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 season's 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.

The Land Snail, Eobania vermiculata, as a Bioindicator of the Heavy Metal Pollution in the Urban Areas of Sulaimani, Iraq

Land snails are crucial consumers in the terrestrial environment and beneficial significant bioindicators to evaluate the chemical impact in the ecosystem, especially on urban lands. The present study aimed to investigate the concentration of heavy metals such as As, Cr, Ni, Pb, and Zn in urban soil and study whether Eobania vermiculata acts as a bioindicator for heavy metal contamination in an urban area. Thirty soil and snail samples in triplicate from each sampling site were taken from the urban areas of Suliamani. After a microwave-assisted digestion procedure, every sample was analyzed by inductively coupled plasma-optical emission spectrometry. Results showed that the concentration of chromium (Cr) in each snail sample was significantly high. The maximum Cr concentration (15.87 mg kg−1) was recorded in the snail sample collected from Ali Kamal Park, which was adjacent to a very crowded traffic road. The As concentration in snail samples ranged from 0.08 to 1.004 mg kg−1, and it was below the permissible limits. However, the concentrations of heavy metals in urban soil locations were below their background measurements, except for nickel (Ni) which was above the permissible limits. The safest site in the study area was Chaviland 1, while the most contaminated site was the Ha-wary Shar Park. The snails bioaccumulated metals in their tissues in the following order, Cr > Zn > Ni, and this bioaccumulation occurred more on the main road locations, which represented potentially contaminated places due to anthropogenic activities. Moreover, there was no correlation among the heavy metals within the soil samples when compared to the similar metals in the snail samples, due to the low concentration of heavy metals in soil, excluding Ni, from where the snail samples were collected. Consequently, the land snail, E. vermiculata, is an appropriate sentinel organism for some metals, mainly for Cr, and the bioindicator monitoring with this snail should be extended to mixtures of heavy metals, since such relationships frequently occur in soil.

Terrestrial Biota as Bioindicators for Microplastics and Potentially Toxic Elements

Plastic products used in our daily life remain in the environment for a long time. Plastics decompose gradually into smaller fragments (<5 mm) known as microplastics. There are different sources of microplastics contamination, including plastic bags, masks, synthetic textiles, and various coatings. Microplastics’ smaller size enhances toxic pollutants’ adsorption, through which they are easily digested by small biota and finally accumulated along the food chain. Many studies are found concerning marine microplastic distribution and pollution; however, rarely do they address terrestrial contamination. The terrestrial species Eobania vermiculata, Rumina decollata, Porcellio, Armadillo, Lumbricus terrestris, and Scolopendra were evaluated as bioindicators for soil pollution by microplastics and some potentially toxic metallic elements. Microplastics were isolated with the help of caustic potash. The particles were characterized by infrared spectroscopy (FTIR); some associated potentially toxic metals were assessed in the filtrate by inductively coupled plasma spectrometry (ICP). The following polymers were present in all studied samples: copolyamide, nylon, high- and low-density polyethylene, polyamide, and polyester. In addition, the metallic elements antimony, iron, aluminum, selenium, and zinc were determined with different concentrations. Thus, terrestrial biota can serve as bioindicators for microplastic pollution of soil, which could act as a vector for potentially toxic elements.

First record of Eobania vermiculata (O. F. Müller, 1774) (Gastropoda: Eupulmonata: Helicidae) in Romania

Eobania vermiculata (O. F. Müller) is recorded for the first time in Romania. Other Mediterranean and Balkan species have entered the south of Romania – Dobrogea, or will do so in the near future. We expect the rest of Romania to be invaded, because the Danube is not an insurmountable barrier for some of these species.

First record of Phasmarhabditis sp. from eggs of Eobania vermiculata (Müller) snails in Egypt and their response to host size

Background Gastropods are very prevalent animals. In Egypt, terrestrial snails represent important economic pests, infesting and causing severe damages to ornamental plants, orchard trees, vegetables, and field crops. The overuse of molluscicides against these destructive pests leads to more environmental pollution. Therefore, searching for biological control agents became necessary to avoid the hazard of chemical molluscicides. Phasmarhabditis hermaphrodita, isolated from slugs was used as a bio-control agent against snails and slugs. Few investigations available on gastropod egg parasites. Therefore, the present study interested in the isolation of parasitic nematodes from the snail eggs to study their possible role as biological control agents for gastropod pests. Results This is the first record to isolate the snail parasitic nematode, Phasmarhabditis sp., from eggs of the Egyptian terrestrial snail, Eobania vermiculata (Müller). Infectivity of this nematode was investigated for eggs, juvenile and mature snails, E. vermiculata and Limax flavus L. slugs, and also eggs of the non-local species, Achatina fulica Bowdich and one adult of it was only available. The investigation revealed a capability of the isolated nematode to infect and kill E. vermiculata snail, L. flavus slugs, and their eggs. Also, it could infect and kill the eggs of non-local snail species, A. fulica, and its only individual adult available which was obtained from an agricultural quarantine sample. The results indicated also that released individuals of the nematodes, recovered from snails, were significantly larger in size than those recovered from eggs and vice versa. Conclusion It could be concluded that the isolated parasitic nematode may be able to play a role in controlling different stages of the gastropods including eggs. This make the control more effective in protecting host plants before the pest causing damage. The nematode was more effective on local pest species than non-local species. Moreover, the size of the parasite was proportional with the size of the host pest.

Hibernation Period in Some Land Snail Species (Gastropoda: Helicidae): Epiphragmal Structure and Hypometabolic Behaviors

In this study, the hypometabolism behavior, epiphragm formation process, and the mineral composition of the epiphragmal structure of the Helix pomacella, Eobania vermiculata, Helix melanostoma, and Helix asemnis land snails were investigated during the hibernation period. 100 snails selected among mature individuals, 25 from each species, were collected from nature for the research. The snails were placed in four 50x50x5 cm pans containing 20-cm-deep humus soil. Snails were fed with lettuce by free feeding until the hibernation period. Hypometabolism behavior of snails that had hibernated between November and December 2018, and January and February 2019 were examined as entering the hibernation stage, hibernation stage, and leaving the hibernation stage. The ionic concentration (Calcium, Iron, and Phosphorus) of the epiphragm layer formed during the hibernation process was analyzed, its formation duration, and its degradation at the end of the hibernation period were examined. In the study, it was determined that the weight before hibernation reduced by 18-22% in all examined species (H. pomacella, E. vermiculata, H. melanostoma, and H. asemnis). The highest values in terms of epiphragm formation duration (19±0.30 days), weight (0.41±0.26 g), and thickness (0.310±0.22 mm) were determined in H. asemnis. In terms of the ionic concentration, the highest Calcium level was determined in H. asemnis (29.96±0.12 mg/g) while the highest Phosphorus level (4.02±0.20 mg/g) was determined in E. vermiculata, and the highest Iron content was found in H. pomacella (19.50±0.33 mg/g). The degradation duration of the epiphragm layer at the end of hibernation was determined the longest in E. vermiculata (7 days) whereas the shortest in H. pomacella (3 days). As a result of the present research, it was seen that the epiphragm layer is important for snails in terms of a sustainable life cycle and that the ecological tolerances of snails depend on the epiphragmal structure.