Despite growing environmental concerns about perfluoroalkyl and polyfluoroalkyl substances (PFAS) worldwide, the ultra-short-chain PFAS, for example, trifluoroacetic acid (TFA), have been largely neglected in the context of soil pollution. Given the persistence and increasing occurrence of TFA in the soil environment, accumulated TFA could impact soil properties and functions. Therefore, we investigated the effects of a wide range of concentrations of TFA (0.001–100 μg g⁻¹) on chemical, physical and biological indicators of soil health, using a six-week microcosm experiment. Our results showed that TFA treatments decreased soil pH, sulphate content, soil respiration, litter decomposition and bacterial abundance, and increased phosphate content (p < 0.05). These effects were observed for TFA concentrations ≥1 μg g⁻¹. As expected, because of its strong acidity, TFA decreased soil pH, and this change likely contributed to effects on other soil parameters and functions, for example, reducing bacterial abundance and soluble nutrients. However, importantly, TFA clearly also affected soil parameters at concentrations at which soil pH was not changed. Soil aggregation, fungal abundance, and enzyme activities were not affected by TFA in this study. Considering the current reported environmental levels of TFA of <2.4 μg g⁻¹, only litter decomposition would be affected under current field conditions. Our data also show that future accumulation of higher concentrations, or hotspots of TFA, will likely negatively affect soils with similar properties as our test soil. Thus, we demonstrated that microbial processes can be impacted by the accumulation of the ‘forever chemical’ TFA in the tested sandy, low organic matter soil.

中文翻译：

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土壤参数和功能对三氟乙酸的浓度依赖性响应

尽管全球对全氟烷基和多氟烷基物质 (PFAS) 的环境问题日益关注，但在土壤污染的背景下，超短链 PFAS，例如三氟乙酸 (TFA)，在很大程度上被忽视了。鉴于土壤环境中 TFA 的持续存在和不断增加，累积的 TFA 可能会影响土壤性质和功能。因此，我们通过为期六周的微观实验研究了各种浓度的 TFA（0.001-100 μg g ^{-1 ）对土壤健康的化学、物理和生物指标的影响。}我们的结果表明，TFA 处理降低了土壤 pH 值、硫酸盐含量、土壤呼吸、凋落物分解和细菌丰度，并增加了磷酸盐含量 ( p < 0.05)。^{在 TFA 浓度≥1 μg g -1}时观察到这些影响。正如预期的那样，由于其强酸性，TFA 降低了土壤 pH 值，这种变化可能会影响其他土壤参数和功能，例如减少细菌丰度和可溶性养分。然而，重要的是，在土壤 pH 值不变的浓度下，TFA 显然也会影响土壤参数。在本研究中，土壤聚集、真菌丰度和酶活性不受 TFA 的影响。考虑到目前报告的 TFA 环境水平 <2.4 μg g ^-1，在当前的田间条件下，只有凋落物分解会受到影响。我们的数据还表明，未来更高浓度或 TFA 热点的积累可能会对与我们的测试土壤具有相似特性的土壤产生负面影响。因此，我们证明了微生物过程会受到测试的沙质、低有机质土壤中“永久化学”TFA 的积累的影响。