2.4 Heavy metal analysis
For heavy metal (Cr, Cu, Cd, Co and Pb) determination, one gram of soil was digested with 15 mL of aqua regia (HNO3: HCl in 3:1 ratio) and 1 gram Sugarcane and Sorghum shoot sample with 15 mL of triacid mixture (HNO3:H2SO4:HClO4 in 5:1:1 ratio) at 80 °C till a transparent solution was obtained (Allen et al.,, 1986).
The digested samples were filtered and diluted with de-ionized water up to 50 mL and analyzed for the metals viz.