What is soil conservation? What are contaminated sites?
Soil is an indispensable foundation of life for humans, animals and plants. It provides foodstuffs and raw materials, stores and filters water and decomposes contaminants. It offers areas for settlement, transport and leisure activities and is an archive of natural and cultural history. However, soil cannot fulfil all these functions at the same time. In addition, some of these functions are hampered by pollution, erosion, decreasing humus layers and compaction. Damage cannot be remedied in the short term as fertile soils are the result of slow physical, chemical and biological processes: it takes 200 to 300 years for one centimetre of soil to build up.
It is cause for concern that the use of soil for settlements and transport makes it increasingly lost for other functions. Every second, an area of around 11 square meters is turned over to settlements or transport in Germany. Almost half of this area is sealed. Natural soil functions such as permeability, the ability to store water, fertility and provision of habitats for organisms are lost through surface sealing.
Old industrial and commercial installations where substances hazardous to the environment were handled and sites where waste was treated or disposed of can pose a threat to soil.
If soil is contaminated in such a way that it becomes hazardous to human health or the environment, these sites are referred to as contaminated sites. Apart from the sites contaminated by industrial development, there are also sites contaminated by military use and the production of military goods.
- The German government aims to conserve the limited resource of soil in such a way as to ensure that the diverse functions of soil will be fully available to future generations as well.
- Soil organisms play an important role in conserving natural soil functions. The national strategy on biological diversity takes this into account by providing a range of measures.
- In order to protect humans and the environment from hazards, contaminated sites and areas suspected of posing risks must be registered, examined, evaluated and rehabilitated if necessary. Precautionary measures are taken as well.
- By 2030 the development of areas for settlement and transport is to be reduced from around 58 ha/day in 2017 to 30 ha/day.
- Soil can store large amounts of carbon dioxide. It plays an important role with regard to climate.
- Adverse effects on soil such as water and wind erosion must be reduced and the organic substance of soils must be conserved with a view to the potential impacts of climate change.
The German government's policy
The Federal Environment Ministry advocates the improvement of the scientific and legal bases that are needed to ensure or restore soil functions for the long term.
Important instruments: Federal Soil Act and Federal Soil Protection and Contaminated Sites Ordinance
Since the late 90s the Federal Soil Act (BBodSchG) and Federal Soil Protection and Contaminated Sites Ordinance (BBodSchV) have provided a nationwide legal basis for soil conservation and the evaluation and rehabilitation of contaminated sites. Through these provisions the precautionary approach has been anchored more firmly. This ensures legal certainty and investment security for owners and investors.
National Sustainability Strategy
The German government aims to ensure the effective protection of human health and consumers with this precautionary soil protection policy. In line with the national strategy it therefore promotes minimising the undesired input of substances into soils.
Soil conservation through international cooperation
Erosion, substance loads, loss of humus and nutrients, salinisation and acidification pose grave problems for humans and the environment in many countries. The German government has committed to many international conventions in order to counteract soil damage, and it shares German experience in the framework of bilateral projects.
Soil conservation starts at home. Allowing a few weeds to grow instead of aiming for a perfectly trimmed lawn helps to secure soil as a habitat for many small organisms. Avoiding pesticides as far as possible and designing areas for rain water to seep away helps to maintain important functions of soil. And on the road? Switching off the engine at railway gates or traffic lights avoids nitrogen emissions that are a cause for acid rain which pollutes the soil. It also goes without saying that no waste should be dumped in natural landscapes. Harmful substances could seep into the soil and damage it for us and future generations.