Use of Oxidative Stress and Genotoxic Biomarkers of Aquatic Beetles Anaceana globulus (Coleoptera: Hydrophilidae) as Biomonitors of Water Pollution

摘要

Background and Objective: Contamination of water lakes by toxic chemical pollutants is one of the largest threats to environment and human health. They occur in the environment as a result of natural processes and/or as pollutants from human activities. Lakes are important natural resources for agricultural crops and fish production particularly in the developing countries . In Egypt, lake Mariut is one of the aquatic ecosystems suffers extremely from almost all possible human activities, so it is considered the polluted site, while lake Edku is considered the reference one due to less impact of human activities and environmental problems. Materials and Methods: Insect samples of Anaceana globulus (Coleoptera: Hydrophilidae) were collected from reference and polluted lakes. Oxidative stressors and chromosomal aberrations of insect tissues were studied. Statistical analysis (student t-test) was applied to show the significance difference between data collected from both sites. Results: Water pollution of lake Mariut caused changing in water characteristics that lead to a great alteration in its physiochemical parameters. Heavy metals : Copper, zinc, manganese, iron, lead, cadmium and cobalt were also detected significantly in water samples and in insect body samples collected from the polluted site. The accumulated toxic heavy metals in body insect samples in addition to the unhealthy environmental physiochemical conditions lead to significant changes in oxidative stress biomarkers. These changes represented by a significant decrease in the activity of glutathione peroxidase, catalyase and glutathione content as well as the total protein content. On the other hand, significant increases in activities of aspartate transaminase, alanine transaminase and malondialdehyde concentration were recorded. Moreover, these pollutants induced significantly chromosomal aberrations such as fragments, stickiness, gaps and polyploidy. Additionally, binucleated and micronucleus cells were observed in the insect metaphase cells. Conclusion: The evaluation study of using aquatic beetles as a monitor of water pollution was reflecting the dramatically increasing of mutagenicity. Also, the damage by oxidative stress was probably pronounced related to the decreased antioxidant capacity. It gives a good indicator for the level of ecotoxicology and the severe impact of human activities on the selected habitats.