**2.2 Sample digestion**

The homogenized sample was digested according to the method described by the Association of official Analytical Chemists [12]. Two (2 g) of the homogenized tissues was weighed into bottles and transferred into labeled boiling tube in a fume cupboard, 5 ml of 10% HCl acid was added to the sample and stirred. It was then treated with 5 ml of 10% HNO3, and warmed on a water bath to dissolve. The digested sample was allowed to cool at room temperature and then filtered through 0.45 μm into volumetric flask. The concentrations of heavy metals in the samples were determined with an Atomic Absorption Spectrophotometer (GB Avanta PM AAS, S/N A6600 with detection limit for individual metals of study in the range of 0.001–0.02 mgkg−1). The concentrations were blank-corrected and expressed as μgg−1 dry weight of sample analyzed.
