Effect of Catastrophic Floods on the Spatial Distribution and Vertical Migration of Pahs in Soil of Flooded Areas

Abstract

A focus on soil quality issues in the EU has resulted in extensive studies aimed to development of a Soil Framework Directive as well as of other new relevant regulations and standards, in parallel with setting up a harmonized European Soil Monitoring System for routine soil monitoring/ screening with use of reference analytical methods. Polycyclic Aromatic Hydrocarbons (PAHs) belong to the most problematic contaminants from the local sources and diffuse inputs to be monitored and controlled. This study presents the screening survey for 16 PAHs carried out in 2000 in the area severely impacted by the catastrophic flood of 1997 in the Odra River valley in Poland, which affected also Czech Republic and Germany. Within this survey, 16 PAH contents in soils due to river sediments deposition resulting from the flood, as well as the effect of flood on the distribution of PAHs in soils of the affected area were assessed (by the GC-MS reference methods) in view of soil quality standards and need for remediation. The postflood PAH spatial distribution with use of the Geographical Infor- mation System (GIS) showed distinct correlation with floodwater flow conditions, while total 16 PAH and specific compounds concentrations in the upper soil layer 0-0.20 m appeared to be mostly within the standard limits. In 17% of composite samples, 16 PAH concentrations were found to be considerably elevated, up to the values >1,000 �� g/kg, and exceeded the standards for agricultural soils in particular samples. PAH compounds displayed also different vertical migration potential in soils. The occurrence of the maximum PAH concentrations in the floodwater stagnation areas