全氟和多氟烷基类化合物(PFASs)的环境转化与分类管控

全氟和多氟烷基类化合物(per- and polyfluoroalkyl substances, PFASs)具有环境持久性、生物累积性和生物毒性(PBT)，其暴露所引发的环境与健康风险已在世界范围内引起关注. 近期，有学者提议将PFASs作为一类高持久性物质进行全面管控，并淘汰PFASs的所有非必要用途. 鉴于PFASs在工业领域的不可或缺性，加快PFASs的淘汰进程势必会对社会和经济产生较大影响. 因此，淘汰PFASs需要一个漫长的过渡期. 在这期间，亟需开展积极有效的应对措施，最大程度地将PFASs暴露对生态环境乃至人体健康产生的潜在危害降到最低. 笔者认为加强PFASs的降解转化研究是目前较为有效且可行的策略之一，这将有助于理解PFASs的PBT特性，进而推动PFASs的分类管理. 笔者提出可在“疑似靶向/非靶向高分辨率质谱技术开发”“PFASs的传递、积累、代谢和消除行为”和“PFASs转化产物与不良健康影响之间关系的系统毒理学网络”等方面开展PFASs的降解转化研究. 通过高效筛查识别PFASs的分子转化机制，解析转化产物的PBT性质，进而对PFASs进行合理归类划分，并为制定PFASs及替代品的分类管控决策提供依据. 

Environmental Transformation and Classified Management of Per- and Polyfluoroalkyl Substances (PFASs)

Per- and polyfluoroalkyl substances (PFASs) with persistence, bioaccumulation, and toxicity (PBT) properties have gained attention worldwide because of their potential environmental risks and adverse health effects. Regulation of PFASs remains a big concern for society. Based on the knowledge that C-F is the strongest single bond in organic chemistry, PFASs are considered as high persistent substances by some scientists. Therefore, it is recommended that PFASs be managed as a highly persistent category and that all ‘nonessential’ uses of these chemicals should be phased out. In view of their wide application in various fields, involving huge socio-economic impacts, accelerating the phase-out of PFASs is bound to have a huge impact on society and economy. It is therefore a long way to go in reaching consensus on PFASs management. As a result, phasing out PFASs requires a lengthy transition period. Currently, meaningful actions are needed to minimize the potential exposure risk of PFASs while meeting their social needs. In fact, there are approximately 5000 PFASs available on the global market. Studies indicate that the transformation behaviors of PFASs happen under different conditions, which result in various kinds of new emerging PFASs in natural environment and biota. There are limited data on the PBT properties of these new PFASs. Actually, some new PFASs are environmentally friendly themselves, but they can degrade to highly toxic and persistent PFASs such as PFOS, PFOA and PFHxS. These transformation products thereby become indirect sources of traditional PFASs in the environment, which would eventually lead to constant human exposure to these chemicals. Thus, it is very important to study the transformation of PFASs. Transformational studies can help identify transformational products with lower persistence and toxicity, which will provide valuable insights into the design of safer fluorinated alternatives. Here, for the first time, we propose that strengthening the study on the transformation of PFASs is an important strategy for classifying and managing fluorinated alternatives, and this will provide technical framework and support for the regulation of fluorinated alternatives. Furthermore, we make these proposals on the way forward for investigating transformational process of PFASs. Firstly, nontargeted and high-resolution mass spectrometry technologies must be continually developed, as these investigation methods are able to implement high throughput analysis of transformation products by assembling formulas and possible structures from molecular precursor and fragment data of existing PFASs. Secondly, the transmission, accumulation, metabolism, and elimination behaviors of PFASs in different matrices should be of high concern. In this regard, a combination of multi-omics, high-throughput toxicity testing, theory calculation, and machine learning is recommended to explor the potential mechanisms, and the essential factors affecting the process. Through this, the transformation products with PBT properties can be ascertained, prioritized, and managed. Lastly, biological networks elaborating the relationship between PFASs transformation products and adverse health effects should be established. The transformation products of PFASs may eventually pose adverse public health risks, which suggests that mapping a systematic transformation network would be beneficial to the classified management of fluorinated alternatives. This is challenging because of their diverse structures and huge numbers, however, the accomplishment of the first two proposals above will facilitate this process.