Sorption of Enrofloxacin and Ciprofloxacin in Agricultural Soils: Effect of Organic Matter

Abstract

Large amounts of fluoroquinolones (FQs), highly used antimicrobials in veterinary medicine, enter the soil directly through the application of manure contaminated with these chemicals. The environmental mobility of this contaminant is mainly governed by its retention in soil. The aim of this study was to examine the contribution of humic acid (HA), an organic matter (OM) surrogate, to the sorption of FQs in natural soils. Sorption of enrofloxacin and ciprofloxacin was studied in two completely different Spanish agricultural soils with similar pH. The soils tested were amended with different concentrations of HAs (0%, 1%, 3% and 5%; wt/wt). The results showed that addition of HA to the soil samples increased the magnitude of sorption and changed the sorption behaviour. However, the effect was only apparent at 3-5% HA content and its extent was dependent on both the sorbent and the sorbate. At soil pH around 7.5, when zwitterionic species predominate in the solution, sorption of FQs onto the soil seems to be governed by OM content, which provides a source of available sites for cation-exchange mechanisms.

Methane production from antibiotic bearing swine wastewater using carbon‐based materials as electrons' conduits during anaerobic digestion

“…Below these pH values, the surface of the materials is positively charged; conversely, over these pH values, negative charges prevail on surface. In addition, due to OTC (pK a1 = 3.3, pK a2 = 7.5, pK a3 = 8.9) 33 and ERX (pK a1 = 6.09, pK a2 = 7.9) 34 are molecules that act as zwitterions at the pH value (7.64) in which the adsorption tests were conducted, it is expected that electrostatic attractions occur between positive and negative charges of functional groups of materials and antibiotics to promote adsorption. For instance, the adsorption on GAC at pH 7.64 occurs due to its negative charges in acid sites (eg, deprotonated carboxylic groups: COO − ) at this pH value, which are attracted to positive charges of protonated pyrazine ring of the zwitterionic form of ERX.…”

Toxic Effects of Single Antibiotics and Antibiotics in Combination on Germination and Growth of Sinapis alba L.

“…The direct phytotoxicity of antibiotics on plant growth can be estimated by using phytotoxkits but needs to be proven by plant growth experiments. In the conducted trials, very high concentrations of antibiotics were tested for their toxicity on plant growth to evaluate the effect concentrations (EC 25 , EC 50 , and EC 70 ) as key data for toxicity. Even if such high contaminations were rarely found in manure samples or soils, they could be of relevance.…”

“…Most antibiotics show adsorption to the soil matrix or to the soil organic matter, and this can change bioaccumulation and the toxicity considerably. Adsorption of EN to soil organic matter as proposed by Teixido et al [50] can be neglected in the presented pot trial as sand was used as a substrate. Therefore, in our case, adsorption resulting from charge-charge interactions between EN and quartz sand surfaces as observed by Hari et al [51] seemed to be likely, as EN was strongly bound to the soil surface and could not be detected deeper than 5 cm below the surface.…”

Occurrence, Distribution, and Ecological Risk Assessment of Antibiotics in Selected Urban Lakes of Hanoi, Vietnam

“…Among five investigated groups of antibiotics, quinolones were ubiquitously detected in sediment with highest frequencies ranging from 64% to 100%, except for MXF which only was found in Yen So Lake. It was noted that the sorption of quinolones was remarkably strong compared to other antibiotics [50]. Concentrations of OFL varied from 3.51 ng/g to 113.9 ng/g (mean: 32.6 ng/g, DF � 36%, DF � 36%) in West Lake and ranged from 281.36 ng/g to 4,017 ng/g (mean: 1,416 ng/g, DF � 93%) in Yen So Lake.…”