Characterization of Dissolved Organic Matter from Agricultural and Livestock Effluents: Implications for Water Quality Monitoring

Guizhi Qi, Borui Zhang, Biao Tian, Rui Yang, Andy Baker, Pan Wu and Shouyang He ()
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Guizhi Qi: Key Laboratory of Karst Georesources and Environment, Guizhou University, Ministry of Education, Guiyang 500025, China
Borui Zhang: Key Laboratory of Karst Georesources and Environment, Guizhou University, Ministry of Education, Guiyang 500025, China
Biao Tian: Key Laboratory of Karst Georesources and Environment, Guizhou University, Ministry of Education, Guiyang 500025, China
Rui Yang: Key Laboratory of Karst Georesources and Environment, Guizhou University, Ministry of Education, Guiyang 500025, China
Andy Baker: School of Biological, Earth and Environmental Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
Pan Wu: Key Laboratory of Karst Georesources and Environment, Guizhou University, Ministry of Education, Guiyang 500025, China
Shouyang He: Key Laboratory of Karst Georesources and Environment, Guizhou University, Ministry of Education, Guiyang 500025, China

IJERPH, 2023, vol. 20, issue 6, 1-14

Abstract: There is growing concern about the impact of agricultural practices on water quality. The loss of nutrients such as nitrogen and phosphorous through agricultural runoff poses a potential risk of water quality degradation. However, it is unclear how dissolved organic matter (DOM) composition is associated with pollution levels in water bodies. To address this, we conducted a cross-year investigation to reveal the nature of DOM and its relationship to water quality in agricultural effluents (AEs) and livestock effluents (LEs). We discovered that DOM fluorescence components of AEs were mainly from autochthonous and terrestrial sources, while in LEs it was primarily from autochthonous sources. LEs showed a higher β:α and biological index (BIX) than AEs, indicating that LEs had higher biological activity. Compared to the LEs, DOM in AEs exhibited a higher humification index (HIX), illustrating that DOM was more humic and aromatic. Overall, our results suggest that the BIX and fluorescence index (FI) were best suited for the characterization of water bodies impacted by LEs and AEs. Excitation–emission matrix spectroscopy and parallel factor (EEMs-PARAFAC) analysis showed that DOM in AEs was mainly a humic-like material (~64%) and in LEs was mainly protein-like (~68%). Tryptophan-like compounds (C1) were made more abundant in AEs because of the breakdown of aquatic vegetation. The microbial activity enhanced protein-like substances (C1 and C2) in LEs. Our study revealed a positive correlation between five-day biochemical oxygen demand (BOD 5 ) concentrations and tyrosine-like substance components, suggesting that fluorescence peak B may be a good predictor of water quality affected by anthropogenic activities. For both LEs and AEs, our results suggest that peak D may be a reliable water quality surrogate for total phosphorus (TP).

Keywords: DOM; fluorescent components; EEMs-PARAFAC; surrogate for water quality; livestock effluents; agricultural effluents (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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