Single and joint oxidative stress-related toxicity of sediment-associated cadmium and lead on Bellamya aeruginosa.
The biotoxicity of heavy metals in sediments toward benthic organisms has evoked great concern for the health of freshwater ecosystems. This study applied a sediment toxicity testing protocol to investigate the single and joint toxicity of cadmium (Cd) and lead (Pb) on Bellamya aeruginosa. B. aeruginosa were exposed to different concentrations of Cd (5, 25, and 100 mg/kg), Pb (20, 100, and 400 mg/kg), and their different concentration combinations. A suite of biomarkers, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), metallothionein (MT), malondialdehyde (MDA), and acetylcholinesterase (AChE), were measured after 7, 14, 21, and 28 days of exposure to evaluate their oxidative stress status. Cell apoptosis of soft tissue was also determined after exposure. Results revealed that these endpoints represented sensitive biomarkers for the characterization of the oxidative stress response induced by these metals. Specifically, a decrease of SOD and GPx and an increase of MDA were indicative of the potential failure of the antioxidant defense system in neutralizing the reactive oxygen species (ROS) generated in the exposure of the Pb-treated group. The integrated biomarker response (IBR) index revealed the most significant sub-lethal toxicity for Pb-spiked sediments, leading to the highest rate of cell apoptosis (70.8%). Exposure to Cd resulted in a time- and dose-dependent effect on MT levels, which suggested active detoxification of this metal. Exposure to the mixture resulted in amelioration of Pb toxicity, likely due to the competitive binding of Cd to active enzyme, with the result of an observed antagonistic interaction. This study indicated that B. aeruginosa represents a good biomonitor for assessing Cd and Pb contamination of sediments, and laid the foundation for their potential risk assessments in freshwater ecosystems.
['Liu|Xiang|X|', 'Chen|Qiuwen|Q|', 'Ali|Nasir|N|', 'Zhang|Jin|J|', 'Wang|Min|M|', 'Wang|Zhiyuan|Z|']
D000818:Animals D015415:Biomarkers D002104:Cadmium D002374:Catalase D017753:Ecosystem D005618:Fresh Water D005979:Glutathione Peroxidase D007854:Lead D008315:Malondialdehyde D008668:Metallothionein D019216:Metals, Heavy D018384:Oxidative Stress D011550:Pseudomonas aeruginosa D017382:Reactive Oxygen Species D013482:Superoxide Dismutase
Cadmium Lead Bellamya aeruginosa Sediment toxicity Biomarkers Oxidative stress