Quantity and distribution of some heavy metals in seawater at shipbreaking industries located in Ban Nong Faeb, Mab Ta Phud, Rayong province

Abstract

Seawater samples were collected at 1 meter depth off the Mab Ta Phud coastal area, in the vicinity of the ship-breaking plant, during October 1988 to May 1990. The samples were analyzed for concentrations of lead, copper, zinc and iron both in particulate and dissolved forms. Each sample was also analyzed for dissolved organic carbon. Tissues of pen shells, Atrina vexillum, collected from Ban Pla near the ship-breaking plant area were also analyzed. Some products resulted from ship-breaking activity were collected for leaching experiments to confirm the solubility of heavy metals in seawater. In addition, the variations of four heavy metal concentrations within a tidal cycle and due to current effect were observed. A comparison of four heavy metal concentrations found in seawater was conducted by different approaches. The purpose of this comparison was to identify their contamination extents during different ship-breaking activities. The results shown that the ship-breaking activity caused heavy metals contamination in seawater. Contaminated lead, copper and zinc were found to be more in the form of dissolved than particulate. Iron contamination was found more in the form of particulate than dissolved. The analysis of pen shells, Atrina vexillum, tissues indicated that they were contaminated by all those four heavy metals originated by ship-breaking activity. The result of the leaching experiment shown that the material fragments caused heavy metal contaminations in seawater. The concentrations of four heavy metal concentration in seawater both in particulate and dissolved forms at any fixed station varied with the water movement.