Phytotoxicity of amoxicillin to the duckweed Spirodela polyrhiza: Growth, oxidative stress, biochemical traits and antibiotic degradation. (June 2018)

• Record Type: Journal Article
• Authors: Singh, Vineet; Pandey, Bhawna; Suthar, Surindra
• Is Part Of: Chemosphere. Volume 201(2018)
• Page Start: 492
• Page End: 502
• Publication Date: 2018-06
• Subjects: Ecotoxicology -- Emerging contaminants -- Pharmaceutical residues -- Aquatic toxicity -- Biodegradation; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.03.010
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The increasing availability of antibiotics in wastewater has created a serious threat to non-target organisms in the environment. The aim of this study was to evaluate the potential toxicity of amoxicillin on duckweed Spirodela polyrhiza during a short-term exposure (7 d). The duckweed was exposed to a range of environmentally relevant (0.0001–0.01 mg L −1 ) and high (0.1 and 1 mg L −1 ) concentrations of amoxicillin. Subsequently, biomarkers of toxicity such as growth, pigments (Chl a, Chl b and carotenoids), antioxidative enzyme activity (catalase, CAT; superoxide dismutase, SOD; and ascorbate peroxidases, APX), and biochemical content (protein, lipid and starch) were analysed in their fronds. The high dose (1 mg L −1 ) of amoxicillin caused a significant (p < 0.05) decrease in photopigments, protein, starch and lipid content and an increase in carotenoids/total Chl and Chl a/Chl b ratios in fronds of Spirodela polyrhiza. The results showed a shift in biomarkers: a decrease in frond growth and relative growth rate (RGR) (16.2–53.8%) and an increase in the activities (mmol mg protein −1 ) of CAT (0.021–0.041), APX (0.84–2.49) and SOD (0.12–0.23) in fronds. The significantly (p < 0.05) greater reduction in amoxicillin content in duckweed setups (84.6–100%) than in the control (62.1–73%) suggested that phytodegradation is an important mechanism in removing antibiotics from water, apart from hydrolysis and photodegradation, which occur in control setups. Overall, the results suggested a toxic effect of amoxicillin on Spirodela polyrhiza, even at low concentrations, and nonetheless, the duckweed contributed directly to the degradation of antibiotics in the water and throughout the phytoremediation process. Graphical abstract: Image 1 Highlights: To our best knowledge, this is first study on toxicity of amoxicillin to Spirodela polyrhiza. The amoxicillin induced the production of CAT, SOD, APX, etc. in plants. Amoxicillin reduced significantly (84–100%) in reactor, suggesting phytodegradation, hydrolysis and photodegradation as major mechanisms for antibiotic removal.