Energy crop at heavy metal-contaminated arable land as an alternative for food and feed production: Biomass quantity and quality

Abstract

Anthropogenic impacts, for example residues from mining, industrial processes such as smelting or overuse of pesticides and fertilisation, are causing degradation and elevated heavy metal concentrations in farmland soils. Food or feed crops grown on this land can become contaminated with heavy metals with their consumption potentially leading to the accumulation of contaminants in human or animal populations, causing both chronic and acute health problems. Arable soils contaminated with heavy metals have a negative influence on regional economies by restricting sustainable agricultural development and the trade of goods. Second-generation bioenergy crops, based on perennial lignocellulosic crop species, are considered to be the future of the bioenergy industry and are the focus of intense research. Perennial energy crops have a low demand for nutrient inputs and higher lignin and cellulose contents than the biomass of annual crops. Moreover, they appear to be a viable economic alternative to food or feed production at heavy metal-contaminated arable lands. Besides offering an immediate cash crop for polluted soils, their deployment may eventually lead to the future recovery of those areas for arable crops thanks to their capacity for phytoremediation. This chapter presents an overview of the cultivation possibilities of different second-generation energy crop species on heavy metal-contaminated soils, with an emphasis on their impact on biomass yield and elemental composition. In addition, potential end uses of this contaminated biomass, using thermal and biochemical conversion, are reviewed and discussed from the energy generation and post-processing residue disposal point of view.