Heavy trace metals and macronutrients status in herbal plants of Nigeria

The concentration levels (ppm) of selected toxic trace metals (Fe, Mn, Cu, Pb and Zn) and macronutrients (Na, K, Mg and Ca), along with P, were estimated in some of the important herbal plants of the southwest part of Nigeria. The atomic absorption spectrophotometer was employed for the estimation conducted on 10 plant species collected from different locations within Ogbomoso. The plants were Anacardium occidentale, Azadirachta indica, Butyrospermum paradoxum, Mangifera indica, Morinda lucida, Ocimum canum, Solanum erianthum, Solanum torvum, Zingiber officinale and Hyptis suaveolens. The metal contents in the samples were found at different levels. The highest mean levels (ppm) of Zn (35.1±0.01) and Cu (24.4±0.01) were found in Hyptis suaveolens while those of Mn (685±0.02) and Ca (51 340±21) were found in Morinda lucida. The result also showed that Ocimum canum had the highest amounts of K (36 600±350), P (3700±35) and Fe (241±0.05). Anacardium occidentale had the highest concentration of Na (613±0.60) while Azadirachta indica had the highest mean concentrations of Pb (0.49±0.03) and Mg (5630±12).