Polycyclic aromatic hydrocarbons (PAHs) have received extensive attention because of their widespread presence in various environmental media and their high environmental toxicity. Thus, figuring out the long-term variances of their occurrence and driving force in the environment is helpful for environmental pollution control. This study investigates the concentration levels, spatial variance, and source apportionment of PAHs in suspended particulate matter of Freiberger Mulde river, Germany. Results show that the concentrations of the 16 priority PAHs suggested by USEPA (Σ₁₆PAHs) were in the range of 707.0–17,243.0 μg kg⁻¹ with a mean value of 5258.0 ± 2569.2 μg kg⁻¹ from 2002 to 2016. The relatively high average concentrations of Σ₁₆PAHs were found in the midstream and upstream stations of the given river (7297.5 and 6096.9 μg kg⁻¹ in Halsbrucke and Hilbersdorf, respectively). In addition, the annual average concentration of Σ₁₆PAHs showed an obvious decreasing pattern with time. Positive Matrix Factorization (PMF) receptor model identified three potential sources: coke ovens (7.6–23.0%), vehicle emissions (35.9–47.7%), and coal and wood combustion (34.5–47.3%). The source intensity variation and wavelet coherence analysis indicated that the use of clean energy played a key role in reducing PAHs pollution levels in suspended sediments. The risk assessment of ecosystem and human health suggested that the Σ₁₆PAHs in the given area posed a non-negligible threat to aquatic organisms and humans. The data provided herein could assist the subsequent management of PAHs in the aquatic environment.

Shale-gas extraction imposes persistent, low-intensity, multi-factor disturbances on terrestrial soil ecosystems, driven by flowback-fluid-derived salinization, drilling-residue deposition, and moderate petroleum hydrocarbon contamination. However, microbial community assembly mechanisms and the corresponding ecological strategies under such combined chronic perturbations remain insufficiently understood. This study employed 16S rRNA gene sequencing, quantitative PCR, and molecular ecological network (MEN) analysis to characterize the soil microbiome within the Changning shale-gas field, Sichuan Basin, China. The results revealed that microbial communities in shale-gas wellpad soils formed highly modular (M = 0.786), non-random “small-world” co-occurrence networks, indicating intrinsically stable microbial systems. Via Z_i-P_i topological classification, six low-abundance (<0.63%) keystone taxa were identified: three module hubs (OTU11572, OTU14908, OTU11976) and three connectors (OTU8845, OTU13035, OTU8962), phylogenetically affiliated with Acidobacteriota, Chloroflexi, and Actinobacteriota. These keystone organisms exhibited typical K-strategy traits, including high network connectivity (degree = 21–24), metabolic stability, and dependence on inter-taxa cooperative interactions. Significant positive correlations were detected between these K-strategy keystone species and anaerobic functional genes (nirS, nirK, dsrAB) responsible for denitrification and sulfate reduction, highlighting their adaptation to fluctuating redox environments generated by drilling-cutting accumulation. Distance-based redundancy analysis (Db-RDA) further demonstrated that electrical conductivity (representing salinization stress from flowback-water intrusion) and soil organic matter acted as the dominant environmental filters shaping microbial community composition, outweighing the influence of labile inorganic nutrients. Overall, this work provides novel evidence that K-selection dominates microbial community assembly under chronic soil disturbance associated with shale-gas extraction. Keystone K-strategists sustain modular network stability through the combination of metabolic plasticity and anaerobic respiratory adaptation. These findings expand r/K-selection theory to anthropogenically disturbed soil habitats and offer theoretical guidance for soil ecological restoration and risk assessment for shale-gas exploiting regions.

Introduction: Sustainable strategies are needed to remediate total petroleum hydrocarbon (TPH)-contaminated soils. Methods: A 90-day pot experiment combined soybean cultivation with different concentrations of nano-zinc oxide (nano-ZnO), followed by soil physicochemical, amplicon sequencing, microbial network, metabolomic, and multi-omics analyses. Results: Combined application of soybean and 60 mg/kg nano-zinc oxide (nano-ZnO) significantly enhanced soil fertility and enzyme activities, achieving a 68.7% total petroleum hydrocarbon (TPH) removal rate over 90 days. Amplicon sequencing revealed soybean cultivation primarily structured bacterial and fungal communities. The rhizosphere buffered microbial diversity against TPH and nanoparticle stress, and co-occurrence networks showed the combined treatment fostered the most complex, stable cross-kingdom interactions. Soil metabolomics indicated a targeted rhizosphere response to nano-ZnO, enriching flavonoids and biosurfactant precursors, contrasting with the non-specific stress response in bare soil. Multi-omics integration identified a functional guild ( Pseudomonas , Sphingomonas , Rhodococcus , and Fusarium ) associated with TPH dissipation. Discussion: These results suggest that soybean remodels its rhizosphere microbiome structure and metabolic function to synergize with nano-ZnO, accelerating the recovery of petroleum-contaminated soils.