Soil pollution poses a worrisome threat to agricultural productivity, food safety and human health, but far too little is known about the scale and severity of that threat. This was stated by a recently-released Food and Agriculture Organization (FAO) report titled Soil Pollution: A Hidden Reality, at the start of a three-day global symposium at the headquarter of the United Nations agency in Rome.

It added that industrialisation, war, mining and the intensification of agriculture have all left a legacy of soil contamination across the planet, while the growth of cities has seen soil used as a sink for ever greater amounts of municipal waste.

”Soil pollution affects the food we eat, the water we drink, the air we breathe, and the health of our ecosystems,” said Maria Helen Semedo, deputy director general, FAO, at the start of the symposium.

“The potential of soils to cope with pollution is limited; the prevention of soil pollution should be a top priority worldwide,” she added.

”But even though agricultural intensification, industrial output, and urbanisation continue at a rapid pace, no systematic assessment of the status of soil pollution at the global level has ever been undertaken,” FAO’s new report noted.

”Studies conducted so far have largely been limited to developed economies, so there are massive information gaps regarding the full nature and extent of the problem,” according to FAO’s survey of the existing scientific literature.

The report said, “What little we do know is cause for concern.”

For example, in Australia, some 80,000 sites are now estimated to suffer from soil contamination. China has categorised 16 per cent of all its soils — and 19 per cent of its agricultural soils — as polluted.

There are approximately three million potentially polluted sites in the European Economic Area and the West Balkans.

In the United States, 1,300 sites appear on that country’s Superfund National Priorities list of pollution hot spots.

”Numbers like these help us understand the types of dangers pollution poses to soils, but do not reflect the complete extent of soil pollution around the world, and highlight the inadequacy of available information and the differences in registering polluted sites across geographic regions,” said Hidden Reality.

During the symposium, experts and policymakers will discuss the threat of soil pollution and begin mapping out a more cohesive international response.

Danger to food and health
Soil pollution often cannot be visually perceived or directly assessed, making it a hidden danger — with serious consequences.

It impacts food security both by impairing plant metabolism, and thus, reducing crop yields, as well as by making crops unsafe for consumption. Pollutants also directly harm organisms that live in soil and make it more fertile.

And, of course, soil contaminated with dangerous elements (for example, arsenic, lead and cadmium), organic chemicals like polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) and pharmaceuticals such as antibiotics and endocrine disruptors pose serious risks to human health.

What causes soil pollution?
By far, most soil pollution is due to human activities.

Industrial activities including mining, smelting and manufacturing; domestic, livestock and municipal wastes; pesticides, herbicides, fertilisers used in agriculture, petroleum-derived products that are released into or break down in the environment and fumes generated by transportation — all contribute to the problem.

So-called emerging pollutants are also a growing concern. These include pharmaceuticals, endocrine disruptors, hormones and biological pollutants; e-waste from old electronics, and the plastics that are nowadays used in almost every human endeavour.

”Almost no science on the fate of plastics in soils exists,” observed Hidden Reality, adding that most e-waste continued to be disposed of in landfills rather than recycled.

The event at FAO represented the first step in identifying and plugging global information gaps and advancing a more cohesive international response to the threats posed by soil pollution.

That includes establishing an agenda for action to promote implementation of the Voluntary Guidelines for Sustainable Management developed by FAO and partners in 2016, as well as recent international commitments to better manage soil pollution.