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, warns a new FAO report released at the start of a global symposium.
Industrialization, 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, says Soil Pollution: A Hidden Reality.
For example, in Australia, some 80,000 sites are now estimated to suffer from soil contamination. China has categorized 16 percent of all its soils — and 19 percent of its agricultural soils — as polluted. There are approximately 3 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.
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 PCBs (polychlorinated biphenyls) and PAHs (polycyclic aromatic hydrocarbons) or pharmaceuticals such as antibiotics or endocrine disruptors pose serious risks to human health.
By far, most soil pollution is due to human activities.

Industrial activities including mining, smelting and manufacturing; domestic, livestock and municipal wastes; pesticides, herbicides, fertilizers used in agriculture; petroleum-derived products that are released into or break-down in the environment; 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, observes Hidden Reality, while most e-waste continues to be disposed of in landfills rather than recycled.)