Soil pollution implies the presence of chemicals and materials in soil that have a significant adverse effect on any organisms or soil functions. Soil pollutants include inorganic and organic compounds, some organic wastes and the so-called “chemicals of emerging concern” in amendments added to soils.

Soil pollution has a direct impact on food security and there is a direct link between the quality and safety of the food we eat and the level of soil pollutants. Because some pollutants are taken up by plants through different pathways, they accumulate in the food chain, compromising the safety of the food consumed by both humans and animals. Additionally, soil pollution affects food availability by reducing crop yields due to toxic levels of pollutants that hamper crop growth and reduce soil biodiversity, thus increasing the problem of food security.

In addition, soil contamination may facilitate and accelerate other degradation processes. It leads to losses of biodiversity and, therefore, to the loss of soil carbon and to a lower aggregates stability, which increase soil erodibility and accelerates soil erosion. Soil pollution affects not only food production, but also the quality of groundwater and endangers the ecosystem services provided by the soil. 

The Global Symposium on Soil Pollution, to be held from 2 to 4 May 2018 at FAO headquarters is the first step in implementing the Voluntary Guidelines for Sustainable Soil Management in terms of preventing and reducing harmful substances in soil as a way to maintain healthy soils and food safety in accordance with the Sustainable Development Goals.

Specifically, the symposium outcomes should provide scientific evidence to support actions and decisions to prevent and reduce soil pollution for increased food security and nutrition, and ecosystem services, and promote the remediation of polluted sites.

The specific objectives of the symposium are to: 

1. Examine the current scientific and technical understanding of soil pollution and its effects on food production and safety;
2. Critically reflect on the impact of land use decisions at the national level (e.g. related to mining, and intensive agriculture and livestock production) on soil pollution and eventually, air and water where polluted soil or its pollutants can be transported by erosion processes or water runoff;
3. Identify limitations and prioritize key challenges related to restoring polluted sites;
4. Review existing international policies, agreements and frameworks addressing sources of pollution to agricultural land in order to assess their effectiveness and propose ways to improve them; and
5. Survey and review the use of soil thresholds for pollutants globally and explore additional research and policy needs.