Living near Geneva, close to the shores of beautiful Lac Léman, the largest lake of the Alps, I tend to admire the view of the magnificent mountains on the French side. Those mountains act as natural filters for the rain and molten snow to emerge at a spring called Cachat near Évian-les-Bains. As you might know, this water is bottled without any additives as Evian, and distributed all over the world as premium spring water. Just recently, in mid-July, I was surprised to see a headline in the news stating “Evian drinking water tainted with pesticides, Swiss researchers find”.(1) The story was shared by most local news outlets, and came at a volatile political time in Switzerland. Two popular initiatives, that aim to ban federal subsidies for farmers that use pesticides and herbicides, are currently being discussed in parliament, and will soon be voted on by the electorate. So, what is going on? The research story showcases the power of modern analytical sciences to identify and track transformation products of synthetic substances—in this case, the fungicide chlorothalonil. It had been used for half a century until it was recently banned in the EU and Switzerland because of its suspected carcinogenic properties. The authors of the study,(2) Juliane Hollender and co-workers from the Swiss Federal Institute of Aquatic Science and Technology (Eawag), developed and applied analytical approaches to assess the fate of such molecules. Just last year, this group reported on transformation products of chlorothalonil in the environment, of which one key candidate, a polar, sulfonic acid derivative called R471811, was found for the very first time along with 11 other transformation products never reported before.(3) For this, the authors performed a targeted screening of all pesticides used in Switzerland in the past few years, a total of 396 organic molecules. Added to this list were 1120 possible transformation products they looked for. High resolution mass spectrometry, together with prioritization and identification routines, allowed the researchers to arrive at 187 detected suspect structures that were then further narrowed down and identified. The limit of quantitation for the technique, stated as about 0.5 ng L^–1 (about 1 pM), was achieved by vacuum-assisted evaporative concentration of the samples followed by HPLC-MS/MS. It turns out that the transformation product R471811, the toxicity of which is unclear, is detectable in all tested water sources, even where anthropogenic influences are known to be extremely low. This points to a high stability and environmental persistence of the compound. The average concentration in groundwater samples influenced by agriculture was 515 ng L^–1. In contrast, the compound was found at 5 ng L^–1 in Lake Zurich, and at 6 ng L^–1 in Evian water (used as a gold standard for uncontaminated water).(2) If one would manually introduce R471811 into an untainted Lake Zurich (3.9 km³ water volume), how much would be needed to reach this concentration? Twenty kilograms. To compare, the FDA estimates an annual use of 6.8 million kg of chlorothalonil per year in the U.S. alone.(4) For the measurement sciences, such studies are a triumph because they showcase the power of modern analytical techniques that can identify and quantify the fate of micropollutants in complex aquatic systems. For the chemical sensing community, on the other hand, this should serve to guide us where expectations lie. Think of the difficulty and complexity of this challenge the next time you are describing the detection of a pesticide with a sensor. Environmental systems are dynamic and complex, and pollutants will form transformation products that are chemically distinct from the parent molecule. And this will all happen in a complicated matrix at impossibly low concentrations. For the general public, reading about pollutants found everywhere is certainly very distressing. But a challenging study such as this should be celebrated for what it is, and not reduced to a catchy but misleading headline. Concentrations do matter, as the Swiss alchemist Paracelsus already knew in the early 1500’s. We do not yet understand the toxicity of this transformation product, and of course such studies strongly suggest that we need to learn more. If we can detect something now that we could not before, one more piece of the puzzle of our interwoven and complicated world is being revealed. It allows us to make better decisions cautiously and accompanied by good science. To better grasp such complex systems, good data originating from the measurement sciences and a wider appreciation for complex problems, not only in the scientific community, but also in the wider public, is needed. Views expressed in this editorial are those of the author and not necessarily the views of the ACS. This article references 4 other publications.

