Size partitioning and mixing behavior of trace metals and dissolved organic matter in a South China estuary

Publication date: 15 December 2017
Source:Science of The Total Environment, Volumes 603–604
Author(s): Wenhao Wang, Min Chen, Laodong Guo, Wen-Xiong Wang
The Jiulong River estuary, located in the southeastern China, suffered from metal pollution due to industrial effluent releases. Mixing of effluent and estuarine water may have significantly affected the size distribution of trace metals and their environmental fate. In the present study, colloidal size distribution of organic matter and selected metals were quantified using asymmetric flow field-flow fractionation (AF4) and ICP-MS. We demonstrated a dominance of dissolved metals in the 1–10kDa fraction, and metals such as Cu, Zn, Ni, Co, Pb, Cd and Mn were mostly regulated by terrestrial fulvic acid. The larger inorganic colloids played a limited role, although Fe reduction was likely to affect the size partitioning of colloidal Mn. The holding pond represented a source of trace metals and chromophoric and humic-like dissolved organic matter to the estuary. Scavenging or removal behavior became evident following the intermittent mixing, and the small sized colloidal organic complexes were responsible for binding and stabilizing trace metals. Variations in particle size distributions indicated different sources, fates and geochemical controls of the metals. Our results highlighted the impacts of both natural and anthropogenic processes on the transformation of trace metals among phases in this dynamic estuary system.

Graphical abstract

http://ift.tt/2rPj1qG