RÉSUMÉ
The present study was conducted to determine the concentration of heavy metals in some selected medicinal plants taken from District Karak, Khyber Pakhtunkhwa, Pakistan. Essential and non essential heavy metals such as Zn, Fe, Mn, Cu, Ni, Cr, Pb and Cd were investigated in Rhyzia stricta, Withania coagolans, Conyza canadensis, Steleria media, Medicago denticulata, Parthenium hysterophorous, Malvastrum tricuspidatum and Launaea nodicaulis by using Atomic Absorption Spectrometry. Plants showed different metal concentration in the range of: 10.11-55.98mg/kg for Zn, 40.47-101.87mg/kg for Fe, 29.11-105.46mg/kg for Mn, 15.06- 34.52mg/kg for Cu, 1.02-10mg/kg for Ni, 0.01-0.76mg/kg for Cr, 0.99-15.46mg/kg for Pb and 0.10-1.41mg/kg for Cd. High contents of Fe and Mn were found in all eight plants. Other heavy metals were present in low quantity. The purpose of this study was to identify each type of metal associated with a given plants contaminated by environmental pollution and also to highlight the toxic heavy metals present in these plants.