Officials from the Phuket Marine Biological Centre (PMBC) rushed to collect water samples from three locations at Patong Beach on March 25 after receiving complaints that the water had turned brown and that bathers were complaining of itching and breaking out into skin rashes. (See story here.)
Samples were collected from the Pakbang Canal outflow at the southern end of the beach, near the Police Box at the end of Bangla Rd and at Loma Park.
“The dissolved oxygen (DO) and pH levels are totally safe,” PMBC Chief Somkiat Khokiattiwong told The Phuket News on Wednesday (Mar 30).
“The change in the colour of the water was due to a bloom in Chaetoceros plankton. This type of plankton often blooms near shore when the temperature, the air and the sun are right. When it flourishes, the area will benefit, especially small marine animals,” he said.
“As for skin rashes, this kind of plankton might be itchy, but it’s not poisonous. This happens every year,” he added.
Mr Somkiat gave the water test results as follows:
- Pak Bang Canal: Salinity 30, Temp 30ºC, pH 7.55, DO 5.98
- Ruamjai Rd: Salinity 29, Temp 32ºC, pH 7.59, DO 4.17
- Police box (Bangla Rd): Salinity 30, Temp 32ºC, pH 7.80, DO 7.42
- Chalermprakiat Rd: Salinity 30, Temp 30ºC, pH 7.67, DO 5.70
Asked whether the plankton bloom could have been triggered by wastewater released into Patong Bay , Pornsri Suthanarak, the director of the Phuket Regional Environmental Office 15, said, “I do not think wastewater will be released without passing through the Patong Municipality treatment system first.”
Asked again, she said, “I have no comment about it.”
However, Ms Pornsri offered, “Such algae blooms are most often caused by a combination of large amounts of nutrients in the water along with suitable temperatures for a spike in plankton growth.
“We were informed of the incident at Patong Beach and we agree with the PMBC’s findings. Our office conducts water tests only twice a year, but we will step in when we receive special requests.”
Asked of her concerns about wastewater in tourism beach areas such as Patong, Ms Pornsri said, “I am concerned about tourist areas, because of trash, wastewater and other environmental hazards.
“We really want people to realize the environment in Phuket is the tourism attraction.”
The Patong plankton bloom follows a sea slug mass death scare at Kamala Beach earlier this month, when black water streaming from a canal across the beach infiltrated the beach water.
However, that incident, also investigated by the PMBC, was also described as a “natural phenomenon”. (See story here.)


