Heavy metal concentrations in Threadfin fish (Eleutheronema tetradactylum) from Dumai Waters: Size dependence and safe human consumption analysis

Abstract

The coastal waters of Dumai, which are directly facing Rupat Island and the Strait of Malacca, are influenced by various coastal activities that are likely to provide inputs for pollutants such as heavy metals that can eventually accumulate in biota, including fish. This condition not only threatens the balance of the ecosystem and the life of aquatic biota, but can also affect the health of people who consume fish from these waters. This study aims to analyze the concentration of heavy metals in threadfin fish (Eleutheronema tetradactylum) collected from Dumai coastal waters and to determine the safe limit of weekly consumption by the community without harmful effects to health. Threadfin fish were taken with a variation in size between 19 to 34 cm, then they were analyzed for heavy metal concentrations (Pb and Cu) in the flesh by referring to the SNI 6989-84:2019 procedure. The results showed that fish with larger sizes accumulated more Pb and Cu metals (2.220 and 0.028 μg/g) compared to medium-sized fish (1.207 and 0.026 μg/g) and small-sized fish (0.811 and 0.015 μg/g). The metal concentration differed significantly (p<0.05) between the three sizes. The longer the size of the fish, the concentration of Pb and Cu will increase. Likewise with the fish weight, the heavier the fish, the concentration of Pb and Cu will also increase. The PTWI value that has been determined by WHO will be achieved if adults with a body weight of 60 kg consume Threadfin fish as much as 1,061 kg/week and 9,130.43 kg/week, while children with a body weight of 15 kg consume the fish as much as 0.265 kg/week and 2,282.6 kg/week, for Pb and Cu.