The dissipation and transport of veterinary antibiotics in a sandy loam soil (original) (raw)
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The sorption and transport of a sulphonamide antibiotic in soil systems
Toxicology letters, 2002
Veterinary medicines are administered to animals to treat disease and protect their health. After administration, the substances can be metabolised and a mixture of the parent compound and metabolites may be excreted in the urine and faeces. For animals on pasture, the excreta will be released directly to soil whereas for intensively reared animals, the main route of entry will be through slurry and manure spreading. Whilst the behaviour of other classes of substance (e.g. pesticides and nutrients) that are applied to soil is well understood, limited information is available on the transport and fate of veterinary medicines applied to soils. Laboratory and field studies were, therefore, performed to investigate the sorption behaviour of the sulfonamide antibiotic, sulfachloropyridazine, in soil and to assess the potential for sulfachloropyridazine to move from soil to surface waters and groundwaters. Sorption coefficients (K D ) for the compound in soil and soil/slurry mixtures were low (ranging from 0.9 to 1.8 l kg − 1 ) and indicated that the substance would be highly mobile. Field studies on a clay field supported these observations and demonstrated that, after application, the compound was rapidly transported to surface waters, concentrations of up to 590 mg l − 1 being observed in drainage waters. Leaching studies at a sandy site indicated that the substance had a low potential to leach to groundwaters, concentrations in the soil pore water being below or close to analytical detection limits. An assessment of currently available models for predicting concentrations of veterinary medicines entering surface waters indicated that for sulfachloropyridazine, the methods provide reasonable estimates, predicted concentrations being within a factor of two of the maximum measured concentrations. The approaches may not, however, be appropriate for use on highly hydrophobic substances or for predicting groundwater concentrations.
Tetracycline and Sulfonamide Antibiotics in Soils: Presence, Fate and Environmental Risks
Processes
Veterinary antibiotics are widely used worldwide to treat and prevent infectious diseases, as well as (in countries where allowed) to promote growth and improve feeding efficiency of food-producing animals in livestock activities. Among the different antibiotic classes, tetracyclines and sulfonamides are two of the most used for veterinary proposals. Due to the fact that these compounds are poorly absorbed in the gut of animals, a significant proportion (up to ~90%) of them are excreted unchanged, thus reaching the environment mainly through the application of manures and slurries as fertilizers in agricultural fields. Once in the soil, antibiotics are subjected to a series of physicochemical and biological processes, which depend both on the antibiotic nature and soil characteristics. Adsorption/desorption to soil particles and degradation are the main processes that will affect the persistence, bioavailability, and environmental fate of these pollutants, thus determining their pot...
Impacts of Global Climate Change, 2005
Veterinary antibiotics used in livestock operations have been identified as one of the major sources of antibiotics in the environment. Antibiotics, such as sulfonamides, used in feedlots are excreted in a partially metabolized form in the urine and fecal material of livestock animals. The current practice of land application of untreated lagoon waste from livestock operations has a serious potential to contaminate groundwater. This paper intends to elucidate some of the key aspects of the mobility of sulfonamides, such as sulfachloropyridazine (SCPD) and sulfamerazine (SMRZ), in the environment. To achieve this objective, column studies were performed for SCPD and SMRZ in three soils: Missouri loam, North Carolina loamy sand, and Iowa sandy loam. A pulse containing a suite of eight antibiotics was injected instantaneously and the filtrate was analyzed for antibiotics concentrations. In all three soils, based on the initial soil pH, both SCPD and SMRZ were observed to be highly mobile at high pH value; however, significant retardation was observed at lower pH. Enhanced mobility of these compounds observed at high pH was due to the cumulative effect of the anionic form of antibiotics, the polar nature of soil material, and the increased solubility observed at high pH value. Conversely, severe attenuation of these compounds observed at lower pH values was due to the increased interaction of cationic and neutral forms of antibiotics with soil material. The recoveries and the sorption experiment performed for SCPD and Iowa sandy loam indicated that the mobility of sulfonamides, in general, is contingent upon the alkalinity of the soil. Considerable decrease in the sorption coefficient was observed at high pH value.
