Changes in the physicochemical properties of polyethylene microplastics before and after aging and their effects on the phytotoxicity of tetracycline
In this study,the morphological characteristics,specific surface area,pore size,particle size,contact angle,and Fourier transform infrared spectroscopy of polyethylene microplastics(PE-MPs)before and after aging were measured to analyze the changes of their physicochemical properties.Chinese cabbage seeds were used as test organisms to explore the effects of PE-MPs on tetracycline(TC)phytotoxicity through early plant growth experiments.Results showed that the particles of PE-MPs broke and became smaller after aging;the particle size(Dx50)decreased from 91.4 μm to 77.3 μm,while the specific surface area increased from 4.150 8 m2·g-1to 4.967 1 m2·g-1.The contact angle decreased from 103° to 79°,indicating a change from hydrophobicity to hydrophilicity.The number of oxygen-containing functional groups increased,and a new absorption band of carbonyl(C=O)was found at 1 650-1 800 cm-1.Compared with TC alone,0.5 mg·L-1 and 5 mg·L-1 TC had no significant effect on the germination of Chinese cabbage seeds in the presence of PE-MPs before and after aging;however,the inhibitory effects on the elongation of radicles and the synthesis of photosynthetic pigments in cotyledons intensified with the increase of PE-MPs content.Among them,the maximum reduction in relative radicle length was 18.9 percentage points,and the maximum reduction in the relative content of photosynthetic pigments was 51.1 percentage points.Compared with PE-MPs before aging,the exacerbation effect of PE-MPs on TC phytotoxicity weakens after aging.
polyethylene microplasticstetracyclineaginghydrophilicity-hydrophobicityphytotoxicityphotosynthetic pigments in cotyledons
万方数据
维普
