Trace Metal Concentrations and Distributions in Sea Water of the South China Sea, Area II: Sabah, Sarawak and Brunei Darussalam

Abstract

Water samples off Sabah, Sarawak and Brunei Darussalam were collected during July–August 1996 and May 1997 and analyzed for dissolved and particulate cadmium, copper, iron, lead and nickel. Dissolved metals were coprecipitated with cobalt-APDC while particulate metals were digested with aqua regia and hydrofluoric acid. The concentrations of metals were measured using graphite furnace atomic absorption spectrophotometer. Concentrations of cadmium, copper, lead and nickel were in the same concentration ranges of unpolluted coastal water elsewhere except for some high concentrations of cadmium at some stations offshore. Iron concentrations were much higher than other regions, and the concentrations were about twenty times those found in the Gulf of Thailand and east coast of Malay Peninsula. High concentrations of these five metals in the offshore area in the July-August sampling possibly came from the Indonesian water flowing northward due to the influence of the wind from the south.