Microstructure Analysis and Chemical and Mechanical Characterization of the Shells of Three Freshwater Snails

Survival strategies in arsenic-contaminated environments: Comparative insights from native and exotic aquatic species

The aim of this work was to study the sublethal effects, biokinetics, subcellular partitioning and detoxification of arsenic in two native Chinses species, Bellamya quadrata and Cipangopaludina cathayensis, as well as an exotic South American species, Pomacea canaliculata. The exotic species exhibited higher tolerance than native species. Physiologically based pharmacokinetic model results showed that the exotic species P. canaliculata exhibited a lower bioaccumulation rate and a greater metabolism capacity of As. Subcellular partitioning of As revealed that P. canaliculata exhibits superior As tolerance compared to the native species B. quadrata and C. cathayensis. This is attributed to P. canaliculata effective management of the metal sensitive fraction and enhanced accumulation of As in the biologically detoxified metal fraction. Under As stress, the biochemical parameters (superoxide dismutase, malondialdehyde, glutathione and glutathione S-transferase) of the exotic species P. canaliculata changed less in the native species, and they returned to normal levels at the end of depuration period. Our study provides evidence of the superior survival capability of the exotic species P. canaliculata compared to the native species B. quadrata and C. cathayensis under environmentally relevant levels of As contamination.

Biomimetic Use of Food-Waste Sources of Calcium Carbonate and Phosphate for Sustainable Materials-A Review

Natural and renewable sources of calcium carbonate (CaCO3), also referred to as "biogenic" sources, are being increasingly investigated, as they are generated from a number of waste sources, in particular those from the food industry. The first and obvious application of biogenic calcium carbonate is in the production of cement, where CaCO3 represents the raw material for clinker. Overtime, other more added-value applications have been developed in the filling and modification of the properties of polymer composites, or in the development of biomaterials, where it is possible to transform calcium carbonate into calcium phosphate for the substitution of natural hydroxyapatite. In the majority of cases, the biological structure that is used for obtaining calcium carbonate is reduced to a powder, in which instance the granulometry distribution and the shape of the fragments represent a factor capable of influencing the effect of addition. As a result of this consideration, a number of studies also reflect on the specific characteristics of the different sources of the calcium carbonate obtained, while also referring to the species-dependent biological self-assembly process, which can be defined as a more "biomimetic" approach. In particular, a number of case studies are investigated in more depth, more specifically those involving snail shells, clam shells, mussel shells, oyster shells, eggshells, and cuttlefish bones.

Transcriptomic and metabolomic analysis of the mechanisms underlying stress responses of the freshwater snail, Pomacea canaliculata, exposed to different levels of arsenic

Arsenic (As) pollution poses an important problem, but limited information is available about the physiological effects of As on freshwater invertebrates. Here, we investigated the physiological effects of chronic As exposure on Pomacea canaliculata, a freshwater invertebrate. High level of As (Ⅲ, 5 mg/L) inhibited the growth of P. canaliculata, whereas low level of As (Ⅲ, 2 mg/L) promoted growth. Pathological changes in shell and cellular ultrastructure due to As accumulation likely explain the growth inhibition at high As level. Low level of As simulated the expression of genes related to DNA replication and chitosan biosynthesis, potentially accounting for the growth promotion observed. High level of As enrichment pathways primarily involved cytochrome P450, glutathione, and arachidonic acid-mediated metabolism of xenobiotics. ATP-binding cassette (ABC) transporters, specifically the ABCB and ABCC subfamilies, were involved in As transport. Differential metabolites were mainly associated with the metabolism and biosynthesis of amino acids. These findings elucidate the dose-dependent effects of As stress on P. canaliculata growth, with low levels promoting and high levels inhibiting. Additionally, our findings also provide insights into As metabolism and transport in P. canaliculata.

