Patong Municipality Says Black Seawater Was Caused by Non-Toxic Plankton Bloom
Patong officials said black seawater seen at Patong Beach was caused by a non-toxic plankton bloom, while warning against swimming during the discoloration period because of possible skin irritation.
Patong Municipality has clarified that black seawater seen along parts of Patong Beach was caused by a plankton bloom, not direct wastewater discharge.
According to the Marine and Coastal Resources Research Center, laboratory tests found two species of non-toxic phytoplankton in the discolored water: Chaetoceros sp. and Peridinium sp. Authorities said the bloom is a natural phenomenon.
Although the plankton identified is not poisonous, experts advised people not to swim during the discoloration period because contact with the water may cause skin irritation. The center said the condition usually clears naturally within three to seven days as waves and currents disperse the plankton.
Patong Municipality said it will carry out random inspections of local businesses to prevent illegal wastewater discharge and to make sure treatment systems are working effectively. Officials said the measures are intended to reduce factors that could worsen plankton blooms.
The municipality also said it will coordinate with relevant agencies to continue monitoring the situation.
