Determination of pharmaceuticals in environmental waters by liquid chromatography/electrospray ionization/tandem mass spectrometry

A Multi-Residue Analytical Method for Assessing the Effects of Stacking Treatment on Antimicrobial and Coccidiostat Degradation in Broiler Litter

Antimicrobial drugs and coccidiostat compounds are commonly used in poultry farming. These compounds are subsequently excreted and released into the environment via broiler litter (BL) and can re-enter the food chain as fertilizer or animal feed. Such residue in animal feed can encourage the appearance of antibiotic-resistant bacteria as well as toxicity. Most analytical methods used to identify and quantitate these drug residues are traditional, and are specific to some antimicrobials and present limitations in assessing complex matrixes like BL. The aim of this study was to develop a multi-residue analytic method for assessing 30 antimicrobial drugs and coccidiostats associated with BL. We investigated the presence and the effects of biotic stack treatment on the degradation of drug residue in BL. Liquid-liquid extraction (LLE) and solid phase extraction (SPE) were replaced by Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) clean-up steps and detected by liquid chromatography mass spectrometry (LC/MS/MS). Results show that a wide spectrum of residues were detected from 0.4 to 8.9 mg kg-1. Following lab-scale stacking treatment, tilmicosin and eight coccidiostats persisted in BL (26-100%). This research supports the need for better understanding, regulation, and management of the use of BL that might carry a high risk of residue drugs.

Veterinary pharmaceutical as emerging contaminants in wastewater and surface water: An overview

Veterinary pharmaceuticals have become of interest due to their indiscriminate use. Thus, this paper compiles studies on detection in surface and wastewater, and the treatment applied for their removal. Additionally, a case study was performed to evaluate its commercialization, as the ecological risk assessment for the most relevant compounds. 241 compounds were detected. The highest concentrations were found for antibiotics such as oxytetracycline, amoxicillin, and monensin, with values up to 3732.4 µg/L. Biological treatments have been mainly reported, obtaining removal greater than 80% for sulfadiazine, sulfamethazine, sulfamethoxazole, enrofloxacin, and oxytetracycline. Considering the case study, enrofloxacin and oxytetracycline were widely commercialized. Finally, there was a low risk for the species exposed to enrofloxacin, in contrast, the species exposed to oxytetracycline presented a high risk of long-term mortality. Concluding that veterinary compounds have emerged as a significant concern regarding water source contamination, owing to their potential adverse effects on aquatic biota and even human. This is particularly relevant because many water bodies that receive wastewater are utilized for drinking water purposes. Consequently, the development of comprehensive, full-scale systems for efficient antibiotic removal before their introduction into water sources becomes imperative. Equally important is the need to reconsider their extensive use altogether.

Electrospray ionization mass spectrometry adduct formation by mobile phase additives: A case study using nitrile functional groups containing selective androgen receptor modulators

RATIONALE

The formation of mass adducts is common during electrospray ionization mass spectrometry (ESI-MS). However, the mechanism that leads to adduct formation is poorly understood and difficult to control. Multiplication of mass adducts at once will adversely impact the sensitivity of mass analysis and cause misinterpretation of the level of detection. Prior studies on selective androgen receptor modulators (SARMs) revealed an immense mass adduct formation in both positive and negative ESI modes.

METHODS

In this study, additives in the mobile phases are investigated as a potential means of controlling mass adduct formation in various SARMs.

RESULTS

The first evidence of chloride adduct formation when SARMs are detected via ESI-MS has been reported in this research. A series of mobile phase combinations were tested to achieve the optimal condition for HPLC-MS. A comparison was also made between adduct formation on various grades of water used for preparing the mobile phase. A validation study using equine urine and plasma was also conducted to assess the suitability of the developed method.

CONCLUSION

The results of this study will allow for a more accurate identification of SARMs, which will make it easier to investigate their illicit use in horse racing.

