College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China.
Faculty of Engineering and Physical Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK.
J Hazard Mater. 2024 Nov 5;479:135682. doi: 10.1016/j.jhazmat.2024.135682. Epub 2024 Aug 28.
Perfluorooctanoic acid (PFOA), an emerging pollutant, has been frequently detected in organic solid waste. It becomes a major concern for compost application, but studies on its toxic effects during composting are rare. This study evaluated the impact of PFOA presence at the environmentally relevant level on the humification process and microbiology during composting. The results showed that the PFOA presence (15.5 μg/kg dry) caused 45.5 % and 40.5 % decreases in the total organic carbon and humic acid-like substances, respectively. PFOA negatively affected microbial activity during the thermophilic period, as evidenced by the increases in reactive oxygen species and lactate dehydrogenase concentration. It altered the microbial community with an enrichment of Bacteroidota, conducive to resisting press. Unexpectedly, the PFOA presence induced hormesis at the maturity period, consistent with stimulated carbon metabolism (i.e., glycolysis and oxidative phosphorylation). The modulated microbial metabolism stimulated the catabolic metabolism of small-molecule humus precursors and reduced intracellular quinone availability. Furthermore, the secretion of auxiliary activities for crude fiber degradation was suppressed, which decreased the generation of extracellular quinone, and thereby impeded the humification process. These findings deciphered the metabolic response of composting to PFOA presence and highlighted the potential carbon loss of PFOA-containing composting.
全氟辛酸（PFOA）作为一种新兴污染物，已在有机固体废物中频繁检出。其存在对堆肥应用构成了主要威胁，但关于其在堆肥过程中产生的毒性效应的研究却很少。本研究评估了在环境相关水平下存在的 PFOA 对堆肥过程中腐殖化过程和微生物学的影响。结果表明，PFOA 的存在（15.5 μg/kg 干重）分别导致总有机碳和类腐殖质物质减少了 45.5%和 40.5%。PFOA 在高温期对微生物活性产生负面影响，这表现为活性氧和乳酸脱氢酶浓度的增加。它改变了微生物群落，使 Bacteroidota 富集，有利于抵抗压力。出乎意料的是，PFOA 的存在在成熟阶段引起了兴奋效应，与刺激的碳代谢（即糖酵解和氧化磷酸化）一致。调节后的微生物代谢刺激了小分子腐殖质前体的分解代谢，降低了细胞内醌的可用性。此外，辅助粗纤维降解的活性物质的分泌受到抑制，从而减少了细胞外醌的生成，从而阻碍了腐殖化过程。这些发现揭示了堆肥对 PFOA 存在的代谢反应，并强调了含 PFOA 的堆肥中潜在的碳损失。
