IN a bid to stop illegal dumping of pollutants into the nation's water systems, South Korea's environment ministry will conduct a three-day nationwide investigation of suspected polluters in four major rivers. Ministry officials said the investigation will focus on some 600 industrial units, restaurants, hotels and dairy farms which allegedly dump wastewater directly into the Han, Naktong, Kum and Yongsan rivers. These rivers meet much of the nation's water demand.

More than 120 ministry officials will visit the establishments to check for excessive levels of pollutants in their affluents.

According to the officials secret dumping of contaminants will also be monitored closely through regular inspections of on-the-spot wastewater treatment systems. Those who violate government regulations on wastewater disposal will be punished sternly, said the officials.

Users of sub-standard wastewater treatment equipment will be asked to shut down their establishments or step up their treatment facilities, the ministry said. Steps have to be taken immediately as the country faces an acute water shortage in the dry winter months. Besides, discharge of pollutants may lead to serious health hazards, the ministry said.