典型纳米金属氧化物对氨氧化菌Nitrosomonas europaea的生物胁迫影响

对比研究了3种典型纳米金属氧化物颗粒(NPs,包括纳米TiO2(n-TiO2),纳米CeO2(n-CeO2)和纳米ZnO(n-ZnO))在不同作用浓度下(0,0.1,1,10,50mg/L)对污水生物脱氮系统中代表性氨氧化菌─ Nitrosomonas europaea连续作用6h的毒性效应及作用规律.结果表明,3种NPs对N.europaea的生物胁迫效应与其投加浓度均呈正相关.其中,50mg/L的n-CeO2, n-ZnO与对照组相比,可显著降低N.europaea细菌浓度,破坏细胞膜完整性,抑制氨氧化速率.相同浓度条件下, n-ZnO对N.europaea的毒性影响最大, n-TiO2影响最小.虽然n-ZnO释放的Zn2+对N.europaea具有明显的毒性效应,但n-ZnO及其产生的尺寸效应仍是其生物胁迫产生的重要来源.

Biological effects of typical metal oxide nanoparticles on Nitrosomonas europaea

The biotoxicities and impact patterns of three widely used nanoparticles (NPs) TiO2, CeO2and ZnO (n-TiO2, n-CeO2 and n-ZnO) on the typical ammonia oxidizing bacteria, Nitrosomonas europaea were investigated. N.europaea was exposed to the NPs at a series of concentrations (0, 0.1, 1, 10, 50mg/L) for 6h. The effects of NPs on N.europaea were positively correlated with the exposed NP concentrations and the 50mg/L n-CeO2 and n-ZnO significantly impaired the cell membrane integrity, cell density, and ammonia oxidization rate. n-ZnO showed the highest biotoxicity among the three NPs while n-TiO2 showed the least. n-ZnO with its nano-size was considered to induce the serious nanotoxicities on N.europaea although the Zn2+ dissolved from n-ZnO also contributed to n-ZnO toxicty.