A New Model for Effective Remediation and Comprehensive Utilization of Cd–Pb Composite Contaminated Farmland by Ornamental Plants

Heavy metal composite pollution, such as Cd–Pb, occurs commonly in agriculture soils around the world, potentially harming the ecological environment and human health via food chain/network migration. There are numerous strategies for treating and rehabilitating polluted farmland today, including the use of attractive plants for phytoremediation. However, it is unclear how to use attractive plants to properly treat and fully utilize Cd–Pb composite damaged farms. The combined Cd–Pb pollution of agriculture in Xieping village, Huixian county, Gansu province is increasingly prevalent. Therefore, based on the results of literature research and the actual situation of the study area, nine kinds of ornamental plants with Cd–Pb composite pollution remediation potential and comprehensive utilization value were first selected in this paper, and the greenhouse test was carried out in the Cd–Pb composite pollution farmland in the study area. Second, the bioconcentration factor (BCF), transfer coefficient (TF), and economic feasibility principle were utilized to select the best treatment plants, and a novel model of effective remediation and comprehensive exploitation of Cd–Pb composite damaged farmland was developed. The results showed that the nine tested plants grew well under the Cd–Pb combined pollution stress, and all of them showed certain tolerance. However, the biomass, Cd–Pb accumulation, enrichment and transport capacity of the different plants were significantly different. Among them, Paeonia suffruticosa Andr., Rumex acetosa L., Calendula officinalis L., Rose chinensis Jacq., Tagetes erecta L. and Impatiens balsamina L. show excellent restorative abilities. Combining the ornamental value, safety and economy of flowering plants, P. suffruticosa, R. chinensis, C. officinalis, T. erecta and I. balsamina were finally selected as the plants for the effective remediation and comprehensive utilisation of Cd–Pb composite pollution in farmland. In conclusion, this study proposes a new model for the effective remediation and comprehensive utilisation of heavy metal composite pollution in farmland by flowering plants with economic feasibility .