Spatial and environmental characteristics of colloidal trace Cu in the surface water of the Yellow River Estuary, China

Dynamic variations in chemical composition and size distribution of dissolved copper (Cu) along the river-sea interface in the Yellow River Estuary (China) were investigated. On average, similar to 64% and similar to 8% of bulk dissolved Cu (<0.45 mu m) were partitioned in the <1 kDa fraction and 1-100 kDa, respectively. The other 28% were in the 100 kDa-0.45 mu m colloids, which indicates that this fraction may dominate the overall morphology of colloidal Cu. The <3 kDa Cu fraction was susceptible to environmental parameters and the >3 kDa fraction was related to the behavior of dissolved organic carbon. 1-100 kDa Cu migrated more violently than >100 kDa Cu and tended to be a stable polymer, with stability increasing towards the sea. The source of <1 kDa Cu was complex and may be supplemented by the decomposition of small molecular colloids and the addition of the sediments or particles ligands.

Automated summary

Dynamic variations in the chemical composition and size distribution of dissolved copper along the river-sea interface in the Yellow River Estuary were found. Different fractions of copper were impacted by environmental parameters and dissolved organic carbon differently, with 1-100 kDa copper migrating more violently and tending to be a stable polymer.