Medina Hector, Farmer Carson
School of Engineering, Liberty University, Lynchburg, VA 24515, USA.
Toxics. 2024 Aug 20;12(8):610. doi: 10.3390/toxics12080610.
The Environmental Protection Agency (EPA) of the United States recently released the first-ever federal regulation on per- and polyfluoroalkyl substances (PFASs) for drinking water. While this represents an important landmark, it also brings about compliance challenges to the stakeholders in the drinking water industry as well as concerns to the general public. In this work, we address some of the most important challenges associated with measuring low concentrations of PFASs in drinking water in the field in real drinking water matrices. First, we review the "continuous monitoring for compliance" process laid out by the EPA and some of the associated hurdles. The process requires measuring, with some frequency, low concentrations (e.g., below 2 ppt or 2 ng/L) of targeted PFASs, in the presence of many other co-contaminants and in various conditions. Currently, this task can only (and it is expected to) be accomplished using specific protocols that rely on expensive, specialized, and laboratory-scale instrumentation, which adds time and increases cost. To potentially reduce the burden, portable, high-fidelity, low-cost, real-time PFAS sensors are desirable; however, the path to commercialization of some of the most promising technologies is confronted with many challenges, as well, and they are still at infant stages. Here, we provide insights related to those challenges based on results from and machine learning studies. These challenges are mainly due to the large amount and diversity of PFAS molecules and their multifunctional behaviors that depend strongly on the conditions of the media. The impetus of this work is to present relevant and timely insights to researchers and developers to accelerate the development of suitable PFAS monitoring systems. In addition, this work attempts to provide water system stakeholders, technicians, and even regulators guidelines to improve their strategies, which could ultimately translate in better services to the public.
美国环境保护局（EPA）最近发布了有史以来首个针对饮用水中全氟和多氟烷基物质（PFASs）的联邦法规。虽然这是一个重要的里程碑，但它也给饮用水行业的利益相关者带来了合规挑战，并引发了公众的关注。在这项工作中，我们解决了一些与在实际饮用水基质中现场测量低浓度PFASs相关的最重要挑战。首先，我们回顾了EPA制定的“合规连续监测”流程以及一些相关障碍。该流程要求在存在许多其他共污染物以及各种条件下，定期测量目标PFASs的低浓度（例如，低于2 ppt或2 ng/L）。目前，这项任务只能（并且预计）通过依赖昂贵、专门且是实验室规模仪器的特定协议来完成，这增加了时间并提高了成本。为了潜在地减轻负担，需要便携式、高保真、低成本、实时的PFAS传感器；然而，一些最有前景的技术的商业化之路也面临着许多挑战，并且它们仍处于起步阶段。在此，我们基于实验结果和机器学习研究提供与这些挑战相关的见解。这些挑战主要是由于PFAS分子的数量众多和种类多样以及它们强烈依赖介质条件的多功能行为。这项工作的目的是向研究人员和开发人员提供相关且及时的见解，以加速合适的PFAS监测系统的开发。此外，这项工作试图为水系统利益相关者、技术人员甚至监管机构提供指导方针，以改进他们的策略，这最终可能转化为为公众提供更好的服务。
