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Charcoal production activities at the Matang Mangrove Forest Reserve (MMFR) in Peninsular Malaysia have a potential to emit volatile compounds such as Hg back into the ambient environment, raising concerns on the public health and safety. The present study was aimed at analyzing Hg concentration from different plant/animal tissues and sediment samples (in total 786 samples) to understand clearly the Hg distribution at the MMFR. Leaves of Rhizophora spp. showed higher Hg concentration with an increasing trend from young, to mature, to senescent and decomposing stages, which was possibly due to accumulation of Hg over time. The low Hg concentration in Rhizophora roots and bark suggests a limited absorption from the sediments and a meagre accumulation/partitioning by the plant tissue, respectively. In the case of mangrove cockles the concentration of Hg was lower than the permissible limits for seafood consumption. Although the mangrove gastropod - Cassidula aurisfelis Bruguiere had rather elevated Hg in the muscle tissue, it is still less than the environmental safely limit. Beside the chances of atmospheric deposition for Hg, the sediment samples were found to be unpolluted in nature, indicating that in general the MMFR is still safe in terms of Hg pollution.

Southeast Asia is known as a center of biodiversity of the earth. As economic growth of this region is remarkable, conservation of biodiversity is a top priority issue. For this purpose, it is important to monitor the environmental condition in effective ways. We are trying to detect pollutants in coastal and estuary waters through the expression level of pollutant-responsive genes of rice fishes of the genus Oryzias, widely distributed in Asia. Japanese medaka O. latipes is a useful model because whole genome sequence is available. Javanese medaka O. javanicus and Indian medaka O. dancena, both of which are widely distributed in Southeast Asia and adaptable to seawater, are also potential models. One possible method for pollution monitoring is the use of transgenic fish bearing artificialgene construct containing the pollutant-responsive promoter and a reporter gene. For example, transgenic strains that can detect estrogen-like substances have already been established. It is also probable to detect pollutants by quantifying mRNA or proteins expressed from the pollutant-responsive gene. In any case, the most important point is to identify the gene that responds to specific pollutants. Comprehensive transcriptomic analyses are powerful tool for this purpose. Organotin-responsive genes are being screened at present.

The partial toxicity tests of copper (Cu2+), zinc (Zn2+) and cyanide (CN-) for young cobia (Rachycentron canadum) fishes 45 days-old were conducted in Doson station during ten days (yr 2005). These three toxic substances affected strongly the growth rate of the Cobia fish (length and weight of the body), even at the lowest treated concentration. The LC50 values of copper, zinc and cyanide were 0.32 mg l-1; over mg l-1 and 0,049 mg l-1, respectively. Based on the statistical analysis of growth rate of cobia by determining 1C25, IC50, NOEC and LOEC values, we have addressed the safe concentrations of these two heavy metals and cyanide in the environmental aquaculture which must be lower than 0.025 mg Cu l-1, 0.5 mg Zn l-1 and 0.005 mg CN l-1, respectively. The result also showed that cyanide was the most toxic to Cobia, followed by copper and zinc.