Rice husking factories in the central region have been found dumping waste into a river that has served as the main local water source for generations.
Thanh Nien reporters observed giant blocks of rice husk floating along two kilometers of the O Lau River in Quang Tri Province. The river also runs through Thua Thien-Hue Province.
Local residents said the blocks were only "the top of the iceberg" as more husks had sunk to the bottom of the river.
But currents caused by passing motorboats often kick up the sunken husks, they said.
Nguyen Cong Ky, a 60 year old resident from Quang Tri, said rice husking factories in the area "regard the O Lau River as their garbage dump."
Another resident said the factories operate most between April and October every year.
"Husks soaked in the water stink badly after many days and we can't stand the smell," the resident said on the condition of anonymity.
The river is the main water source of almost 400 Quang Tri families who do not have access to tap water.
"Now the rice husks are adding to various waste in the river and we still have to use it for a bath and as drinking water," the resident said.
Vo Quoc Dung, a commune official in Quang Tri, said that commune authorities have called on several different agencies asking for help but no one has intervened.