Feasibility of using peanut (Arachis hypogaea L.) for phytoattenuation on lead-contaminated agricultural land—an in situ study

• Peanut for phytoattenuation of Pb-contaminated soils yields 38.35 t ha−1 y−1.
• Peanut for phytoattenuation with 17.6 kg ha−1 y−1 of lead removed.
• The lead content of kernel is lower than the limit of EU animal fodder.
• 6.3 t ha−1 y−1 of kernel is valuable as animal feed and generated revenues.
• Planting peanut can produce economic income during the phytoremediation.

Phytoremediation is the most environmentally friendly remediation technology for mitigating agricultural land contamination. However, phytoremediation is a slow process. If the harvested plants cannot provide economic benefits, phytoremediation technology may not be applicable. In this study, peanut (Arachis hypogaea L.) and rape plants (Brassica campestris L.) were planted on Pb-contaminated farmland with a Pb concentration of 5600 mg kg−1. The objectives were to investigate the effect of Pb-contaminated soil on peanut growth, estimate Pb-removal efficiency and evaluate the economic benefits of using peanut products as biomass energy or for other purposes. All these efforts were for the assessment of the feasibility of using peanut plants for the Pb-contaminated land phytoremediation. The study found that biomass energy yield and Pb removal rate were both higher for peanuts than for rapeseed plants. Planting peanuts produced 38.35 t ha−1 y−1 of dry matter, and removed 17.6 kg ha−1 y−1 of Pb. As a biofuel, peanut dry matter can generate a heat value of 654.5 GJ ha−1 y−1, which is comparable to that produced by burning 31.3 t of raw coal. The output of peanut kernel was 6.3 t ha−1 y−1 with Pb content less than the European Union’s maximum limit for animal feeds, and would be valuable as animal feed. A period of 317 years would be required to remove all phytoavailable-Pb from this site by using peanuts. This study concluded that using peanut plants is feasible for the phytoremediation, which can be supported by revenues derived from the crops in Pb-contaminated farmland.