Effects of landuse changes to water quality and green mussels (Perna viridis) due to development along Danga-Pendas coastal area

Abstract

The effects of landuse changes have become significant with reduction in water quality and thus affecting aquatic life in their ecosystem. A large area in Johor Straits starting from Singapore-Malaysia Second Link Bridge to Danga Bay have been identified as a suitable location for the expansion of mussels and caged-fish industries by the National Fisheries Institute of Malaysia. However, this area has been chosen as a part of the massive development projects of Iskandar Development Region (IDR). Therefore this would definitely increase the level of pollutants in coastal water. The objectives of this study are to determine the effects of landuse changes to water quality along this river as well as to analyze the effects of water quality on green mussels (Perna viridis). This study was carried out along Danga- Pendas coastal area with eleven sampling points for water quality and four mussels sampling points. Study parameters include dissolved oxygen (DO), temperature, salinity, pH, ammoniacal nitrogen, total dissolved solid (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and heavy metals for zinc, lead, cadmium and nickel. Sampling was carried out from November 2008 to April 2009. All water and mussels samples were then analyzed in laboratory based on the standard procedures. In order to observe the variation on landuse change, satellite image; Landsat TM and ETM for year 1991, 2000, 2005 and 2008 were used. Processes includes geometric correction, atmospheric correction, images classification and change detection were carried out for each image to obtain the final output of landuse changes statistics. Results obtained from the processes and laboratory analysis indicate that there were reduction in water quality especially in heavy metals when compared to Interim National Water Quality Standard (INWQS) and Interim National Marine Water Quality Standard (INMWQS) with increased of build-up and open area due to development. Lead and cadmium recorded in green mussel were mostly higher than the permissible limit allowed by Malaysian Food Regulation 1985 whereas zinc concentration was below than the limit. Generally, there are significant relationship between landuse and water quality and thus with green mussel. As development increased, quality of water decreased and heavy metals accumulation in green mussel were also increased. The severity of the water quality along study area was classified as slightly polluted and proper management and prevention planning should be carried out to preserve the coastal environment.