About the Biotic Ligand Model (BLM)
EPA's 2007 aquatic life freshwater quality criteria for copper is based on the Biotic Ligand Model (BLM). The BLM is a metal bioavailability model that uses receiving water body characteristics and monitoring data to develop site-specific water quality criteria. Input data for the BLM include: temperature, pH, dissolved organic carbon (DOC), major cations (Ca, Mg, Na, & K), major anions (SO4 & Cl), alkalinity, and sulfide.
EPA has developed this special interest module to provide the user with valuable information on the BLM.
This introductory presentation provides an overview of the copper BLM and addresses commonly asked questions, such as:
- What is the BLM?
- Why is the BLM an improvement over EPA's old hardness-based copper criteria?
- How do the BLM-derived criteria compare to the hardness-based criteria?
- What input parameters are needed to run the BLM?
- How has the BLM approach been applied in practice?
This short video (4:22) demostrates the BLM software. After watching this video, you will understand how to load an input file, run the model, view the model's output, and export the results. The BLM software and user's guide can be downloaded.
Additional information on implementing EPA's national recommended copper criteria.
Note: this video has no associated audio content.
BLM Software video(1 pg, 16 MB)
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- WQS Academy: Biotic Ligand Model and Copper Criteria (PDF)(17 pp, 247 K, March 2016, 820Q16001)