How often have we learnt about this kind of alarmism and hysteria in the past 50 or more years? Similar soil contamination has been claimed many times!
Beware this is a meta study using extrapolation! This study was possibly driven by the presumption/preconception of increasing demand for critical minerals! Just the title of this study strongly indicates that the researchers were not objective, but biased!
I am not sure the study properly distinguishes between natural and human contamination. The author's use the ideological term "anthropocene era". Anthropocene is obscene! Junk science!
Look also how many huge blind spots/areas there are on this global map.
"Researchers have created the first global map of toxic metals in soils, showing that vast swaths of land are contaminated from a combination of factors including industrial pollution and the erosion of bedrock.
The map reveals a transcontinental corridor of metal-laced soil that stretches from southern Europe to China, as well as hot spots across Africa and the Americas. The map suggests that anywhere from 900 million to 1.4 billion people worldwide could be exposed to elevated levels of at least one toxic metal, with 14% to 17% of global farmland potentially affected.
To create a global picture, the researchers
first scoured the scientific literature for data on arsenic, lead, and five other relatively common toxic elements.
Next, the researchers used machine-learning algorithms to extrapolate metal concentrations from these samples to places that lacked soil measurements. According to the analysis, the most widespread toxic metal is cadmium, with an estimated 9% of topsoil worldwide bearing high levels. Cadmium, which moves easily through the soil, comes from natural erosion of bedrock and zinc mining.
Other researchers say soil levels on their own don’t necessarily signal risks to crops or people. That depends on chemical details influencing how likely the metals become incorporated into plants, for example, in a form that’s dangerous. But as demand grows for critical minerals to build everything from batteries to wind turbines, the authors stress that nations should test more soil for toxic metals and give international aid to support sampling efforts in understudied regions such as sub-Saharan Africa."
From the editor's summary and abstract:
"Editor’s summary
Metals and metalloids are ubiquitous in soils, originating from bedrock and from human activities and infrastructure. These compounds can be toxic to humans and other organisms, and their soil distribution and concentrations at global scale are not well known. Hou et al. analyzed data from more than 1000 regional studies to identify areas of metal toxicity and explore drivers of these trends.
They estimate that 14 to 17% of cropland exceeds agricultural thresholds for at least one toxic metal.
Climate and topography, along with mining activity and irrigation, predicted which soils would exceed metal thresholds. Soil metal pollution is a global issue that will likely increase with the growing demand for toxic metals in new technologies. ...
Abstract
Toxic metal pollution is ubiquitous in soils, yet its worldwide distribution is unknown.
We analyzed a global database of soil pollution by arsenic, cadmium, cobalt, chromium, copper, nickel, and lead at 796,084 sampling points from 1493 regional studies and used machine learning techniques to map areas with exceedance of agricultural and human health thresholds.
We reveal a previously unrecognized high-risk, metal-enriched zone in low-latitude Eurasia, which is attributed to influential climatic, topographic, and anthropogenic conditions.
This feature can be regarded as a signpost for the Anthropocene era. We show that 14 to 17% of cropland is affected by toxic metal pollution globally and estimate that between 0.9 and 1.4 billion people live in regions of heightened public health and ecological risks."
Toxic metals abound in soils worldwide, new global map reveals "An analysis combining nearly 800,000 soil measurements charts threats to agriculture and human health"
Fig. 1. Global soil pollution by toxic metals exceeding agricultural thresholds (AT).
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