Soil dissolved organic matter(DOM)plays an essential role in the Three Gorges Reservoir(TGR)as a linkage between terrestrial and aquatic systems.In particular,the reducing capacities of soil DOM influence the geochemi...Soil dissolved organic matter(DOM)plays an essential role in the Three Gorges Reservoir(TGR)as a linkage between terrestrial and aquatic systems.In particular,the reducing capacities of soil DOM influence the geochemistry of contaminants such as mercury(Hg).However,few studies have investigated the molecular information of soil DOM and its relationship with relevant geochemic al reactivities,including redox properties.We collected samples from eight sites in the TGR areas and studied the link between the molecular characteristics of DOM and their electron donation capacities(EDCs)toward Hg(II).The average kinetic rate and EDC of soil DOM in TGR areas were(0.004±0.001)hr-1 and(2.88±1.39)nmol e-/mg DOMbulk,respectively.Results suggest that higher EDCs and relatively rapid kinetics were related to the greater electron donating components of ligninderived and perhaps pyrogenic DOM,which are the aromatic constituents that influenced the reducing capacities of DOM in the present study.Molecular details revealed that even the typical autochthonous markers are important for the EDCs of DOM as well,in contrast to what is generally assumed.More studies identifying specific DOM molecular components involved in the abiotic reduction of Hg(II)are required to further understand the relations between DOM sources and their redox roles in the environmental fate of contaminants.展开更多
基金supported by the National Science Foundation of China(Nos.41977275 and 41877384)the Internal Funding for Early Careers from the Department of Forest Ecology and Management(FEM)of the Swedish University of Agricultural Science(SLU)+1 种基金the funding of the Sino-Swedish Mercury Management Research Framework(SMaRef)from the Swedish Research Council(VR)(No.D697801)supporting his researcher position at the Swedish University of Agricultural Sciences(SLU)
文摘Soil dissolved organic matter(DOM)plays an essential role in the Three Gorges Reservoir(TGR)as a linkage between terrestrial and aquatic systems.In particular,the reducing capacities of soil DOM influence the geochemistry of contaminants such as mercury(Hg).However,few studies have investigated the molecular information of soil DOM and its relationship with relevant geochemic al reactivities,including redox properties.We collected samples from eight sites in the TGR areas and studied the link between the molecular characteristics of DOM and their electron donation capacities(EDCs)toward Hg(II).The average kinetic rate and EDC of soil DOM in TGR areas were(0.004±0.001)hr-1 and(2.88±1.39)nmol e-/mg DOMbulk,respectively.Results suggest that higher EDCs and relatively rapid kinetics were related to the greater electron donating components of ligninderived and perhaps pyrogenic DOM,which are the aromatic constituents that influenced the reducing capacities of DOM in the present study.Molecular details revealed that even the typical autochthonous markers are important for the EDCs of DOM as well,in contrast to what is generally assumed.More studies identifying specific DOM molecular components involved in the abiotic reduction of Hg(II)are required to further understand the relations between DOM sources and their redox roles in the environmental fate of contaminants.
