不同粒径聚苯乙烯微球对长额象鼻溞的毒性效应

Research of environmental toxic effects of different particle sizes of polystyrene microspheres on cladoceran (Bosmina longirostris)

为探究微塑料对淡水生物的生物学毒性效应,选取淡水中常见的浮游动物长额象鼻溞(Bosmina longirostris)为试验动物,在实验室条件下研究了3种粒径(0.5、5、20μm)的聚苯乙烯微球(PS)对长额象鼻溞存活、形态和繁殖的影响。结果表明:不同粒径的PS对长额象鼻溞的急性毒性均随时间的延长和浓度的增加而增大,各PS浓度组长额象鼻溞24 h致死率显著高于对照组(P<0.05),0.5、5、20μm粒径的PS对长额象鼻溞的48 h LC_(50)分别为21.65、19.26、47.61 mg/L;PS对长额象鼻溞母体和子代的形态影响显著,3种粒径PS组母体的体长、体高均显著大于对照组(P<0.05),而第一胎幼溞的体长、体高却变小,且显著小于对照组(P<0.05),随着繁殖代数的增加,PS的影响逐渐减弱,第二胎幼溞的体长与对照组已无显著性差异(P>0.05);PS可延长长额象鼻溞母体寿命,增加其总生殖量及缩短产前发育期,不同粒径PS组的内禀增长率均显著大于对照组(P<0.05),以0.5μm粒径组最高,为(0.2274±0.0002)d^(-1)。研究表明,PS对长额象鼻溞的存活、形态和繁殖均产生了影响,其毒性大小与粒径、浓度相关,本研究结果可为进一步研究微塑料对水生生物的毒性效应提供参考。

In order to explore biological toxic effects of microplastics on freshwater organisms,freshwater zooplankton cladoceran(Bosmina longirostris)was cultured in a light incubator and exposed to polystyrene microspheres(PS,density of 1.05 g/cm~3)with diameter of 0.5 and 5μm at concentration of 0,5,10,15,20,25 and 30 mg/L and PS with diameter of 20μm at concentration of 0,10,20,30,40 and 50 mg/L at(22±1)℃and a photoperiod of 12L∶12D.The results showed that the acute toxicity of different particle sizes of PS to cladoceran Bosmina longirostris was shown to be increased with the extended time increase in concentration,with significantly greater 24 h lethality of the animals than that in the control group(P0.05).The 48 h LC_(50)of different particle sizes of PS for cladoceran Bosmina longirostris was shown to be 21.65 mg/L in 0.5μm,19.26 mg/L in 5μm and 47.61 mg/L in 20μm.The morphology of the parent and offspring was significantly affected by PS.The body length and body height were significantly greater in the parent in the test group than that in the control group(P0.05),while the first spawned larvae were small in body length and height,which was significantly lower than that in the control group(P0.05),with the increase in reproductive generations the effect being gradually weakened,and the body length of the offspring of the second generation was no longer significantly different from that in the control group(P0.05).PS led to prolong the maternal lifespan,increase the total reproductive volume and shorten the prenatal development period of cladoceran Bosmina longirostris.There was significantly greater intrinsic growth rate in the different particle sizes of PS group than that in the control group(P0.05),with the maximum at 0.5μm particle(0.2274±0.0002)d~(-1).It is found that polystyrene microspheres have an impact on the survival,morphology and reproduction of Bosmina longirostris,and its toxicity is involved in particle size and concentration.The findings provide reference for further research on the toxic effects of microplastics on aquatic organisms.