Characterization of Hydrothermally Decomposed and Synthesized CaCO3 Reinforcement from Dead Snail Shells

The development of new materials from marine resources presents a significant challenge due to the complexity of the associated materials and biology technologies. During this work, the snail shell, which naturally increases in thickness over time to protect the snail, has been identified as one of them. In this study, we investigated the use of powdered snail shells as a potential alternative to ceramics in the creation of customized composites. Our main objective is to explore the hydrothermal decomposition of the snail shell powder to remove undesirable components. To achieve this, we crushed and ground-washed dead snail shells and subjected them to hydrothermal decomposition using an autoclave and furnace at a temperature of 200, 220, 250, or 300 °C. We then analyzed the resulting samples using scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) techniques to determine changes in their composition and structure. Our findings demonstrate that all samples contained the elements Ca, C, and O, as confirmed by SEM/EDS results. XRD results show that hydrothermal decomposition at 250 °C led to good crystallization with maximum peak intensities observed at various diffraction angles. This indicates that the resulting material may have promising properties for use in composite materials. Overall, our study provides valuable insights into the use of snail shell powder as a potential material source for customized composites. Future studies could explore the optimization of the hydrothermal decomposition process and investigate the mechanical properties of the resulting materials to further develop this promising avenue of research.

One-health approach on the future application of snails: a focus on snail-transmitted parasitic diseases

Snails are fascinating molluscs with unique morphological and physiological adaptive features to cope with various environments. They have traditionally been utilized as food and feed sources in many regions of the world. The future exploitation of alternative nutrient sources, like snails, is likely to increase further. Snails, however, also serve as an intermediate host for several zoonotic parasites. A category of parasitic infections, known as snail-transmitted parasitic diseases (STPDs), is harmful to humans and animals and is mainly driven by various trematodes, cestodes, and nematodes. The environment plays a crucial role in transmitting these parasites, as suitable habitats and conditions can facilitate their growth and proliferation in snails. In light of diverse environmental settings and biologically categorized snail species, this review evaluates the dynamics of significant STPDs of zoological importance. Additionally, possible diagnostic approaches for the prevention of STPDs are highlighted. One-health measures must be considered when employing snails as an alternative food or feed source to ensure the safety of snail-based products and prevent any adverse effects on humans, animals, and the environment.

Bioaccumulation of heavy metals in a gastropod species at the Kole wetland agroecosystem, a Ramsar site

Heavy metal concentrations were evaluated in the Pila globosa tissues and the adjacent aquatic environment of the Kole wetland agroecosystem, a Ramsar site, southwest coast of India. Metal concentrations were analyzed to assess the spatial distribution, contamination levels, bioaccumulation potential, and potential risk to the human population and the migratory birds that forage the wetland agroecosystem. The recorded concentrations of heavy metals in P. globosa tissues and the aquatic environment followed the hierarchal order: Fe > Cu > Mn > Cr > Zn > Ni > Cd > Pb mg/kg and Fe > Zn > Ni > Cr > Mn > Pb > Cu > Cd mg/L, respectively. Elevated levels of heavy metals were recorded in the P. globosa tissues than the adjacent aquatic environment thus, highlighting their potential for bioaccumulation. The recorded concentrations of heavy metals in the P. globosa tissues exceeded the permissible limits for Fe, Cu, Mn, Ni, Cr and Cd at several sampling sites. However, in the aquatic environment, the concentrations of all heavy metals were within the permissible limits except for elemental Ni. Inter-elemental correlations between the P. globosa tissues and the aquatic environment recorded antagonistic associations that inhibit metal co-accumulations between the biotic and the abiotic environments. Source identification based on Principle Component Analysis revealed dynamic modes of variability for heavy metals, indicating agro-pesticides and fertilizers as the likely source of heavy metal contamination. Among heavy metals, greater bioaccumulation capacity was recorded for Cu, a moderate for Fe, and comparatively less bioaccumulation for Mn, Zn, Pb, Cr, and Ni. The health risk assessment based on the Target Hazard Quotient and Hazard Index revealed potential toxicity risk to the human population and the migratory birds including the transcontinental migrants that forage the Kole landscapes. Finally, the study emphasizes on long-term monitoring and surveillance programs to identify the multiple stressors most probably, the point sources of contamination and the diffuse sources along the Central Asian flyway for migratory birds to ensure protection of the threatened species and reduce the risk to the human population. Vulnerability to heavy metal toxicity shows that the Kole wetland agroecosystem, a Ramsar site for transcontinental migrants is likely at risk due to heavy metal bioaccumulation in gastropods, hence, requires urgent retrospection. The results of the study highlight that the biosorption potential of P. globosa, can be utilized for bioremediation of metal-contaminated wetlands and agroecosystems.

