Phytoremediation of Cadmium and Lead Contaminated Soil by Bacterial Augmentation, Graphitic Carbon Nitride and Zea mays L.

Abstract

Heavy metals are on top of the list in the environmental pollution with the ratio of ten by two in contaminating the agriculture soil and water. Zea mays L. is used as food and significant industrial raw material in dairy, poultry, and preservation techniques. This increased ratio of metals in agriculture soil is because of the rapid industrialization, use of agro-chemicals and irrigation with contaminated water. Furthermore, Cd, the sixth most toxic heavy metal, that is released from phosphate fertilizers or get into soil from industrial effluent and disturbs the ecosystems and physiological process in organisms. On the other hand, Pb comes from petroleum industry, coal and fertilizers causes serious health related issues in soil, plants, and animals. Heavy metals are persistent and difficult to remediate via conventional techniques, which are costive and no or less environmentally friendly. However, a novel bio-nanotechnology in combination with phytoremediation proves to be a good technique to remediate the Pb and Cd effectively. In this study the contaminated soil was analyzed for heavy metals remediation with metallotolerant bacteria. Pot experiment was conducted with Zea mays L. as hyperaccumulator, bacteria, and Graphitic carbon nitride (g-C3N4), individually and in combination. The results revealed that the stabilization of Pb and Cd was maximum in treatment (T15) with combination of g C3N4+inoculum+Zea mays L. followed by Zea mays L. +inoculum > Zea mays L.+ g-C3N4 > g-C3N4 + inoculum. The results showed that the concentration 100mg/kg of g-C3N4 with inoculation of Serratia marcescens strain in rhizosphere of Zea mays L. (T14) stabilized 76.15% of Cd and 75.02% of Pb in soil while with concentration 200mg/kg of g-C3N4 with inoculation of Serratia marcescens strains in rhizosphere of Zea mays L. (T15) stabilized 81.52% of Cd and 82.32% of Pb in contaminated soil. The treatment N + B + P (T15) also showed highest biomass that were (4.33 g -1 plant FW). The treatment T15 also showed highest bacterial count that were 1.44*107 cells/g of soil. It is concluded that the combine application bacterial strains and g-C3N4 may be used for the growth of edible crops on Cd and Pb contaminate soil.