This report aims to give a general view of the present state of contamination of agricultural soils and manures like sewage sludge, liquid manure and compost in Switzerland with two groups of organic micropollutants: polynuclear aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB). Overall PAH concentrations for soils ranged between 60-575 mu g Sigma PAH/kg dw (mean value 175 mu g/kg dw). The corresponding values for the other matrices were: cattle slurries 87-309 mu g/kg (165 mu g/kg), pig slurries 66-339 mu g/kg (143 mu g/kg), sewage sludge 1.7-15 mg/kg (6.3 mg/kg) and compost 0.8-2.7 mg/kg (2 mg/kg). PCB levels for soils averaged 14 mu g Sigma PCB/kg dw and represented typical background concentrations. PCB values in cattle slurries were slightly higher (20 mu g/kg) and significantly higher in pig slurries and compost (37 and 32 mu g/kg). The highest PCB concentrations were found in sewage sludges (0.4 mg/kg). Application of these sludges onto soils at rates normally used in Switzerland (0.5 tons dw/ha.y) does however not represent a serious contamination problem. A qualitative analysis of the environmental samples showed that besides the 16 EPA PAHs frequently used for quantification mainly alkylated derivatives as well as N-S-and-O-PAHs were detected. These compounds, although usually found in low quantities, should be considered more seriously when estimating the toxicity of PAHs in the environment.
