The objective of the present work was to obtain scientific information on the ecological health of three freshwater lakes (Awassa, Koka, and Ziway) situated in the Ethiopian Rift Valley by investigating possible trace element contamination accumulated in fish. Accordingly, fish liver and kidney samples were collected from three commercially important fish species (Barbus intermedius, Clarias gariepinus, and Oreochromis niloticus) in the lakes to determine the concentrations of chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), and lead (Pb), using ICP-MS. Trace element concentrations were generally higher in O. niloticus compared with concentrations in B. intermedius and C. gariepinus. Compared to background values of most freshwater fish species, higher liver concentrations of Cu in C. gariepinus and O. niloticus, Mn in O. niloticus, Co in all except B. intermedius, and Zn in C. gariepinus from Lakes Ziway and Awassa were found. Cr, Co, Ni, Cd, and Pb were enriched in kidney, while Mn, Cu, Zn, As, and Se seems retained in the liver tissues. Assessment of transfer factors indicated that bioaccumulation from water and diet occurred, while uptake from sediments was low. Furthermore, the transfer factor values were generally higher for essential elements compared to the non-essential elements. Multivariate statistical analyses showed that the differences between the trace element levels were generally not significant among the lakes (p = 0.672), while significant differences were found between the fish species (p = 0.042), and between accumulation in kidney and liver (p = 0.002).

本研究的目的是通过调查鱼类中可能积累的微量元素污染来获得有关位于埃塞俄比亚裂谷的三个淡水湖（Awassa，Koka和Ziway）的生态健康的科学信息。因此，从湖泊中的三种商业上重要的鱼类（Barbus intermedius，Clarias gariepinus和Oreochromis niloticus）中收集鱼肝和肾脏样品，以确定铬（Cr），锰（Mn），钴（Co），镍的浓度。使用ICP-MS分析（Ni），铜（Cu），锌（Zn），砷（As），硒（Se），镉（Cd）和铅（Pb）。痕量元素浓度在一般较高尼罗与浓度相比B. intermedius和C. gariepinus。相对于大多数淡水鱼类的背景值，在Cu中的更高浓度的肝脏C.鲇和尼罗罗非鱼，Mn的尼罗，Co的所有除B.中间型，和Zn中C.鲇从Ziway湖和Awassa那里发现了。Cr，Co，Ni，Cd和Pb富含肾脏，而Mn，Cu，Zn，As和Se似乎保留在肝组织中。对转移因子的评估表明，水和食物的生物蓄积发生了，而沉积物的吸收却很低。此外，与非基本元素相比，基本元素的传递因子值通常更高。多变量统计分析表明，各湖泊中微量元素水平之间的差异通常不显着（p  = 0.672），而鱼类之间（p  = 0.042）以及肾脏和肝脏的蓄积之间（p  = 0.002）。