Abstract

Nanoplastics are considered contaminants of emerging concern at the global scale. The recent evidence of their occurrence in seawater from the Mediterranean Sea calls for a thorough evaluation of their impact on marine life and in particular on vulnerable life stages such as planktonic embryos. Here, we investigated the impact of increasing nominal concentrations of 50 nm amino-modified (PS-NH₂) and 60 nm carboxy-modified (PS-COOH) polystyrene nanoparticles (PS NPs) on the embryonic development of the ascidian Ciona robusta (phylum Chordata), a common benthic invertebrate living in Mediterranean coastal areas with the peculiarity of being an early chordate developmental model. A strong agglomeration of PS-COOH (approx. 1 µm) was observed in natural sea water (NSW) already at time 0, while PS-NH₂ resulted still monodispersed (approx. 130 nm) but largely aggregated after 22 h with a microscale dimension similar to those negatively charged. However, their effect on C. robusta embryos development largely differed at 22 h: PS-COOH did not affect larvae phenotypes nor their development, while PS-NH₂ caused a dose-dependent effect (EC₅₀ (22 h) of 7.52 μg mL⁻¹) with various degrees of phenotype malformations (from mild to severe) and impairment of larval swimming. Embryos (up to 30%) exposed to 15 µg mL⁻¹PS-NH₂ resulted not developed and the majority was unable to hatch. Calculated PS-NH₂ EC₅₀ resulted higher than those available for other marine invertebrate species, suggesting a protective role of the egg envelopes surrounding C. robusta embryos toward nanoplastics exposure.

摘要

纳米塑料被认为是全球范围内受到关注的污染物。关于它们在地中海海水中发生的最新证据要求对它们对海洋生物，尤其是对浮游胚胎等脆弱生命阶段的影响进行彻底评估。在这里，我们研究了增加的标称浓度的50 nm氨基修饰的（PS-NH ₂）和60 nm羧基修饰的（PS-COOH）聚苯乙烯纳米颗粒（PS NPs）对海鞘罗氏Ci的胚胎发育的影响。（Chordata属），生活在地中海沿岸地区的一种常见的底栖无脊椎动物，其独特之处在于它是早期的cho鱼发育模型。在时间0时，已经在天然海水（NSW）中观察到PS-COOH的强烈团聚（约1 µm），而PS-NH ₂仍旧单分散（约130 nm），但在22 h后以微尺度大量聚集尺寸类似于带负电荷的尺寸。然而，它们对强壮梭状芽孢杆菌胚胎发育的影响在22 h时差别很大：PS-COOH既不影响幼虫表型也不影响其发育，而PS-NH ₂引起剂量依赖性效应（EC ₅₀（22 h））为7.52μgmL ^-1）表现出不同程度的表型畸形（从轻度到重度）和幼体游泳障碍。暴露于15 µg mL ^-1 PS-NH _2的胚胎（最多30％）未发育，大多数无法孵化。计算PS-NH ₂ EC ₅₀产生比那些可用于其他海洋无脊椎动物物种更高，表明围绕蛋信封保护作用罗巴斯达胚胎朝向nanoplastics曝光。