toxicity (WET) Test Review Criteria document provides the regulatory context for WET testing and related services provided by labs. Having an understanding of the purpose of WET testing in Washington State can help labs provide better service to permittees and other clients. The document provides details on sample handling, test conditions for specific WET tests, acceptability of test results, and related activities such as treatment chemical or ballast water biocide evaluation.

The authority for whole effluent toxicity (WET) activities in Washington State comes from RCW 90.48.520, chapter 173-205 WAC (the WET rule), and chapter 173-201A WAC (state water quality standards). Interested persons can access these laws and rules online at:

http://www.ecy.wa.gov/laws-rules/index.html

Chapter I of this document will assist labs in providing toxicity testing services to permittees. National Pollutant Discharge Elimination System (NPDES) permits define how provisions in the WET rule apply to each permittee. Labs should follow the instructions in a client′s permit. It is important that labs get a copy of the toxicity testing pages of a permit in order to provide the best service. Permits are available from a client or online at:

http://www.ecy.wa.gov/programs/wq/permits/wwdischargepermits.html

Permit language for WET can be complicated because it will contain a series of steps in a regulatory process. The step to follow will depend at times on the results of the previous step. Regardless of the guidance to labs in the document, labs should not deviate from the instructions in any valid permit unless the deviation has been approved by the Department of Ecology.

Chapter II of this document will assist accredited labs in providing acceptable toxicity tests for permittees. Proper sample handling, test conditions, control performance, and reporting of results produce acceptable tests. Chapter II of the document discusses these factors in detail.

Appendices to the document define anomalous test results and describe how labs and permittees should respond when they happen. Anomalous test results occur when the lab conducts the WET test properly, but the results are considered unreliable according to anomalous test identification criteria. Appendices also describe evaluating the safety of storm water treatment chemicals and ballast water biocides. The use of rapid screening tests is described in an appendix. Other appendices provide supporting information for test analysis, hardness adjustment, testing chlorinated discharges, and determining compliance with power standards.

All questions concerning this document or the WET testing program should be directed to Randall Marshall, (360) 407-6445, or rmar461@ecy.wa.gov