Workers on a maritime surveillance ship collect sample of the polluted sea water at the oil spills affected sea area in North China's Bohai Bay, on July 15, 2011. The oil spills near Platform C at Penglai 19-3 oil field were first detected on June 4. [Photo/Xinhua]

A worker on a maritime surveillance ship collects sample of the polluted sea water at the oil spills affected sea area in North China's Bohai Bay, on July 15, 2011. [Photo/Xinhua]