Reducing plant uptake of a brominated contaminant (2,2′,4,4′‑tetrabrominated diphenyl ether) by incorporation of maize straw into horticultural soil

Abstract

Application of crop residues is a conventional practice that contributes to crop production through nutrient returns and other benefits to soil health: driving soil physicochemical and biological functions. However, little is known about the impacts of straw residue incorporation on the bioavailability of organic pollutants and associated changes in microbial community structure in contaminated soils. In this study, maize straw was added to a soil contaminated with a model polybrominated diphenyl ether (BDE-47). A pot experiment was conducted and planted with carrot (Daucus carota L.). We found that straw addition greatly reduced the bioavailability of BDE-47, changed the bacterial community structure and affected a range of soil physiochemical properties. Moreover, the amount of BDE-47 that had accumulated in carrot roots and aboveground tissues was significantly reduced. This study may therefore describe an effective agronomic strategy to reduce the bioavailability of polybrominated diphenyl ethers (PBDEs) in a soil used to grow high value vegetable crops. This strategy draws on traditional wisdom and shows promise as a practical method to support horticultural production systems, remediate soils, and help to ensure food safety.