The 105 meter long tanker-barge Jessica released pollution into the Rhine-Herne Canal.   Authorities were alerted to a 15 kilometer long oil spill in the waterway.   The authorities discovered the Jessica was the vessel releasing the oil and detained the vessel at Oberhausen.   An estimated 100 litres of diesel had leaked through a damage vent.   The canal was closed a short time to allow recovery, but the diesel had disappated too much to be removed from the waterway.  No reports of injuries.  No reports if the vessel or master was fined.