Parveen Naseeba, Joseph Anuja, Goel Sudha
School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India.
School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India.
Sci Total Environ. 2024 Jan 1;906:167640. doi: 10.1016/j.scitotenv.2023.167640. Epub 2023 Oct 6.
Natural organic matter (NOM) is the primary precursor of disinfection by-products (DBPs). However, as emerging environmental contaminants continue to increase in natural waters, there is a possibility of new precursors of DBPs. We investigated the potential of microplastics (MPs), a growing environmental concern, for leaching organic matter (OM) and subsequent DBP formation. Two experimental setups were used, including chlorinated water containing MPs (Cl-MP), and non-chlorinated water containing MPs (Non-Cl-MP), using polyethylene (PE), polyethylene tetrahydrate (PET), polypropylene (PP), and polyvinyl chloride (PVC) as MP materials. The UV absorbance spectra of Cl-PET/PP/PVC showed peaks at 218 nm, which were significantly correlated with dissolved organic carbon (DOC), indicating lower aromaticity of the leached OM. The DOC concentrations in Cl-MP samples were several times higher than those in Non-Cl-MP samples. The leached OM from MPs formed trihalomethanes (THMs) and haloacetic acids (HAAs) in Cl-MP samples. Among the MPs tested, PVC showed the highest total THM formation after 7 days, followed by PET, PE, and PP. Brominated THMs were predominant, while HAAs were highly chlorinated. THM formation increased with contact time for PE, PET, and PVC, and decreased for PP. Compared to THMs, the concentration of HAAs was low (highest total THM = 185.5 μg/L per g-MP and highest total HAA = 120.7 μg/L per g-MP). Further, the total THM concentration decreased and the total HAA concentration increased over the reaction period, indicating the leaching of different types of OM with increasing contact time. Additionally, the differences in the pattern of DOC leaching and DBP formation among different MPs suggested changes in the leached OM.
天然有机物（NOM）是消毒副产物（DBPs）的主要前体物。然而，随着天然水体中新兴环境污染物不断增加，存在产生新的DBP前体物的可能性。我们研究了微塑料（MPs）这一日益受到环境关注的物质释放有机物（OM）以及随后形成DBP的可能性。采用了两种实验装置，包括含MPs的氯化水（Cl-MP）和不含MPs的非氯化水（Non-Cl-MP），使用聚乙烯（PE）、聚对苯二甲酸乙二酯（PET）、聚丙烯（PP）和聚氯乙烯（PVC）作为MP材料。Cl-PET/PP/PVC的紫外吸收光谱在218 nm处有峰值，与溶解有机碳（DOC）显著相关，表明浸出的OM芳香性较低。Cl-MP样品中的DOC浓度比Non-Cl-MP样品高几倍。MPs浸出的OM在Cl-MP样品中形成了三卤甲烷（THMs）和卤乙酸（HAAs）。在所测试的MPs中，PVC在7天后显示出最高的总THM生成量，其次是PET、PE和PP。溴化THMs占主导，而HAAs则高度氯化。PE、PET和PVC的THM生成量随接触时间增加，而PP的则减少。与THMs相比，HAAs的浓度较低（最高总THM = 每克MP 185.5 μg/L，最高总HAA = 每克MP 120.7 μg/L）。此外，在反应期间总THM浓度降低，总HAA浓度增加，表明随着接触时间增加，不同类型的OM被浸出。此外，不同MPs之间DOC浸出和DBP形成模式的差异表明浸出的OM发生了变化。
