Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region.
Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region; HKBU Institute of Research and Continuing Education, Shenzhen Virtual University Park, Shenzhen, China.
Environ Pollut. 2019 Nov;254(Pt B):113066. doi: 10.1016/j.envpol.2019.113066. Epub 2019 Aug 17.
Sorption studies of organic pollutants by microplastics (MPs) in single-solute systems are well established in the literature. However, actual aquatic environments always contain a mixture of contaminants. Prediction of the fate and biological effects of MPs-mediated chemical exposure requires a better understanding of sorption-desorption processes of multiple organic contaminants by MPs. In this study, the altered sorption and desorption behaviors of individual organic UV filters (BP-3 and 4-MBC) in the presence of cosolutes (BP-3, 4-MBC, EHMC and OC) on two types of MPs (LDPE and PS) were examined. In most cases, co-occurrence of other organic UV filters appeared to have an antagonistic effect on the sorption of primary solute, which was consistent with trends found in previous studies. Nevertheless, the sorption uptake of 4-MBC as primary solute on PS was enhanced in the presence of cosolute(s), arising presumably from solute multilayer formation caused by laterally attractive π-π interactions between adsorbed cosolute(s) and 4-MBC molecules. Such formation of multilayer sorption in multi-solute systems depends on the solute hydrophobicity and concentration as well as inherent sorptivity of MPs. Our further desorption experiments revealed that the bioaccessibility of primary solute was significantly elevated with cosolutes, even though competitive sorption was observed under the same experimental conditions. These findings supplement the current knowledge on sorption mechanisms and interactions of multiple organic contaminants on MPs, which are critical for a comprehensive environmental risk assessment of both MPs and hazardous anthropogenic contaminants in natural environments.
在单溶质体系中，微塑料（MPs）对有机污染物的吸附研究在文献中已有充分的报道。然而，实际的水生环境中通常会包含多种污染物的混合物。为了预测 MPs 介导的化学物质暴露的归宿和生物效应，需要更好地理解 MPs 对多种有机污染物的吸附-解吸过程。在本研究中，考察了两种类型的 MPs（LDPE 和 PS）上共存溶质（BP-3、4-MBC、EHMC 和 OC）对单个有机紫外滤光剂（BP-3 和 4-MBC）的吸附和解吸行为的改变。在大多数情况下，其他有机紫外滤光剂的共存在某种程度上表现出对主要溶质吸附的拮抗作用，这与之前研究中的趋势一致。然而，在共存溶质的存在下，PS 上作为主要溶质的 4-MBC 的吸附摄取量增加了，这可能是由于侧向吸引力π-π 相互作用导致吸附的共存溶质和 4-MBC 分子之间形成了多层溶质。这种多溶质体系中的多层吸附的形成取决于溶质的疏水性、浓度以及 MPs 的固有吸附性。我们进一步的解吸实验表明，尽管在相同的实验条件下观察到竞争吸附，但主要溶质的生物可利用性随着共存溶质的存在而显著提高。这些发现补充了关于 MPs 上多种有机污染物的吸附机制和相互作用的现有知识，这对于 MPs 和自然环境中人为有害污染物的综合环境风险评估至关重要。
