期刊
WATER RESEARCH
卷 108, 期 -, 页码 68-77出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.watres.2016.10.052
关键词
Inorganic arsenic; DOM property; Molecular weight; Complexation; Toxicity
资金
- National Natural Science Foundation of China [51290283, 51378041]
- Beijing Natural Science Foundation [8142027]
- Specialized Research Fund for the Doctoral Program of Higher Education [20131102110035]
- Major Science and Technology Program for Water Pollution Control and Treatment of China [2012ZX07501001]
The intrinsic physicochemical properties of dissolved organic matter (DOM) may affect the mobility and toxicity of arsenic in aquatic environments. In the present study, the humic acid (HA) was ultra-filtered into five fractions according to molecular weight, and their physicochemical properties were characterized. Complexation of HA fractions with arsenite and arsenate was first determined by differential pulse polarography (DPP). The influences of HA fractions on arsenic toxicity were then examined using Daphnia magna as a model organism. As(V) had a higher affinity with HA than As(III), and their complexation was dependent on the total acidity and fluorescence characteristics of DOM. We demonstrated that the acidity and fluorescence also better explained the As toxicity to daphnids than UV absorbance and hydraulic diameter. Arsenic speciation determined by DPP significantly affected the toxicity of arsenite and arsenate. The results extended the free-ion activity model application to the case of arsenic. The present study clearly indicated that DOM with different molecular weights has distinct physicochemical properties, and could influence the speciation and toxicity of As to different extent. (C) 2016 Elsevier Ltd. All rights reserved.
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