the fate of polychlorinated biphenyls inkarstic soil

during the croatian homeland war in 1991, the capacitor batteries of the zadar electric powersubstation (ts 110/35 kv) were damaged, resulting in the severe pollution of the soil with polychlorinatedbiphenyls (pcbs). due to porosity of karstic soil pcbs represent great environmental and human health risksthat need some action. the polluted soil was collected and an experimental field was formed. this paperreports the behaviour of pcbs in karstic soil over an extended period of time under field conditions. verticalmovement of pcbs through the soil profiles was also observed. the soil was sampled four times. the initialmedian levels of aroclor 1248 in the surface soil layer were 76.5 μg g-1. the levels of pcb in the soil layerscollected after initial stage were quite variable. in general, pcb patterns were dominated by low-chlorinatedhomologue groups (6) were relatively stable. the results show that the total pcbconcentration in the soil around the roots significantly dropped by 36% while in the deeper soil layerdecreased for 18%.