DOM derivations determine the distribution and bioavailability of DOM-Se in selenate applied soil and mechanisms. (April 2020)

• Record Type: Journal Article
• Authors: Wang, Dan; Peng, Qin; Yang, Wen-Xiao; Dinh, Quang Toan; Tran, Thi Anh Thu; Zhao, Xing-Da; Wu, Jiang-Tong; Liu, Yong-Xian; Liang, Dong-Li
• Is Part Of: Environmental pollution. Volume 259(2020)
• Publication Date: 2020-04
• Subjects: Selenium -- Straw amendment -- DOM -- Bioavailability -- Spectroscopy; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.113899
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Straw amendment and plant root exudates modify the quality and quantities of soil dissolved organic matter (DOM) and then manipulate the fractions of soil selenium (Se) and its bioavailability. Two typical soils with distinct pH were selected to investigate the effect of different contributors on DOM-Se in soil. The mechanisms relying on the variation in DOM characteristics (quality, quantity and composition) were explored by UV–Vis, ATR-FTIR and 3D-EEM. Straw amendment significantly (p < 0.05) suppressed the selenate bioavailability. The reduction in wheat Se content was greater in krasnozems than in Lou soil, as more HA fraction appeared in krasnozems. The root exudates of wheat mainly elevated the low molecular hydrophilic compounds (Hy) in soil, which contributed to the SOL-Hy-Se fractions and thus grain Se in soils (p < 0.01). However, straw amendment promoted DOM transforming from small molecules (Hy and FA) to aromatic large molecules (HA), when accompanied with the reduction and retention of Se associated with these molecules. As a result, selenium bioavailability and toxicity reduced with DOM amendment and DOM-Se transformation. Graphical abstract: Image 1 Highlights: Straw amendment significantly inhibited selenate bioavailability in Lou soil and krasnozems. Root exudates stimulated more SOL-Hy-Se fraction and thus enhanced Se availability. Formation of HA-Se from selenate resulted in the reduction and retention of Se in soil. Abstract : The wheat root and straw amendment affect selenate bioavailability through the Hy and FA/HA components and their functional groups in soil DOM.