The Ha Tinh Department of Natural Resources and Environment announced the test results on Wednesday of the sea water which was taken from some beaches in Cam Xuyen District.
"The overall water quality is within the approved levels and there were no strange substances found in the water samples," the department said. "Scientific documents state that the phenomenon is caused by the blooming of a kind of algal known as Noctiluca scintillans which is also called red tide. It will disappear after 3-7 days."
The coastal area of about three kilometres in Cam Nhuong Commune and Thien Cam Town in Cam Xuyen District has seen reddish water streaks over the past few days. This rarely occurs in the area and fishermen are quite concerned, being hesitant to fish near the shore.
The same situation was reported in the area a year ago.