Determination of copper complexation in surface microlayer of Daya Bay and Jiaozhou Bay

Copper complexing ligands concentration (C C) and conditional stability constant of the sea surface microlayer (SML) and subsurface layer (SSL) samples, collected from Daya Bay of Guangdong Province and Jiaozhou Bay of Shandong Province, were determined by anodic stripping voltammetry (ASV) technique. C C of Daya Bay in the SML ranged from 6.19×10-7 to 3.52×10-7 mol/L. C C of Jiaozhou Bay in the SML ranged from 5.30×10-7 to 3.03×10-7 mol/L in August 1998 and from 3.46×10-7 to 1.36×10-7 mol/L in May 2000. The C C concentrations were higher in all surface microlayer samples, compared with corresponding subsurface samples. The average enrichment factors of copper complexation in the SML observed above were 1.58, 1.41 and 1.56, respectively. The enrichment of C C concentration in the microlayer demonstrated that organic ligands had certain buffer action on the toxicity of the enriched trace metals in the same layer. Conditional stability constants of the SML in Jiaozhou Bay were lower than those of the SSL; however, it showed just opposite for Daya Bay. BOD (biological oxygen demand) and COD (chemical oxygen demand) indicated the organic matter content, also showed enriched in the SML. C C had an obvious relationship with BOD or COD.