Schmid College of Science and Technology, Chapman University, One University Drive, Orange, CA, 92866, USA.
Department of Chemistry, Western Washington University, 516 High Street, Bellingham, WA, 98229, USA.
Environ Sci Pollut Res Int. 2020 Apr;27(11):12673-12682. doi: 10.1007/s11356-020-07880-8. Epub 2020 Jan 31.
Interest in understanding the cycling of ethanol in the environment has grown as ethanol use as a gasoline additive has increased. The production of acetaldehyde from ethanol was measured in Southern California coastal seawater. The rate of increase of acetaldehyde was positively correlated with the rate constant for ethanol biodegradation and bacteria count and was consistent with two consecutive first-order reactions where acetaldehyde is first biologically produced from ethanol then consumed. Correlation with bacteria counts suggested that acetaldehyde degradation was also a biological process. The rate constants for acetaldehyde production from ethanol and acetaldehyde loss averaged 3.0 ± 3.4 × 10 min and 2.3 ± 4.5 × 10 min respectively. The branching ratio for acetaldehyde production from ethanol was 0.46 ± 0.26 and estimated acetaldehyde biological production rates ranged from 0.022 to 0.800 nM min. With high bacterial counts, biological production rates from ethanol exceeded photochemical production rates from chromophoric dissolved organic matter. Overall, acetaldehyde production rates were larger than biodegradation rates, suggesting these waters are a source of acetaldehyde to the atmosphere. Extrapolation to higher ethanol concentrations associated with spills suggests that the production rate of acetaldehyde will initially increase and then decrease as ethanol concentrations increase.
随着乙醇作为汽油添加剂的使用量增加，人们对了解环境中乙醇循环的兴趣日益浓厚。本研究测定了南加州沿海水域中乙醇生成乙醛的速率。乙醛的生成速率与乙醇生物降解速率常数和细菌计数呈正相关，与连续的两个一级反应一致，其中乙醛首先由乙醇生物生成，然后被消耗。与细菌计数的相关性表明，乙醛的降解也是一个生物过程。乙醇生成乙醛和乙醛损失的速率常数分别平均为 3.0±3.4×10 -1 min -1 和 2.3±4.5×10 -1 min -1 。乙醇生成乙醛的分支比为 0.46±0.26，估计的乙醛生物生成速率范围为 0.022 到 0.800 nM min。在高细菌计数条件下，乙醇的生物生成速率超过了色质溶解有机物的光化学生成速率。总的来说，乙醛的生成速率大于生物降解速率，这表明这些水体会向大气中输送乙醛。对与溢油相关的更高乙醇浓度的推断表明，随着乙醇浓度的增加，乙醛的生成速率最初会增加，然后会降低。
