表面活性剂对沉积物中纳米TiO_2与Cd单一及复合污染生态毒理学效应的影响

Impacts of surfactants on the ecotoxicological effects of TiO_2-NP and/or Cd contamination in sediments

为评价表面活性剂十二烷基苯磺酸钠(SDS)对沉积物中人工纳米颗粒(ENP)与共存污染物复合污染生态毒理学效应的影响,以底栖动物铜锈环棱螺(Bellamya aeruginosa)为受试生物,采用沉积物慢性生物测试,研究不同浓度SDS作用下非毒性浓度二氧化钛纳米颗粒(TiO2-NP)与不同浓度镉(Cd)单一及联合作用对铜锈环棱螺肝胰脏细胞DNA损伤、Na+,K+-ATPase活性、脂质过氧化产物MDA含量和蛋白质羰基PCO含量的影响.结果显示,沉积物中低浓度Cd(5μg g-1)单独处理对铜锈环棱螺不表现出明显的毒性,高浓度Cd(25μg g-1)单独处理则具有较为明显的毒性,SDS的存在可以显著增强Cd对铜锈环棱螺的毒性(P<0.05).沉积物中非毒性浓度TiO2-NP可以增强低浓度Cd对铜锈环棱螺的毒性,但不影响高浓度Cd对铜锈环棱螺的毒性.SDS显著增强TiO2-NP与Cd复合污染对铜锈环棱螺的毒性(P<0.05),而且随SDS浓度的升高而增加.因此,在评价人工纳米颗粒的生态风险时,不仅要考虑人工纳米颗粒自身的毒性、人工纳米颗粒与共存污染物的相互作用,也要注重表面活性剂等因子的影响.

Surfactants may alter the interaction between engineered nanoparticles（ENP） and coexisting pollutants,and further influence the ecotoxicity of these pollutants.This research aimed to evaluate the impacts of the surfactant sodium dodecyl benzene sulfonate（SDS） on the ecotoxicological effects of TiO2-NP and Cd combined contamination in freshwater sediments by deposit-feeding gastropoda Bellamya aeroginosa.We investigated the effects of TiO2-NP and/or Cd contamination in the presence of different concentrations of SDS on DNA damage,Na^＋,K^＋-ATPase activities,malondialdehyde（MDA） levels,and protein carbonyl（PCO） levels in the hepatopancreas of B.aeroginosa following 21-d chronic sediment bioassay.The results showed that low concentration（5 μg g^-1） of Cd had no toxicity to B.aeroginosa,while relatively high concentration（25 μg g^-1）displayed obvious toxicity,and that SDS could significantly enhance the toxicity of Cd to B.aeroginosa.TiO2-NP with nontoxic concentration could enhance the toxicity of Cd with low concentration to B.aeroginosa,but had no effects on the toxicity of Cd with high concentration.SDS could significantly enhance the toxicity of TiO2-NP and Cd combined contamination to B.aeroginosa in a SDS-concentration-dependent manner.When assessing the potential environmental risk of ENP,we should not only focus on the toxicity of ENP itself,or the interaction between ENP and coexisting contaminants,but also should consider the potential impacts of surfactants and other environmental factors.