Influence of physicochemical parameters on PPCP occurrences in the wetlands

There have been many global studies on the occurrence and distribution of pharmaceuticals and personal care products (PPCPs) in the aquatic resources, but reports on the effects of physicochemical properties of water on their concentrations are very scarce. The amounts and removal of these contaminants in various environmental media are dependent on these physicochemical properties, which include pH, temperature, electrical conductivity, salinity, turbidity, and dissolved oxygen. Here, we reviewed the influence of these properties on determination of PPCPs. Reports showed that increase in turbidity, electrical conductivity, and salinity gives increase in concentrations of PPCPs. Also, neutral pH gives higher PPCP concentrations, while decrease in temperature and dissolved oxygen gives low concentration of PPCPs. Nevertheless, it is quite challenging to ascertain the influence of water quality parameters on the PPCP concentration, as other factors like climate change, type of water, source of pollution, persistence, and dilution factor may have great influence on the concentration of PPCPs. Therefore, routine monitoring is suggested as most water quality parameters vary because of effects of climate change.

Occurrence and fate of pharmaceuticals, personal care products (PPCPs) and pesticides in African water systems: A need for timely intervention

The occurrence of emerging contaminants (ECs) such as pharmaceuticals, personal care products (PPCPs) and pesticides in the aquatic environment has raised serious concerns about their adverse effects on aquatic species and humans. Because of their toxicity and bioactive nature, PPCPs and pesticides have more potential to impair water systems than any other contaminants, causing several adverse effects, including antibiotic resistance, reproductive impairment, biomagnification, bioaccumulation, etc. Over 35 publications from Africa have reported on the occurrence and fate of PPCPs and pesticides in African water systems with little or no data on remediation and control. As a result, adequate intervention strategies are needed for regulating the persistence of PPCPs and pesticides in African water systems.

When river water meets seawater: Insights into primary marine aerosol production

The impact of inorganic salts and organic matter (OM) on the production of primary marine aerosols is still under debate. To constrain their impact, we investigated primary aerosols generated by a sea-spray generator chamber using surface water samples from rivers, estuaries, and seas that were collected along salinity gradients in two temperate Korean coastal systems and one Arctic coastal system. Salinity values showed an increasing trend along the river-estuary-coastal water transition, indicating the lowest amount of inorganic salts in the river but the highest amount in the sea. In river samples, the lowest number concentration of primary aerosol particles (1.01 × 10³ cm^-3) was observed at the highest OM content, suggesting that low salinity controls aerosol production. Moreover, the number concentration of primary aerosols increased drastically in estuarine (1.13 × 10⁴ cm^-3) and seawater (1.35 × 10⁴ cm^-3) samples as the OM content decreased. Our results indicate that inorganic salts associated with increasing salinity play a much larger role than OM in aerosol production in river-dominated coastal systems. Laboratory studies using NaCl solution supported the conclusion that inorganic salt is a critical factor in modulating the particles produced from river water and seawater. Accordingly, this study highlights that inorganic salts are a critical factor in modulating the production of primary marine aerosols.

Spatial and seasonal variations of endocrine disrupting compounds in water and sediment samples of Markman Canal and Swartkops River Estuary, South Africa and their ecological risk assessment

The presence of pharmaceuticals in surface water and sediment has sparked up a global concern, as they could cause harm to human health. In this study, we investigated five pharmaceuticals (caffeine, carbamazepine, sulfamethoxazole, testosterone, and trimethoprim) in surface water and sediment samples from Swartkops River Estuary and Markman Stormwater Canal, in the Eastern Cape Province, South Africa. Ultra-Performance Liquid Chromatography (UPLC) systems coupled with a hyphenated quadrupole-time-of-flight mass spectrometry (QTOF-MS) was used for the analysis. Of the five pharmaceuticals investigated, three were detected in sediment samples at concentrations ranging from BDL - 23.86 μg/kg (dw). Caffeine and sulfamethoxazole were below the detection limit. The finding of this current study suggests that Markman and Motherwell's stormwater canals were potential contributors to pollution in Swartkops River Estuary. Ecotoxicity risk assessment indicated that trimethoprim and carbamazepine could constitute potential risk to aquatic organisms in Markman Canal and Swartkops Estuary, suggesting the need for proper control measure to prevent the pollution from toxicants in aquatic resources.

