Effect-Based Trigger Values Are Essential for the Uptake of Effect-Based Methods in Water Safety Planning

Area of Science:

• Environmental Toxicology
• Analytical Chemistry
• Water Quality Management

Background:

• Effect-based methods (EBMs) are recommended for water quality monitoring due to their ability to detect mixture effects of chemicals.
• High sensitivity of in vitro bioassays necessitates effect-based trigger values (EBTs) to distinguish between acceptable and unacceptable water quality.
• EBTs are essential for the broader adoption of EBMs by the water industry and regulatory agencies.

Purpose of the Study:

• To provide an overview of currently available EBTs for various bioassays.
• To propose a simple method for predicting interim EBTs for assays lacking established values.
• To develop an interpretation framework for EBM results exceeding EBTs in drinking water safety planning.

Main Methods:

• Review and compilation of existing EBTs for drinking and surface water monitoring.
• Development of a predictive approach for interim EBTs based on reference compound effect concentrations.
• Creation of an interpretation framework for action when EBM results surpass EBTs.

Main Results:

• EBTs have been established for assays targeting specific receptor-mediated effects, adaptive stress responses, and apical effects.
• A proposed simple method for predicting interim EBTs showed good agreement with literature-derived values.
• An interpretation framework was developed to guide actions for exceeding EBTs in water safety planning.

Conclusions:

• EBTs are vital for interpreting EBM results in water quality monitoring.
• The proposed method offers a reliable way to establish interim EBTs.
• The interpretation framework will aid in the routine implementation of EBMs for drinking water safety.