School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan, 430023, China.
School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan, 430023, China.
Environ Res. 2024 Nov 1;260:119679. doi: 10.1016/j.envres.2024.119679. Epub 2024 Jul 24.
Glyphosate, a commonly used organophosphorus herbicide in rice-crayfish cropping regions, may alter regional phosphorus cycle processes while affecting the structure of microbial communities. However, the effects of glyphosate residues on rice-crayfish systems remain unclear. In this study, we assessed the spatial and temporal distribution characteristics of glyphosate and its primary degradation products, as well as the impact mechanisms of glyphosate on microbial communities and the phosphorus cycle in rice-crayfish systems such as paddy fields, breeding ditches and recharge rivers. The detection rates of glyphosate and aminomethylphosphonic acid (AMPA) were 100% in rice-crayfish systems. Concentrations of glyphosate in the water phase and soil/sediment were as high as 0.012 μg/L and 7.480 μg/kg, respectively, and concentrations of AMPA were as high as 17.435 μg/L and 13.200 μg/kg, respectively. Glyphosate concentrations were not affected by rainfall or sampling site, but concentrations of AMPA in the water phase of recharge rivers were affected by rainfall. The glyphosate concentration was significantly and positively correlated with RBG-16-58-14 abundance, and the AMPA concentration was significantly and positively correlated with Actinobacteria and Lysobacter abundance, and negatively correlated with Cyanobacteria abundance (P < 0.05). The highest abundances of phoD, phnK, and ppx genes were found in all soils/sediments. Glyphosate concentration in soil/sediment was significantly and positively correlated with the abundance of phoD gene encoding an organophosphorus-degrading enzyme and ppx gene encoding poly inorganic phosphate (Pi) hydrolase (P < 0.05). In addition, the glyphosate concentration was significantly and positively correlated with the Ca-bonded Pi content (P < 0.05). This implies that glyphosate may promote the production of stable Pi in rice-crayfish systems by increasing the abundance of phoD and ppx genes. The results of this study reveal the impact mechanism of glyphosate on the phosphorus cycle in rice-crayfish systems and provide a basis for the risk assessment of glyphosate.
在稻-虾共作区，草甘膦是一种常用的有机磷除草剂，它可能会改变区域磷循环过程，同时影响微生物群落的结构。然而，草甘膦残留对稻-虾系统的影响尚不清楚。在本研究中，我们评估了草甘膦及其主要降解产物在空间和时间上的分布特征，以及草甘膦对稻田、养殖沟渠和补给河流等稻-虾系统中微生物群落和磷循环的影响机制。在稻-虾系统中，草甘膦和氨甲基膦酸（AMPA）的检出率均为 100%。水相和土壤/沉积物中草甘膦的浓度高达 0.012μg/L 和 7.480μg/kg，AMPA 的浓度高达 17.435μg/L 和 13.200μg/kg。草甘膦浓度不受降雨或采样点的影响，但补给河流水相中的 AMPA 浓度受降雨影响。草甘膦浓度与 RBG-16-58-14 丰度呈显著正相关，AMPA 浓度与放线菌和 Lysobacter 丰度呈显著正相关，与蓝藻丰度呈显著负相关（P<0.05）。所有土壤/沉积物中 phoD、phnK 和 ppx 基因的丰度最高。土壤/沉积物中草甘膦浓度与编码有机磷降解酶的 phoD 基因和编码聚无机磷（Pi）水解酶的 ppx 基因的丰度呈显著正相关（P<0.05）。此外，草甘膦浓度与 Ca 结合 Pi 含量呈显著正相关（P<0.05）。这意味着草甘膦可能通过增加 phoD 和 ppx 基因的丰度，促进稻-虾系统中稳定 Pi 的产生。本研究结果揭示了草甘膦对稻-虾系统磷循环的影响机制，为草甘膦风险评估提供了依据。
