Bioaccumulation and histopathological effect on the gills and liver of silver barb (Barbonymus gonionotus) exposed to the heavy metal nickel

The silver barb (Barbonymus gonionotus) is one of the freshwater fish which is often found in river, specifically the Java and Sumatra islands in Indonesia. A water environment that has been exposed into nickel will cause fish bioaccumulation and cause histopathological changes in the gills and liver of the fish, especially in the silver barb. This research aimed to observe the bioaccumulation and histopathological effect on the gills and liver of silver barb from nickel (Ni) under different concentration treatments. This research used the experimental method where the parameters observed were the nickel level of content in the gills and liver, as well as the histopathological changes after the nickel exposure. The bioaccumulation level was measured using the AAS (Atomic Absorption Spectrophotometric) method. The result showed that the nickel concentration given affected the bioaccumulation level and caused histopathological changes in the gills and liver of the silver barb. The highest bioaccumulation level was observed in the nickel exposure using a 1.8196 ppm dose resulting in a 1.85095 ppm accumulation in gills and 4.3982 ppm accumulation in liver. The changes that occurred in the gills were oedema, hyperplasia, and lamellae fusion, while the changes in the liver included vacuolization, congestion, and necrosis.