Co-contaminants and factors affecting the sorption behaviour of two sulfonamides in pasture soils (original) (raw)
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… of 19th World …, 2010
We have investigated the sorption potential of three sulfonamides (SAs) in six New Zealand dairy farming soils using a modified batch equilibrium method employing 0.005 M CaCl 2 as background solution. Both liquid and solid phases were extracted to analyse for the antibiotic concentrations in order to avoid underestimation that may arise a result of photolysis or biotic degradation. The experimental data were later used to construct Freundlich isotherms to determine the effective distribution coefficients. Low log K oc value for all SAs suggests considerable leaching potential for SAs under conditions that are conducive for leaching. The sorption affinity for all soils followed the trend SCP>SMZ>SMO.
Effects of Sorbate Speciation on Sorption of Selected Sulfonamides in Three Loamy Soils
Journal of Agricultural and Food Chemistry, 2007
Sorption of sulfamethazine (SMN) and sulfathiazole (STZ) was investigated in three soils, a North Carolina loamy sand, an Iowa sandy loam, and a Missouri loam, under various pH conditions. A significant increase in the sorption coefficient (K D ) was observed in all three soils, as the sulfonamides converted from an anionic form at higher pH to a neutral/cationic form at lower pH. Above pH 7.5, sulfonamides exist primarily in anionic form and have higher aqueous solubility and no cationic character, thereby consequently leading to lower sorption to soils. The effect of speciation on sorption is not the same for all sulfonamides; it is a function of the pH of the soil and the pK a of the sulfonamides. The results indicate that, for the soils under investigation, SMN has comparatively lower K D values than STZ. The pH-dependent sorption of sulfonamides was observed to be consistent in all three soils investigated. The K D values for each speciated formscationic, neutral, and anionicswere calculated using an empirical model in which the species-specific sorption coefficients (K D0 , K D1 , and K D2 ) were weighted with their respective fractions present at any given pH.
The Science of the total environment, 2014
We investigated the sorption potential and transport behaviour of three sulfonamides, namely, sulfamethoxazole (SMO), sulfachloropyridazine (SCP) and sulfamethazine (SM), and a conservative bromide tracer (Br(-)) in two undisturbed soil columns collected from the dairy farming regions in the North Island of New Zealand. Based on the low log Koc values obtained from the sorption study, all three sulfonamides are likely to have high mobility, making them a potential threat to surface and ground water. Soil column studies also showed that the mobility of the sulfonamides varied among soils and antibiotic type. Sulfonamides exhibited a mobility pattern similar to that of conservative Br(-) tracer. Considerable retardation was observed for the Hamilton soil, and the delayed peak arrival time (or maxima) was due to the role of sorption-related retention processes under saturated flow conditions. Residual antibiotic concentrations for SMO and SCP were detected in all soil sections includin...
Sulfadimethoxine and sulfaguanidine: Their sorption potential on natural soils
Chemosphere, 2012
Sulfonamides (SAs) are one of the oldest groups of veterinary chemotherapeutic agents. As these compounds are not completely metabolized in animals, a high proportion of the native form is excreted in feces and urine. They are therefore released either directly to the environment in aquacultures and by grazing animals, or indirectly during the application of manure or slurry. Once released into the environment, SAs become distributed among various environmental compartments and may be transported to surface or ground waters. The physicochemical properties of SAs, dosage and nature of the matrix are the factors mainly responsible for their distribution in the natural environment. Although these rather polar compounds have been in use for over half a century, knowledge of their fate and behavior in soil ecosystems is still limited. Therefore, in this work we have determined the sorption potential of sulfadimethoxine and sulfaguanidine on various natural soils. The influence on sorption of external factors, such as ionic strength and pH, were also determined. The sorption coefficients (K d ) obtained for the sulfonamides investigated were quite low (from 0.20 to 381.17 mL g À1 for sulfadimethoxine and from 0.39 to 35.09 mL g À1 for sulfaguanidine), which indicated that these substances are highly mobile and have the potential to run off into surface waters and/or infiltrate ground water. Moreover, the sorption of these pharmaceuticals was found to be influenced by OC, soil solution pH and ionic strength, with higher K d values for soils of higher OC and lower K d values with increasing pH and ionic strength.
