RESUMO
Microplastics are among the most difficult new pollutants to remove in wastewater treatment plants. In order to explore the occurrence form, size distribution, composition, removal efficiency, migration law, and fate behavior characteristics of microplastic particles in sewage plants, taking a sewage treatment plant in Hohhot as an example, a total of 17 sampling sites were set up. The LAS X software counted the shape, abundance, and size of microplastics and conducted a full-process analysis. The results showed thatï¼ fibrous microplastics had the highest abundance and widest distribution and were the main form of existence, accounting for 61.8% of the total abundanceï¼ the size of microplastics ranged mainly between 0 and 1.00 mm, and among the four sizes, the abundance of microplastics 0.25 to 0.50 mm in China was the highest, accounting for 32.9%. Among the eight types of plastic components detected, polyester substances ï¼PET, PBTï¼, cellulose, and polypropylene ï¼PPï¼ were the main components, accounting for 25%, 21%, and 17%, respectively. The influent abundance of the sewage plant was ï¼73 ±5ï¼ n·L-1, the effluent abundance was ï¼14 ±2ï¼ n·L-1, and the overall removal rate was ï¼80.8 ±12.1ï¼%. Among the three treatment stages of the sewage plant, only the primary treatment played a role in removal, and the abundance of microplastics surged in the secondary treatment. Different structures playing a major role in the removal of microplastics were fine grids ï¼49.2 ±7.4ï¼% and secondary sedimentation tanks ï¼92.4 ±13.9ï¼%. Microplastics mainly existed in the form of fibers, fragments, and films. The proportion of fibers was approximately 70%, and the size of fragments was mainly concentrated between 0.50 and 5.00 mm. Most fragments were in the range of 5.00 mm, accounting for 50%, making them the main form apart from fibrous. The film-like size was mostly concentrated in the range of less than 0.50 mm, accounting for more than 10%. Therefore, improving the removal of small-sized fibrous and film-like microplastics and large-sized fragmented microplastic particles can effectively reduce the pollution risk of microplastics in the environment caused by sewage plant drainage.
Assuntos
Cidades , Microplásticos , Eliminação de Resíduos Líquidos , Águas Residuárias , Poluentes Químicos da Água , Microplásticos/análise , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação , China , Esgotos/química , Plásticos , Tamanho da Partícula , Polipropilenos , Monitoramento AmbientalRESUMO
Most cancers are caused by somatic mutations. Some common mutations in the same cancer type can form a "signature" to specifically predict the prognosis or to distinguish it from other cancers. In this study, 710 somatic cell mutations were identified in 142 cases, including digestive, lung and urogenital cancers, and the digestive cancers were further divided into liver, stomach, intestinal, esophageal and cardia cancer. The above mutations were located in 166 genes. In addition, a group of high-frequency mutation genes with specific characteristics were screened to form predictive signatures for each cancer. Verification using TCGA suggested that the signatures could predict the stages, progression-free survival, and overall survival of digestive, intestinal, and liver cancers (P < 0.05). The validation cases further confirmed the predictive role of digestive and liver cancers signatures in diagnosis and prognosis. Overall, this study established predictive signatures for different cancer systems and their subtypes. These findings enable a better understanding in cancer genome, and contribute to the personalized diagnosis and treatment.