A sustainable biosorption technique for treatment of industrial wastewater using snail shell dust (Bellamya bengalensis)

Water, an essential commodity available to mankind, is constantly under pollution threat. Industries are one of the major causative factors for its poor quality and therefore all organisms depending upon it, directly or indirectly are affected by various life-threatening problems. Thus, the treatment of discharge waste into the freshwater ecosystem is the dire need of the hour. The objective of the study is valorization of discarded snail shells for treatment of industrial wastewater. In the present study, industrial wastewater was treated using snail shell dust obtained from Bellamya bengalensis to assess change in water quality parameters. Various physico-chemical parameters like pH, total dissolved solids, electric conductivity, dissolved oxygen, biological oxygen demand, chemical oxygen demand, calcium, magnesium, total hardness, chlorides, bicarbonates, orthophosphates, sulfates, nitrates, and ammonia-N were assessed after its treatment with snail shell dust. Based on the present observation, it was concluded that all studied parameters except dissolved oxygen showed a remarkable decline in concentration after treatment with snail shell dust at the rate of 15 g per liter at the end of 4 days. Moreover, increased dissolved oxygen concentration also endorsed an enhancement in water quality. Statistical analysis through Pearson correlation and indices, viz., WQI (Water quality index) as well as Nemerow's Pollution index when applied to the present data, also supported an improvement in the water quality. The findings thus endorsed the utilization of snail shell dust as an eco-friendly technique and can be substituted as a sustainable method for the treatment of industrial wastewater.

A Critical Review of Snail Shell Material Modification for Applications in Wastewater Treatment

Sea material is becoming increasingly popular and widely used as an adsorbent in wastewater treatment. Snail shell, a low-cost and natural animal waste material, has been shown to have a high calcium content (>99%) and a large potential surface area for the development of sustainable adsorbents. This paper presents a novel synthesis of methods for using snail shell absorbent materials in the treatment of wastewater containing heavy metals, textile dyes, and other organic substances. Modified biochar made from snail shells has gained popularity in recent years due to its numerous benefits. This paper discusses and analyzes modification methods, including impregnating with supplements, combining other adsorbents, synthesis of hydroxyapatite, co-precipitation, and the sol-gel method. The analysis of factors influencing adsorption efficiency revealed that pH, contact time, temperature, initial concentration, and adsorbent dose all have a significant impact on the adsorption process. Future research directions are also discussed in this paper as a result of presenting challenges for current snail adsorbents.

Snail Shells as a Heterogeneous Catalyst for Biodiesel Fuel Production

Homogeneous catalysis is relevant for biodiesel fuel synthesis; however, it has the disadvantage of difficult separation of the catalyst. In the present work, heterogeneous catalysis was applied for rapeseed oil transesterification with methanol, while snail shells were used as a catalyst. CaO content in the catalyst was investigated. Transesterification reactions were carried out in a laboratory reactor, ester yield was analyzed using gas chromatography. Response surface methodology was used for process optimization. It was found that the optimum transesterification conditions when the reaction temperature is 64 °C are the following: a catalyst amount of 6.06 wt%, a methanol-to-oil molar ratio of 7.51:1, and a reaction lasting 8 h. An ester yield of 98.15 wt% was obtained under these conditions.

