It has been two weeks since used engine oil was dumped into an upstream spring that flows into the river where Song Da Water Investment JSC, a subsidiary of Vinaconex Water Supply JSC (Viwasupco), pumps crude water for processing.
The water contamination has disrupted the lives of more than 250,000 households in eight suburban and urban districts of the capital city.
Chief of the Office of the Hanoi’s People Committee Vu Dang Dinh was quoted by the local press as saying that all 69 water samples, collected between October 16 and 21, had met the Ministry of Health’s safety criteria for levels of styrene, a carcinogenic substance.
Dinh said that the Hanoi government has asked the municipal Department of Health and the Hanoi Center for Disease Control to take water samples from the eight affected districts affected by styrene-contaminated tap water.
“Clean water from the Da River is now safe for residents to use for their daily activities,” he said, adding that the center is still collecting water sample for further testing.
While it will continue testing the water quality among its household clients until the end of this month, Hanoi Water Co., Ltd, is also continuing to work with Viwasupco to provide clean water to the affected residents free of charge, he said.
The official added that the city government has ordered Song Da Water Investment JSC to install more automatic monitoring systems so that the water treatment plant can regularly check the quality of crude and output water to quickly take corrective measures if similar incidents occur in the future.
Last Saturday, police officers from Hoa Binh Province detained two men for allegedly dumping waste engine oil into the spring. The mastermind turned himself in to the police of Bac Ninh Province the following day.
Nguyen Chuong Dai, 25, and Hoang Van Tham, 33, confessed to the police that Ly Dinh Vu, 37, had hired them to drive a truck from Bac Ninh Province to Thanh Ha Constrexim JSC, a brick and ceramic maker, in Phu Tho Province, both in northern Vietnam, to collect and load the factory’s waste oil onto the vehicle.
Some 10 cubic meters of used oil from the company was fed into 10 empty tanks on the truck, which they drove to Hung Yen Province and parked there overnight.
On October 8, Dai and Tham drove the truck and a car to Ky Son District of Hoa Binh Province, some 60 kilometers west of Hanoi, to dump the oil and then left the scene.
Due to a downpour later that night, the oil was quickly washed into Dam Bai Lake, tapped by the water treatment plant of Viwasupco.
The contamination caused tap water in a large section of Hanoi to reek of an unpleasant, pungent odor – later identified as that of styrene – which was found to be 1.3-3.6 times higher than the permissible level.