Occurrence and variations of pharmaceuticals and personal-care products in rural water bodies: A case study of the Taige Canal (2018-2019)

A systematic monitoring campaign of pharmaceuticals and personal-care products (PPCPs) was performed in the Taige Canal basin, which is located in a rural area of the Yangtze River Delta. A total of 55 out of 61 monitored PPCPs were detected, with concentrations up to 647 ng/L. The maximum concentrations of 75% of monitored antibiotics and 80% of non-antibiotics were above the median values of previously reported maximum concentrations in China, indicating that the basin is heavily contaminated. It is estimated that the PPCP mass flow of the Taige Canal (0.06-0.58 kg/day) entering into Lake Taihu is similar to that of the influent of a wastewater treatment plant. Analysis of the seasonal variation shows that, during the wet season, the average total concentration of sulfonamides was 8 and 11 times that of the normal season and dry season, respectively. The concentration of sulfachlorpyridazine accounted for 40.37% of total antibiotics, suggesting heavy pollution from the animal-breeding industry in this area. The PPCP mass flow rates observed in 2019 were lower than those of 2018 in the same season, and this interannual variation is mainly attributable to water pollution controls in the watershed. Combined analysis of ordination and clustering indicates that the distribution of PPCPs in the Taige Canal is affected by the confluence with Yong'an River and human activities such as water pollution control. Water-sediment distribution analysis demonstrates that the sediment-water distribution coefficients of quinolone and macrolide were higher than those of sulfonamide, lincosamide and chloramphenicol.

Implementing Green Analytical Methodologies Using Solid-Phase Microextraction: A Review

Implementing green analytical methodologies has been one of the main objectives of the analytical chemistry community for the past two decades. Sample preparation and extraction procedures are two parts of analytical method development that can be best adapted to meet the principles of green analytical chemistry. The goal of transitioning to green analytical chemistry is to establish new methods that perform comparably—or superiorly—to traditional methods. The use of assessment tools to provide an objective and concise evaluation of the analytical methods’ adherence to the principles of green analytical chemistry is critical to achieving this goal. In this review, we describe various sample preparation and extraction methods that can be used to increase the greenness of a given analytical method. We gave special emphasis to modern microextraction technologies and their important contributions to the development of new green analytical methods. Several manuscripts in which the greenness of a solid-phase microextraction (SPME) technique was compared to other sample preparation strategies using the Green Analytical Procedure Index (GAPI), a green assessment tool, were reviewed.

Temporal-spatial variation and environmental risk assessment of pharmaceuticals in tributaries of the Han River watershed, South Korea

Eight compounds from three categories of pharmaceuticals [5 antibiotics, 2 non-steroidal anti-inflammatory drugs, and 1 anti-epileptics] were monitored at 24 sites in the tributaries of the Han River watershed in South Korea, 2016. The seasonal occurrence, temporal-spatial variation, potential compound source(s), and a risk assessment of this watershed, which is the largest drinking water source in the country, were investigated. Clarithromycin was detected most frequently (72.2%) with the greatest median concentration (0.151 ± 0.072 μg L^-1), followed by carbamazepine and sulfamethoxazole. The seasonality of the pharmaceuticals was observed, with higher concentrations and detection frequencies in spring than in summer and autumn; this was possibly caused by lower levels of microbial activities associated with lower water temperatures than other seasons. In terms of geographical variation, urban areas had higher pharmaceutical concentrations than rural areas, which was attributed to the former's high population density and largest wastewater treatment plants (WWTPs) regardless of season. The total concentration and detection frequency of WWTPs were 12.4 and 2.5 times higher in downstream sites than upstream sites, thereby conveying that WWTPs were the main source for the presence of pharmaceuticals in tributaries. According to the results produced from calculations of the risk quotient (RQ) of aquatic organisms, clarithromycin and sulfamethazine were identified as posing relatively high ecological risk (RQ > 1) during the spring that was identified for this study. This study can provide policymakers with scientific support for prioritizing pollutant management and collections of global data on emerging pollutants.

Behavior of ionophore antibiotics in aquatic environments in Argentina: The distribution on different scales in water courses and the role of wetlands in depuration

We studied for the first time three ionophore anticoccidial drugs: monensin (MON), lasalocid (LAS), and salinomycin (SAL) as emerging pollutants originating from animal and plant husbandry in surface waters (n = 89) in one of the most extensive hydrological basins in South América (Del Plata basin). The soluble fraction of ionophores was pretreated by solid-phase extraction and analyzed by LC-MS/MS at a limit of detection of 1.7 ng·L^-1. A statistical approach noted the need to report parameters calculated by methods based on the number of observations and the censorship percentage over substitution methods for more precise estimations of environmental data with a high percentage of left-censored data. Water collectors adjacent to intensive-husbandry facilities, placed in direct runoffs from animal excreta, or in wastewater emissions contained median concentrations of MON and SAL approximately 70 times higher than those found in regional tributaries and main courses of 5 sub-basins of the pampas and mesopotamic regions, thus exhibiting a relevance to other similar agricultural pollutants widely reported as pesticides. Chemical speciation of these compounds in surface water was characterized especially for MON and SAL, where the pH and chemical oxygen demand of the natural water body was associated with the concentration of the soluble fraction. The concentrations in abundant rivers such as the Gualeguay deliver a contribution to a natural wetland such as the Paraná-River delta, which registered only one sample with a [MON] ≤ the limit of quantification. Since wetlands possess a limited removal capability, these affluent contributions recorded strongly indicate that attention must be paid to the development of guidelines involving quality criteria for assessing the impact of ionophore antibiotics on such ecosystems.

