“…The most common mechanistic model used for the development of regulatory criteria is the BLM (Di Toro et al, 2001; Niyogi & Wood, 2004; Santore et al, 2001). Substance‐specific BLMs have been developed for several metals (i.e., aluminum, cadmium, cobalt, copper, nickel, lead, and zinc in freshwater systems and copper, nickel, and zinc in saltwater systems) and consist of multiple submodels that mechanistically simulate chemical speciation, competition of ionic bonding, as well as accumulation and toxicity to aquatic species (Adams et al, 2020; Barnhart et al, 2021; Windward Environmental LLC, 2020). Copper is the only contaminant for which USEPA has established aquatic life criteria using the BLM (Santore et al, 2001; USEPA, 2007), and this guidance has suffered from low adoption among states, which may be due to difficulty in statewide implementation and/or the large amount of data needed to parameterize the model (USEPA, 2022a).…”