Application Effect of Biochar, Activated Carbon and Microorganisms on Reducing the Phytotoxicity of Cd and Pb

Abstract

The objective of the current study was to isolate acid production bacteria (APB) from sewage wastewater-irrigated soil. The effect of Cd and Pb at levels of 0-1000 ppm with or without active carbon (AC) or biochar (BC) on the germination of corn seeds (Zea mays L.), and seedlings fresh and dry weight were also examined in germination experiment. In addition, a greenhouse pot experiment was conducted to study the effects of BC, AC, and bacillus (BA) on plant growth of Zea mays in heavy metal contaminated soil. The results showed that the solubilization index for bacterial isolates of APB-1, APB-2, APB-3 and APB-4 was 2.50, 1.62, 2.22, and 3.14, respectively. It was observed that the growth parameters of seedlings decreased with increasing doses of Cd or Pb, showing negative effects of these metals on seeds germination, seedling length, and fresh and dry matter of seedlings. The toxicity effect of Cd appeared to be greater than Pb on the seedling's growth. When applying AC or BC, however, the toxicity effect of toxic metals was reduced, which improved seedlings growth. In the greenhouse pot experiment, the application of AC, BC, or BA significantly increased the plant height and dry matter of maize shoots. It could be concluded that applying pyrolytic carbon-based materials or microbial inoculation enhanced plant growth and it may be due to improving soil quality and/or reducing heavy metals toxicity.