Housefly larvae (Musca domestica) significantly accelerates degradation of monensin by altering the structure and abundance of the associated bacterial community

Vermicomposting of livestock manure using housefly larvae is a promising biotechnology for waste reduction and control of antibiotic pollution. Monensin (MON), an ionophore polyether antibiotic (IPA), is widely used in broiler feed to control coccidiosis. However, MON residues in litter have become a major source of pollution in the environment. In this work, we studied the efficiency of housefly larvae (Musca domestica) on monensin attenuation during a 12-day laboratory scale vermicomposting experiment. We observed a 94.99% reduction in MON concentration after four days in treatment groups, while it took twelve days to remove more than 94.71% of MON in the control group. We found that the bacterial community composition of the substrate was reshaped by housefly larvae. From the treatment groups, three MON-degrading bacterial strains were isolated and identified as Acinetobacter sp., Stenotrophomonas sp. and Alcaligenes sp. based on 16 S rRNA gene sequence analysis. These three strains were among dominant the bacteria in treated substrates, showing between 52.80% and 89.25% degradation of MON in mineral salt medium within 28 days. Furthermore, two MON-degrading bacteria (Stenotrophomonas sp. and Alcaligenes sp.) were more abundant in treatment groups and larvae gut groups compared with those in control groups. The abundance enhancement of MON-degrading bacteria was related to the change in ambient temperature and pH in the substrates, which were affected by housefly larvae activities. Our results confirm that housefly larvae can significantly accelerate degradation of MON in chicken manure by increasing the abundance of MON-degrading bacteria.

Sulfonamides removal under different redox conditions and microbial response to sulfonamides stress during riverbank filtration: A laboratory column study

Riverbank filtration (RBF) as a barrier of pathogenic microorganisms and organic micropollutants recently has been proven capable of removing sulfonamides. However, the study about the effect of redox conditions on biodegradation of common and persistent sulfonamides in RBF is limited and the response of microbial communities to sulfonamides stress during RBF is unknown. In this study, two column set-ups (with residence time 5 days and 11 days respectively), simulating different redox conditions of riverbank filtration systems, were operated for seven months to investigate 1) the long-term effect of redox conditions on ng∙L^-1 level sulfonamides (sulfapyridine, sulfadiazine, sulfamethoxazole, sulfamethazine, sulfaquinoxaline) removal, and 2) the microbial community evolution represented by the phylogenetic and metabolic function shift under non-lethal selective pressures of sulfonamides. The results showed that sulfonamides were more degradable under anoxic conditions than oxic and suboxic conditions. In the sulfonamides stressed community, the phylogenetic diversity increased slightly. Relative abundance of an intrinsic sulfonamides resistant bacteria Bacillus spp. increased, suggesting that sulfonamide resistance developed in specific bacteria under sulfonamides contamination pressure in RBF systems. At the same time, an activated transport function in the stressed microbial community was noticed. The predicted relative abundance of gene folP, which encodes dihydropteroate synthase, also increased significantly, indicating a detoxification mechanism and sulfonamides resistance potential under non-lethal selective pressures of sulfonamides in RBF systems.

An Organic Chemist's Guide to Electrospray Mass Spectrometric Structure Elucidation

Tandem mass spectrometry is an important tool for structure elucidation of natural and synthetic organic products. Fragmentation of odd electron ions (OE⁺) generated by electron ionization (EI) was extensively studied in the last few decades, however there are only a few systematic reviews available concerning the fragmentation of even-electron ions (EE⁺/EE⁻) produced by the currently most common ionization techniques, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). This review summarizes the most important features of tandem mass spectra generated by collision-induced dissociation fragmentation and presents didactic examples for the unexperienced users.

