摘要:
全氟化合物(PFASs)是一类具有疏水基团和亲水基团的新型污染物.目前，在环境条件对PFASs生物富集影响方面已开展了诸多研究，但有关碳质材料(CMs)和溶解性有机质(DOM)共存对PFASs在生物体内富集的影响还未见报道。为探讨这一问题，研究了沉积物-水体系中2种碳质材料木炭(W400)、多壁碳纳米管(MWCNT10)和4种DOM (丹宁酸、富里酸、蛋白胨和腐殖酸)对6种典型PFASs在摇蚊幼虫体内生物富集的影响。结果表明，暴露10 d后(已达到富集平衡状态)，无论体系中是否存在CMs，添加1~50 mg C·L-1不同类型的DOM对PFASs在摇蚊幼虫体内生物富集的影响不显著。无论体系中是否存在DOM，添加CMs均能降低摇蚊幼虫体内PFASs的含量，且MWCNT10对PFASs生物富集的降低比例显著高于W400。与对照相比，添加0.4%的MWCNT10对摇蚊幼虫体内PFASs含量的降低比例为21%~56%，而同等添加量的W400对其降低比例均低于20%。这表明，在沉积物-水体系中，当CMs和DOM共存时，CMs是影响PFASs在摇蚊幼虫体内富集的主要因素，而少量DOM的引入对其影响不大。
Abstract:
Perfluoroalkyl substances (PFASs) are a class of organic anionic fluorinated surfactants with a hydrophobic perfluoroalkyl chain and a hydrophilic functional group. There are some studies on the effects of environmental conditions on PFAS bioconcentration in aquatic organisms. However, co-effects of carbonaceous material (CMs) and dissolved organic matter (DOM) on bioconcentration of perfluoroalkyl substances in aquatic organisms have not been studied. In this study, the co-effects of two types of CMs and four types of DOM on PFAS bioconcentration in Chironomus plumosus larvae were investigated. The CMs included willow-derived chars (W400) and multiwalled carbon nanotubes (MWCNT10) of which the contents were 0.4% dry weight in sediment. The DOM included tannic acid (TA), fulvic acid (FA), peptone (PEP), and humic acid (HA), and their concentrations were 0, 1, 5 and 50 mg C·L-1. The PFASs included perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA). The concentration of each PFAS in sediment was 0.1 mg·kg-1 dry weight. The results showed that, upon bioconcentration equilibrium, regardless of DOM addition or not, the body burden of the six PFASs in larvae decreased in all treatments amended with CMs. Body burden of PFASs decreased more remarkably in the MWCNT10 amended sediment than in the W400 amended sediment. Compared to the control without CM amendment, the body burden of PFASs in larvae decreased by 21%-56% in the sediment amended with MWCNT10 regardless of DOM types and concentrations, while the body burden of PFASs decreased less than 20% in the W400 amended sediment. However, irrespective of the presence and absence of CMs, when DOM types changed or their concentrations increased, the body burden of PFASs in larvae did not change significantly in the sediment amended with 0.4% CMs. Therefore, the CMs played a major role in decreasing the PFAS body burden in larvae, and the small quantity of DOM addition had no significant effects on the body burden of PFASs when the CMs and DOM were co-existent. The results suggest that CMs in sediment should be considered in the bioavailability assessment of PFASs.
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