Sulfamethazine Sorption to Soil: Vegetative Management, pH, and Dissolved Organic Matter Effects
Journal of Environment Quality, 2013
Elucidating veterinary antibiotic interactions with soil is important for assessing and mitigating possible environmental hazards. Th e objectives of this study were to investigate the eff ects of vegetative management, soil properties, and >1000 Da dissolved organic matter (DOM >1000 Da ) on sulfamethazine (SMZ) behavior in soil. Sorption experiments were performed over a range of SMZ concentrations (2.5-50 μmol L −1 ) using samples from three soils (Armstrong, Huntington, and Menfro), each planted to one of three vegetation treatments: agroforestry buff ers strips (ABS), grass buff er strips (GBS), and row crops (RC). Our results show that SMZ sorption isotherms are well fi tted by the Freundlich isotherm model (log K f = 0.44-0.93; Freundlich nonlinearity parameter = 0.59-0.79). Further investigation of solid-to-solution distribution coeffi cients (K d ) demonstrated that vegetative management signifi cantly (p < 0.05) infl uences SMZ sorption (ABS > GBS > RC). Multiple linear regression analyses indicated that organic carbon (OC) content, pH, and initial SMZ concentration were important properties controlling SMZ sorption. Study of the two most contrasting soils in our sample set revealed that increasing solution pH (pH 6.0-7.5) reduced SMZ sorption to the Armstrong GBS soil, but little pH eff ect was observed for the Huntington GBS soil containing 50% kaolinite in the clay fraction. Th e presence of DOM >1000 Da (150 mg L −1 OC) had little signifi cant eff ect on the Freundlich nonlinearity parameter; however, DOM >1000 Da slightly reduced SMZ K d values overall. Our results support the use of vegetative buff ers to mitigate veterinary antibiotic loss from agroecosystems, provide guidance for properly managing vegetative buff er strips to increase SMZ sorption, and enhance understanding of SMZ sorption to soil.
Sorption, Fate, and Mobility of Sulfonamides in Soils
Water, Air, & Soil Pollution, 2011
Sulfonamides (SAs) are one of the broadly used antibiotics in domestic animal operations and have a notable potential of entering the environment through animal manure management practices. In this study, sulfamethazine (SMZ) was used as a prototype to study the sorption, fate, and transport of SAs in soil-water systems using batch and miscibledisplacement experiments. Sulfamethazine was degraded to a polar metabolite (PM). The batch experiments indicated that the linear sorption partitioning coefficient (K d ) values for the PM ranged from 7.5 to 206.2 L kg −1 . Strong relationships between the sorption of PM and various soil fractions and organic matter were also observed. The miscibledisplacement experiments showed that 33-70% of SMZ was degraded within 6 h during transport in the soil columns. Also, 69-99.7% of SMZ and PM were recovered in the effluents suggesting their high mobility. Also, the simultaneous degradation, sorption, and transport of SMZ and PM were described using a two-site chemical nonequilibrium fate and transport model, using the K d values obtained from the batch experiments. The parameters of this model were uniquely estimated using a global optimization strategy, the stochastic ranking evolutionary strategy.
Sorption of Sulfonamide Pharmaceutical Antibiotics on Whole Soils and Particle-Size Fractions
Journal of Environment Quality, 2004
Sørensen, 2000). Consequently, residues of potentially harmful pharmaceutical antibiotics are found in soils Residues of pharmaceutical antibiotics are found in the environand adjacent environmental compartments (Hirsch et ment, whose fate and effects are governed by sorption. Thus, the extent and mechanisms of the soil sorption of p-aminobenzoic acid and al., 1999; Hamscher et al., 2002). Numerous pharmaceufive sulfonamide antibiotics (sulfanilamide, sulfadimidine, sulfadia-tical antibiotics are persistent in the environment (Gazine, sulfadimethoxine, and sulfapyridine) were investigated using topvalchin and Katz, 1994; Hamscher et al., 2002). Hence, soils of fertilized and unfertilized Chernozem and their organic-minthey can enter the food chain via uptake by plants or eral particle-size fractions. Freundlich adsorption coefficients (K f) translocation into ground water (Migliore et al., 1995; ranged from 0.5 to 6.5. Adsorption increased with aromaticity and Boxall et al., 2002). In addition, antibiotics can provoke electronegativity of functional groups attached to the sulfonyl-phenylthe formation of resistant microorganisms (Huysman et amine core. Adsorption to soil and particle-size fractions increased al., 1993; Gavalchin and Katz, 1994). The translocation in the sequence: coarse silt Ͻ whole soil Ͻ medium silt Ͻ sand Ͻ and bioactivity of antibiotics are influenced by soil sorpclay Ͻ fine silt and was influenced by pH. Sorption nonlinearity (1/n Յ tion, governing the distribution and transfer between 0.76) indicated specific interactions with functional groups of soil organic matter (SOM). Phenolic