1.Key Laboratory of Hydrobiology in Liaoning Province，Dalian Ocean University，Dalian 116023，China；2.Beijing Key Laboratory of Fishery Biotechnology，Fisheries Science Institute，Beijing Academy of Agriculture and Forestry Sciences，Beijing 100068，China
Abstract: In order to explore biological toxic effects of microplastics on freshwater organisms, freshwater zooplankton cladoceran (Bosminalongirostris) was cultured in a light incubator and exposed to polystyrene microspheres (PS, density of 1.05 g/cm3) with diameter of 0.5 and 5 μm at concentration of 0, 5, 10, 15, 20, 25 and 30 mg/L and PS with diameter of 20 μm 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 Bosminalongirostris 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 (P<0.05). The 48 h LC50 of different particle sizes of PS for cladoceran Bosminalongirostris was shown to be 21.65 mg/L in 0.5 μm, 19.26 mg/L in 5 μm and 47.61 mg/L in 20 μm. 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 (P<0.05), while the first spawned larvae were small in body length and height, which was significantly lower than that in the control group (P<0.05), 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 (P>0.05). PS led to prolong the maternal lifespan, increase the total reproductive volume and shorten the prenatal development period of cladoceran Bosminalongirostris. There was significantly greater intrinsic growth rate in the different particle sizes of PS group than that in the control group (P<0.05), with the maximum at 0.5 μm particle (0.227 4±0.000 2)d-1. It is found that polystyrene microspheres have an impact on the survival, morphology and reproduction of Bosminalongirostris, 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.
2023, Vol. 38 
