The pipeline was ruptured on February 3 about 20 km (12 miles) from the Daghestani village of Belidzhi, causing about 100 metric tons (733 barrels) of crude to spill from the pipe, with 5 metric tons (37 barrels) seeping into the Rubas River which flows into the Caspian.
"Test results have shown that the content of crude oil in the seawater exceeds the maximum permissible level by 320 times," said Albina Magomedova, the head of Daghestan's hydrometeorology laboratory.
The spill covers an area of around 1,000 square meters around the site of the rupture, extends 4 km (2.5 miles) along the Rubas River.
Floating barriers have been placed in the river to stop the surface oil layer from reaching the sea, but the measures have been largely unsuccessful.
