Achatininae as ecotoxicological bioindicators in terrestrial tropical contaminated socio-ecosystems: a One Health perspective.

Achatininae land snails, including the genera Achatina, Archachatina, and Lissachatina, have long been used in ecotoxicological studies, particularly in tropical environments where standardized terrestrial bioindicators remain limited. Their widespread distribution, close association with soils, and marked physiological sensitivity to contaminants have motivated their recurrent use in both field and laboratory investigations. In this context, Achatininae have often been proposed as functional counterparts to Cornu aspersum, which underpins international standards for growth inhibition and environmental bioavailability testing in temperate regions. This narrative review synthesises the use of Achatininae in terrestrial ecotoxicology. Specifically, we examine how these organisms have been employed to address mechanisms of action of chemical contaminants at the air-plant-soil interface, environmental and toxicological bioavailability of inorganic and organic pollutants through bioaccumulation and effect-based endpoints, and ecological disturbances at the level of malacological communities. Accumulation of metal(loid)s, pesticides and particulate contaminants is consistently documented across laboratory and field studies, whereas effect data are sparser, rarely replicated, and in places contradictory: identical polymer types have produced oxidative stress in one species and no measurable response in another, and the dose-response relationship reported for cadmium was not reproduced for lead. We therefore appraise the strength of the evidence endpoint by endpoint rather than presenting all studies as equivalent. Beyond classical ecological risk assessment, this review emphasizes the relevance of Achatininae within One Health-oriented risk frameworks. These snails are frequently harvested or farmed as a major protein source, placing them at the intersection of soil contamination, food safety, and human exposure. Cross-links between chemical contamination, microbiological hazards, and trophic transfer to predators and humans are discussed, extending the interpretation of ecotoxicological data beyond species-specific effects and secondary poisoning scenarios. Finally, we set out concrete harmonisation recommendations, distinguishing those specific to Achatininae from those generic to soil ecotoxicology, and identify where mechanistic and in silico new approach methodologies can extend the taxonomic reach of existing frameworks while reducing animal testing.