Oxidative stress on land snail Helix aspersa as a sentinel organism for ecotoxicological effects of urban pollution with heavy metals

Abstract

The oxidative stress in the digestive gland of the land snail Helix aspersa was considered as a bioindicator for atmospheric pollution with heavy metals from several industries and vehicular traffic in Kafr El-Zayat city. Regional means of heavy metals concentration of all sites were 0.71, 7.09, 0.71, 2.68, 41.44 and 18.01 mg kg(-1) wet mass for Cd, Mn, Ni, Pb, Zn and Cu, respectively. In addition, the highest values of Cd concentrations were found 1.22 and 1.73 mg kg(-1) wet mass in S1 (Potato International Center) and S4 (The Nile bank), respectively. Lactate dehydrogenase (D-LDH(and recorded lipid peroxidation (LPO) levels were significantly high in S1 and S2 (Traffic station). On the other hand, the highest activity of catalase (CAT) was found in S2 (194.04% of control), while the activity of glutathione peroxidase (GPx) reached the highest significant value in S1. As a matter of fact, glutathione-S-transferase (GST) and glutathione reductase (GR) activities were significantly higher in polluted sites than in reference zone. In contrast, the glutathione (GSH) concentration of exposed animals showed significant decrease in all sites, with the lowest value in S1 (57.61% of control). However, metallothioneins concentration (MT) showed no significant difference in all sites except in S1 which accounted for 127.81% of control. Therefore, the overall results of this study showed the importance of H. aspersa as a sentinel organism for biomonitoring the biologic impact of atmospheric pollution in urban areas.

Keywords: Atmospheric pollution; Biomarkers; Heavy metals; Metallothioneins; Oxidative stress.