CADMIUM, MANGANESE AND LEAD DISTRIBUTION IN THE SOUTH CHINA SEA OFF THE SOUTH TERENGGANU COAST, MALAYSIA DURING POST-MONSOON AND PRE-MONSOON

Concentrations of cadmium, manganese and lead were determined in the water column of the South China Sea off the South Terengganu coast in May 2007 and September 2007. Seawater samples were collected from the surface, middle and bottom layers, in a grid of 18 stations 25 km apart. The dissolved metals were extracted on-board ship and preconcentrated on-line using Chelex-100 packed in Teflon tubing after filtration of seawater. The particulate metals were digested under microwave heating. Trace metals were analysed using ICP-MS and validated against CASS-4 and MESS-3. The concentration of dissolved and particulate metals were in the range of 0.002-0.194 μg/L and 45-249 μg/g for Cd, 0.04-2.71 μg/L and 21-2885 μg/g for Mn and 0.03-0.49 μg/L and 10-4277 μg/g for Pb respectively. All metals were dominantly in the dissolved phase except Cd which was predominantly in the particulate phase during September 2007. The order of mean log KD found was Cd>Pb>Mn. Positive correlation of log KD with suspended particulate matter were found during both sampling periods except during September 2007, Cd was negatively correlated with suspended particulate matter. The present measurements were to provide baseline data for any future comparison of trace metals distribution in the South China Sea off Southern Terengganu coast.