Institute of Environmental Research at Greater Bay, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, China; Institute of Eco-environmental Research, School of Environmental and Natural Resources, Zhejiang University of Science & Technology, Hangzhou, 310023, China.
Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
Chemosphere. 2021 Nov;283:131274. doi: 10.1016/j.chemosphere.2021.131274. Epub 2021 Jun 18.
Various chemical substances, such as potentially toxic trace metals, are used as plastic additives to improve the performance of polymers and extend the service life of plastic products. However, these added trace metals are likely released from plastic into the environment when the plastic becomes a pollutant, although the process is poorly understood. In this study, chemical ageing of commercial polyvinyl chloride (PVC) microplastics using hydrogen peroxide (HO) and natural ageing of PVC that had been added to an alkaline paddy soil were undertaken to evaluate the potential release of trace metals from PVC. Enhanced release of trace metals from PVC with the increasing HO concentrations was observed, in which the released Pb was 1-2 orders of magnitude higher than other metals (p < 0.01). The released Cr, Ni, Pb, Cu, Zn, Cd and Mn accounted for 87.37%, 79.27%, 22.02%, 20.93%, 17.06%, 15.11%, and 11.02% of their total concentrations (0.28 ± 0.03, 0.08 ± 0.01, 13.67 ± 0.18, 1.07 ± 0.02, 2.20 ± 0.18, 0.05 ± 0.00 and 1.26 ± 0.08 mmol kg) in PVC after ageing with 30% HO, respectively. Compared with the control treatment without PVC addition, the concentrations of CaCl-extractable Cu, Mn, Ni, Pb, and Zn in the soil treated with 5% PVC are significantly increased after incubation for 60 days (p < 0.01). In conclusion, chemical and natural ageing have the potential to lead to the release of Cu, Mn, Ni, Pb, and Zn from the commercial PVC into aquatic and terrestrial environments.
各种化学物质，如潜在有毒痕量金属，被用作塑料添加剂，以改善聚合物的性能并延长塑料产品的使用寿命。然而，当塑料成为污染物时，这些添加的痕量金属很可能从塑料中释放到环境中，尽管这一过程知之甚少。在这项研究中，使用过氧化氢（HO）对商业聚氯乙烯（PVC）微塑料进行化学老化，并对添加到碱性稻田土壤中的 PVC 进行自然老化，以评估 PVC 中痕量金属的潜在释放。观察到随着 HO 浓度的增加，痕量金属从 PVC 中释放增强，其中释放的 Pb 比其他金属高 1-2 个数量级（p < 0.01）。释放的 Cr、Ni、Pb、Cu、Zn、Cd 和 Mn 分别占其总浓度（0.28 ± 0.03、0.08 ± 0.01、13.67 ± 0.18、1.07 ± 0.02、2.20 ± 0.18、0.05 ± 0.00 和 1.26 ± 0.08 mmol kg）的 87.37%、79.27%、22.02%、20.93%、17.06%、15.11%和 11.02%。与未添加 PVC 的对照处理相比，在添加 5% PVC 的土壤中孵育 60 天后，CaCl2 可提取的 Cu、Mn、Ni、Pb 和 Zn 的浓度显著增加（p < 0.01）。总之，化学和自然老化有可能导致商业 PVC 中的 Cu、Mn、Ni、Pb 和 Zn 释放到水生和陆地环境中。
