不同粒径塑料微颗粒在斑马鱼腮组织中的积累及其对蒽毒性的影响

Retention of polystyrene particles of different sizes in zebrafish gills and their effect on toxicity of anthracene to gill cells

水环境微塑料颗粒污染非常严重,为了解其对水生动物的毒害效应和生态风险,应用荧光标记聚苯乙烯微球和激光扫描共聚焦荧光显微镜,研究不同粒径(10 nm-1μm)的聚苯乙烯塑料颗粒在斑马鱼(Danio rerio)腮部的积累差异,以及微塑料颗粒存在时对多环芳烃蒽的腮细胞毒性的影响.结果表明,20和50 nm的聚苯乙烯塑料易积累在鱼鳃上,而更大粒径(200,500,1 000 nm)的微塑料颗粒不会滞留在腮部.将染毒后的斑马鱼进行清水实验,鱼鳃上积累的微塑料颗粒也会被清除掉.单独暴露于各种粒径的聚苯乙烯颗粒48 h可导致腮细胞DNA轻微损伤,导致彗星拖尾长度、拖尾DNA比例等轻微增加,单独暴露于200μg/L蒽48 h可严重损伤腮细胞的DNA,彗星拖尾长度、尾DNA比例及尾矩分别从单独塑料颗粒处理的7.1、2.4%和0.65增加到了43.6、44.2%和12.9.当斑马鱼同时暴露于500 nm聚苯乙烯颗粒和蒽时,聚苯乙烯颗粒可以显著降低蒽对DNA的损伤.上述结果表明斑马鱼积累微塑料与粒径相关,但微塑料颗粒对有毒有机污染物毒性的影响较复杂,值得进一步深入研究.

Microplastics pollution is an emerging environmental issue, but the knowledge about its toxicological effects on aquatic animals and ecological risk is very limited. Retention of polystyrene microplastics of different sizes （10 nm to 1 μm） in zebrafish （Danio rerio） gills and their effects on the damage caused by anthracene to DNA of gill cells were investigated. It was demonstrated that 20 and 50 nm polystyrene particles could be retained in zebrafish gills whereas particles of bigger sizes （200, 500, or 1 000 nm） were not found on the gill surface. The retained microplastics could be cleared when the zebrafish had not been exposed to microplastics for one week. The 500 nm polystyrene particles had a slight adverse effect on DNA of gill cells, and exposure to anthracene alone caused significant damage to DNA. Addition of 500 nm polystyrene particles together with anthracene effectively mitigated the damage of anthracene to gill cell DNA. Effects of microplastics on toxicity of toxic organic pollutants needed further study.