• Bodemkwaliteitskartering van de Nederlandse landbouwgronden

      Lagas P; Groot MSM; Koops R; Willems WJ; Lijzen JPA; Gan JBS; van der Velde EG; Booy H; Alkemade JRM; Heusinkveld HAG; Baltissen AHM; LBG; LOC; Bedrijfslaboratorium voor Grond en Gewasonderzoek (Rijksinstituut voor Volksgezondheid en Milieu RIVMRijksinstituut voor Volksgezondheid en Milieu (RIVM)Bilthoven; Bedrijfslaboratorium voor Grond- en Gewasonderzoek (BLGG)Oosterbeek, 1996-02-29)
      A research project has been carried out to assess the quality of agricultural soil in the Netherlands for a total of 42 different combinations of soil type and soil use selected from 13 agricultural regions in the Netherlands. For each combination four representative mixed samples were made to determine the average content of heavy metals and organic compounds and to establish the variation within the region. Results from analyses show higher heavy metal content in the western parts of the Netherlands for cadmium, copper, lead, zinc, mercury and arsenic as a consequence of relatively high atmospheric deposition in that region. In the agricultural soils heavy metal levels are found to be higher than natural background levels as a result of agricultural loads, for example, manure, fertilisers and pesticides and loads due to atmospheric deposition. In several measurements heavy metal levels are found to exceed the Target Value (TV), which is dependent on soil organic matter and soil lutum content (particles < 2 mum). Target values for heavy metals are based on upper limits from background levels. Target values are exceeded by cadmium, copper, zinc, lead and mercury. Results of analyses of organic compounds show the PAHs, which in all samples occur in the greatest proportion, to be fluoranthene, chrysene, benzo(a)anthracene and benzo(ghi)perylene. In all samples from arable land the content of PAHs is above TV. In grassland some samples contain PAHs below TVs. The content of the insecticide lindane exceeds the TV for all samples. In the south sandy region lindane with a content of 1.83 ug kg-1 soil was found in a sample from arable land on sand ; this is 147 x TV. The results of calciumchloride extractions in the analysed samples show cadmium to be the most available (mobile) metal in soil. In sandy soils about 10% of the total content was extracted. Zinc is 3-9% available in sandy soils. The availibility of copper is about 0.5%, nickel 1%, and arsenic 0.3% of the total metal content. Lead is almost non-available in soil (max. 0.07%) as well as chromium (max. 0.04%). A comparison between the results of a similar research project like this, which was carried out in 1986, showed no significant changes in lead, copper and zinc content in a period of six years. For cadmium however the average levels for grassland on clay and sand are about 40% lower. Also, a lower average content is measured for arable land. These lower levels cannot be related to a decrease of the input of cadmium to agricultural land, but are mainly a result of differences in sampling procedure.<br>