Testing the Underlying Chemical Principles of the Biotic Ligand Model (BLM) to Marine Copper Systems: Measuring Copper Speciation Using Fluorescence Quenching

• Published in: Bulletin of environmental contamination and toxicology Vol. 100; no. 1; pp. 76 - 81
• Main Authors: Tait, Tara N., McGeer, James C., Smith, D. Scott
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.01.2018; Springer Nature B.V
• Subjects: Aquatic Pollution; Artificial seawater; Binding sites; Bioavailability; Chemical analysis; Copper; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Fluorescence; Fluorescence spectroscopy; Heavy metals; Ligands; Marine systems; Organic matter; Pollution; Quenching; Risk assessment; Seawater; Soil Science & Conservation; Speciation; Stability constants; Statistical analysis; Statistical methods; Toxicity; Waste Water Technology; Water analysis; Water Management; Water Pollution Control; Water sampling; Biotic ligand model; Marine chemistry; Dissolved organic carbon; Copper speciation; Natural organic matter; Fluorescence quenching
• DOI: 10.1007/s00128-017-2262-8
• ISSN: 0007-4861

Speciation of copper in marine systems strongly influences the ability of copper to cause toxicity. Natural organic matter (NOM) contains many binding sites which provides a protective effect on copper toxicity. The purpose of this study was to characterize copper binding with NOM using fluorescence quenching techniques. Fluorescence quenching of NOM with copper was performed on nine sea water samples. The resulting stability constants and binding capacities were consistent with literature values of marine NOM, showing strong binding with log K values from 7.64 to 10.2 and binding capacities ranging from 15 to 3110 nmol mg  C - 1 . Free copper concentrations estimated at total dissolved copper concentrations corresponding to previously published rotifer effect concentrations, in the same nine samples, were statistically the same as the range of free copper calculated for the effect concentration in NOM-free artificial seawater. These data confirms the applicability of fluorescence spectroscopy techniques for NOM and copper speciation characterization in sea water and demonstrates that such measured speciation is consistent with the chemical principles underlying the biotic ligand model approach for bioavailability-based metals risk assessment.