Interaction effects of oxytetracycline and copper at different ratios on marine microalgae Isochrysis galbana

• Published in: Chemosphere (Oxford) Vol. 225; pp. 775 - 784
• Main Authors: Wu, Changlu, He, Chiquan
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2019
• Subjects: Coordination ratios; Isochrysis galbana; OTC+Cu composites; Oxytetracycline; Ratio; Oxytetracycline; OTC+Cu composites; Isochrysis galbana; Ratio; Coordination ratios
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2019.03.067

Contamination with both oxytetracycline (OTC) and Cu is prevalent in water. OTC can chelate with Cu to form OTC + Cu composites. Through the study of the effects of the interaction of OTC and Cu on the algae Isochrysis galbana at multiple coordination ratios, it was found that the OTC + Cu complex was antagonistic to algae growth after 24 h of exposure but was synergistic in treatment (T) 3 and T4 after 48 and 72 h. Compared with OTC alone, the addition of Cu addition significantly inhibited the biosynthesis of chlorophyll a, but the ratio (R) in the OTC + Cu and OTC treatments gradually increased from T1 to T4. The addition of Cu also led to a significant increase in malondialdehyde and reactive oxygen species, but R gradually decreased and increased, respectively, from T1 to T4. The accumulation of OTC in algae was considerably promoted by the addition of Cu, with R increasing 1.5 in T2 to 2.6 in T4; moreover, the residue of OTC in water was reduced in the presence of algae. OTC alone dramatically inhibited the absorption of Cu by algae, while in the presence of OTC + Cu, only the two high-OTC treatments showed a significant decrease in Cu absorption. In addition, the absorption of Mg was markedly inhibited in all OTC treatments and the adsorption of K in the high-OTC treatment, but these inhibitory effects were alleviated in the OTC + Cu treatment. These results indicated that the effects of the OTC + Cu complex on algae were different from the effects of OTC and Cu alone. •OTC + Cu complex affected algae growth differently from OTC and Cu alone.•Cu and high-OTC affect the biosynthesis and fluorescence of chlorophyll.•Cu addition promotes the accumulation of OTC in algae.•OTC inhibits the absorption of Cu, Mg and K by algae.