Soil temperature elevation enhances phenanthrene phytoremediation by maize through improvement of plant growth and soil microbial activity

As persistent organic pollutants (POPs), excessive accumulation of polycyclic aromatic hydrocarbons (PAHs) in soil poses a serious threat to human health and ecosystem security. Phytoremediation is considered to be a green and sustainable remediation method, during which the plants growth status and the soil ecosystem health may be influenced by soil temperature. To investigate the role of temperature elevation in the phytoremediation of phenanthrene (PHE)-contaminated soils, four kinds of soil temperatures for maize cultivation were set up in this study: ambient temperature (around 23 degrees C), 26 degrees C, 28 degrees C and 30 degrees C. The results showed that the removal efficiency of soil PHE significantly increased in the 28 degrees C treatment group, and the accumulation of PHE in maize was significantly lower than that of the 23 degrees C group. In addition, the results indicated that appropriate soil temperature elevation could effectively enhance maize growth and improve phytoremediation efficiency by regulating maize K+/Na+ ratio, improving soil sucrase, catalase and urease activities and increasing the abundance of some PAHs-degrading bacteria. Overall, this study was the first to find that soil temperature could improve phytoremediation efficiency by regulating soil microbiological systems and promoting maize growth. This study not only demonstrated the potential impact of soil temperature regulation on phytoremediation efficiency, but also bridged the gap between current theoretical and practical research on the optimization of phytoremediation techniques using temperature factors, contributing to the design of efficient and sustainable remediation strategies.