Metal nanoparticles (NPs) released into the aquatic environment will likely accumulate in sediment and be available for sediment-dwelling invertebrates that serve as food for other organisms, such as fish. The aim of the present study was to investigate trophic transfer of copper oxide (CuO) NPs and dissolved Cu (CuCl₂) from natural sediment to the sediment-dwelling worm Tubifex tubifex, and then to the predatory fish Gasterosteus aculeatus (three-spined stickleback). Cu enriched in the stable isotope ⁶⁵Cu was used to increase detection and discriminate newly added/assimilated Cu from background Cu levels. Worms were exposed to sediment spiked with ⁶⁵CuCl₂ or ⁶⁵CuO NPs (∼20 nm) at environmentally relevant concentrations for 7 days and subsequently fed to fish for 7 days. Worms accumulated ⁶⁵Cu during sediment exposure to both ⁶⁵CuCl₂ and ⁶⁵CuO NPs (0.7 and 1.1 μg ⁶⁵Cu per g dw tissue, respectively), resulting in ⁶⁵Cu body burdens significantly different from control. Furthermore, significantly more ⁶⁵Cu was released from the sediment into the overlying water in the ⁶⁵CuO NP exposures compared to the ⁶⁵CuCl₂ exposures. ⁶⁵Cu accumulation in fish feeding on ⁶⁵CuCl₂ and ⁶⁵CuO NP-exposed worms was limited (intestinal tissue: 80 and 65 ng g⁻¹ dw; fish carcass: 7 and 10 ng g⁻¹ dw, and liver: 50 and 10 ng g⁻¹ dw, respectively). Glutathione peroxidase (gpx) mRNA expression was significantly higher in fish feeding on ⁶⁵CuCl₂-exposed worms compared to ⁶⁵CuO NP-exposed worms (though ⁶⁵Cu tissue concentrations were similar). No significant effects were detected for the other investigated genes (ctr1, mta, gcl, gr, sod, cat, zo-1). Our results show that NP-derived Cu can enter freshwater food webs, but bioaccumulation and trophic transfer under environmentally realistic exposures is low (detectable with a tracer) and not different from that of dissolved Cu.

中文翻译：

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CuO NPs从沉积物到蠕虫（Tubifex tubifex）到鱼类（Gasterosteus aculeatus）的营养转移：溶解铜和NPs的稳定同位素示踪剂（65Cu）富集的比较研究

释放到水生环境中的金属纳米颗粒（NPs）可能会沉积在沉积物中，并可用于居住在沉积物中的无脊椎动物，这些无脊椎动物可以作为鱼类等其他生物的食物。本研究的目的是研究天然沉积物中氧化铜（CuO）NPs和溶解的铜（CuCl ₂）的营养转移到沉积物蠕虫Tubifex tubifex，然后再转移到掠食性鱼类Gasterosteus aculeatus（三棘stick回） ）。富含稳定同位素^65的铜可用于增加检测并从背景铜水平中区分新添加/被吸收的铜。蠕虫暴露于掺有⁶⁵ CuCl ₂或^65的沉淀物中CuO NPs（〜20 nm）在与环境有关的浓度下进行7天，然后喂食鱼7天。蠕虫累积⁶⁵沉淀在曝光期间的Cu既⁶⁵的CuCl ₂和^65层的CuO的NP（0.7和1.1微克⁶⁵铜每克干重组织，分别地），造成⁶⁵的Cu身体负担从控制显著不同。此外，与⁶⁵ CuCl ₂暴露相比，在⁶⁵ CuO NP暴露中，从沉积物中释放的⁶⁵ Cu明显更多。以⁶⁵ CuCl _2为食的鱼类中⁶⁵ Cu的积累和⁶⁵个暴露于CuO NP的蠕虫受到限制（肠道组织：分别为80和65 ng g ^-1 dw；鱼的：体：分别为7和10 ng g ^-1 dw；肝脏：50和10 ng g ^-1 dw）。谷胱甘肽过氧化物酶（GPX）的mRNA表达量较高显著在喂鱼上^65个的CuCl _2个-exposed蠕虫相比⁶⁵的CuO NP-暴露蠕虫（尽管^65个的Cu组织浓度是相似的）。对于其他研究基因（ctr1，mta，gcl，gr，sod，cat，zo-1）。我们的结果表明，源自NP的Cu可以进入淡水食物网，但是在环境实际暴露条件下，其生物积累和营养传递很低（可通过示踪剂检测到），与溶解的Cu并无差异。