and carboxylic groups, N-hetero-phases and thus the resulting mobile and bioavailable cyclic compounds, and lignin decomposition products were tentatively fractions of the antibiotics. However, knowledge about assigned as preferred binding sites using statistical analysis of pyrolythe extent and mechanisms of antibiotic sorption in soils sis-mass spectra and adsorption coefficients. Adsorption of sulfonis still scarce (Thiele-Bruhn, 2003). amides to mineral soil colloids was weaker and resulted in a stronger As is with many other pharmaceuticals, sulfonamides desorption from clay-size fractions. Moreover, steric accessibility of are both fairly water-soluble and polar compounds, which organic-mineral complexes in clay-size fractions was significantly reionize depending on the pH of the matrix. In addition duced. With a quantitative structure-property relationship (QSPR) to hydrophobic partitioning, these compounds may sorb model, combining the organic carbon concentration, the sulfonamides' to soils via cation exchange, cation bridging, surface chromatographic capacity factor (k), and nondissociated species concentration (CF a), distribution coefficients (K d) were estimated with a complexes, and hydrogen bonding (Tolls, 2001). Accordcross-validated regression coefficient Q 2 ϭ 0.71. Modeling and molecingly, sorption of sulfonamides, such as sulfapyridine, ular mechanics calculations of antibiotic-SOM complexes showed varies between soils and is affected by the quantity, compreferred site-specific sorption via hydrogen bonds and van der Waals position, and structure of soil colloids (Thiele, 2000). The interactions. Distinct chemical structural properties, such as aromaticeffects of the variation in quantity and quality of soil ity and van der Waals volumes, correlated with the sorption data. components can be elucidated in sorption experiments using particle-size fractions obtained from physical separation of whole-soil samples. These fractions contain A ntibiotic pharmaceuticals are widely used for the mineral colloids and soil organic matter (SOM) of differ
Long-Term Sorption and Desorption of Sulfadiazine in Soil: Experiments and Modeling
Journal of Environmental Quality, 2010
Antibiotics, such as sulfadiazine (SDZ), may enter arable soil by spreading of manure of medicated husbandry or directly by the excrement of grazing animals. Knowledge of the fate of antibiotics in soils is crucial for assessing the environmental risk of these compounds, including possible transport to ground water. Kinetic sorption of 14 C-labeled SDZ (4-amino-N-pyrimidin-2-yl-benzenesulfonamide) was investigated using the batch technique. Th e batch sorption-desorption experiments were conducted at various concentration levels (0.044-13 mg L −1 initial solute concentration) and time scales (0.75-272 d). Sorption of 14 C-SDZ in the investigated silty loam was time dependent and strongly nonlinear in the solution phase concentration. Th e time to reach an apparent sorption equilibrium was about 20 d. However, desorption was very slow, and 41 d were insuffi cient to reach the desorption equilibrium. An inverse modeling technique was used to identify relevant sorption processes of 14 C-SDZ during the batch experiments. Among the investigated two-and three-domain sorption models, adsorption and desorption of 14 C-SDZ were best described with a new model defi ning two sorption domains and four parameters. Whereas sorption in the fi rst sorption domain was nonlinear and instantaneous, solute uptake in the second sorption domain was rate limited following fi rst-order kinetics. Desorption followed the same rate law until an equilibrium distribution was reached. After that, desorption was assumed to be impossible due to partly irreversible sorption. Although the proposed model needs further validation, it contributes to the discussion on complex sorption processes of organic chemicals in soils.
Science of The Total Environment, 2020
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The Science of the total environment, 2014
Adsorption and desorption are important processes that influence the transport, transformation and bioavailability of antimicrobials in soils. The adsorption-desorption characteristics of sulfadimethoxine, sulfaquinoxaline and sulfamethazine in Brazilian soils (sandy, sandy-clay and clay) were evaluated using the batch equilibrium method. The sulfonamides were quantified in the soil solutions by a previously in house validated HPLC-PAD method. The adsorption/desorption data for the sulfonamides in soils fit the Freundlich isotherms well in the logarithmic form. The Freundlich adsorption coefficients ranged from 1.4 to 19.0 μg(1-1/n)(cm(3))(1/n)g(-1), suggesting that all of the sulfonamides weakly adsorbed on the evaluated soils. The Freundlich desorption coefficients ranged from 0.85 to 24.8 μg(1-1/n)(cm(3))(1/n)g(-1), indicating that the sulfonamides tend to be leached from soils with high sand and low organic carbon contents, suggesting that there is high potential for surface and...