Copper, ironand zinccontents in water, pakcoy(Brassica rapa L.)and tilapia (oreochromis niloticus) in the presence of aquaponics

Abstract

This research analyzes the effects of the use of aquaponics on the metal contents (Cu, Fe and Zn) in water, pakcoy, and tilapia. Fish and plant sampling techniques were conducted randomly while the water sampling was taken at three points: the fish pond, the tank after biofiltering, and the hydroponic tank. Sampling was done 4 times, for 0, 10, 20 and 30 days. The method of wet destruction with aquaregia was used for the preparation of the fish and plant samples. Furthermore, the content of Cu, Fe and Zn metals in water, pakcoy and tilapia was detected using flame atomic absorption spectrophotometer (FAAS). The results showed that the concentrations of Cu, Fe and Zn metals were higher on the 10 th day than on the 0 days. But after the 20 th day and the the 30 th day, the concentrations of Cu, Fe and Zn in the pond water were reduced. The concentrations of Cu, Fe and Zn metals in the fish pond were 0.008mg/L, 0.44mg/L and 0.309mg/L respectively on the 30 th day. According to the Government Regulation Number 82 of 2001, the standard of water quality for fish and plant cultivation for Cu, Fe and Zn concentrations are 0.02mg/L, 0.3mg/L and 0.05mg/L respectively. It was therefore resolved that the Cu metal concentrations obtained has satisfied the standard of water quality, while the concentrations of Fe and Zn metals did not attain the alleged standard of water quality. The highest level of Cu metal in the tilapia fish (Oreochromis niloticus) was 22.94mg/kg and this was ascertained on the 20 th day. The highest level of Zn concentration on day 0 was 157.10mg/kg. Similarly, the highest level of Fe content on the 30th day was 826.91mg/kg. On the other hand, the highest level of Cu content in the pakcoy plant was 27.82mg/kg, the highest level of Zn content was 210.81mg/kg and the highest level of Fe content was 2583.61mg/kg and this was detected in the analyzed samples on the 30 th day. The study shows that the content of the Cu and Zn levels in the tilapia and pakcoy plants have exceeded the national standard limit according to Decree of the Director General of Drugs and Food Control POM/03725/B/SKVII/89.