摘要
微塑料(microplastics,MPs)易吸附污染物,改变污染物的生物富集、分布和毒性效应,但其复合暴露对土壤生物的毒性研究却较为薄弱.本文选用赤子爱胜蚓作为受试生物,以个体、亚机体、亚细胞、组织水平上的毒性指标研究不同粒径(30目和100目)和浓度(0.2%和2%)的聚乙烯(polyethylene,PE)颗粒对三氯生(triclosan,TCS)在蚯蚓体内富集分布的特征,及其复合胁迫对蚯蚓毒性效应的影响.研究表明,PE降低了蚯蚓体内TCS的富集量;TCS在蚯蚓亚机体水平的富集量呈现为生殖环带>环带前部>环带后部,在亚细胞水平的富集量呈现为胞外组分>胞内组分,在组织水平的富集量呈现为肠道>表皮的特征;PE介导下,环带前部、胞外组分、肠道TCS的富集量显著降低.100目PE和TCS两类单一暴露组,诱导SOD、MDA、8-OHdG增加以应对抗氧化胁迫,诱导K^(+)Na^(+)-ATP酶、Ca^(2+)-ATP酶升高以维持细胞内外离子平衡,且TCS诱导效应强于PE.相对TCS单一暴露组,PE-TCS复合暴露组未显著增强蚯蚓氧化胁迫相关酶(SOD、CAT).其中,100目PE-TCS复合暴露组8-OHdG显著被诱导,AKP、K^(+)Na^(+)-ATP、Ca^(2+)-ATP显著被抑制.这表明100目MPs在TCS损伤细胞DNA、干扰细胞内外的离子平衡方面均有加重效应.研究可为评价MPs对土壤有机污染物生态风险的潜在影响提供科学依据.
Microplastics(MPs)can absorb various pollutants and alter the biological accumulation,distribution,and toxic effects of other pollutants.Nevertheless,few studies have focused on these combined effects on soil organisms.In this paper,Eisenia foetida was used to evaluate the effect of polyethylene(PE)particles of varying sizes(mesh numbers 30 and 100)and concentrations(0.2%and 2%)on the triclosan(TCS)accumulation and distribution in earthworms at individual,sub-organism,subcellular,and tissue levels.Furthermore,the combined toxic effects on earthworms were investigated.The results revealed that PE particles reduced the accumulation of TCS in earthworms—i.e.,the higher the PE concentration and the greater the amount of PE in the soil,the lower the accumulation of TCS in earthworms.The TCS distribution at the sub-organism level was clitellum>pre-clitellum>post-clitellum,while it was extracellular>intracellular at the subcellular level and intestinal>epidermis at the tissue level.PE particles significantly decreased the TCS distribution in the pre-clitellum,extracellular,and intestinal regions.Superoxide dismutase(SOD),malondialdehyde(MDA),and 8-hydroxydeoxyguanosine monophosphate(8-OHdG)production were induced to resist antioxidant stress caused by the increase in the PE amount and TCS exposure in earthworms.K^(+)Na^(+)-ATP and Ca^(2+)-ATP enzymes exhibited comparable characteristics,thus maintaining ion balance in and out of cells.The induction effect of the TCS exposure group was stronger than that of the PE particles groups.Overall,compared with TCS treatments alone,the combined exposure to PE(ingested and uningested PE particles)and TCS did not enhance oxidative stress-related enzymes.However,the ingested PE particles induced the 8-OHdG index and inhibited the AKP,K^(+)Na^(+)-ATP,and Ca^(2+)-ATP enzyme indices,suggesting that PE increased the effect of DNA damage induced by TCS on earthworms and attenuated the interference of TCS with ion balance in and out of cells in earthworms.These results provide a scientific basis for understanding the impact of microplastics on the ecological risk posed by soil organic pollutants.
作者
沈海欣
冯永雪
马丽丽
Shen Haixin;Feng Yongxue;Ma Lili(College of Environment,Nanjing Normal University,Nanjing 210023,China)
出处
《南京师大学报(自然科学版)》
北大核心
2026年第1期135-143,共9页
Journal of Nanjing Normal University(Natural Science Edition)
基金
国家自然科学基金项目(41603114)
江苏省科技厅自然科学基金项目(BK20161017)。
关键词
微塑料
三氯生
蚯蚓
富集分布
酶活性
microplastics
triclosan
earthworm
accumulation and distribution
enzyme activity
