Nickel (Ni), copper (Cu) and zinc (Zn) determination in Asian swamp eel, Monopterus albus (Zuiew, 1793) collected from paddy fields in Pasir Mas and Bachok, Kelantan, Malaysia

Eel, monopterus albus is one of the common fish and widely available throughout the year in paddy field in Malaysia. However, most people do not know types and concentration level of heavy metals contain in the eel and it could be toxic to the consumers. The objective of the study is to determine the heavy metals concentration of Cu, Zn and Ni, which accumulate in eel from paddy field in Bekelam, Bachok and Pasir Mas using Atomic Absorption Spectrometer (AAS) and to assess on human health using health risk assessment (HRA) toward eel consumption. A total of ten organs of the eel which were heart, kidney, skin, muscle, stomach content, liver, gonad, gill, oesophagus and bone were digested using acid digestion method. Meanwhile, a total of 300 water samples were collected at Bachok (150 samples) and Pasir Mas (150 samples) went through dilution process before analysed using AAS. Result obtained showed that, the water samples in Bachok had the highest concentration of Cu (0.07 mg/L), followed by Zn (0.06 mg/L), and Ni (0.01 mg/L). Meanwhile, the result obtained in Pasir Mas showed that Ni (0.04 mg/L) had the highest concentration followed by Cu (0.02 mg/L) and Zn (0.02 mg/L). Besides, the estimated daily intake (EDI) had been calculated to assess the human health risk. EDI were determined in the edible part of eel (muscle and skin) and were compared with maximum level intake (MLI). EDI had calculated to be lower than MLI, thus, Asian swamp eel at Bachok and Pasir Mas were still safe to be consumed. Moreover, the quality of water in cultivation area complied with Class IV, National Water Quality Standards for Malaysia (standard for irrigation water), where in general, all the measured elements were under permissible limits for aquatic consumption, hence the bio accumulation of heavy metals in aquatic organism could be low.