Concentration of heavy metal in water, sediment and aquatic life at straits of Johor

Abstract

In this study, marine water quality at Johor Straits along Kampung Pasir Putih was investigated. Changes in land use and increased discharge of domestic, agricultural and industrial waste into the coastal water have severely affected the water condition and threatened fishes and green mussels aquaculture activities. The study investigated on the distribution concentration levels of heavy metals, which are Zn, Cu, Cd and Pb in crabs and mussels with addition to sediment samples that were collected. The mean heavy metals concentration level in whole body of crabs and mussels were found in range of 60.4-256.5 mg/g, 21.8-50.3 mg/g, 1.6–4.5 mg/g and 8.2-23.7 mg/g dry weight for Zn, Cu, Cd and Pb, respectively. The patterns of heavy metals distribution in crabs and mussels of the different sampling stations were found to be Zn > Cu > Pb > Cd, where the highest were usually indicated by Zn and Cu which were not consistent in their order, and the lowest were indicated by Cd and Pb. This was due to the different function of heavy metals in crabs and mussels such as for essential purpose, sequestration and even to be excreted. As for sediments, the mean heavy metals concentration level were found in range of 17.7-147.1 mg/g, 17.7-155 mg/g.2, 2.4-5.3 mg/g and 9.8-14.5 mg/g dry weight for Zn, Cu, Cd and Pb, respectively. As the development increase, the quality of water will be decrease, thus, the accumulation of heavy metals in green mussels and crabs will increase. This is proven by the low dissolved oxygen (DO) concentration which was between 1.36 to 6.71 mg/L. The heavy metals concentration in marine water along Kampung Pasir Putih were between 0.01 to 0.6 mg/L for Zn, 0.04 to 0.22 mg/L for Cd, 0.01 to 0.08 mg/L for Cu, and 0.03 to 0.33 mg/L for Pb. Based on the selected parameters conducted, Kampung Pasir Putih is classified as Class 3 according to Malaysia Marine Water Quality Standard (MMWQS). Overall the water quality was affected along the study thus classified as slightly polluted. With that proper management and prevention planning should be carried out to preserve the food environment.