This study investigated the distribution and trophic transfer of copper (Cu) and zinc (Zn) from two freshwater fish species (Channa punctatus and Mastacembelus armatus) to the piscivorous bird Halcyon smyrnensis in River Kalpani, Pakistan. Samples collected from five sites between December 2017 and March 2018 included 64 fish and 15 kingfishers. Target tissues (fish: liver, gill, intestine, muscle; bird: feathers, liver, heart, intestine, muscle, bone, skin) were digested with nitric-perchloric acid and analyzed by flame atomic absorption spectrophotometry; results were expressed as mg kg$^{-1}$ (wet weight for soft tissues, dry weight for feathers and bones) and evaluated using one-way ANOV... More >