Giant Land Snails Emerge as Sentinels of Tropical Soil Contamination in One Health Review

Giant African land snails of the subfamily Achatininae — the genera Achatina, Archachatina and Lissachatina — are being put forward as workhorse bioindicators for ecotoxicology in tropical regions, according to a narrative review published in Ecotoxicology on 23 October 2026 by Maxime Louzon and Jean Didié Memel. The authors argue that these snails, long used in contamination studies, could fill a gap left by the absence of standardized terrestrial test organisms suited to tropical environments.

The review’s central claim is functional rather than taxonomic: Achatininae may serve as tropical counterparts to the garden snail Cornu aspersum, the species that underpins international standards for growth inhibition and environmental bioavailability testing in temperate zones. Because the snails are widespread, live in intimate contact with soils and show marked physiological sensitivity to contaminants, they have been used repeatedly in both field surveys and laboratory experiments across the tropics.

Synthésizing that literature, the authors organize the evidence around three uses. First, Achatininae have helped probe mechanisms of action of chemical contaminants at the air–plant–soil interface. Second, they have been deployed to assess the environmental and toxicological bioavailability of inorganic and organic pollutants, using bioaccumulation measurements and effect-based endpoints. Third, they have served to detect ecological disturbances at the level of malacological communities, where shifts in snail assemblages can signal broader environmental degradation.

The strongest and most consistent signal concerns accumulation. Laboratory and field studies alike document that these snails take up metal(loid)s, pesticides and particulate contaminants from their surroundings, making body burdens a reliable record of what is present and biologically available in a given habitat. Bioaccumulation, in other words, is a well-supported endpoint for this group.

Effect data tell a messier story. The review finds that responses are sparser, rarely replicated and in places contradictory. Identical polymer types produced oxidative stress in one snail species but no measurable response in another, and a dose–response relationship reported for cadmium was not reproduced for lead. Because of such inconsistencies, the authors explicitly weigh the evidence endpoint by endpoint rather than treating all studies as equivalent — a caution for anyone reading single-species results as definitive.

Beyond classical ecological risk assessment, the review situates Achatininae within One Health-oriented risk frameworks. These snails are frequently harvested from the wild or farmed as a major protein source in many tropical countries, which places them directly at the intersection of soil contamination, food safety and human exposure. A contaminated habitat can thus translate into a contaminated food item, linking environmental monitoring to public health.

The authors also discuss cross-links between chemical contamination and microbiological hazards, and the trophic transfer of pollutants from snails to their predators and ultimately to humans. This broadens the interpretation of ecotoxicological data beyond species-specific effects and simple secondary-poisoning scenarios, framing the snail as a node through which contaminants move through ecosystems and food webs.

Finally, the review sets out concrete harmonisation recommendations, distinguishing those specific to Achatininae from those generic to soil ecotoxicology more broadly. The authors identify mechanistic approaches and in silico new approach methodologies as ways to extend the taxonomic reach of existing testing frameworks while reducing the number of animals used in research. For tropical risk assessors, the message is that a locally abundant, edible and physiologically responsive snail could become a formalized sentinel — provided the field first resolves the replication gaps and contradictions that currently weaken its effect-based evidence.

Subject of Research: Use of Achatininae land snails as ecotoxicological bioindicators in tropical terrestrial environments

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

Article References: Louzon, M., & Memel, J. D. (2026). Achatininae as ecotoxicological bioindicators in terrestrial tropical contaminated socio-ecosystems: a One Health perspective. Ecotoxicology, 35(9), Article 187. https://doi.org/10.1007/s10646-026-03176-8

Image Credits: AI Generated

DOI: 10.1007/s10646-026-03176-8

Keywords: Achatininae, bioindicators, ecotoxicology, One Health, soil contamination, bioaccumulation, heavy metals, pesticides, food safety, tropical ecosystems, land snails, risk assessment