Application of anodic stripping voltammetry to predict the bioavailable/toxic concentration of Cu in natural water

In this paper, the concentration of labile Cu measured by differential pulse anodic stripping voltammetry with a double acidification method (DAM-DPASV) was used to predict the growth inhibition of Cu on the alga Scenedesmus oblignus (S. oblignus). The influences of alkalinity, Cl−, and different concentrations of ethylene diamine tetraacetic acid (EDTA) and fulvic acid (FA) on the labile concentration and toxicity of Cu were investigated in reconstituted water and natural water. The results showed that Cl− and alkalinity did not affect labile Cu concentration, but decreased the toxicity of Cu to S. oblignus in the Cu concentration range observed in fresh water. The influences of alkalinity and Cl− could be modeled if Cu-carbonate complexes and Cu-chloride complexes were considered as non-toxic species. Organic complexes of Cu with EDTA and FA did not contribute either to the labile concentration of Cu or to the toxicity of Cu on S. oblignus. The growth inhibition of Cu on S. oblignus in natural water could be predicted by using the bioavailable concentration of Cu, or [Cu*], which could be calculated from the labile Cu concentration using the DAM-DPASV method and the concentrations of Cu-carbonate and Cu-chloride complexes obtained from the MINTEQ A2 model.