Studies on physico-chemical characteristics and sediment environment along the coastal waters in Pulau Tuba, Langkawi, Malaysia

Field observations on physico-chemical characteristics of water and sediment quality were carried out from March, 2005 to Dec, 2005 at 4 different stations (Station 1 – Main Jetty Pulau Tuba, Station 2 – Pulau Tuba Jetty number 2, Station 3 – Simpan Tiga Mangrove Area and Station 4 – Kuah Jetty) along the coastal waters iin Pulau Tuba, Langkawi. The physico-chemical parameters such as temperature (27.43–28.88°C), DO (3.79–6.49 mg/l), pH (7.72–8.20), salinity (33.10–33.96 ppt), TDS (32.27–32.77) g l⁻¹) and specific conductivity (49.83-51.63 mS cm⁻¹) did not show much variation among the stations. While nitrate, nitrite and phosphate were found among the stations, their concentrations varied and ranged from 2.04–26.93 μ g N l⁻¹, 0.86–4.03 μ g N l⁻¹ and 0.27–1.33 μ g P l⁻¹, respectively. Although the textures of the bottom sediment were limited to sand, silt and clay, most of the stations were dominated by black clay with the highest amount (82.97%) being found at station 4. The amount of organic carbon in the sediment ranged from 1.92 – 3.0%, while the highest amount of Fe (366.90 μg g⁻¹ was also found in station 4. Mn (39.75 μg g⁻¹) and Pb (3.15 μ g g⁻¹) were found in stations 3 and 1 respectively. The results showed that there are no significant differences (P > 0.05) among the physico-chemical profiles of the different stations; while the heavy metals and nutrients showed significant differences (P < 0.05) among the stations. Station 4 was the most man induced polluted area due to being the dumping zone of waste materials throughout the year. Nevertheless, all the sampling areas should be given utmost importance for continuous monitoring of nutrients and heavy metals, which could be alarming for the habitat of the aquatic organisms in the near future.