中文翻译：

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测量科学的胜利与不幸。

我生活在日内瓦附近，靠近美丽的LacLéman海岸，这是阿尔卑斯山最大的湖泊，我倾向于欣赏法国一侧壮丽的山脉。这些山是雨水和融雪的天然过滤器，在埃维昂莱班附近的一个叫做卡恰特的春天出现。如您所知，这种瓶装水没有像依云（Evian）一样添加任何添加剂，并且作为优质泉水在世界范围内分配。就在最近的7月中旬，我很惊讶地看到新闻标题为“瑞士研究人员发现依云饮用水被农药污染”。（1）这个故事被大多数当地新闻媒体所分享，而且动荡不安。瑞士的政治时期。目前正在议会中讨论两项旨在禁止联邦政府对使用杀虫剂和除草剂的农民提供补贴的普遍举措，并将很快由选民投票。那么发生了什么？该研究故事展示了现代分析科学在识别和跟踪合成物质转化产物（在本例中为杀真菌剂百菌清）中的能力。它被使用了半个世纪，直到最近由于其怀疑的致癌特性而在欧盟和瑞士被禁止使用。该研究的作者，[2]来自瑞士联邦水生科学技术研究院（Eawag）的Juliane Hollender和同事开发并应用了分析方法来评估此类分子的命运。就在去年，该小组报告了百菌清在环境中的转化产物，其中一个关键候选物是极性磺酸衍生物，称为R471811，首次与其他从未报道过的转化产物一起被发现。（3）为此，作者针对瑞士在过去几年中使用的所有农药（总共396种有机分子）进行了有针对性的筛选。他们正在寻找的列表中添加了1120种可能的转换产品。高分辨率质谱分析以及优先级划分和识别程序，使研究人员可以得出187个可检测的可疑结构，然后进一步缩小范围并进行识别。该技术的定量极限，约为0.5 ng L 他们正在寻找的列表中添加了1120种可能的转换产品。高分辨率质谱分析以及优先级划分和识别程序，使研究人员可以得出187个可检测的可疑结构，然后进一步缩小范围并进行识别。该技术的定量极限，约0.5 ng L 他们正在寻找的列表中添加了1120种可能的转换产品。高分辨率质谱分析以及优先级划分和识别程序，使研究人员可以得出187个可检测的可疑结构，然后进一步缩小范围并进行识别。该技术的定量极限，约为0.5 ng L通过真空辅助蒸发浓缩样品，然后进行HPLC-MS / MS，可达到^–1（约1 pM）。事实证明，即使在已知的人为影响极低的情况下，在所有测试的水源中都可以检测到毒性尚不清楚的转化产物R471811。这表明该化合物具有高稳定性和环境持久性。受农业影响的地下水样品中的平均浓度为515 ng L ^–1。相反，在苏黎世湖中发现该化合物的浓度为5 ng L ^{– 1，}在依云水中发现的化合物为6 ng L ^–1（用作未污染水的金标准）。（2）如果有人手动将R471811引入未污染的水中苏黎世湖（3.9 km ³水量），需要多少才能达到该浓度？二十公斤。相比之下，FDA估计仅在美国每年每年就使用680万公斤百菌清。（4）对于测量科学而言，这样的研究是成功的，因为它们展示了可以识别和定量分析的现代分析技术的力量。复杂水生系统中微污染物的命运。另一方面，对于化学传感界来说，这应该可以指导我们期望值在哪里。下次您要描述使用传感器检测农药时，请考虑一下这一挑战的难度和复杂性。环境系统是动态且复杂的，污染物将形成化学上不同于母体分子的转化产物。而这一切都将在一个复杂的矩阵中以不可能的低浓度发生。对于普通大众来说，阅读到处可见的污染物无疑是非常令人沮丧的。但是，应该对诸如此类的具有挑战性的研究加以表扬，而不应将其归为引人注目的但令人误解的标题。浓度确实很重要，正如瑞士炼金术士Paracelsus在1500年代早就知道的那样。我们尚不了解这种转化产物的毒性，当然，此类研究强烈表明我们需要学习更多。如果我们现在能检测到以前无法检测到的东西，那么这个相互交织和复杂的世界的难题又被揭示出来了。它使我们能够谨慎地做出更好的决策，并伴随着良好的科学。为了更好地掌握这种复杂的系统，需要来自测量科学的良好数据以及对复杂问题的广泛理解，不仅在科学界，而且在广大公众中也是如此。本社论中表达的观点只是作者的观点，不一定是ACS的观点。本文引用了其他4个出版物。