New Study Warns of Widespread Heavy Metal Contamination in Soils

A groundbreaking study published in the journal Science has revealed that up to 1.4 billion people across the globe live in areas where soils are contaminated with dangerous levels of toxic heavy metals, posing a major threat to food security, public health, and the environment.

The research, led by Deyi Hou and his team, analysed nearly 800,000 soil samples from 1,493 regional studies and used advanced machine learning to map global contamination levels. The findings show that between 14 to 17 percent of the world’s cropland—roughly 242 million hectares—is polluted with at least one heavy metal beyond safe thresholds for agriculture and human health.

The study warns that this widespread soil pollution could significantly reduce crop yields and introduce harmful substances into the food chain, threatening the safety of food and water supplies. Cadmium was identified as the most prevalent contaminant, with particularly high concentrations in South and East Asia, the Middle East, and parts of Africa. Cadmium exposure is linked to serious health risks including kidney damage and cancer.

Other metals commonly exceeding safe levels include nickel, chromium, arsenic, and cobalt. These toxic elements are persistent in soil and can remain for decades, leading to long-term health issues such as neurological damage and developmental delays from chronic exposure.

One of the study’s most striking discoveries is the identification of a previously unrecognised “metal-enriched corridor” spanning low-latitude regions of Eurasia. This high-risk zone is shaped by a combination of natural geological processes like metal-rich bedrock and volcanic activity, as well as human factors such as mining, industrialisation, and irrigation practices. Climate conditions and landscape features also influence metal accumulation in soils.

As global demand for critical metals continues to rise, the researchers caution that soil contamination will likely intensify without urgent intervention. The study calls for stronger environmental regulations, enhanced soil monitoring, sustainable agricultural practices, and public awareness campaigns to address what it describes as a major but underappreciated global environmental and public hesalth crisis.

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