Chemistry Central Journal, 2014
The increased use of veterinary antibiotics in modern agriculture for therapeutic uses and growth promotion has raised concern regarding the environmental impacts of antibiotic residues in soil and water. The mobility and transport of antibiotics in the environment depends on their sorption behavior, which is typically predicted by extrapolating from an experimentally determined soil-water distribution coefficient (Kd). Accurate determination of Kd values is important in order to better predict the environmental fate of antibiotics. In this paper, we examine different analytical approaches in assessing Kd of two major classes of veterinary antibiotics (sulfonamides and macrolides) and compare the existing literature data with experimental data obtained in our laboratory. While environmental parameters such as soil pH and organic matter content are the most significant factors that affect the sorption of antibiotics in soil, it is important to consider the concentrations used, the an...
Environmental behavior and analysis of veterinary and human drugs in soils, sediments and sludge
Trends in Analytical Chemistry, 2003
uman and veterinary drugs are continually being released in the environment mainly as a result of manufacturing processes, disposal of unused or expired products, and excreta. Because of their physical and chemical properties, many of these substances or their bioactive metabolites end up in soils and sediments, where they can accumulate and induce adverse effects in terrestrial or aquatic organisms. Among these effects, bacterial resistance is increasingly observed and is caused by the extensive use of antibiotics in animal and fish farming and the growing practice of adding manure and sewage sludge to agricultural fields, which is of particular concern. Literature on the environmental analysis and occurrence of drugs has addressed a very small percentage of these compounds, so very little information is available about the fate and the potential effects of drugs in the environment. This article presents an overview of recent developments in the determination of veterinary and human drugs in solid environmental matrices, including soil, sediment and sludge. The analysis of pharmaceuticals in the such samples has always been carried out by high-performance liquid chromatography coupled to ultraviolet detection, and, to a lesser extent, to mass spectrometry and fluorescence detection. In most cases, sample pretreatment includes extraction of the solid sample and further purification of the extract by solid phase extraction with C18 sorbents. In addition to analytical articles, this overview includes papers concerning usage of drugs, as well as sources, fate, persistence, and effects of pharmaceuticals in solid environmental matrices.
Sorption kinetics of chlortetracycline and tylosin on sandy loam and heavy clay soils
Antibiotics may appear in the environment when manure, sewage sludge, and other organic amendments are added to soils. There is concern that the presence of antibiotics in soils may lead to the development of antibiotic-resistant bacteria which may spread to the rest of the environment. This paper aims at evaluating the sorption kinetics of two antibiotics frequently used in pig production. The results indicate that sorption of chlortetracycline (CTC) and tylosin (TYL) in sandy loam and clay occurs very fast. More than 95% of the CTC adsorption is completed within 10 min on both soils and of TYL within 3 h. These results suggest that 24-h soil and antibiotic solution mixtures is enough for sorption studies. Also, there is less likelihood that these antibiotics will leach through soil and appear in the ground water since their sorption on soils is very high unless they are carried by soil particles through preferential flow. There was also no effect of soil sterilization on sorption kinetics of these antibiotics thus suggesting that there is minimal probability of the antibiotics degrading by microorganisms during 24- to 48-h adsorption studies.
Occurrence and Environmental Fate of Veterinary Antibiotics in the Terrestrial Environment
Water, Air, & Soil Pollution, 2011
A wide variety of veterinary antibiotics (VAs) has been detected in environmental water samples, and this is of potential environmental concern due to their adverse effects. In particular, the potential for development of antibiotic-resistant bacteria has raised social concerns leading to intensive investigation regarding the influence of antibiotics on human and ecosystem health. One of the main sources of antibiotic effluence to the environment is livestock manures that often contain elevated levels of VAs that survive normal digestive procedures following medication in animal husbandry because unlike human waste, waste generated on farms does not undergo tertiary wastewater treatment, and consequently, the concentration of antibiotics entering the environment is expected to be larger from farming practices. Animal feed is often supplemented with VAs to promote growth and parasite resistance in the medicated animals, and this practice typically resulted in higher use of VAs and consequential excretion from livestock through urine and feces. The excretion rate varied depending on the type of VA used with around 75, 90, and 50-100% being excreted for chlortetracycline, sulfamethazine, and tyolsin, respectively. The excreted VAs that initially present in livestock manures were degraded more than 90% when proper composting practice was used, and hence, this can be employed as a management strategy to decrease VA environmental loads. The reduction of VA concentrations during composting was mainly attributed to abiotic processes rather than biotic degradation. The VAs released to soils by the application of manure and manure-based composts can be degraded or inactivated to various degrees through abiotic process such as adsorption to soil components. Depending on the antibiotic species and soil properties, residues can be transferred to groundwater and surface water through leaching and runoff and can potentially be taken up by plants.