Polychlorinated biphenyls (PCBs) are classified as persistent organic pollutants (POPs) due to their potential threat to both ecosystems and human health. The Tibetan Plateau (TP), characterized by its low temperatures, pristine ecological conditions, and remoteness from anthropogenic influences, serves as the investigation region. This study analyzed water samples from the temperature glacial watershed and employed the risk assessment method established by the United States Environmental Protection Agency (US EPA) to assess both carcinogenic and non-carcinogenic risks of PCBs in five age groups. The total concentrations of PCBs (& sum;3PCBs) varied from 738 to 1914 ng/L, with a mean value of 1058 ng/L, which was comparable to or exceeded levels reported in the surface water around the TP. Notably, the riverine sites located near the villages and towns exhibited the highest pollution levels. Our analyses indicated that glacier melting, long-range atmospheric transport (LRAT), reductive dechlorination processes, and various anthropogenic activities might be potential sources of PCB emission in the Meili Snow Mountains. According to the established national and international water quality standards, as well as toxic equivalency concentrations (TEQs) for dioxin-like PCBs (DL PCBs), the PCB concentrations detected in this study could result in serious biological damage and adverse ecological toxicological effects. However, the PCBs in all samples posed a negligible cancer risk to five age groups, and a non-carcinogenic risk to adults. These findings contribute valuable insights into the risks and sources of PCBs and may serve as a foundational reference for subsequent study of these compounds in the Meili Snow Mountains area of the southeastern TP.

Liquid crystal monomers (LCMs) are emerging pollutants that have attracted attention recently due to their unique chemical properties and wide applications. However, in-depth research on LCMs' potential risks to soil health remains blank. Therefore, 107 LCMs and nine soil health characterization proteins/enzymes were selected as research objects in this study. A grading evaluation system for soil health toxicological effect indicators under LCMs exposure was constructed from five dimensions (i.e., soil animals, soil plants, soil microorganisms, soil carbon, nitrogen and phosphorus cycles, and human health) by molecular docking and molecular dynamics simulation methods. Priority control lists for soil health toxicological effects under LCMs exposure were developed based on the proposed evaluation system, with rationality verified through non-bonded interaction, 2DQSAR and Meta-analysis. Results showed that 32, 56 and 19 LCMs presented unacceptable, potential, and acceptable soil health risks, respectively. The oxidative damage of LCMs to plant leaves, the toxicity to earthworm growth and development, and its effects on key enzymes of the soil nitrogen cycle were suggested to be the priority-attention indicators. This is the first study that provides theoretical support for revealing the toxicological effects of LCM exposure on soil health and relevant pollution control strategies.

Ipconazole (IPC) is a chiral triazole fungicide and commonly used for disease control in seeds. This study investigated the bioactivity and potential mechanism of ipconazole against pathogenic microorganisms at the chiral perspective. It explored the accumulation behavior of ipconazole enantiomers within the soil-earthworm system and evaluated its toxic effects on earthworms. Bioactivity evaluation revealed that the bioactivity order of ipconazole against three plant pathogens is (-)-1S,2 R,5S-IPC > rac-IPC > (+)-1R,2S,5R-IPC, and the bioactivity of (-)-1S,2 R,5S-IPC is 34.6-129.5 times higher than that of (+)-1R,2S,5R-IPC. Molecular docking found that (-)-1S,2 R,5S-IPC has a stronger binding affinity for the target protein CYP51 to cause activity differences. Accumulation and metabolism studies revealed that (-)-1S,2 R,5S-IPC is more persistent than that of (+)-1R,2S,5R-IPC, and ipconazole was primarily metabolized into hydroxylated ipconazole through hydroxylation in the soil-earthworm system. Toxicological evaluation found growth inhibitory effects and histopathological damage to earthworms at an exposure concentration of 1.5 mg kg(-1) ipconazole. Further investigation indicated that these toxic effects of ipconazole were caused by inducing oxidative damage and influencing the functional gene expression of related growth. These research findings will further enhance the understanding of the activity and risks of ipconazole enantiomers, contributing to the safer use of ipconazole in the agricultural environment.