Removal of copper from the vineyard land of Pješivci (Montenegro) using amino acids

Copper compounds in the form of fungicides are most commonly used as a measure of protection against vine diseases. Typically, around a dozen treatments are done throughout a year with a dispersion of approximately 5–10 kg of Cu per hectare. For many years, the remediation of heavy metals has often involved the use of ex-situ soil washing with chelating reagents. Amino acids have a lower metal chelation capability compared to EDTA and its derivatives, but they have numerous other advantages in comparison. The main goal of this research was to investigate the ability of 9 amino acids and one dipeptide to extract Cu from various vineyard soil samples and compare their chelating ability with other ‘green’ chelating agents. The average content of Cu extracted with amino acids is 34.7 ± 16.7 mg/kg or 30.3 ± 5.43 wt% relative to the pseudo-total content. This is more than what was extracted with carboxylic acid salts (9.91 ± 7.49 mg/kg or 8.45 ± 5.56 wt%) but less than with EDTA (98.5 ± 42.7 mg/kg or 79.9 ± 7.12 wt%). The descending order of tested amino acids relative to the removed Cu (mg/kg) is: His > Ser > Thr > Leu > Gly > Val > Phe > Gly-Gly ~ Ala > Arg. The results of this paper show that the amino acid structure is the most important factor for efficient Cu extraction, while the physicochemical properties of the vineyard soil have less impact.