PAHs and DDTs in soil and sediment of inland water bodies of Warsaw city and its surroundings

Abstract

Concentrations of polycyclic aromatic hydrocarbons (PAHs) and dichlorodiphenyltrichloroethane (DDT) in soil and sediment of inland water bodies in Warsaw and its surroundings, covering an area of 1200km2, were obtained during the work on the ‘Geochemical atlas of Warsaw and Εnvirons, 1:100,000’. Soil samples from a depth of 0–30cm were collected on a regular grid of 1×1km in Warsaw, and 2×2km outside its administrative boundaries. Sediment samples were collected from rivers, streams, ditches, canals, lakes and ponds. The distance between sampling sites in watercourses was 1,5km (within the borders of Warsaw) and 2km (outside the city). Analyses of PAHs and DDT compounds were made by gas chromatography–mass spectrometry (GC-MS), and gas chromatography with electron capture detection (GC-ECD), respectively.Within the borders of Warsaw the soil is characterised by elevated or high levels of PAHs and DDTs. Outside the city, especially to the east, large areas are differentiated by their low concentrations in soil. The highest PAH concentrations (>20,000mg/kg) were found in soil located near railway lines and in industrial and post-industrial areas. The highest contamination by p,p′-DDT and its metabolites is observed in soil of cultivated fields and gardens. The highest concentration of total DDTs (5400mg/kg) was found in allotment gardens in the eastern part of Warsaw. At some places, high predominance of p,p′-DDT concentration over the concentrations of its metabolites was observed, which indicates recent introduction of these compounds into soil. The PAH and DDT concentrations in sediment samples were lower than in soil. High PAH levels were observed mainly in the sediment of ponds and canals, and high DDTs concentrations were found in the sediment of ditches and canals.