Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Sci Total Environ. 2024 Dec 1;954:176499. doi: 10.1016/j.scitotenv.2024.176499. Epub 2024 Sep 25.
The coastal environment is an important ecosystem connecting land and sea, and arsenite (As(III)) in coastal seawater can seriously affect human health through the food chain. However, the effects of dissolved organic matter (DOM) extracted from coastal algae and rivers on As(III) photooxidation remain unclear. Results show that coastal algal DOM (CA-DOM) is significantly more effective than Suwannee River natural organic matter (SRNOM) in photooxidation of As(III), with a rate 8.3 times higher after correcting for light screening effects. CA-DOM accelerates As(III) photooxidation mainly through the DOM pathway, contributing 78.7 % to the process, whereas NOM contributes only 37.2 % for SRNOM. CA-DOM consists primarily of low-excited tyrosine and tryptophan-like protein substances, whereas SRNOM consists of humic and fulvic acid-like substances. Thus, CA-DOM exhibits a higher steady-state concentration of DOM, and the DOM reacts much faster with As(III) than the NOM. The increase in CA-DOM concentration can significantly accelerate the photooxidation of As(III), whereas the effect of SRNOM concentration is negligible. Increased salinity can accelerate As(III) photooxidation for all types of DOM. Our results provide new insights into the role of DOM from different sources in the photooxidation of As(III) in the natural environment or engineering applications.
沿海环境是连接陆地和海洋的重要生态系统，海水中的亚砷酸盐（As(III)）可以通过食物链严重影响人类健康。然而，从沿海藻类和河流中提取的溶解有机物质（DOM）对 As(III)光氧化的影响仍不清楚。结果表明，沿海藻类 DOM（CA-DOM）在 As(III)的光氧化中比苏万尼河天然有机物质（SRNOM）的效果显著，在纠正光屏蔽效应后，其光氧化速率提高了 8.3 倍。CA-DOM 通过 DOM 途径加速 As(III)的光氧化，对该过程的贡献为 78.7%，而 NOM 对 SRNOM 的贡献仅为 37.2%。CA-DOM 主要由低激发酪氨酸和色氨酸样蛋白质物质组成，而 SRNOM 由腐殖酸和富里酸样物质组成。因此，CA-DOM 表现出更高的 DOM 稳态浓度，DOM 与 As(III)的反应速度比 NOM 快得多。CA-DOM 浓度的增加可以显著加速 As(III)的光氧化，而 SRNOM 浓度的影响可以忽略不计。增加盐度可以加速所有类型 DOM 的 As(III)光氧化。我们的研究结果为不同来源的 DOM 在自然环境或工程应用中对 As(III)光氧化的作用提供了新的见解。
