Abstract:
The pollution of Pazincica river occurred in August 1997 as a consequence of uncontrolled leakage of vast quantities of oil from a ruptured pipe that connects the oil reservoir and the oil combustion facility of the factory KTI "Pazinka". The oil together with waste waters from the factory first discharged into the watercourse Saltarija and then flowed into the downstream part of Pazincica River. The spilled combustion oil was a threat to the groundwater of the wider region of Istria so extensive and intensive measures were undertaken for its removal. Within these prevention measures two speleological investigations of the Pazincica ponor (Pazinska jama- Foiba di Pisino) were undertaken. It was determined that due to favourable hydrological conditions (the discharge of Pazincica river was 50 l/s) and the fast reaction time of the intervention, only small quantities of oil managed to enter the ponor. On the other hand approximately 168 m3 of combustion oil was detached from the surface watercourse. Unfortunately the speleological examination of the ponor determined a high degree of underground pollution caused by discharge of waste waters from the city of Pazin and its industries into the Pazincica River. Also traces of past unregistered combustion oil pollution were found within the cavern.