Heavy metals contaminate up to 17 pct of world's arable land

LONDON

Up to 17 percent of cropland worldwide is contaminated with at least one type of toxic heavy metal, posing health risks to up to 1.4 billion people, scientists have warned.

Published in the journal Science, their study is a first-of-its-kind global overview of heavy metal contamination in soils, based on a meta-analysis, an approach drawing on data from many previous studies, of almost 800,000 samples.

The team led by environmental specialist Deyi Hou of China's Tsinghua University focused in on areas where concentrations of at least one of seven metals, arsenic, cadmium, cobalt, chromium, copper, nickel and lead, were above recommended safe limits for agriculture and human health.

Metals can be toxic to people, animals and plants at different doses, spreading into different ecosystems through food chains and water.

By running their samples through artificial intelligence-assisted analysis, the researchers found that between 14 and 17 percent of arable land is contaminated by at least one of the metals.

Between 900 million and 1.4 billion people live in "high-risk areas."

Heavy metal contamination can stem from both natural geological processes and human activity such as industrial waste, agriculture or mining.

The researchers noted that there was not enough data in some regions, especially Africa, to allow for designing targeted programs to pare down risks.