Chapter 28 The value of nitrilotriacetate in chelate-assisted phytoremediation

Abstract

This chapter discusses potential use of nitrilotriacetate (NTA) as an alternative to ethylenediaminetetraacetic acid (EDTA) and other poorly degradable aminocarboxylates that are proposed as ligands in chelate-assisted phytoextraction. NTA is known to be fairly biodegradable, and has replaced EDTA in detergents, although its metal complexes are not as strong. NTA solubilizes soil-polluting metals much more efficiently than low-molecular weight organic acids such as citrate and oxalate, and it also has the advantage of being commercially available in large quantities at reasonable costs. The chapter presents outcomes of the study that focused on batch experiments, hydroponic cultures and finally pot and field studies assessing the effect of chelating agents on the bioavailability and uptake of metals by accumulator plants. Effect of NTA on metal solubility in clay suspension solutions and in soils is explained. The chapter describes influence of NTA on metal uptake by tobacco in hydroponic culture.. Influence of NTA on metal uptake from nutrient solution with montmorillonite is elaborated. The chapter also provides details of pot and field experiments.. Results are discussed, which show that NTA, not only has a strong potential to solubilize heavy metals in soil, but also enhances the uptake and translocation of heavy metals into the shoots of remediation plants.