A section of Shing Mun River several hundred meters long near Fo Tan was dyed blue Monday, prompting fears that the river might have been contaminated by industrial waste.
Thousands of dead fish had been spotted in the Tai Wai section of the river over the last few days, Apple Daily reported Tuesday.
Local residents suspected industrial waste water might have been discharged into the river illegally by companies in the nearby Fo Tan industrial area.
A secondary school student surnamed Chan said she has seen the river turn purple and blue in the past and there was always an unpleasant smell.
The Drainage Services Department (DSD) and the Environmental Protection Department (EPD) said they are monitoring the situation.
The DSD said it has been investigating the cause of the blue colour, while the EPD said water samples have been obtained for examination.
Sha Tin district councilor Scarlett Pong Oi-lan said that while the number of dead fish found in the river since the beginning of the month has stabilized, she spotted new ones Monday.
Pong expressed concern that the worsening of sediment pollution in the river bed might have caused the massive number of fish deaths.
A rowing trainer, who often trains on the river, said he is worried that the water quality is fast deteriorating and could affect the health of rowers who train there.
Dr. Cheng Luk-ki, division head of scientific research and conservation for Green Power, said the blue color could possibly be caused by industrial dyes, which could be toxic to humans.
Cheng urged government departments to work together to improve water quality during the dry seasons.
He said sewage should not be directly discharged into storm drains but should instead be taken to a sewage treatment facility.
Meanwhile, a resident who often fishes at the river says the pollution and the surfacing of thousands of dead fish have not affected him.
The man, surnamed Law, said he has been eating fish he catches in the river for many years and has never worried about the hygiene.
– Contact us at [email protected]