Heavy metals accumulation in urban soils of Belarus： Testing, mapping and ecological risk assessment

Soil pollution is among priority environmental problems in Belarus, especially in cities. Main compound of the health risk are connected with soil pollution-consumption of plants production cultivated at polluted soils. Now in Belarus cultivation of vegetables and potatoes is rather typical at allotment gardens, in rural parts of cities and towns and in suburban regions. Mapping of soil pollution and study of pollutant accumulation in plant production in connections with soil contamination and health risk assessment were conducted in a few large cities of Belarus （Minsk, Gomel, Svetlogorsk, etc）. Investigation includes sampling of soils and vegetation according to a certain plan, sample processing, chemical analysis, results assimilation, mapping, and risk assessment. Contents of soluble compounds （nitrates, sulphates etc.）, total and reactive heavy metals （lead, zinc, cadmium, etc.） were determined. Heavy metal contents were determined by AAS. Elevated levels of heavy metals were detected in soils used for growing vegetables and potatoes. Priority pollutants, as for urban soils on the whole, are lead and zinc. Average accumulation coefficient （related to local background values） for investigated areas within the limits 2.1-7.8. Contents of lead exceeding Maximum Permissible Concentrations （MPC） were detected in 16% of the samples collected in kitchen gardens of Gomel, of zinc in 38% of the samples from kitchen gardens of Svetlogorsk. Average content of zinc in cabbage, carrot and red beet in background conditions amounts to 4 mg/kg, in potatoes, 3.6 mg/kg. In samples of agricultural production from Svetlogorsk the contents of zinc vary from 1.7 to 156.6 mg/kg; average content in cabbage, 25.8 mg/kg, in red beet, 18.0, carrot, 11.8, potatoes, 5.6 mg/kg. For ecological risk assessment from polluted agricultural products consumption the concept of reference dose was applied.