Tracking the bioaccumulation, the metabolization and synergy between Nanoplastics and Per- and polyfluoroalkyl substances (PFAS) in the food web

关于纳米塑料（NP）对水生生物影响的调查使用的浓度比公海中预测的浓度高2至7个数量级。这将社区划分为由于观察到的毒理学效应而发出警报的社区和预测环境中NP浓度远低于任何阈值效应的社区。由于缺乏合适的NP模型、跟踪方法和环境现实浓度的监测策略，符合目的的实验设计受到阻碍。我们最近使用14 C标记的NP和常规核技术，模拟了长期暴露于15 ug/L NP的扇贝中NP的潜在积累（图1）。全氟烷基和多氟烷基物质（PFASs）是一类持久性化学物质，广泛存在于各种消费品和环境中，是塑料制品的添加剂。少数全氟辛烷磺酸已被证明具有生物累积性和/或对不同生物类群具有毒性，全氟辛烷磺酸和全氟辛酸已被列入关于持久性有机污染物的《斯德哥尔摩公约》。然而，其运输和毒理机制尚不清楚，NPs的潜在媒介作用也被误解。NPs和PFAS的组合可能会导致人类和动物的健康风险更高。因此，三个相关问题i-iii与NPs/PFAS的混合物相关，尽管这一主题意义重大，但相关问题仍未得到解答;具体而言：i）NPs是否通过长期接触达到亚ppb水平并达到高组织浓度？ii）我们能否跟踪和量化组织中NP的亚ppb浓度？iii）NP是否随着时间的推移以亚ppb水平在食物网中积累？（四）NP和PFAS是否对生物群具有协同效应？我们提出了一种创新的方法，将克服跟踪和量化的NPs及其共污染物（PFASs）在亚ppb浓度的转化分析的局限性。通过将14 C标记与加速器质谱（AMS）的最终灵敏度和分析能力相结合，这种新方法将回答NP和PFAS是否在食物链中积累和转化？14 C-纳米聚苯乙烯的标记由PI开创。然而，这种方法目前仅适用于聚苯乙烯聚合物且浓度为10 ug/L。进一步的创新是必要的，以标记由世界上生产最多的塑料组成的NP，即，聚乙烯（32%）和聚丙烯（23%），由于其不同的理化性质，可能具有不同的毒代动力学和组织分布。只有AMS测量的更高灵敏度才能通过使用14 C标记的NP在亚ppb水平上进行工作。AMS技术通常用于地质样品中~（14）C的测定和定年。在这里，它将首次应用于生态毒理学问题，通过测量14 C标记的污染物（即，NP）。在药物研究中进行的14 C微剂量AMS测量，使用元素分析仪（EA）燃烧和双阱界面，看起来有希望测量亚ppb水平的14 C标记的NP。然而，AMS的样品制备确实是一个核心挑战，即使是地质样品。每个应用必须开发自己的制备方法，该方法应：1）使用无碳化学品; 2）避免材料在AMS分析之前降解为CO2; 3）避免碳同位素分馏; 4）避免交叉污染; 5）实现生态毒理学应用的高通量分析。

Investigations on the effects of nanoplastics (NP) on aquatic organisms used concentrations between 2 to 7 order-of-magnitudes higher than those predicted in the open ocean. This divided the community between those sounding the alarm due to the observed toxicological effects, and those predicting that NP concentrations in the environment are far below any threshold-effect. Fit-to-purpose experimental designs have been hindered by a lack of appropriate NP models, tracking methods, and monitoring strategies for environmentally realistic concentrations.Using 14C-labelled-NP and conventional nuclear techniques, we recently modelled potential accumulation of NPs in scallops, chronically exposed (Fig 1) to 15 ug/L NP. Astonishingly, this suggests that NP might already be beyond threshold-effects in organisms and harming the marine biota.Perfluoroalkyl and polyfluoroalkyl substances (PFASs), a large class of persistent chemicals and known to be an additive of plastics products, are widespread through consumer products and present in various environmental bodies. A small number of PFASs have been shown to bioaccumulate and/or toxic to different taxa, with PFOS and PFOA listed under the Stockholm Convention on persistent organic pollutants. However, the transport and and toxicological mechanism still unclear and the potential vectorisation by NPs misunderstood.The combination of NPs and PFASs could potentially lead to higher health risks in humans and animals. Therefore, the three relevant questions i-iii are relevant for the mixture of NPs/PFASs.Despite the significance of the topic, relevant questions remain unanswered; specifically:i) Are NPs accumulating through a chronic exposure at sub-ppb levels and reach high tissue concentrations?ii) Can we track and quantify sub-ppb concentration of NP in tissues? iii) Do NP accumulate in the food web over time at sub-ppb levels?iv) Does NP and PFASs have a synergy effect on the biota?We propose an innovative approach that will overcome the analytical limitations of tracking and quantifying the transformation of NPs and their co-contaminants (PFASs) at sub-ppb concentrations. By combining 14C-labelling with the ultimate sensitivity and analytical power of the Accelerator Mass Spectrometry (AMS), this new approach will answer whether NP and PFASs are accumulating and transforming in the food chain? The labelling of 14C-nanoploystyrene was pioneered by the PI. This approach is however currently only available for polystyrene polymers and concentration 10 ug/L. Further innovations are necessary to label NPs composed of the most produced plastic worldwide, i.e., polyethylene (32%) and polypropylene (23%), which may have different toxicokinetic and tissue distribution due to their different physico-chemical properties. Only the higher sensitivity of AMS measurements will enable work at sub-ppb levels by using 14C-labelled NPs. The AMS technique generally used for detection and datation of 14C in geological samples. Here, it will be applied for the first time to ecotoxicological issues by measuring 14C-labelled contaminants (i.e., NPs). 14C micro-dose AMS measurements performed in pharmaceuticals studies, using elemental analyser (EA) combustion and double-trap interface, look promising for measuring 14C-labelled NPs at sub-ppb levels. However, sample preparation for AMS is indeed a central challenge, even for geological samples. Each application must develop their own preparation method, which should: 1) uses carbon-free chemicals; 2) avoid degradation of material into CO2 prior AMS analysis; 3) avoid carbon isotope fractionation; 4) avoid cross-contamination, and 5) enable a high throughput analysis for ecotoxicological application.