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Effects of polystyrene nanoplastics and PCB-44 exposure on growth and physiological biochemistry of Chlorella vulgaris

The Science of The Total Environment 2024 7 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Qingzhi Zheng, Qingzhi Zheng, Hanru Wu, Lei Yan, Yanling Zhang, Jun Wang

Summary

Researchers studied the combined effects of polystyrene nanoplastics and a common industrial pollutant (PCB-44) on a freshwater green algae species over both short and long exposure periods. They found that both contaminants individually inhibited algae growth and disrupted cell functions, but their combined presence intensified the damage. The study highlights that when nanoplastics and chemical pollutants co-exist in water, they can create compounding harmful effects on aquatic organisms.

Polymers

Both NPs and PCBs are emerging contaminants widely distributed in the environment, and it is worth exploring whether the combination of the two contaminants causes serious pollution and harm. Therefore, we studied the effects of PS-NPs and PCB-44 alone and together after 96 h and 21 d of exposure to C. pyrenoidosa. The results showed that PS-NPs and PCB-44 affected the cell cycle of C. pyrenoidosa and inhibited its normal growth. Under PS-NPs and PCB-44 stress, the relative conductivity of the algal solution increased, the hydrophobicity of the algal cell surface decreased, and the synthesis of chlorophyll a and chlorophyll b was reduced. In addition to physiological, there are biochemical effects on C. pyrenoidosa. PS-NPs and PCB-44 exposure induced oxidative stress with significant changes in the enzymatic activities of SOD and CAT together with MDA content. Moreover, the relative expression of photosynthesis-related genes (psbA, rbcL, rbcS) all responded, negatively affecting photosynthesis. In particular, significant toxic effects were observed with single exposure to PCB-44 and co-exposure to PS-NPs and PCB-44, with similar trends of effects in acute and chronic experiments. Taken together, exposure to PS-NPs and PCB-44 caused negative effects on the growth and physiological biochemistry of C. pyrenoidosa. These results provide scientific information to further explore the effects of NPs and PCBs on aquatic organisms and ecosystems.

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