Division of Environmental Science and Ecological Engineering, College of Life Sciences and Biotechnology, Korea University,Seoul 02841, Korea; Department of Marine Science and Research Institute of Basic Sciences, College of Natural Science, Incheon National University, Incheon 22012, Korea.
Division of Environmental Science and Ecological Engineering, College of Life Sciences and Biotechnology, Korea University,Seoul 02841, Korea.
Sci Total Environ. 2019 Feb 15;651(Pt 1):162-170. doi: 10.1016/j.scitotenv.2018.09.068. Epub 2018 Sep 6.
One of the most important concerns about marine microplastics is their role in delivery of chemical contaminants to biota. The contribution of microplastic ingestion to the overall uptake of five hydrophobic organic chemicals (HOCs) [α-, β-, and γ-hexachlorocyclohexanes (HCHs), pentachlorobenzene (PeCB), and hexachlorobenzene (HeCB)] by fish is evaluated in this study. Partition coefficients of all five HOCs between surfactant micelles and simulated intestinal fluid (SIF), as well as between protein and SIF, were experimentally determined. Desorption of model HOCs from a polyethylene film into an artificial gut solution was measured to estimate the fraction of HOCs that can be absorbed from microplastics during their gut retention time. Monte-Carlo simulation (n = 100,000) showed that the uptake via microplastic ingestion will be negligible for HCHs as compared to uptake via other exposure routes, water ventilation and food ingestion. On the other hand, microplastic ingestion might increase the total uptake rate of PeCB and HeCB due to their accelerated desorption from microplastics into the artificial gut solution under the model scenario, assuming an extremely high intake of microplastics. However, the steady-state bioaccumulation factor was predicted to decrease with increasing ingestion of microplastics, showing a dilution effect by microplastic ingestion. Results indicate that HOCs that are close to be at phase equilibrium between microplastics and environmental media are not likely to be further accumulated via ingestion of microplastics; this is true even for cases, where ingestion of microplastics contributes significantly to the total uptake of HOCs. Therefore, future studies need to focus on hydrophobic plastic additives that may exist in microplastics at a concentration higher than their equilibrium concentration with water.
海洋微塑料最重要的问题之一是它们在将化学污染物输送给生物群中的作用。本研究评估了微塑料摄入对鱼类吸收 5 种疏水性有机化学品（HOCs）[α-、β-和γ-六氯环己烷（HCHs）、五氯苯（PeCB）和六氯苯（HeCB）]的总体影响。实验测定了这 5 种 HOC 在表面活性剂胶束和模拟肠液（SIF）之间以及在蛋白质和 SIF 之间的分配系数。测量了模型 HOC 从聚乙烯薄膜到人工肠液中的解吸，以估算在肠道保留时间内可以从微塑料中吸收的 HOC 分数。蒙特卡罗模拟（n=100,000）表明，与通过其他暴露途径（水通风和食物摄入）相比，HCHs 通过微塑料摄入的吸收量可以忽略不计。另一方面，由于在模型情况下 PeCB 和 HeCB 从微塑料中加速解吸到人工肠液中，微塑料摄入可能会增加 PeCB 和 HeCB 的总吸收速率，假设大量摄入微塑料。然而，稳态生物积累因子预计会随着微塑料摄入量的增加而降低，表明微塑料摄入具有稀释作用。结果表明，接近微塑料和环境介质之间相平衡的 HOC 不太可能通过摄入微塑料进一步积累；即使在微塑料摄入对 HOC 总吸收量有显著贡献的情况下，情况也是如此。因此，未来的研究需要集中在可能存在于微塑料中的疏水性塑料添加剂上，这些添加剂的浓度高于其与水的平衡浓度。
