Abstract Watershed activities in the Dumai River and land conversion in the Estuary of the Masjid River will affect the quality of Dumai coastal waters, one of which is an increase in suspended solids. TSS is solids in water, consisting of biotic components such as phytoplankton, zooplankton, bacteria, fungi, or abiotic components such as detritus, sand, silt, clay and inorganic particles with …