|ZHIGAO, ZHOU - OLD DOMINION UNIVERSITY|
|HUA, BIN - LINCOLN UNIVERSITY OF MISSOURI|
|XIAOYAN, CAO - OLD DOMINION UNIVERSITY|
|YANG, JOHN - LINCOLN UNIVERSITY OF MISSOURI|
|Olk, Daniel - Dan|
|BAOLIN, DENG - UNIVERSITY OF MISSOURI|
|FENGJING, L - LINCOLN UNIVERSITY OF MISSOURI|
|RENYING, LI - OLD DOMINION UNIVERSITY|
|MAO, JINGDONG - OLD DOMINION UNIVERSITY|
Submitted to: Aquatic Sciences - Research Across Boundaries
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2015
Publication Date: 10/1/2015
Citation: Zhigao, Z., Hua, B., Xiaoyan, C., Yang, J., Olk, D.C., Baolin, D., Fengjing, L., Renying, L., Mao, J. 2015. Chemical compositions of dissolved organic matter from various sources as characterized by solid-state NMR. Aquatic Sciences - Research Across Boundaries. 77(4):595-607.
Interpretive Summary: The health and behavior of rivers can be affected by the types of organic compounds in their waters, which can be determined by human activities on the surrounding lands. In this study we found that the types of organic compounds at different locations in the Missouri River were affected by local wastewater release, landfills, and natural vegetation. The organic compounds also changed between steps in wastewater treatment. These results indicate the ability to associate land use with changes in the organic compounds in adjacent rivers. The results will benefit water scientists, stream biologists, organic chemists, and decision-makers of land use.
Technical Abstract: Dissolved organic matter (DOM) in surface waters plays an important role in biogeochemical and ecological processes. This study used solid-state NMR techniques to explore the molecular signatures of riverine DOM in relation to its point and nonpoint sources. DOM samples were isolated from (1) two streams draining watersheds of different land uses, (2) landfill leachates of two ages, (3) sequential wastewaters from raw, wastewater treatment plant (WWTP) facility- and wetland-treated wastewaters, and (4) the Missouri River upstream and downstream one of its tributaries, into which wastewater effluents from the nearby WWTP were discharged. Compared with that from a grass/forest land, the riverine DOM from cropland comprised more O-alkyl C, aromatics and COO/N-C=O groups, but less alkyl C. Downstream of the tributary into which WWTP waste was dicharged, the chemical composition of riverine DOM displayed higher alkyl C but lower NCH, COO/N-C=O and aromatics compared to upstream DOM. The point sources including landfill leachates and wastewaters had higher DOC concentrations than did the Missouri River as the receiving river and had chemical compositions varying with age or treatment. The landfill leachate DOM from a >10 year-old landfill cell contained more O-alkyl C than that from a younger cell. Compared with raw wastewater DOM, the DOM from the wastewater after the WWTP facility- treatment had less alkyl C but more aromatic C, and the DOM from the wastewater after the further wetland treatment had less O-alkyl C but more alkyl C than that after the WWTP facility- treatment. This study demonstrated that the solid-state NMR was a promising tool to examine the chemical structures and molecular linkages of aquatic DOM from various sources.