Valdez Harder (spearsoil66)
48 (95% confidence interval [CI] 0.27-0.86) for the second highest quartile of manganese, 0.37 (95% CI 0.21-0.68) and 0.36 (95% CI 0.19-0.65) for the third highest and highest quartiles of iron, respectively, and 0.53 (95% CI 0.29-0.94) for the highest quartile of zinc, compared with the lowest quartiles of these three elements. Plasma manganese, iron, and zinc levels protect against CKD in elderly people aged ≥90 years in longevity areas. Photolysis of pesticides has been widely investigated for evaluating their environmental behavior and agricultural effectiveness after crop spraying. However, little information about the effects of the water-soluble substances in atmosphere on photodegradation of pesticides is available. In current study, we found that photolysis of applied dithianon fungicides on real plant leaves was much faster than that in sealed stock aqueous suspensions under simulated sunlight. To simulate the natural conditions, for the first time, photodegradation of dithianon in air-saturated solutions containing typical dissolved atmospheric substances (DAS) including CO2 (HCO3-/CO32-), NO2 (NO3-), Fe3+ (Fe3+-complexes), and humic-like substances (HULIS) exposed to simulated solar irradiations were carried out in lab-scale. Fulvic acid (FA) was used as a surrogate for atmospheric HULIS in this study. The dithianon photodegradation was significantly enhanced in the presence of DAS and the photo-generated reactive species such as ·OH, 1O2, CO3·- and 3FA∗ play important roles according to the results of reactive species quenching, electron spin resonance spectroscopy, and laser flash photolysis experiments. Moreover, the photodegraded intermediates and final products of dithianon on plant leaves have been identified by HPLC-MS analysis, and its possible photodegradation pathways were proposed. This work indicated that, except for direct photolysis, indirect photosensitive degradation induced by the dissolved photo-active substances in atmosphere should be considered for evaluating the degradation of the applied pesticides on crops. Developing rare earth elements (plus yttrium, REY) as a group of environmental tracer requires comprehensive understandings in their geochemical behaviors associated with natural organic matter. Recent work highlighted the promotions on REY mobilization and cerium oxidation by siderophores during silicate dissolution, but the mechanism remained ambiguous. Here, we performed batch fluid-rock interaction experiments to explore the functions of siderophore desferrioxamine B (DFOB) and humic acids (HA) towards REY mobility and partitioning during REY-bearing ferrihydrite dissolution. To acquire in-depth knowledge of organic controls on REY, we used multiple strategies, including elemental, multispectral, and electrochemical analyses, to investigate the organic regulation on REY geochemistry. This study sheds light on the function of ligand-specific selectivity and solid-fluid organic molecular fractionation, primarily dependent on hydrochemical settings (pH, organic compounds, ionic strength, and oxicity). Our results confirm the catalytic oxidation ability of ligand, which forms DFOB-Ce(IV) (K = 1042, electrochemistry), producing positive Ce anomalies in solutions by ligand-driven redox shifting. Both HA and DFOB showed high affinities to HREY, and facilitated LREY/HREY partitioning. The mobilization of REY and the development of Ce anomalies were limited by HA coatings that modified surface properties and disturbed the approach of DFOB. Excess siderophores attack inert HA coatings, facilitating REY liberation and Ce redox activities. The release of REY and catalytic oxidation of Ce can be inhibited at high ionic strength or under oxygen deficiency. Our study reveals that natural organic matter significantly influences the fate of REY in iron oxides, and crucial for the biogeochemical cycles of REY in nature. The root soil interaction affects metal bioavailability in the rhizosph
