Heavy metals in agricultural land

Development

The desired quality standards for cadmium and zinc are exceeded in the south-east of the Netherlands as a result of industrial activities in the past in that region. The desired quality standards for cadmium, zinc, mercury, nickel, copper and lead are exceeded in the western peatland area (mainly due to the presence of urban compost from the past with high heavy metal levels).

Policy

The policy objective for the long term for heavy metals in agricultural land is conformity with the desired quality standard for all substances. The atmospheric deposition of heavy metals has declined in recent decades as a result of, among other things, the clean-up of the zinc industry in the south of the Netherlands and the introduction of unleaded petrol. Levels of heavy metals have also fallen in cattle feed and chemical fertiliser.

Relevance

High levels of heavy metals in the soil of rural areas have a negative effect on soil ecosystems. High (and rising) levels in agricultural land may also constitute a threat to the quality of agricultural crops (De Vries et al., 2001).

Technical note

The data used here come from approximately 3,200 sites in the Netherlands and were gathered during various monitoring programmes between 1960 and 1995 (Van Drecht et al., 1996). Since changes in the soil are slow to occur, measurements from such a long period as a basis for a description of the current situation.

References

Vries, W. de, P.F.A.M. Römkens, et al. (2001). Risico's van bodemverontreiniging in het landelijk gebied. Alterra report 244. Wageningen.

Groot, M.S.M., J.J.B. Bronswijk, et al. (1998). Landelijk Meetnet Bodemkwaliteit; Resultaten 1995. RIVM (rapportnr. 714 801 024), Bilthoven.

National Soil Quality Monitoring Network;

Drecht, G. van, L.J.M. Boumans et al. (1996). Landelijke beelden van de diffuse metaalbelasting van de bodem en de metaalgehalten in de bovengrond, alsmede de relatie tussen gehalten en belasting. RIVM (rapportnr. 714 801 006), Bilthoven.