Soil Pollution

Primary reference(s)

Rodríguez-Eugenio, N., M. McLaughlin and D. Pennock, 2018. Soil Pollution: A Hidden Reality. Food and Agriculture Organization of the United Nations. www.fao.org/3/i9183en/i9183en.pdf

Additional scientific description

Human activities over thousands of years have left a legacy of polluted soils worldwide. Much of it is local soil contamination which occurs commonly in connection to past and present mineral extraction, industrial activities, waste management and disposal, and includes remnants of hazardous materials such as obsolete pesticides. Countless chemical agents, some of them highly persistent, are found at various levels in the ground and can enter groundwater and surface water, locally produced food, and can even become airborne (gases, vapours, dusts, particulates). Soil pollution and its adverse health effects have been documented in many cases, but the magnitude of the overall impact on human health is not known. This is in contrast to air or water pollution, for which reliable estimates of their impacts have been available for two decades (FAO, 2018).

Soil pollution has been identified as one of the main soil threats affecting global soils and the ecosystem services that they provide (FAO and ITPS, 2015). Soil pollution poses a serious risk to human health through direct contact (dermal exposure, inhalation of polluted soil particles, intentional ingestion of polluted soil) or indirectly, by consuming plants or animals that have accumulated significant amounts of soil contaminants (FAO, 2018). For example, in an area of Japan where soil has been contaminated with cadmium from zinc/lead mines, Itai-itai disease used to be widespread and is still seen in women over 50 years of age. Itai-itai disease is characterised by osteomalacia, osteoporosis, painful bone fractures and kidney dysfunction (WHO, 2019). Health risks associated with the widespread soil pollution by radionuclides released during the Chernobyl disaster in 1986 are an enduring memory for many people (Rodríguez-Eugenio et al., 2018).

Despite efforts in many regions of the world to estimate the extent of soil pollution, the lack of harmonised and comprehensive data at national, regional and global level limits the mobilisation of economic resources to minimise soil pollution and to achieve public and private commitment to combating soil pollution. There is a need to translate sound scientific evidence into concrete actions to prevent, control and remediate soil pollution (FAO, 2018).

Remediation of polluted soils is essential, and research continues to develop novel, science-based remediation methods. Increasingly, expensive physical remediation methods such as chemical inactivation or sequestration in landfills are being replaced by science-based biological methods such as enhanced microbial degradation or phytoremediation (Rodríguez-Eugenio et al., 2018). The maintenance of soil health and the prevention and reduction of soil pollution are possible through promoting sustainable soil management practices, environmentally friendly industrial processes, reduction of waste generation, recycling and reuse of goods, and sustainable waste storage (FAO, 2018).

The risks to human health posed by contaminated soils is assessed by comparing a representative soil concentration with chemical specific assessment criteria indicative of ‘safe’ levels of exposure. There is no international standard for deriving these criteria. For example, Jennings (2013) compared the range of American standards with standards used elsewhere around the world. A total of 5949 guidance values for 57 elements were identified across the US regulatory authorities and assessment criteria values were seen to have been published in at least 71 other United Nations member states.

Metrics and numeric limits

No globally agreed metrics have been identified.

Examples of drivers, outcomes and risk management

Soil plays a key role in food production and food quality, in climate regulation and in the provision of raw materials and other resources. Notwithstanding the enormous scientific progress made to date, protection and monitoring of soil condition at national and global levels still face complicated challenges impeding effective on-the-ground policy design and decision making (FAO, 2018).

Key drivers for the assessment of contaminated land in the UK, primarily in the context of urban development, include remediation of contamination identified as impacting on groundwater quality or ecology and remediating brownfield sites for a change of land use and in particular development for housing. To this local management, using soil guidance values and land quality management is essential (European Commission, no date). As examples of local risk assessment and management the sites of the 2000 Olympic Games in Sydney and the 2012 Olympic Games in London (Mead et al., 2013) were successfully remediated contaminated land sites. However, further remediation could be required for any future land-use change involving more sensitive end-use, such as redevelopment for domestic gardens.

A number of assessment models and tools are available via CLARINET, the Concerted Action of the European Commission’s Environment and Climate Research and Development Programme, which provides access to technical recommendations based on the concept of Risk Based Land Management for decision-making (EUGRIS, 2008). Also, in the European context, NICOLE is a European forum for the dissemination and exchange of good practice, practical and scientific knowledge and ideas to manage contaminated land in a sustainable and collaborative way.

The outcome document of the Global Symposium on Soil Pollution ‘Be the Solution to Soil Pollution’ (FAO, 2018) recommends an active and effective implementation of the Voluntary Guidelines for Sustainable Soil Management, which were developed through an inclusive process and endorsed by the 155th session of the FAO Council (Rome, 5 December 2016) (FAO, 2017). Their implementation is important in order to progress with the accomplishment of several of the sustainable soil management objectives, such as: to ensure that the availability and flows of nutrients are appropriate to maintain or improve soil fertility and productivity, and to reduce their losses to the environment; to reduce soil salinisation, sodification and alkalinisation; to ensure that water is efficiently infiltrated and stored to meet the requirements of plants and ensure the drainage of any excess; to ensure that contaminants are below toxic levels, i.e., those which would cause harm to plants, animals, humans and the environment; to guarantee that soil biodiversity provides a full range of biological functions; and to undertake soil management (FAO, 2018).