Oxidative stress responses in two marine diatoms during acute n-butyl acrylate exposure and the toxicological evaluation with the IBRv2 index

• Published in: Ecotoxicology and environmental safety Vol. 240; p. 113686
• Main Authors: Du, Shuhao, Meng, Fanping, Duan, Weiyan, Liu, Qunqun, Li, Hao, Peng, Xiaoling
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-07-2022; Elsevier
• Subjects: Antioxidants; Diatoms; Integrated Biomarker Response Version 2 (IBRv2); n-Butyl acrylate (nBA); Toxicity; n-Butyl acrylate (nBA); Antioxidants; Integrated Biomarker Response Version 2 (IBRv2); Diatoms; Toxicity
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2022.113686

n-Butyl acrylate (nBA), a typical hazardous and noxious substance (HNS), is the largest-volume acrylate ester used to produce various types of polymers. With the increasing volume of nBA subject to maritime transportation, its accidental leakage poses a great risk to the marine organisms. Therefore, it is necessary to evaluate the ecological risk of nBA in marine environments. In this study, two species of marine microalgae, Skeletonema costatum and Phaeodactylum tricornutum, were used to explore the toxic effects of nBA based on their growth, pigment content, and oxidative stress. The growth of each species was significantly inhibited by nBA, showing a 96 h-EC50 value of 2.23 mg/L for P. tricornutum and 8.19 mg/L for S. costatum, respectively. Although chlorophylls a and c exerted a hormesis effect in P. tricornutum, contents of pigments generally decreased at high concentrations. In P. tricornutum, all detected antioxidants (reduced glutathione, GSH; superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GPx) were stimulated at concentrations ranging from 1.50 to 3.82 mg/L. However, these elevations were not enough to reduce the oxidative damage caused by nBA, because the content of malondialdehyde (MDA) increased continuously during 96-h exposure. For S. costatum, the activities of only two antioxidants (GSH and CAT) were enhanced, which is enough to prevent the MDA content from rising, even at higher concentrations of nBA (5–10 mg/L). The Integrated Biomarker Response Version 2 (IBRv2) index that combines responses of the above five oxidative stress biomarkers, was not only correlated positively with nBA concentration but could also indicate the occurrence of oxidative stress caused by acute concentration of nBA. These findings showed that P. tricornutum was sensitive to nBA compared to S. costatum, and the IBRv2 index was an effective tool for evaluating ecotoxicological effects on marine microalgae due to nBA spills.
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•Phaeodactylum tricornutum was more sensitive to n-Butyl acrylate (nBA) than Skeletonema costatum.•The IBRv2 indices and the concentration of nBA had positive linear relationships (R² > 0.90).•The response sensitivity ranking of oxidative stress indicators in P. tricornutum was SOD > CAT > GSH > MDA > GPx.•In S. costatum, CAT and GPx were the main biomarkers that respond to nBA exposure.