The aim of this study was to assess the accumulation and seasonal variations of 20 toxic and trace elements in the abdominal and dorsal muscle (DM), liver and gut contents (GCs) of Cyprinus carpio, and in the sediments and zooplankton from semi-intensive aquaculture ponds during a six-month production season (from May to October). Sediments showed the highest concentrations of the measured elements, followed by zooplankton, fish GCs and livers, while the lowest levels were present in fish muscles. Correspondence analysis revealed that the elemental composition of the fish GCs was mostly similar to that of the sediment and zooplankton. The element concentrations of carp liver and muscles were more similar to each other. Overall, the results indicate that fish liver was the main target organ accumulating Cu, Se and Zn, regardless of their initial amounts in the environment. A seasonal decrease of a range of elements in fish liver (Al, Co, Fe, Li, Mn, Ni, Pb and Sr) was evident towards the end of the investigation period. In addition, the fish DM showed a seasonal accumulation of Sr and Li. However, toxic elements i.e. As, B, Ba Hg and V did not show such a seasonal variation, and were evenly distributed between fish liver and muscles. The concentrations of some elements, such as As, in fish tissues were similar or even higher than in literature data from polluted sites, but none of them exceeded the maximum acceptable concentrations prescribed by Serbian legislation or by FAO or EU regulation.
Impact of rice-fish/shrimp co-culture on the N2O emission and NH3 volatilization in intensive aquaculture ponds