Heavy metal pollution status in the Malaysian aquatic environment

Abstract

The objective of this paper was to review the status of the Malaysian aquatic environment with respect to heavy metals. Much of the work on metals focused on measurements in biota and sediments, but very little research has been done on dissolved and particulate metals in water, metal speciation in sediments or on the bioavailability of metals. Cadmium (Cd), Copper (Cu), Lead (Pb) and Zinc (Zn) received much attention but due to technical difficulties, Arsenic, (As), Mercury (Hg), Tin (Sn) and other hydride elements have not been well studied. The sources of metal pollution come from manufacturing, agriculture, sewage and motor vehicle emissions. The few reliable studies on metals in water indicate that some rivers were contaminated with Pb, Cu and Zn. Measurements in fish, bivalves and shrimp indicate no contamination of these resources by metals. However contamination by Cd and Pb was noted in some littoral shore molluscs such as Thais sp. as well as rock oysters (Saccostrea sp.) which may be due to non-anthropogenic sources. Sediments of the Juru and Langat rivers are contaminated by Pb and Zn, while the Langat River was heavily contaminated by Cd. The concentrations of Zn and Pb in coastal sediments off Juru in Penang, and in the Johor Strait were two and three times higher than global shale values. The source of Pb pollution was thought to be derived from the use of leaded petrol. Metal levels in sediments of the Malacca Strait and the South China Sea were generally similar to global shale values.