Use of dredged sediments on agricultural soils from viewpoint of potentially toxic substances

A set of 29 pond sediments samples was collected. The sediments were separated into three groups, field, village, and forest pond sediments. The sediment samples were taken from pond bottoms and sediment heaps. The sedi ment characteristics (pH, CEC, Al-exchangeable, C ox , humus substances), the content of potentially toxic elements and persistent organic pollutants were analysed in the sediments and compared between sediment groups. The comparison of sediment contamination with Czech legislation for sediment use in agriculture was conducted. The village sediments were more loaded by potentially toxic elements and persistent organic pollutants than the others. The pH value of sediments was considered as the properties regulating the retention of potentially toxic elements and their mobility (Al, Cd, Zn). Polycyclic aromatic hydrocarbons (PAHs) were the most problematic POPs group in the sediments. The correlation showed poor dependency of POPs (especially PAHs) content on the content and quality of sediment organic matter.