Heavy metal accumulation in the skeleton of Porites lutea from Ngam island, Trat province, Thailand

Abstract

For investigating variation of heavy metal concentration in growth bands of coral skeletons, Poriteslutea samples were collected from Ngam Island, Trat province, Thailand. The skeleton samples were cleaned using oxidative and reductive treatments to effectively eliminate detritus and organic materials and were acid-digested. Five heavy metals, cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn), in the growth bands of Porites lutea were analyzed using Flame Atomic Absorption Spectrometry (FAAS) and Graphite Furnace Atomic Absorption Spectrometry (GFAAS). As a result, the range of heavy metals found in coral skeletons (μg/g as dry weight) was: Cd (0.01-0.19), Cr (0.28-2.25), Cu (2.40-7.71), Pb (0.18-1.13), and Zn (7.64-15.05). The levels shown in descending order were as follows: Zn > Cu > Cr >Pb> Cd. All metals in this study were found in lower concentration when compared with other studies in a polluted area. This study indicated that Porites lutea a good environmental indicator of marine pollution in Ngam Island, and can be useful for past proxy data.