Using biotic ligand models to predict metal toxicity in mineralized systems. (June 2015)

• Record Type: Journal Article
• Authors: Smith, Kathleen S.; Balistrieri, Laurie S.; Todd, Andrew S.
• Is Part Of: Applied geochemistry. Volume 57(2015:Jun.)
• Page Start: 55
• Page End: 72
• Publication Date: 2015-06
• Subjects: Environmental geochemistry -- Periodicals; Water chemistry -- Periodicals; Geochemistry -- Social aspects -- Periodicals; Geochemistry -- Periodicals; 551.9
• DOI: 10.1016/j.apgeochem.2014.07.005
• Languages: English
• ISSNs: 0883-2927

Abstract

Highlights: Review applicability of biotic ligand models (BLMs) at mined and mineralized sites. Describe scientific concepts and features of BLMs. Discuss evolution of water-quality criteria. Identify challenges in implementing BLMs at mined and mineralized sites. Present case studies to illustrate use of BLMs at mined and mineralized sites. Abstract: The biotic ligand model (BLM) is a numerical approach that couples chemical speciation calculations with toxicological information to predict the toxicity of aquatic metals. This approach was proposed as an alternative to expensive toxicological testing, and the U.S. Environmental Protection Agency incorporated the BLM into the 2007 revised aquatic life ambient freshwater quality criteria for Cu. Research BLMs for Ag, Ni, Pb, and Zn are also available, and many other BLMs are under development. Current BLMs are limited to 'one metal, one organism' considerations. Although the BLM generally is an improvement over previous approaches to determining water quality criteria, there are several challenges in implementing the BLM, particularly at mined and mineralized sites. These challenges include: (1) historically incomplete datasets for BLM input parameters, especially dissolved organic carbon (DOC), (2) several concerns about DOC, such as DOC fractionation in Fe- and Al-rich systems and differences in DOC quality that result in variations in metal-binding affinities, (3) water-quality parameters and resulting metal-toxicity predictions that are temporally and spatially dependent, (4) additional influences on metal bioavailability, such as multiple metal toxicity, dietary metal toxicity, and competition among organisms or metals, (5) potential importance of metal interactions with solid or gas phases and/or kinetically controlled reactions, and (6) tolerance to metal toxicity observed for aquatic organisms living in areas with elevated metal concentrations.