The snails are rich fauna, while bivalve are the second. More than 150 aquatic check FAQ nonmarine mollusc species have been recorded from the Malaysian region. Melanoisdes tuberculata (M��ller 1774) is from class Gastropoda with shells higher than wide (elongate), conical, usually light brown in colour, and it is a cosmopolitan species [8]. M. tuberculata is a species of freshwater snail with an operculum, a parthenogenetic, aquatic gastropod mollusc in the family Thiaridae. The average shell length is about 20�C27mm and this species is native to subtropical and tropical northern Africa and southern Asia (Indo-Pacific region, Southern Asia, Arabia, and northern Australia), but they have established populations throughout the globe. The snail has an operculum that can protect it from desiccation and can remain viable for days on dry land [9].

It is a warm-climate species, prefers a temperature range of 18 to 32��C, and is primarily a burrowing species that tends to be most active at night. This snail feeds primarily on algae (microalgae) and acts as an intermediate host for many digenetic trematodes. M. tuberculata is a viviparous, gonochoric species with polyploid strains that reproduces by apomictic parthenogenesis. Because meiosis usually does not occur, offspring are identical to their mother. Females can be recognized by their greenish coloured gonads while males have reddish gonads. Under good conditions, females will produce fertilized eggs that are transferred to a brood pouch where they remain until they hatch. M.

tuberculata will begin reproducing at a size as small as 5 to 10mm in length and broods may contain over seventy offspring embryos which develop in the mother [10�C12].Molluscs have long been regarded as promising bioindicator and biomonitoring subjects. They are abundant in many terrestrial and aquatic ecosystems, being easily available for collection. They are highly tolerant to many pollutants and exhibit high accumulations Batimastat of them, particularly heavy metals [13, 14]. Little information exists in the literatures concerning the toxic effects of metals for this snail. So far, only a few studies have been reported on metal toxicity to M. tuberculata [15, 16] and most of the studies were on the accumulation of metals [14, 17, 18]. Therefore, the purpose of this study was to determine the acute toxicity of eight metals (Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn) to the freshwater mollusc M. tuberculata and to examine the bioconcentration of these metals in the body after four days of exposure.2. Materials and MethodsSnails M. tuberculata were collected from canals in the university in Bangi, Selangor, Malaysia. Identification of the species was based on Panha and Burch [8].