Effect of soil biochar concentration on the mitigation of emerging organic contaminant uptake in lettuce

Abstract

Although crop uptake of emerging organic contaminants (EOC) from irrigation water and soils has been previously reported, successful mitigation strategies have not yet been established. In this study, soil was amended with a wood-based biochar (BC) at two rates (0, 2.5 and 5% w/w) to evaluate the effect on mitigation of EOC uptake (i.e. bisphenol A, caffeine, carbamazepine, clofibric acid, furosemide, ibuprofen, methyl dihydrojasmonate, tris(2-chloroethyl)phosphate, triclosan, and tonalide) in lettuce (Lactuca sativa L.). After 28 days of irrigation with water containing EOCs at 15 µg L-1, the average EOC concentration in roots and leaves decreased by 20–76% in biochar amended soil relative to non BC-amended soil. In addition, the enantiomeric fractions (EF) of ibuprofen (IBU) in biochar amended soils (EF = 0.58) and unamended soils (EF = 0.76) suggest that the IBU sorbed fraction in BC is more recalcitrant to its biodegradation.