State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Chinese Academy of Sciences, Guangzhou, 510640, China.
Water Res. 2020 May 1;174:115635. doi: 10.1016/j.watres.2020.115635. Epub 2020 Feb 19.
In this study, we investigated how the desorption and degradation processes of radiolabeled benzo[a]pyrene (BaP) that was aged in various marine sediments were influenced by sedimentary organic matter properties. The stable OC fraction (STOC) and the demineralized fraction (DM) were isolated and characterized via advanced solid-state C nuclear magnetic resonance spectroscopy (NMR) and a CO gas adsorption technique, respectively. Sodium persulfate preferentially removed the unstable OC fractions (USOC) and the aromatic C groups, and the residual STOC fractions were enriched with aliphatic C groups. The aliphatic C showed stronger resistance to degradation by persulfate than that of the aromatic C. A first-order kinetic model described the degradation process by sodium persulfate solutions very well (R > 0.997). The desorption percentages, degradation percentages and rates k (h) of BaP gradually decreased from the estuarine sediments to the offshore marine sediments and were highly significantly and negatively correlated with STOC-bulk, F-bulk, and V-bulk (R>0.903, p < 0.01). It was demonstrated that sodium persulfate degraded not only desorbed BaP but also a portion of the bound BaP fraction that was difficult to desorb. The BaP fractions that sorbed on USOC were degraded initially; then, the fractions of BaP that were released from STOC were degraded. This study demonstrated the important roles of STOC, aliphatic moieties, and micropores in the degradation process of BaP during the NaSO treatment of the sediments.
在本研究中，我们调查了在不同海洋沉积物中老化的放射性标记苯并[a]芘（BaP）的解吸和降解过程如何受到沉积物有机质特性的影响。通过先进的固态 C 核磁共振波谱（NMR）和 CO 气体吸附技术，分别分离和表征了稳定有机碳（STOC）和去矿物质（DM）部分。过硫酸钠优先去除不稳定的有机碳（USOC）和芳香族 C 基团，残留的 STOC 部分富含脂肪族 C 基团。脂肪族 C 比芳香族 C 更能抵抗过硫酸盐的降解。一级动力学模型很好地描述了过硫酸钠溶液的降解过程（R > 0.997）。BaP 的解吸百分比、降解百分比和速率 k（h）从河口沉积物逐渐降低到近海海洋沉积物，与 STOC-总、F-总和 V-总呈高度显著负相关（R>0.903，p<0.01）。结果表明，过硫酸钠不仅降解了解吸的 BaP，而且还降解了一部分难以解吸的结合态 BaP 。首先降解吸附在 USOC 上的 BaP 部分；然后，从 STOC 释放的 BaP 部分被降解。这项研究表明，在沉积物的 NaSO 处理过程中，STOC、脂肪族部分和微孔在 BaP 的降解过程中起着重要作用。
