Model predictions of copper speciation in coastal water compared to measurements by analytical voltammetry.
Environ Sci Technol
; 46(14): 7644-52, 2012 Jul 17.
Article
in En
| MEDLINE
| ID: mdl-22724636
ABSTRACT
Trace metal toxicity to aquatic biota is highly dependent on the metals chemical speciation. Accordingly, metal speciation is being incorporated in to water quality criteria and toxicity regulations using the Biotic Ligand Model (BLM) but there are currently no BLM for biota in marine and estuarine waters. In this study, I compare copper speciation measurements in a typical coastal water made using Competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV) to model calculations using Visual MINTEQ. Both Visual MINTEQ and BLM use similar programs to model copper interactions with dissolved organic matter-DOM (i.e., the Stockholm Humic Model and WHAM-Windermere Humic Aqueous Model, respectively). The total dissolved (<0.4 µm filter) copper concentration, [CuT] in the study sites ranged from <10 nM close to the open Baltic Sea to ca. 50 nM in the vicinity of a marina in the Stockholm Archipelago. The corresponding free copper concentration [Cu2+], measured by CLE-ACSV ranged from 1013.2 M to 1012.0 M for the reference and marina sites, respectively, whereas the corresponding [Cu2+] modeled calculations ranged from 1012.5 M to 1011.6 M. The low copper to DOM ratios (similar to 0.0004 mg Cu per mg DOC) in these coastal waters ensured that ambient dissolved copper was overwhelmingly chelated to strong Cubinding ligands (12 < log KCuL1,Cu2+Cond >14). The modeled [Cu2+] could be fitted to the experimental values better after the conditional stability constant for copper binding to fulvic acid (FA) complexes in DOM in the SHM was adjusted to account for higher concentration of strong Cu-binding sites in FA.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Seawater
/
Water Pollutants, Chemical
/
Chemistry Techniques, Analytical
/
Ecosystem
/
Copper
/
Electrochemical Techniques
/
Models, Theoretical
Type of study:
Prognostic_studies
/
Risk_factors_studies
Country/Region as subject:
Europa
Language:
En
Journal:
Environ Sci Technol
Year:
2012
Document type:
Article
Affiliation country: