Saturated Spring
Gary Lamberti, the Rev. Julius A. Nieuwland, C.S.C., Professor of Aquatic Science in the Department of Biological Sciences at the University of Notre Dame, 从事淡水生态系统生态学和环境生物学研究40余年.
他发表了200多篇研究论文，探索人类对河流和湿地生态系统的影响, the ecology and control of invasive aquatic plants and animals, and the impacts of emerging contaminants in the Great Lakes watershed.
But it was during a chance encounter with Graham Peaslee他在电竞赌博平台举办的一次活动上说，他是物理与天文学系的核物理学家 Environmental Change Initiative in 2019, 兰伯蒂了解到一种他尚未研究过的污染物：全氟和多氟烷基物质（PFAS）.
Peaslee is a leading expert on PFAS, 一类具有极强的化学和热稳定性的氟化化合物, inherently repellent to oil, water, soil, and stains. 这些化学物质广泛用于工业和商业应用，从不粘锅到消防泡沫. 皮斯利开创了一种检测包括快餐包装在内的消费品中PFAS的新方法, cosmetics, textiles, plastic containers, face masks, and even drinking water.
The chemicals can migrate off surfaces onto skin, into food and dust, creating multiple pathways of exposure. 我们吸入它们，摄入它们，吸收它们——它们在我们的血液中积累.
PFAS与包括免疫抑制在内的几种不良健康状况有关, hormonal dysregulation, developmental delays in children, low birth weight and accelerated puberty, high blood pressure in pregnant women, and an increased risk of some cancers, such as kidney and testicular cancer.
They do not degrade or break down, 科学家表示，它们可以在环境中存在数千年, earning them another name: “forever chemicals.”
Molecular structure of PFAS
It all sounded eerily familiar to Lamberti. A toxic, persistent chemical, the use of which had contaminated lakes, wetlands, rivers—even ocean waters; saturated the soil; polluted the air; and posed a hazardous risk to all living organisms...
He’d seen this before with dichloro-diphenyl-trichloroethane, better known as DDT, 一种合成的高持久性杀虫剂，在1950年代和60年代广泛使用. 对环境污染以及这种化学物质对野生动物和人类的毒性的担忧日益加剧，导致了相关法规的出台，并最终在20世纪70年代由美国环境保护局（environmental Protection Agency）发布了取消该产品的命令.
“PFAS,” Lamberti said, “is the DDT of the 21st century.”
Lamberti had more than a few ideas for PFAS studies. 当涉及到兰伯蒂熟悉的密歇根湖的PFAS污染时，研究是有限的.
In 2020, 他和皮斯利着手研究了一些申请拨款的提案，并开始了一项关于密歇根湖鱼类的新研究. 此前的研究发现，五大湖大部分地区的鱼类都含有可测量的PFAS. 兰伯蒂知道五大湖的鱼被永久性化学物质污染了, 这些化学物质会在环境中持续存在，并在血液中积累——他想知道这是否可能是他所谓的“母性卸载”.”
Could female fish pass on PFAS to their offspring?
Officials with the Indiana Department of Natural Resources, the Michigan Department of Natural Resources, and the US Fish and Wildlife Service routinely sample fish, water, 和沉积物来评估密歇根湖渔业的状况和健康, 每年为印第安纳州的经济贡献数百万美元, Michigan, Illinois, and Wisconsin, while supporting thousands of jobs in charter and commercial fishing.
兰伯蒂的实验室与每个组织合作收集奇努克鲑鱼的样本, coho salmon, 以及沿密歇根湖支流迁徙到产卵场的钢头鱼. 研究人员总共从成熟的雄性和雌性鱼身上收集了42个样本.
When the samples arrived in 2021, the Michigan Department of Environment, Great Lakes, 和能源部已经确定了全州大约213个PFAS热点，其中许多通过水路连接到五大湖.
An analysis of the male and female salmon muscle tissue, as well as eggs extracted from the female fish, 显示85%含有可测量浓度的全氟辛烷磺酸（PFOS）, a type of PFAS that was phased out of use in 2002, and 19 percent tested positive for perfluorooctanoic acid (PFOA), another class of PFAS phased out of use in 2015.
但这项研究最令人担忧的结果是，与雌性鲑鱼的肌肉组织相比，卵中的全氟辛烷磺酸浓度高出100倍.
“几种不同的机制可以解释为什么PFAS会从母亲遗传到卵子,” Lamberti explained. “可能是母鱼从湖水中积累了PFAS，并在卵巢发育期间将其传递给卵子. 另一种可能性是，母亲在发育过程中食用了被PFAS污染的食物，并将其营养传递给了卵子. That’s what we still don’t know. Either way, 这就产生了一个污染物的“生物运输”问题，因为鲑鱼从湖泊迁移到更清洁的河流.”
Lamberti’s lab is looking at the “riverine PFAS cycle,首先是迁徙的鲑鱼，它们的卵是其他鱼类和野生动物的首选食物来源. When consumed, the PFAS can bioaccumulate in stream fish, 然后这些细菌会传给它们自己的卵，或者鱼自己被吃掉——有时被人类吃掉——从而导致一个永无止境的污染循环.
For another study, 实验室测量了密歇根湖200多条捕食者和猎物的PFAS浓度, including alewives, sculpins, salmon, and lake trout. 目的是更清晰地了解密歇根湖鱼类的浓度，并更好地了解生物放大的潜力, the dietary passage of compounds from one organism to another.
The study showed PFAS were present in 98 percent of those samples. 结果表明，这些化学物质正在从被捕食的鱼传递到捕食的鱼, suggesting a dietary connection.
这项研究引发了其他研究，表明鱼的器官（包括心脏）中含有更高的浓度, liver, and kidneys—and in blood taken from those samples.
“The lowest concentrations were seen in muscle tissue,” Lamberti said. “所以，吃鱼片可能是较低剂量的PFAS，但它绝对不干净.”
先前在实验室的研究表明，类似的鱼样本也含有可测量的多氯联苯, mercury, and other chlorinated compounds.
“我们需要更多地了解这些化学物质的途径，”Lamberti说. “How do they get into the fish? 要么是通过饮食，要么是通过环境中的水和沉积物. We’re trying to learn more about how PFAS interact with the food web. 我们需要知道它们是如何从环境中进入食物网并最终进入人们食用的鱼类的. That’s why we’re meticulously sampling water, sediment, plants, and wildlife in the lake—to trace the pathways. Because only then can you think about remediation.”
But what does remediation look like? How do you eliminate chemicals engineered to stand the test of time?
How do you clean up forever?