Growth and antioxidative response of two mangrove plants to interaction between aquaculture effluent and BDE-99

• Published in: The Science of the total environment Vol. 662; pp. 796 - 804
• Main Authors: Farzana, Shazia, Cheung, Siu Gin, Zhou, Hai Chao, Tam, Nora Fung Yee
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.04.2019
• Subjects: aquaculture; Aquaculture effluent; Avicennia marina; BDE-99; biomass; catalase; China; dominant species; enzyme activity; hormesis; Hormesis model; Kandelia; leaves; malondialdehyde; mangrove swamps; Mangroves; oxidative stress; peroxidase; polybrominated diphenyl ethers; superoxide anion; superoxide dismutase; Toxicity; wastewater; China; Mangroves; Hormesis model; BDE-99; Aquaculture effluent; Toxicity
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.01.263

Mangroves are subject to contamination of polybrominated diphenyl ethers (PBDEs) due to waste and wastewater disposal, and aquaculture effluent (AE) from nearby aquaculture activities. However, the response of mangrove plants to these two stresses and their interaction has seldom been reported. A six-month microcosm study, planted with either Kandelia obovata (Ko) or Avicennia marina (Am), the two most dominant species in South China mangrove swamps, was conducted to investigate the effects of BDE-99, and the interactions of BDE-99 (one of the most abundant PBDE congeners) and AE on growth and physiological responses of these plants. In addition to mixed stressors, both stressors were also applied individually. Results showed that Avicennia was more tolerant to BDE-99 contamination than Kandelia, as reflected by the reduced biomass, but increased superoxide radical (O2−⁎) release and malondialdehyde (MDA) content in Kandelia. Addition of AE alleviated toxicity of BDE-99 in Kandelia by promoting biomass but lowering oxidative stress and MDA production. The hormesis model also demonstrated that the interaction between BDE-99 and AE on leaf and root MDA and O2−⁎ content in both Kandelia and Avicennia were mostly antagonistic. Activities of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD) in both leaf and root of Kandelia were reduced by BDE-99. On the contrary, BDE-99 significantly enhanced the three enzyme activities in Avicennia root at month 3. Addition of AE also significantly enhanced root CAT, POD and SOD activities, and leaf SOD in both plant species to remove excess ROS produced under BDE-99 exposure. These results indicated that the tolerance of mangrove plants to oxidative stresses depended on antioxidative enzymes that were inducible. [Display omitted] •BDE-99 posed toxicity to Kandelia obovata (Ko) but not in Avicennia marina (Am).•BDE-99 reduced antioxidative enzymes activity in Ko.•Aquaculture effluent (AE) enhanced plant biomass and alleviated BDE-99 toxicity.•AE combat BDE effects on antioxidative enzymes and reduced oxidative stress in Ko.•Interaction of BDE-99 and AE on malondialdehyde in mangroves were antagonistic.