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 report by the Food and Agriculture Organization (FAO) entitled Soil pollution: a hidden reality. The report concludes with some case studies of the best available techniques for assessing and remediating contaminated soils.
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, state the authors of the report.
But even though agricultural intensification, industrial output and urbanisation continue at a rapid pace, no systematic assessment of the status of soil pollution at global level has ever been undertaken, FAO's report notes.
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 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.
According to the report, 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. They also highlight the inadequacy of available information and the differences in registering polluted sites across geographic regions.
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.
Most of the 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 as well as 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. In addition to the above-mentioned pharmaceuticals, they include hormones and biological pollutants, "e-waste" from old electronics and the plastics that are nowadays used in almost every human endeavour.
Publication: Rodríguez-Eugenio, N., McLaughlin, M. and Pennock, D. 2018. Soil Pollution: a hidden reality. Rome, FAO. 142 pp.