Concentration of arsenic and mercury in the oyster (Crassostrea iredalei) from Setiu lagoon, Terengganu

Abstract

This study was conducted to determine the concentration of arsenic (As) and mercury (Hg) in the Crassostrea iredalei and examine the correlation between the metal concentration in C. iredalei with sediment and water levels. The mean concentrations of As and Hg in the C. iredalei tissues were significantly different at varying times of sampling. The highest concentration of As in the C. iredalei was found at Station 5, which was 43.91 ± 0.54 µg g⁻¹ (first sampling) and 22.65 ± 0.78 µg g⁻¹ (second sampling). While for water, Station 5 (9.62 ± 1.35 µg L⁻¹) showed the second lowest concentration of As after Station 10 (7.93 ± 3.17 µg L⁻¹) at first sampling. During the second sampling, the highest concentration of As was 0.32 ± 0.01 µg L⁻¹ at Station 5. Overall, the concentration of Hg in the C. iredalei was in the range of non-detectable to 0.03 µg g⁻¹ (wet wt.), which is below the safety limit (Hg < 0.05 µg g⁻¹). However, the As concentration was in the range 0.55 to 2 µg g⁻¹ (wet wt.) with concentration values in C. iredalei from Stations 1, 3, 4, and 5 having concentrations exceeding the safety limit of Malaysian Food Act 1983.

Keywords:

• oyster
• Crassostrea iredalei
• arsenic
• mercury
• Setiu lagoon