To determine the concentration of lead Pb and cadmium Cd in a water sample collected from a polluted river using atomic absorption spectroscopy AAS , you would need to follow these steps:1. Collect a representative water sample from the polluted river.2. Prepare the sample for analysis by filtering it to remove any suspended particles and then acidifying it with a small amount of concentrated nitric acid HNO3 to preserve the sample and dissolve any metal particulates.3. Prepare a series of standard solutions containing known concentrations of lead and cadmium. These standards will be used to create a calibration curve for each metal.4. Analyze the standard solutions and the water sample using an atomic absorption spectrometer. The instrument will measure the absorbance of light by the metal ions in the sample and compare it to the absorbance of the standard solutions.5. Create a calibration curve for each metal by plotting the absorbance values of the standard solutions against their known concentrations. Use the calibration curve to determine the concentration of lead and cadmium in the water sample.6. Report the concentrations of lead and cadmium in the water sample, typically in units of micrograms per liter g/L or parts per billion ppb .Please note that without the actual data from the atomic absorption spectroscopy analysis, it is impossible to provide specific concentrations of lead and cadmium in the water sample. The steps outlined above are the general procedure for determining the concentrations of these metals using AAS.