The School of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, Edinburgh, EH14 4AS, UK; School of Biological and Marine Sciences, University of Plymouth, Plymouth, PL4 8AA, UK.
The School of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, Edinburgh, EH14 4AS, UK; Vlaams Instituut voor de Zee, Flanders Marine Institute, Wandelaarkaai 7, 8400, Ostend, Belgium.
Environ Pollut. 2020 Aug;263(Pt A):114422. doi: 10.1016/j.envpol.2020.114422. Epub 2020 Mar 19.
Plastic polymers such as polyvinyl chloride (PVC) may contain chemical additives, such as lead (Pb), that are leachable in aqueous solution. The fragmentation into microplastics (MPs) of plastics such as PVC may facilitate desorption of chemical additives and increase exposure of aquatic animals. In this study, the role of chemical additives in the aqueous toxicity of PVC, high-density polyethylene (HDPE) and polyethylene terephthalate (PET) MPs were investigated in early-life stage zebrafish (Danio rerio) by assessment of changes in expression of biomarkers. Exposure of zebrafish larvae to PVC for 24 h increased expression of metallothionein 2 (mt2), a metal-binding protein, but no changes in expression of biomarkers of estrogenic (vtg1) or organic (cyp1a) contaminants were observed. HDPE and PET caused no changes in expression of any biomarkers. A filtered leachate of the PVC also caused a significant increase in expression of mt2 and indicated that a desorbed metal additive likely elicited the response in zebrafish. Metal release was confirmed by acid-washing the MPs which mitigated the response in mt2. Metal analysis showed Pb leached from PVC into water during exposures; at 500 mg PVC L in water, 84.3 ± 8.7 μg Pb L was measured after 24 h. Exposure to a Pb-salt at this concentration caused a comparable mt2 increase in zebrafish as observed in exposures to PVC. These data indicated that PVC MPs elicited a response in zebrafish but the effect was indirect and mediated through desorption of Pb from PVC into the exposure water. Data also indicated that PVC MPs may act as longer-term environmental reservoirs of Pb for exposure of aquatic animals; the Pb leached from PVC in 24 h in freshwater equated to 2.52% of total Pb in MPs leachable by the acid-wash. Studies of MPs should consider the potential role of chemical additives in toxicity observed.
塑料聚合物，如聚氯乙烯（PVC），可能含有可在水溶液中浸出的化学添加剂，如铅（Pb）。塑料如 PVC 微塑料（MPs）的碎片化可能会促进化学添加剂的解吸，并增加水生动物的暴露。在这项研究中，通过评估生物标志物表达的变化，研究了 PVC、高密度聚乙烯（HDPE）和聚对苯二甲酸乙二醇酯（PET） MPs 中化学添加剂在斑马鱼早期生命阶段的水溶液毒性中的作用。暴露于 24 小时的 PVC 会增加金属结合蛋白金属硫蛋白 2（mt2）的表达，但未观察到雌激素（vtg1）或有机污染物（cyp1a）生物标志物表达的变化。HDPE 和 PET 不会引起任何生物标志物表达的变化。PVC 的过滤浸出液也会导致 mt2 的表达显著增加，这表明解吸的金属添加剂可能引起了斑马鱼的反应。通过酸洗 MPs 证实了金属的释放，这减轻了 mt2 的反应。金属分析表明，Pb 在暴露过程中从 PVC 浸出到水中；在水中 500 mg PVC L 的情况下，暴露 24 小时后测量到 84.3±8.7μg Pb L。在该浓度下暴露于 Pb 盐会导致斑马鱼 mt2 增加，与暴露于 PVC 时观察到的情况相当。这些数据表明，PVC MPs 引起了斑马鱼的反应，但这种影响是间接的，是通过从 PVC 中解吸 Pb 进入暴露水中介导的。数据还表明，PVC MPs 可能成为水生动物暴露的 Pb 的长期环境储存库；在淡水中，24 小时内从 PVC 浸出的 Pb 相当于可通过酸洗浸出的 MPs 中总 Pb 的 2.52%。 MPs 的研究应考虑观察到的毒性中化学添加剂的潜在作用。
