KOTA KINABALU: A year-long water quality study carried out on the country’s largest and most biologically diverse wetlands located in Sabah shows that pollution is killing marine life.
The study conducted on Sg Melangking and Sg Kerapu in the Lower Kinabatangan-Segama Wetlands found water samples with abnormally low dissolved oxygen and high ammonia levels, a combination lethal to aquatic life.
Programme coordinator of Lower Kinabatangan Segama Programme Neville Yapp said the study was conducted after local communities in the Mumiang area raised queries about the recurring death of fish in the rivers.
The community of Mumiang had partnered with the Sabah Forestry Department, water quality experts and other conservation-related organisations to investigate the cause, he added.
Yapp said dissolved oxygen levels had dropped to as low as 1mg/L and ammonia levels to as high as 46.9 mg/L, at both rivers. A total of 18,000 samples were taken.
He said observation and water quality data collected by the communities indicated eutrophication, supporting the argument that both rivers were polluted by agro-chemicals that induced excessive algae bloom.
Such conditions often occurred in rivers polluted by excess artificial mineral, nutrient, phosphate-containing fertilisers, or biowaste discharged by agriculture and other socio-economic activities, he said.
Apart from the two rivers, water quality data was also collected from pristine water bodies at the Tabin Wildlife Reserve to serve as a reference.
Sabah Forestry Department chief conservator of forests Datuk Mashor Mohd Jaini congratulated the communities for their efforts in carrying out the sampling and encouraged other stakeholders to help as well.
“I hope the data and findings of the water quality monitoring project will raise awareness of this issue and improve the quality of the wetlands’ water,” he added.
The water quality unit of Mumiang collected water samples twice monthly from 18 sampling points and tested these for parameters such as dissolved oxygen, pH level, total dissolved solids, electric conductivity, specific seawater gravity, oxidation reduction potential, ammonia, nitrate, salinity and blue-green algae presence.
The Lower Kinabatangan-Segama Wetlands also serves as a source of livelihood to traditional villages and about 20,000 coastal fishermen from Sandakan.