GUANGZHOU - A maroon oil belt was discovered near where a ship carrying chemicals sank in waters off Guangdong province Tuesday, according to local maritime officials Thursday.

The Republic of Korea registered Kenosathena was loaded with 7,000 tons of concentrated sulfuric acid when it sank after water entered its ballast tank in waters 4.1 nautical miles (7.6 km) offshore near Shanwei city at 4:30 pm Tuesday, according to a statement released by the State Oceanic Administration, South China Sea branch.

Four observation stations were set up in nearby waters to test the water's pH. The test results of the three stations were a little below 8.0, lower than the pH of 8.15 tested in November, 2010. But it was not clear whether the inconsistency was caused by the ship's sulfuric acid leak, it said.

The ships had 140 tons of fuel in its tank when it sank. So far, no leakage had been detected, it said.

Based on the ocean currents, if there was any leakage, the pollutants were likely to form an oval zone and move westward, it said.