Healthy soil as the invisible determinant of a healthy environment: A critical review

Soil is a living, finite resource that shapes chemical fate, microbial ecology, nutrient supply, and climate regulation, yet environmental science and policy often treat it as an inert substrate. Approximately one-third of global soils are moderately to highly degraded, with an estimated 36 Gt of topsoil being lost to erosion annually, and erosion-related health and environmental externalities costing the US ∼$67 billion annually. 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 review summarizes evidence linking soil condition and management to measured exposure metrics and health outcomes. It 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, with persistent pollutants in soils constituting 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, undervalued ecosystem services, and institutional fragmentation collectively contribute to 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, with empirical validation remaining 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.