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Responses of Antioxidant Enzymes in Catfish Exposed to Liquid Crystals from E-Waste
Department of Chemistry, Jackson State University, Jackson, MS 39217, USA
Department of Civil & Environmental Engineering, Jackson State University, Jackson, MS 39217, USA
School of Environmental Science and Engineering, South China University of Technology, Guangzhou 510641, P. R. China
* Author to whom correspondence should be addressed.
Received: 30 October 2007; Accepted: 30 April 2008 / Published: 30 June 2008
Abstract: Liquid crystals (LCs) are typically elongated organic molecules with a non-uniform distribution of electrical charges leading to a dipole. LCs are widely used in displays of computers and other electronic devices. The rapid obsolescence rate of electronics results in large amounts of liquid crystal displays (LCDs) entering the environment. Data on health effects of LCs on living creatures are currently limited to some acute toxicity tests by a few major LC manufacturers. These tests concluded that the vast majority of LCs are not acutely toxic. Since the amount of LCs in electronic devices is very small, the health effects of LCs at low concentrations or doses become important. Catfish were used as the test animals in this study. Four major enzymes of the fish’s antioxidant defense system catalase (CAT), superoxide dismutase (SOD), selenium-dependent glutathione peroxidase (Se-GPx), and glutathione-Stransferase (GST) were chosen as biomarkers to examine effects of LCs, which were taken from obsolete laptop personal computers made in the early 1990s. The catfish were fed with food containing different contents of LCs for 40 days. Activities of the four chosen enzymes in fish livers were assayed. The results showed that there were significant inductions of CAT, SOD, and Se-GPx activities in response to the LC doses. The plots of the enzyme activities versus LC doses suggested an occurrence of oxidative stress when the dose reached about 20 μg LC/g fish·d. It was concluded that LCs can cause pollutant-induced stress to catfish at low doses. CAT, SOD and Se-GPx are effective biomarkers to give early warning on potential health effects of LCs on some aquatic lives including catfish.
Keywords: Liquid crystals; antioxidant enzyme; biomarker; E-waste; catfish
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MDPI and ACS Style
An, R.; Li, Y.; Niu, X.; Yu, H. Responses of Antioxidant Enzymes in Catfish Exposed to Liquid Crystals from E-Waste. Int. J. Environ. Res. Public Health 2008, 5, 99-103.
An R, Li Y, Niu X, Yu H. Responses of Antioxidant Enzymes in Catfish Exposed to Liquid Crystals from E-Waste. International Journal of Environmental Research and Public Health. 2008; 5(2):99-103.
An, Ran; Li, Yadong; Niu, Xiaojun; Yu, Hongtao. 2008. "Responses of Antioxidant Enzymes in Catfish Exposed to Liquid Crystals from E-Waste." Int. J. Environ. Res. Public Health 5, no. 2: 99-103.