Impact of contamination on biology, biochemical, and histology of Eobania vermiculata and Monacha obstructa during different seasons in Ismailia, Egypt

Land snails are found to be an appropriate sentinel organism, and the biomarkers chosen are effective for terrestrial heavy metal biomonitoring. The study aimed to compare the biological, biochemistry, and histology of two land snails in the Ismailia governorate, Egypt during different seasons. Random snails were collected from January 2015 to December 2015 from two sites in the Ismailia Governorate, on wet days during each seasons middle month. Soft tissues were taken from the dissected snails. It was noticed that most of the morphometric parameters measured shell height (ShH), last whorl width (LWW), maximum diameter (MaxD), aperture height (AH), and aperture width (AW) were higher in Eobania vermiculata (Sp. 1) than those measured in Monacha obstructa (Sp. 2), except for shell height measurement, which was the same in both species. The growth rate of Sp. 1 and Sp. 2 changed seasonally. In the more polluted areas with heavy metals, lipid peroxidation (LPO) was higher in snails and total protein content than in the snails collected from the less polluted areas for all seasons. However, the snails displayed lower levels of glutathione (GSH) as compared to snails at a less polluted site. GSH and LPO levels, on the other hand, have a negative relationship between them. Histopathological alterations in the digestive gland were more obvious in the general architecture of the digestive gland that had lost its tubular appearance. The excretory cells showed an increase in their excretory granules number and size while calcium cells decreased. Also, gonad follicles have lost their normal architecture with the degeneration of some stages of spermatogenesis and oogenesis. In conclusion, There was a strong correlation between GSH levels and total protein content in the same soft tissues. GSH and LPO levels, on the other hand, have a negative relationship. The overall results display the usefulness of E. vermiculata and M. obstructa land snails as bioindicator organisms and support the application of this ecotoxicological approach for evaluating the biologic impact of toxins. E. vermiculata is more abundant than M. obstructa. The density, morphometric, biochemical, and histology of E. vermiculata and M. obstructa were different at different seasons.