Fate of the antibiotic sulfadiazine in natural soils: Experimental and numerical investigations

Abstract

Based on small-scale laboratory and field-scale lysimeter experiments, the sorption and biodegradation of sulfonamide sulfadiazine (SDZ) were investigated in unsaturated sandy and silty-clay soils. Sorption and biodegradation were low in the laboratory, while the highest leaching rates were observed when SDZ was mixed with manure. The leaching rate decreased when SDZ was mixed with pure water, and was smallest with the highest SDZ concentrations. In the laboratory, three transformation products (TPs) developed after an initial lag phase. However, the amount of TPs was different for different mixing-scenarios. The TP 2-aminopyrimidine was not observed in the laboratory, but was the most prevalent TP at the field scale. Sorption was within the same range at the laboratory and field scales. However, distinctive differences occurred with respect to biodegradation, which was higher in the field lysimeters than at the laboratory scale. While the silty-clay soil favored sorption of SDZ, the sandy, and thus highly permeable, soil was characterized by short half-lives and thus a quick biodegradation of SDZ. For 2-aminopyrimidine, half-lives of only a few days were observed. Increased field-scale biodegradation in the sandy soil resulted from a higher water and air permeability that enhanced oxygen transport and limited oxygen depletion. Furthermore, low pH was more important than the organic matter and clay content for increasing the biodegradation of SDZ. A numerical analysis of breakthrough curves of bromide, SDZ, and its TPs showed that preferential flow pathways strongly affected the solute transport within shallow parts of the soil profile at the field scale. However, this effect was reduced in deeper parts of the soil profile. Due to high field-scale biodegradation in several layers of both soils, neither SDZ nor 2-aminopyrimidine was detected in the discharge of the lysimeter at a depth of 1 m. Synthetic 50 year long simulations, which considered the application of manure with SDZ for general agricultural practices in Germany and humid climate conditions, showed that the concentration of SDZ decreased below 0.1 μg/L in both soils below the depth of 50 cm.

Evaluation of Sulfadiazine Degradation in Three Newly Isolated Pure Bacterial Cultures

“…Similarly, in Microbacterium lacus strain SDZm4, SDZ was transformed into 2-aminopyrimidine [ 20 ]. The metabolite 2-aminopyridine was observed not only by microbial process, but also detected during photolysis, electrochemical oxidation and sorption experiments by soils [ 1 , 18 , 31 , 32 ]. Furthermore, in strain 2APm3, 2-aminopyrimidine was metabolized into two by-products with one of that identified as 2-amino-4-hydroxypyrimidine [ 21 ].…”

Recent Developments and Applications of the HYDRUS Computer Software Packages

“…The types of applications are very broad, ranging between agricultural problems evaluating different irrigation schemes, the effects of plants on the soil water balance and groundwater recharge (see Agricultural Applications section below), to many environmental applications simulating the transport of different solutes and particle‐like substances (see Transport of Particle‐Like Substances section) as well as evaluating the effects of land use and environmental changes. While many early applications focused mostly on subsurface flow processes, the relatively general formulation of the transport and reaction terms in the HYDRUS models makes it possible to simulate the fate and transport of many different solutes including nonadsorbing tracers, radionuclides (e.g., Pontedeiro et al, 2010; Matisoff et al, 2011; Merk, 2012; Xie et al, 2013), mineral N species (e.g., Li et al, 2015), pesticides (Pot et al, 2005; Dousset et al, 2007; Köhne et al, 2009b), chlorinated aliphatic hydrocarbons (e.g., Kasaraneni et al, 2014; Ngo et al, 2014), hormones (e.g., Casey et al, 2005; Arnon et al, 2008; Chen et al, 2013), antibiotics (e.g., Wehrhan et al, 2007; Unold et al, 2009; Chu et al, 2013; Engelhardt et al, 2015), explosives and propellants (e.g., Dontsova et al, 2006, 2009; Alavi et al, 2011), as well as many particle‐like substances such as viruses, colloids, bacteria, nanoparticles, and carbon nanotubes (see Transport of Particle‐Like Substances section).…”

“…Agricultural applications of the HYDRUS modules often involve evaluations of various irrigation schemes (e.g., Cote et al, 2003; Ben‐Gal et al, 2004; Gärdenäs et al, 2005; Dabach et al, 2013), studies of root water uptake and groundwater recharge (e.g., Turkeltaub et al, 2014; Neto et al, 2016), and the transport of agricultural contaminants (Wehrhan et al, 2007; Unold et al, 2009; Engelhardt et al, 2015). For example, Gärdenäs et al (2005) used HYDRUS (2D/3D) to evaluate water and N leaching scenarios for three different microirrigation systems (surface and subsurface drip and sprinkler irrigation) and five different fertigation strategies.…”

Lead removal from aqueous solutions by raw sawdust and magnesium pretreated biochar: Experimental investigations and numerical modelling

“…Several numerical models have been used for the prediction of inorganic and organic pollutants transport at laboratory scale, in real sites and for hypothetical pollution cases (Engelhardt et al, 2015;Jacques et al, 2008;Jellali et al, 2010;K€ ohne et al, 2009;Suarez et al, 2007). They demonstrated that the rates of pollutants migration depend on a wide range of physical and chemical porous media characteristics such as permeability, porosity, dispersivity, interconnectivity of macropores, mineralogy and organic constitution (Jacques et al, 2008;K€ ohne et al, 2009).…”