Experimental assessment of potentially toxic metals and nutrient content at various morphological parts of two economic plants grown on spent engine oil (SEO) treated soils

Metals interact with nutrients in plants grown on spent engine oil (SEO) soils; thus, relationship of metals and nutrients in several morphological parts of economical plants cultivated on SEO soils using a 3 × 4 factorial and a totally randomized design is documented. The polluted-vegetated soils were SEO treated at 0, 2, 4, 8% v/w and planted <i>T. paniculatum</i> and <i>T. fruticosum</i> separately. Before treatment, SEO tested positive for Cd, Zn, Pb, Cr, Cu, Fe and Ni, while at treatment, non-vegetated soils accumulated Pb, Cu, Zn, Ni, Fe. The <i>T. paniculatum</i> on SEO had more Cd among plants. ANOVA indicated significant (<i>P</i> < 0.05) relationship between metals, SEO and treated soils. A Post hoc indicated Fe and Pb levels differed significantly across SEO vegetated soils, while PCA suggests treated plant roots and leaves accumulated more of the toxic metals. These plants parts should not be consumed from SEO-polluted areas.