Phosphate ion removal from aqueous solution using snail shell dust: biosorption potential of waste shells of edible snails

The freshwater snails, Filopaludina bengalensis and Pila globosa are widely used for human consumption and as a feed in aquaculture in India and Bangladesh. The generation of shells as a waste product following meat extraction from the live snails incites their utilisation as a potential biomaterial. Shell dust was prepared from the dried shells of F. bengalensis (FSD) and P. globosa (PSD) and employed for phosphate adsorption from aqueous solutions. Batch adsorption experiments were performed to examine the effects of various experimental conditions, such as biosorbent dose, agitation speed, temperature, contact time, pH, initial concentration of phosphate ions, and presence of co-existing ions. SEM, EDS, ICP-OES, FTIR, and XRD results indicated that phosphate ions were adsorbed onto the surface of shell dust particles. The experimental data fitted with the Langmuir isotherm with a maximum adsorption capacity of 62.50 and 66.66 mg g^-1 for FSD and PSD. The pseudo-second order kinetic model was well fitted, indicating the chemical adsorption process, and the thermodynamic parameters indicated that the adsorption mechanism of phosphate was spontaneous, feasible, and endothermic. Therefore, the results have established the potentiality of the waste shells of edible snails to be used as an eco-friendly and low-cost biosorbent for phosphate removal from wastewater.

The Study on Mechanical and Electrical Properties of AA6061/Snail Shell Composites

Metal matrix composites are in high demand for various applications in the industrial sector and engineering firms. Therefore, new materials with enhanced mechanical and ecologically favourable characteristics must be designed and produced. This study focuses on the possibility of developing an aluminium matrix composite using agro-waste materials as reinforcement in preference to other industrial chemicals and materials. The morphological analysis carried out on the AA6061 + 15% snail shell at 100 μm showed the formation of homogenous particle size with stepped crystals. The micrographs of the developed composite were obtained using XRD (X-ray diffraction analysis), which indicated the presence of calcium and hydroxyapatite from the snail shell on the aluminium composite. Electrical analysis performed on the developed composite showed an increase in the conductivity from 32.03 Ωm−1 to 34.59 Ωm−1 as the snail shell reinforcements were increased, thus improving the capability of the developed MMC to transfer electricity due to the occurrence of the snail shell particulate within the composite.

Effects of Environmental Factors and Infecting Trematodes on the Size and Inorganic Elements of Bithynia siamensis goniomphalos Snails in Northeast Thailand

Infection with the foodborne trematode, Opisthorchis viverrini, is a major public health issue in southeast Asia. The freshwater snail, Bithynia siamensis goniomphalos, is an intermediate host of O. viverrini and other trematode species. Understanding the effects of environmental conditions and infecting trematodes on B.s. goniomphalos snails is thus crucial for the potential influences on trematode transmission. This study measured environmental variables of water and soil properties, and analyzed B.s. goniomphalos snails for their trematode infection, snail shell length, and inorganic elemental concentration, from 30 localities in northeast Thailand. The results showed that prevalence of trematode infection in B.s. goniomphalos was 3.82%. Nine types of trematode cercariae were identified, with virgulate type 1 as the most common (1.23%). Opisthorchis viverrini-infected snails were mostly found in low-humic gley soils in Sakon Nakhon Province, and were associated with water dissolved oxygen and soil pH. Compared with uninfected snails, larger sizes were observed in virgulate type 1 and pleurolophocerca-infected snails, whereas hypercalcification was noticed in virgulate type 1, virgulate type 3, and pleurolophocerca-infected snails. Infected snails were more sensitive toward environmental conditions, possibly because of the dynamic parasitic processes between trematodes and hosts. Among the environmental factors, soil texture (i.e., sand, silt, and clay compositions) exhibited more significant correlations with B.s. goniomphalos shell characteristics regardless of the trematode infection types. The findings of this study underscore the need to consider the effects of environmental conditions and trematode species-specific pathogenic processes for a more effective and sustainable parasitic control and prevention effort.

Hierarchical self-assembly into chiral nanostructures

One basic principle regulating self-assembly is associated with the asymmetry of constituent building blocks or packing models. Using asymmetry to manipulate molecular-level devices and hierarchical functional materials is a promising topic in materials sciences and supramolecular chemistry. Here, exemplified by recent major achievements in chiral hierarchical self-assembly, we show how chirality may be utilized in the design, construction and evolution of highly ordered and complex chiral nanostructures. We focus on how unique functions can be developed by the exploitation of chiral nanostructures instead of single basic units. Our perspective on the future prospects of chiral nanostructures via the hierarchical self-assembly strategy is also discussed.