Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea.
Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea.
J Hazard Mater. 2021 Aug 15;416:125832. doi: 10.1016/j.jhazmat.2021.125832. Epub 2021 Apr 9.
Adverse effects of microplastics (MPs) are exacerbated by plastic additives such as benzophenone-3 (BP-3). The aim of the present study was to evaluate the role of extracellular polymeric substances (EPS) of Chlorella vulgaris in leaching BP-3 additive (3.0 ± 0.2% wt/wt) from polyethylene MP fragments (99.8 ± 4.1 µm) and subsequent bioconcentration in Daphnia magna. BP-3 leaching in M4 medium was higher at pH 8 than at pH 6, because of the higher solubility of BP-3 (pK=7.07) at pH 8. However, EPS reduced BP-3 leaching in M4 medium, possibly because of repulsive interactions between the negatively charged EPS and anionic BP-3. Thus, BP-3 leaching was greater at lower pH (6 >8) and EPS concentration (20 >50 mg L as total organic carbon), which was well related to BP-3 sorption capacity of EPS. Although BP-3 uptake in D. magna was decreased at pH 8 by increasing EPS concentration, the bioconcentration of BP-3 in D. magna was increased, possibly because of reduced BP-3 elimination. These findings suggest the important role of EPS in the bioconcentration of anionic plastic additives, which should be further evaluated to understand the underlying toxicokinetic mechanisms.
微塑料 (MPs) 的不良影响因苯并三唑-3 (BP-3) 等塑料添加剂而加剧。本研究旨在评估小球藻胞外聚合物物质 (EPS) 在从聚乙烯 MP 碎片 (99.8 ± 4.1 µm) 中浸出 BP-3 添加剂 (3.0 ± 0.2%wt/wt) 和随后在大型溞中生物浓缩中的作用。在 pH 值为 8 时，M4 培养基中的 BP-3 浸出率高于 pH 值为 6 时，这是由于 BP-3（pK=7.07）在 pH 值为 8 时的溶解度更高。然而，EPS 降低了 M4 培养基中 BP-3 的浸出率，这可能是由于带负电荷的 EPS 和阴离子 BP-3 之间的排斥相互作用。因此，在较低的 pH 值 (6>8) 和 EPS 浓度 (20>50 mg L 作为总有机碳) 下，BP-3 的浸出率更高，这与 EPS 对 BP-3 的吸附能力密切相关。尽管 EPS 浓度增加会降低 D. magna 中 BP-3 的摄取，但 D. magna 中 BP-3 的生物浓缩却增加了，这可能是由于 BP-3 的消除减少了。这些发现表明 EPS 在阴离子塑料添加剂生物浓缩中的重要作用，应进一步评估以了解潜在的毒代动力学机制。
