A large oil slick was discovered on the surface of the Danube River in Ukraine\'s southern Odessa region, authorities reported Tuesday. A pool of about 400 square meters has appeared, after fuel oil was spilled into the river from a \"Timekstron-2\" freighter near the port city of Reni on Monday, the State Service for Emergencies reported. Emergency crew are containing the pollution and they will try to determine how much oil leaked, it said. According to preliminary reports, there is no threat of polluting the water supply as the oil did not spread along the riverbed.