Evaluation of Heavy Metals Concentrations in Plants of Biostimulated Contaminated Soils in Port Harcourt, Southern Nigeria

Pot experiments were carried out in the Teaching and Research Farm and in the greenhouse of Crop/Soil Science Department, Faculty of Agriculture, Rivers State University of Science and Technology, Port Harcourt to evaluate heavy metals (lead, zinc, copper, cadmium and Chromium) concentrations in maize (Zea mays L.), pumpkin (Telfairia occidentalis L.), okra (Abelmoschus esculentus L.) and vetiver tillers (Vetiveria zanzinoides) in automobile and industrial waste dump soils amended with 5 t ha-1 poultry dung (PD) and freshwater hyacinth organic matter (WH). Treatments were replicated six (6) times; (3) replicates in the greenhouse and in the field respectively in order to simulate different environmental conditions for the experiments. Results showed that pumpkin field plants for the Automobile dump soil had the highest lead contents (0.67, 1.57, and 1.03 mg/kg) in the un-amended, PD and WH amended soil respectively while in the industrial waste dump soil, vetiver, pumpkin, okra field plants had 0.52, 0.82 and 0.74mg/kg in the soil without amendment, PD and WH amended soil respectively. The highest copper contents (13.53, 22.48, 21.29 and 9.40, 19.09, 15.49 mg/kg) were obtained in the field maize plants of Automobile and industrial waste dump soils without amendment, amended with PD and WH respectively. The highest zinc concentrations (4.67, 10.40, 8.41 and 4.52, 7.78, 4.89 mg/kg) were obtained in field pumpkin plants of Automobile and industrial waste dump soil respectively. Cadmium and chromium values were also higher in the pumpkin plants of both Automobile and in the industrial waste dump soil treatment options in the field.