ABSTRACT
Water
quality testing was compulsory for management of safe and reliable water
sources. Various sources of pollution and destruction of mangrove forest
decrease the quality of river water. Thus a study was conducted to determine
the water quality status of mangrove forest river water of Awat-Awat Lawas
Sarawak and compare the water quality status of disturbed and undisturbed
mangrove forest river in that area. Samples from twelve sampling stations were
collected from both mangrove forest river from October 2013 to March 2014. In-situ data collected (pH, temperature,
dissolved oxygen (DO), salinity, turbidity, total dissolved solid (TDS),
conductivity) and laboratory analysis (biochemical oxygen demand (BOD),
chemical oxygen demand (COD), ammoniacal nitrogen (AN), total suspended solid
(TSS)) were conducted according to the Standard method of Examination of Water
and Wastewater AHPA 2005. Six water parameters: pH, DO, BOD, COD, AN and TSS
value were used in calculating the Water Quality Index (WQI). Mean values for
disturbed area were follows, pH (7.07), temperature (29.93°C), salinity (15.64
PSU), turbidity (55.13 NTU), DO (4.59 mg/L), BOD (0.73 mg/L), COD (10.16 mg/L),
AN (0.14 mg/L), TSS (53.92 mg/L), TDS (23.14 mg/L) and conductivity (2.61
ms/m). Undisturbed area results were, pH (6.84), temperature (28.32°C),
salinity (14.65 PSU), turbidity (35.41 NTU), DO (2.39 mg/L), BOD (0.55 mg/L),
COD (15.82 mg/L), AN (0.13 mg/L), TSS (53.23 mg/L), TDS (22.82 mg/L) and
conductivity (2.34 ms/m). There were no significant differences between two
locations except for DO. Both water qualities of disturbed and undisturbed
mangrove forest river were found under Class III, which describe that the water
bodies are in moderate quality status.