The distribution of Cd, Cu, Pb and Zn in topsoils of Osnabrück in relation to land use

Abstract The subject of this paper is heavy-metal concentrations in topsoils in Osnabruck and its environs. Two-hundred and twenty-six soil samples were taken from a depth of 2–10 cm over an area 16 × 16 km 2 . The pH of the samples was determined and the Cu, Zn, Cd and Pb concentrations measured. The largest accumulations compared with the limits specified by VDLUFA 1 (Kloke, 1980) were found for Pb. Throughout the area investigated, 18% of the samples contained > 100 mg/kg Pb. With a few exceptions the cadmium concentrations may be described as normal, but the accumulations of this highly mobile heavy metal at certain locations must be regarded as critical. A noticeable feature in the countryside around Osnabruck was the increased concentration of heavy metals in the sedimentation area of the river Hase (up to 200 mg/kg Cu in the soil) and the river Dute (up to 530 mg/kg Pb and 1530 mg/kg Zn in the soil) as well as in the vicinity of metal-working factories. Elevated heavy-metal levels of geogenic origin were detected on the hill crests of the Teutoburger Wald. In the twon itself the highest concentrations were found for Pb and Cu: 21% of the samples contained > 100 mg/kg Pb and 15% contained > 100 mg/kg Cu. The extremely high values around a metal-working factory in Widukindland (north-east of Osnabruck) were a striking feature. When recorded in the form of a soil pollution map the results of such a survey make it possible to identify unusually polluted areas; they can also be analyzed further to provide more detailed information. In view of some considerable heavy-metal concentrations in the soil of Osnabruck it would be advisable to investigate these locations more closely for their effects on plant nutrition and the food chain and to prevent a direct hazard to children playing there.