老化聚苯乙烯纳米塑料对铜绿微囊藻的影响

为探究新生和老化聚苯乙烯纳米塑料（PSNPs）对铜绿微囊藻生长和产毒特性的影响，本研究通过紫外老化制备了50nm的老化PSNPs，开展了不同浓度（0.1，1，10mg/L）新生和老化PSNPs对铜绿微囊藻的长期（37dd）暴露试验.结果表明，紫外老化处理使PSNPs表面出现裂纹，平均粒径变小，羰基指数由0.023上升至1.055.两种PSNPs均会在铜绿微囊藻细胞表面聚集，其中老化PSNPs暴露造成的细胞形态损伤更严重，并对铜绿微囊藻造成剂量正相关的生长和光合抑制，氧化损伤，促进了微囊藻毒素（MC-LR）的合成和释放.在相等暴露剂量下，老化PSNPs对铜绿微囊藻上述生理过程的调控作用更强.其中，10mg/L新生和老化PSNPs暴露下，最终藻密度比对照组分别降低了26.65%和45.07%，丙二醛（MDA）含量的最大值是对照组的1.74和1.93倍，最终胞外MC-LR含量是对照组的1.26和1.44倍.老化PSNPs对胞外MC-LR相对更强的促进作用，是由其诱导的MC-LR合成增加和细胞膜破损所共同导致的.

Effects of aged polystyrene nanoplastics to Microcystis aeruginosa.

To investigate the effects of pristine and aged polystyrene nanoplastics (PSNPs) on the growth and toxin-producing ability of Microcystina aeruginosa, 50nm aged PSNPs was prepared by UV aging method, and long-term exposure of different concentrations (0.1, 1, 10mg/L) of pristine and aged PSNPs to Microcystina aeruginosa was conducted for 37days. The results showed that cracks appeared on the surface of aged PSNPs, meanwhile the average particle size was reduced, and the carbonyl index increased from 0.023 to 1.055. Both pristine and aged PSNPs would aggregate on the cell surface of Microcystis aeruginosa, in which the exposure of aged PSNPs caused severer cell morphological damage, and triggered dose-related growth and photosynthesis inhibition, oxidative damage and promotion of microcystin (MC-LR) synthesis and release. Compared with the control group, the final density of Microcystis aeruginosa in 10mg/L pristine and aged PSNPs treatments decreased by 26.65% and 45.07%, the highest malondialdehyde (MDA) content was 1.74 and 1.93 times of the control, and the final extracellular MC-LR content was 1.26 and 1.44 times of the control, respectively The relatively higher promotion of extracellular MC-LR content under 10mg/L of aged PSNPs exposure at the end of the experiment was resulted from the increased synthesis of intracellular MC-LR and the damage of cell membrane.