Concentration of lead and the proportion of sedimentary organic matter , clay minerals , non-clay minerals and soil gradation , City of Nasiriyah , Southern Iraq. Baghdad Sci.J [Internet]. 2018 Dec. 30 [cited 2025 Jun. 18];12(1):34-9. Available from: https://bsj-ojs.uobaghdad.edu.iq/index.php/BSJ/article/view/2941