Impact of biochar amendment on the uptake, fate and bioavailability of pharmaceuticals in soil-radish systems

Biochar amendment changed soil-bound fractions of silver nanoparticles and ions but not their uptake by radish at an environmentally-relevant concentration

“…The elemental content of biochar was 76.9% C, 0.2% N, and 1.2% H by weight. Specific surface area and pore volume were determined to be 543.6 m 2 /g and 0.3 cm 3 /g, respectively (Li et al 2020). Its structural morphology was examined using scanning electron microscopy (SEM, JEOL 7500F, Japan) and had highly porous structure and rough surfaces (Fig.…”

“…It had a pH of 7.8, OM of 2.3%, and cation exchange capacity (CEC) of 7.9 meq/100 g. Biochar amendment (0.1% and 1.0%) had an insignificant influence on the soil pH ( Fig. S3), OM, and CEC (Li et al 2020). The background Ag concentration in the soil was measured at 0.26 mg/kg.…”

“…Radish plants were grown in soil pots spiked with Ag (Ag NPs or AgNO 3 ) and fifteen selected pharmaceuticals (acetaminophen, caffeine, carbadox, carbamazepine, estrone, lamotrigine, lincomycin, monensin, oxytetracycline, sulfadiazine, sulfamethoxazole, triclosan, trimethoprim, tylosin, and 17 β-estradiol) to mimic the co-contamination of pharmaceuticals, engineered nanoparticles, and/or heavy metals (Deng et al 2017). This paper only reported the study on Ag, and the work on pharmaceuticals was reported in a companion paper (Li et al 2020). The addition of pharmaceuticals did not change the biomass and Ag uptake of radish plants.…”

“…The experimental design is summarized in Table S1 and described at the following. To evenly distribute Ag in the soil, about 1 kg of the soil was first spiked with Ag NPs or Ag + along with the fifteen pharmaceuticals in acetone and then thoroughly mixed in a fume hood (Li et al 2019(Li et al , 2020. After evaporation of the solvent, the spiked soil portion and a predetermined amount of biochar were mixed with a predetermined amount of the clean soil in a clean motorized concrete mixer to homogenize the spiked Ag and pharmaceuticals into the soil.…”

“…All plant samples were kept in a desiccator until further use. Meanwhile, the soil samples in the radish-growing and radish-free pots were collected, and soil pore water was extracted immediately using a centrifugation-filtration method described previously (Li et al 2019(Li et al , 2020. Briefly, aliquots (25 g) of a soil sample was placed on a layer of glass wool in a 20 mL disposable plastic syringe.…”