Effects of northeast monsoon on trace metal distribution in the South China Sea off Peninsular Malaysia G. Adiana & N. A. M. Shazili & M. A. Marinah & J. Bidai Received: 13 February 2013 / Accepted: 10 August 2013 / Published online: 22 August 2013 # Springer Science+Business Media Dordrecht 2013 Abstract Concentrations of trace metals in the South China Sea (SCS) were determined off the coast of Terengganu during the months of May and November 2007. The concentrations of dissolved and particulate metals were in the range of 0.019–0.194 μg/L and 50– 365 μg/g, respectively, for cadmium (Cd), 0.05– 0.45 μg/L and 38–3,570 μg/g for chromium (Cr), 0.05–3.54 μg/L and 21–1,947 μg/g for manganese (Mn), and 0.03–0.49 μg/L and 2–56,982 μg/g for lead (Pb). The order of mean log K D found was Cd>Cr>Pb>Mn. The study suggests that the primary sources of these metals are discharges from the rivers which drain into the SCS, in particular the Dungun River, which flows in close proximity to agricultural areas and petrochemical industries. During the north- east monsoon, levels of particulate metals in the bottom water samples near the shore were found to be much higher than during the dry season, the prob- able result of re-suspension of the metals from the bottom sediments. Keywords Dissolved metals . Particulate metals . Chelex-100 . South China Sea . Distribution coefficient . Northeast monsoon Introduction Trace metals exist in seawater in both dissolved and particulate phases, and their bioavailability depends on the complexation process with organic matter (Censi et al. 2006). The concentration of trace metals present in the water column varies due to changing inputs and seasonal effects on biological, geochemical, and phys- ical properties (Valdés et al. 2008). In some cases, nutrient-typed trace metals being are depleted in the surface water and enriched with depth as a result of gravitational settlement and the decomposition of par- ticulate matter (Cuong et al. 2007). Metals return to the water column through the decomposition of organ- isms, as well as via the dissolution of sinking fecal pellets and mineralization. Studies on metal concentrations in seawater (Table 1) indicate that the metal concentrations within Southeast Asia regions are comparable, except in areas polluted by specific metals due to agriculture, industrial run-off, effluent discharge, and domestic activities. Environ Monit Assess (2014) 186:421–431 DOI 10.1007/s10661-013-3387-9 G. Adiana (*) : J. Bidai Institute of Oceanography and Environment, Universiti Malaysia Terengganu, Mengabang Telipot, 21030 Kuala Terengganu, Malaysia e-mail: adiana.ghazali@yahoo.com N. A. M. Shazili Marine Science Department, Faculty of Maritime Studies and Marine Science, Universiti Malaysia Terengganu, Mengabang Telipot, 21030 Kuala Terengganu, Terengganu, Malaysia M. A. Marinah Chemistry Department, Faculty of Science and Technology, Universiti Malaysia Terengganu, Mengabang Telipot, 21030 Kuala Terengganu, Terengganu, Malaysia