ECN publication
Leaching of inorganic contaminants towards groundwater - Impact assessment of the Dutch Soil Quality Decree on Groundwater
Spijker, J.; Groenenberg, B.J.; Comans, R.N.J. |; Dijkstra, J.J.
Published by: Publication date:
ECN Environment & Energy Engineering 26-8-2015
ECN report number: Document type:
ECN-E--15-044 ECN publication
Number of pages: Full text:
205 Download PDF  

Since the industrial revolution, Dutch soils have gradually been diffusely contaminated by human activities like industry, agriculture and road traffic. Nevertheless, most soils comply with the threshold levels of the Dutch Soil Quality Decree. However, in the long term (several hundreds of years) underneath (diffusely) contaminated soils the increasing concentrations of heavy metals in groundwater may become a risk. These substances can leach from the upper soil and gradually contaminate the groundwater. The National Institute for Public Health and the Environment recommends that for sustainable groundwater management these long-term effects are taken into account. Special attention is needed for the concentrations of cadmium, nickel and zinc. It is unrealistic to undo the impact of human activities on soils. However, it is important for spatial planning to reckon with the effects of soil contamination on groundwater – for example, when diffusely contaminated soils are being reused. For sustainable groundwater management the groundwater function (ecosystemservice) should not deteriorate as a result of these effects – for example, when groundwater is used for drinking water production or when groundwater feeds a sensitive surface water ecosystem. At locations with residential or industrial activities, higher metal soil concentrations are allowed in accordance with use. For the model calculations the worst case scenarios from the Dutch Soil Quality Decree are simulated. In these scenarios soils have the maximum concentrations allowed (the so-called Maximum Values). The National Institute for Public Health and the Environment recommends refining the model scenarios to gain insight into the specific situations in which these increased concentrations in groundwater can occur. It is also recommended that the model be improved so that it can be used to address general questions concerning the relationship between heavy metal impact on soils and groundwater quality – for example, in the case of sustainable spatial planning and the re-use of contaminated soils and waste products.

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