The ability of humic and fulvic acids (isolated from lignite with a simple, quick, and inexpensive method) to bind the active ingredients of herbicides contaminating drinking water is evaluated. During this study drinking water samples are contaminated with formulated herbicides (imazamox or a mixture of thifensulfuron methyl and tribenuron methyl), while humic and fulvic acids are used as reducing agents. The maximum reducing ability presented by humic and fulvic acids is 72.72% for thifensulfuron methyl and tribenuron methyl and 37.52% for imazamox. Humic acids’ binding ability is superior to that of fulvic acids.

Humic acids (HAs) and fulvic acids (FAs) are naturally occurring compounds that influence the fate and transportation of various compounds in the soil. Although HAs and FAs have multiple uses, the reports about their sorbent potential for environmental pollutants are scanty and sparse. In this study, HA and FA, isolated from lignite samples from two mines in Greece, were studied as sorbent materials for three active compounds of plant protection products, namely glyphosate (herbicide), cypermethrin (pyrethroid insecticide), and azoxystrobin (fungicide). According to the results, both HA and FA are promising sorbent materials for these active compounds, with HA achieving better sorption for cypermethrin and azoxystrobin, while FA was found to be more efficient for glyphosate. Moreover, their performance was not compromised by other components commonly found in commercially available herbicides/insecticides/fungicides. In addition, no significant leaching of the sorbed compounds was recorded. Finally, the two materials achieved similar sorption efficiency of the compounds from lake water.