Healthy Soil as the Invisible Determinant of a Healthy Environment: A Critical Review

Soil is a living, finite resource governing chemical fate, microbial ecology, hydrology, nutrient supply, and climate regulation, yet environmental health science and policy routinely treat it as an inert substrate. Approximately one-third of global soils are moderately to highly degraded; an estimated 36 Gt of topsoil is lost to erosion annually, and erosion-related health and environmental externalities cost the United States alone approximately 67 billion per year. Despite existing soil governance frameworks in many jurisdictions, no global system of health-linked routine soil surveillance comparable to air and water quality monitoring has been established, and these burden indicators do not quantify causal effect sizes for soil-to-health links. This narrative scoping review maps evidence linking soil state and management to measured exposure metrics and, where available, to health endpoints. It explicitly grades evidence maturity across five pathways: food chain contamination, water quality impairment, airborne particulate exposure, direct microbial contact, and antimicrobial resistance dissemination. Soil degradation amplifies chemical, biological, and climate-related health risks spanning outcomes from micronutrient deficiencies to soil-transmitted helminthiases, burdening billions of people; persistent pollutants in soils constitute an additional food-chain exposure burden. Evidence maturity varies markedly: food-chain, water, and air-dust pathways are well-characterized, whereas the soil–gut axis and antimicrobial resistance links remain largely inferential. Temporal lags, spatial heterogeneity, unpriced ecosystem services, and institutional fragmentation collectively perpetuate soil’s invisibility in environmental health practice. Monitoring, intervention, and governance approaches are evaluated, highlighting the roles of multi-omics, remote sensing, exposomics, and regenerative land management. A provisional tiered threshold framework is proposed, comprising screening-level indicators, site-specific risk assessment, and actionable management triggers linked to health-relevant endpoints; empirical validation remains a research priority. Soil needs to transition from a background substrate to measurable, manageable infrastructure within an expanded One Health framework. Its governance should match the level of ambition applied to air and water protection. • Soil shapes health exposures through food, water, air, and microbial routes. • Soil degradation increases contaminant mobility, pathogen risk, and climate hazards. • Evidence maturity varies by pathway; food-chain and water links are strongest. • A monitoring-and-trigger framework is needed for soil-explicit One Health action.