Document Type : Original Article
Authors
1
Biology Department, Faculty of Science, Jazan University, KSA/Faculty of Science, Al-Azhar University (Asuit-Egypt)
2
Biology Department, Faculty of Science, University of Jeddah, KSA
3
Biology Department, Faculty of Science, Jazan University, KSA/Zoology Department, Faculty of Science, Damanhour University, Egypt
4
Zoology Department, Faculty of Science, Damanhour University, Egypt
5
Agricultural Genetic Engineering Research Institute (AGERI), Cairo, Egypt
Abstract
The environmental problems have raised the interest for bio-indicators able to reflect their environment. Among these life forms, the insects may contribute to a viable evaluation of the sustainability degrees. The Egyptian Mediterranean coast exhibits six lakes which are situated along the Nile Delta coast; Northern Delta lakes; Manzala, Borollus, Edku, and Mariut, and to the east of the Suez Canal, Port-Fouad and Bardawil. The current study aimed to evaluate different heavy metals in aquatic insects Ochthebius (Asiobates) rugulosus Wollaston 1857, taken from Lake Manzala, and to estimate their effect on the oxidative stress markers to employ insects as sensitive bio-monitors for environmental pollution. A lot of fluctuations were observed affected by the poor connection of the water body of the lake Manzala. The mean level concentrations of Pb, Cd, Cu and Zn in loc.#1, whereas; 0.98, 3.02, 0.35 and 1.99 µg/l; respectively with the arrangement of Cu < Pb < Zn < Cd in location #1 whereas it was reported as 1.8, 3.64, 1.32 and 2.2 µg/l in location#2, giving the arrangement of Pb < Cu < Zn < Cd in loc.#2. The mean concentration level of Pb in both locations was less than that recommended by the USEPA, 2005 (2.5-65 µg/l), Cd in the present study was higher than that of the water quality criteria; (0.2-2 µg/l) recommended by USEPA, 2005 in both locations in Lake Manzala. The pH values of water were alkaline throughout the lake. It is concluded from the obtained data that the southeastern region showed worse quality parameters. The pH of the water lake (loc.1; 7.7), (loc.#2; 7.3) was found to be slightly alkaline throughout the spring (March-May, 2018). The pH was within the prescribed limits (6.5-9) of USEPA, 2005. In the current study, Cu and Zn concentration in Ochthebius (Asiobates) rugulosus Wollaston 1857, in Lake Manzala ranged from (0.2-0.1µg/g, 0.07-0.09 µg/g). The mean concentration of heavy metal was significantly (p < 0.05) different in water samples collected from Lake Manzala, Spring; 2018. The arrangement of elements in the insect tissue was as; Cu > Pb > Zn > Cd. There was a significant increase in the mean concentrations level of ALT activity in insects from loc. #2; 42.6 (U/mg protein), while it was 37 (U/mg protein) in that of loc.#1. The mean concentration level of AST activity in insects from loc.#1 was 50.8 (U/mg protein), while it was 59 (U/mg protein) in that of loc.#2. A significant decrease in GPx activity in insects from loc.#2 was found as, 68.74 (mU/mg protein), while it was 77.4 mU/mg protein in that of loc.#1. The results of the present study showed that there was a significant decrease in GPx activity in samples collected from loc.#2 compared with that of loc.#1 telling that insects in loc.#2 are under stress of sewage pollution (Bahr El Baqur) drain. The Pb in insect tissues in loc.#1 is positively correlated with Zn in insect tissues, TP, MDA, and GPx as r=0.693, r=0.854, r=0.873, and r=644; respectively. Cd in insect tissues is positively correlated with AST, TP, MDA and GPx as r=0.870, r=0.690, r=0.666 and r=0.737; respectively. Cu in insect tissues is negatively correlated with AST as r=-0.739. Zn in insect tissues is positively correlated with TP, MDA, and GPx as r=0.742, r=0.810, r=0.951*; respectively. TP is highly positively correlated with MDA and GPx as r=0.983*, and r=0.840*; respectively whereas, MDA is highly positively correlated with GPx as r=0. 882*. In loc.#2, Pb in insect tissues is negatively correlated with Cu in insect tissues, TP, MDA and GPx as r=-0.716, r=-0.916*, r=-0.878* and r=-0.704; respectively. Cd in insect tissues is negatively correlated with MDA as r=-0.655. Cu in insect tissues is positively correlated with TP and GPx as r=0.806 and r=0.658; respectively. Zn in insect tissues is negatively correlated with AST as r=-0.813.
Keywords
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