Studies on water quality and pathogenic bacteria in coastal water Langkawi, Malaysia.

A study on physico-chemical parameters and pathogenic bacterial community was carried out at the coastal waters of Pulau Tuba island, Langkawi. The physico-chemical parameters such as temperature (27.43-28.88oC), dissolved oxygen (3.79-6.49 mg l-1), pH (7.72-8.20), salinity (33.10-33.96 ppt), total dissolved solids (32.27-32.77 g l-1) and specific conductivity (49.83-51.63 mS cm-1) were observed. Station 3 and station 4 showed highest amount of nitrates (26.93 and 14.61 µg at N l-1) than station 1 (2.04 µg at N l-1) and station 2 (4.18 µg at N l-1). The highest concentration (12.4± µg l-1) of chlorophyll a was observed in station 4 in October 2005. High phosphorus content (561mg P l-1) was found in the station 2. Thirteen bacterial isolates were successfully identified using API 20E system. The highest amount of bacteria was observed at Station 4 (3400 CFU ml-1) and the lowest number was at Station 2 (890 CFU ml-1). Out of identified 13 Gram-negative bacterial isolates dominant species were Aeromonas hydrophila, Klebsiella oxytoca, Pseudomonas baumannii, Vibrio vulnificus, Proteus mirabilis, Providencia alcalifaciens and Serratia liquefaciens. Apart from this, oil biodegrading Pseudomonas putida were also identified. The study reveals the existing status of water quality is still conducive and the reasonably diverse with Gram-negative bacteria along the Pulau Tuba Langkawi.

Accumulation of lead and copper in Rhizophora apiculata from Setiu mangrove forest, Terengganu, Malaysia.

The accumulative partitioning of Pb and Cu in the Rhizophora apiculata was studied randomly in the Setiu mangrove forest, Terengganu. Samples of leaves, barks and roots were collected randomly from the selected studied species. Sediments between the roots of the sampled mangrove plants were also collected. The results from analysis for Rhizophora apiculata shows that the concentration of Pb and Cu were accumulated higher in root tissue compared to bark and leaf tissue but lower than surrounding sediment level. The average concentration of Cu for Rhizophora apiculata in leaf, bark, root and sediment was 2.73 , 3.94 , 5.21 and 9.42 mg l-1, respectively. Meanwhile, the average concentration of Pb in leaf, bark, root and sediment was 1.43 , 1.38 , 2.05 and 11.66 mg l-1, respectively. Results of concentration factors (CF) show that the overall the concentration of Pb and Cu were accumulated much higher in roots system of Rhizophora apiculata.