Pulse Brain · Growing Health Evidence Index
Tier 1 — Meta-analysis / systematic reviewPeer-reviewedConventional

Global soil pollution by toxic metals threatens agriculture and human health

Deyi Hou, Xiyue Jia, Liuwei Wang, S. P. McGrath, Yong‐Guan Zhu, Qing Hu, Fang‐Jie Zhao, Michael S. Bank, David O’Connor, Jerome O. Nriagu

Science · 2025

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Summary

This global meta-analysis synthesised soil pollution data from 1,493 regional studies across 796,084 sampling points to map the distribution of seven toxic metals and identify areas exceeding agricultural and human health safety thresholds. The work reveals a previously unrecognised high-risk metal-enriched zone in low-latitude Eurasia and estimates that 14–17% of global cropland is affected by toxic metal pollution, with 0.9–1.4 billion people living in regions of heightened public health and ecological risk. The findings underscore soil metal contamination as a significant yet underappreciated threat to food security and human health in the Anthropocene.

Regional applicability

The UK's temperate climate and regulated agricultural practices may limit exposure compared to the high-risk low-latitude Eurasian zone identified; however, localised soil metal contamination from historical mining, smelting, or industrial activity remains a concern in certain regions and warrants continued monitoring to protect cropland and public health. The study's global methodology and machine learning approach may inform UK soil monitoring programmes and national risk assessments to characterise metal distribution in UK agricultural soils.

Key measures

Percentage of global cropland exceeding toxic metal thresholds (14–17%); proportion of population living in heightened public health and ecological risk zones (0.9–1.4 billion); spatial distribution mapping using machine learning; exceedance of agricultural and human health thresholds for arsenic, cadmium, cobalt, chromium, copper, nickel, and lead

Outcomes reported

The study mapped global distribution of soil pollution by seven toxic metals (arsenic, cadmium, cobalt, chromium, copper, nickel, and lead) across 796,084 sampling points from 1,493 regional studies and identified areas exceeding agricultural and human health thresholds. It quantified the proportion of cropland affected by toxic metal pollution and estimated population exposure in high-risk regions.

Theme
Farming systems, soils & land use
Subject
Pesticides, contaminants & food safety
Study type
Meta-analysis
Study design
Meta-analysis
Source type
Peer-reviewed study
Status
Published
Geography
Global
System type
Arable cereals
DOI
10.1126/science.adr5214
Catalogue ID
BFmob79t6f-dy1k98

Topic tags

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