The application of synthetic aminopolycarboxylic acids to soil increases metal solubility and therefore enhances phytoextraction. However, synthetic chelators barely degrade in soil and threat the human and animal health owing to metal leaching. The aim of this study is to assess the use of a biodegradable (NTA) and a non-degradable chelant (EDTA) for Pb phytoextraction from a soil contaminated by battery-casing disposal. Each synthetic chelant was applied to soil pots cultivated with maize plants at the rates 0, 2, 5, 10, and 20 mmol kg-1. The 5 mmol kg-1 dose of EDTA increased to 1.1% the Pb concentration in maize shoots. The results showed that phytoremediating the site using 5 mmol kg-1 NTA could be feasible with no environmental effects due to Pb leaching over a 5-year period.

Phosphorus fertilizers are intensively used in Brazil since phosphorus often limits the yield in tropical soils. However, these fertilizers can contaminate soils through addition of heavy metals. This work was carried out to study the lead contamination due to addition of four different phosphorus fertilizers as well as the Pb uptake by corn (Zea mays) plants. The fertilizers single superphosphate, triple superphosphate, Araxá rock phosphate, and Gafsa rock phosphate were added at doses equivalent to 0, 100, 300, 500 and 800 kg ha-1 of P2O5. Two successive corn coppings were performed. Gafsa rock phosphate presented the highest Pb concentration. Gafsa application also resulted in the highest Pb concentration in corn shoots.