Cleaning up PFAS

Are we there yet? Read the rest of the package Scrubbing Earth of per- and polyfluoroalkyl substances—a.k.a. PFAS or forever chemicals—could eliminate a list of woes for people and planet. Used for decades in everything from nonstick pans to firefighting foams, PFAS have been linked to increased risks of fertility challenges, developmental delays, cancer, and reduced immune response. They are known for a strong bond between carbon and fluorine, which the environment struggles to break down.

我们快到了吗？阅读本专题的其余部分。清除地球上的全氟和多氟烷基物质（即 PFAS 或“永久性化学品”）可以消除人类和地球面临的一系列困境。PFAS 已被使用了几十年，从不粘锅到消防泡沫，无处不在。它们与生育挑战、发育迟缓、癌症和免疫反应降低的风险增加有关。它们以碳和氟之间强大的化学键而闻名，这种化学键在自然环境中极难分解。

The sticking points PFAS are everywhere: They spew from factories and slough off products and into water with normal use. Scientists have found them in everything from human blood to Antarctic snow. One 2022 report found that 89% of the US population had PFAS in excess of two nanograms per milliliter of blood plasma, a common threshold for potential adverse health effects, and 9% of the population had passed the riskier level of 20 nanograms per milliliter. The PFAS monster is also a moving target. New compounds are still being created and used. There are more than 12,000 of them, and much of the cleanup research focuses on only a small handful.

症结所在：PFAS 无处不在。它们从工厂排放出来，在日常使用中从产品中脱落并进入水中。科学家们在从人体血液到南极雪的各种物质中都发现了它们。2022 年的一份报告发现，89% 的美国人口血浆中 PFAS 的含量超过了每毫升 2 纳克（这是潜在不良健康影响的常见阈值），而 9% 的人口已经超过了每毫升 20 纳克的更高风险水平。PFAS 这个“怪物”也是一个不断变化的目标。新的化合物仍在被创造和使用。目前已有超过 12,000 种此类物质，而大部分清理研究仅集中在极少数几种上。

The progress Cleansing PFAS-contaminated soil is a project in its infancy, but it is possible to prevent more buildup by pulling the chemicals out of water systems. There are two ways to handle this: trap or destroy. Some scientists have found reverse osmosis—a process that pushes water through supertight filters—useful in point-of-use cases, like water filters at kitchen sinks. Other techniques in the pipeline might be more suitable for large-scale removal—for example, at water treatment facilities. One, called foam fractionation, generates bubbles that capture PFAS. More approaches, like ensnaring the chemicals in nanothin layers of charged metal, are also under investigation.

进展：净化受 PFAS 污染的土壤尚处于起步阶段，但通过从水系统中提取这些化学物质，可以防止其进一步积聚。处理方法有两种：捕获或销毁。一些科学家发现，反渗透（一种将水推过超紧密过滤器的过程）在终端使用场景中很有用，例如厨房水槽的净水器。其他正在研发的技术可能更适合大规模清除，例如在水处理设施中。其中一种称为泡沫分馏的技术，通过产生气泡来捕获 PFAS。更多的方法，如将化学物质困在带电金属的纳米薄层中，也正在研究之中。

Trapping, though, is imperfect. You’re left with PFAS-filled brine, which if not properly destroyed (an expensive and energy-sucking endeavor) can still end up in the environment. Jack Huang, a professor of crop and soil sciences at the University of Georgia, is working on destruction. He’s testing a method called electrochemical degradation, which uses electrodes to break down the bonds that hold PFAS together. The product destroyed more than 90% of PFAS mass in tests and has already been licensed by the engineering consulting firm AECOM.

然而，捕获并不完美。你会留下充满 PFAS 的盐水，如果不能妥善销毁（这是一项昂贵且耗能的工作），它们最终仍可能进入环境。佐治亚大学作物与土壤科学教授 Jack Huang 正在研究销毁方法。他正在测试一种称为电化学降解的方法，该方法利用电极来破坏维持 PFAS 结构的化学键。该产品在测试中销毁了超过 90% 的 PFAS，并已获得工程咨询公司 AECOM 的许可。

Ridding life of PFAS is also a policy challenge. There are alternatives; we just need the push to use them. And we’ve had success before: The EPA’s 2010/2015 PFOA Stewardship Program has helped slash the release of water-repellent perfluorooctanoic acid by 95%. More recently, Minnesota, Maine, and New Mexico have passed bans on PFAS in products like cookware and dental floss. Progress meter … 6 Scientists are making strides toward removing and destroying PFAS—but it’ll be all for naught if we don’t turn off the tap.

摆脱 PFAS 也是一项政策挑战。目前已有替代品，我们只需要推动其使用即可。我们过去曾取得过成功：美国环保署（EPA）的 2010/2015 年 PFOA 管理计划帮助将防水全氟辛酸的排放量减少了 95%。最近，明尼苏达州、缅因州和新墨西哥州已通过禁令，禁止在炊具和牙线等产品中使用 PFAS。进度表… 6 科学家们在清除和销毁 PFAS 方面正在取得进展，但如果我们不从源头切断，一切都将徒劳无功。