Occurrence and distribution of trace levels of antibiotics in surface waters and soils driven by non-point source pollution and anthropogenic pressure

Antibiotics in surface waters and soils are growing public health concerns and treated wastewater has often been identified as the main source of antibiotics. However, few studies have been conducted to evaluate the occurrence and concentrations of antibiotics in coastal cities without direct impact of wastewater discharge. In this study, the occurrence of 14 antibiotics including four macrolides, three sulfonamides, three β-lactams, lincomycin, chloramphenicol, furazolidon, and monensin in surface waters and soils in Singapore were analyzed with SPE-LC-ESI-MS/MS. The detected concentrations of antibiotics were all below 82.5 ng/L in surface waters and below 80.6 ng/g dry wt in soils. These concentrations were significantly lower than other cities that were under the impact of treated wastewater discharge, suggesting that reduction of treated wastewater discharge reduces occurrence of antibiotics in the environment. However, the wide occurrence of trace levels of antibiotics suggest that other factors may have contributed to detected environmental antibiotics. Population density was positively correlated with concentrations of clarithromycin, lincomycin, azithromycin, and sulfamethoxazole in surface waters, suggesting that non-point source pollution due to anthropogenic pressure may contribute to the wide detection of trace levels of antibiotics. The potential impact of antibiotic use, natural production, and half-lives of antibiotics were further discussed. Further studies are needed to evaluate how anthropogenic activities other than wastewater discharge may contribute to the occurrence of trace level antibiotics and their associated health risks in urban environments.

An optimized sample treatment method for the determination of antibiotics in seawater, marine sediments and biological samples using LC-TOF/MS

Antibiotics used in marine aquaculture have been reported to accumulate in sediments and non-target aquatic organisms, modifying the biodiversity and the environmental conditions in areas close to the fish farms. Improved analytical methods are required to assess the spread and the impacts of aquaculture antibiotics in the marine environment, as well as to estimate resistance development risks. In this study, we have optimized a method for simultaneous quantitative determination of oxytetracycline, florfenicol and flumequine in marine samples using liquid chromatography coupled to time-of-flight high resolution mass spectrometry (LC-TOF/MS). The method optimization was carried out for seawater, sediment and biological samples (biofilm and two benthic invertebrate species: Gammarus aequicauda and Monodonta articulata). Special attention was paid to the optimization of the extraction and purification steps, testing: liquid-liquid and solid-liquid extractions, the use of silica and other commercial sorbents' clean-up, and single and tandem solid phase extraction procedures. The limits of quantification (MQLs) achieved with the developed method are 0.1-0.5 μg L-¹ in seawater; 1-5 μg kg^-1 in marine sediments; 5-25 μg kg^-1 in biofilm; and 100-500 μg kg^-1 in invertebrates, with good accuracy and precision. Method recoveries in spiked samples are 65-120% in seawater and sediment samples, and 63-110% in the biological samples. The method has been successfully implemented for the determination of antibiotic concentrations in sediment and invertebrate samples collected from a Mediterranean bay in south-east Spain. These represent significant advances in the analysis of antibiotics in environmental samples, especially for wild marine taxa, and attend for a proper assessment of the environmental fate and side effects of aquaculture antibiotics in the marine environment.

Occurrence of β-lactam and polyether ionophore antibiotics in lagoon water and animal manure

The occurrence of micropollutants in agricultural wastes is an emerging area of interest due to the potential impact of these compounds on the environment. A sensitive and reliable analytical method using liquid chromatography-electrospray tandem mass spectrometry has been developed and validated for the determination of three β-lactam and three polyether ionophore antibiotics in lagoon water and animal manure matrices. The method was applied to evaluate the occurrence of these compounds from participating farms in northern Colorado. Seven of the 19 lagoon water samples and two of the six animal manures showed detectable. The three targeted β-lactams (cephapirin, penicillin G, cloxacillin) were found at 0.97-43.31 μg/L in the lagoon water samples. Of the three targeted polyether ionophores, only monensin (94 to 1077 μg/L) was detected in the beef runoff pond water samples. Only cloxacillin was measured in the dairy animal manure samples at levels from 8.09 to 45.20 μg/kg. No cephapirin, penicillin G, cloxacillin, salinomycin, or narasin A were detected in any solid animal manure sample. These results indicate that elevated concentrations of β-lactam and ionophore compounds might be found in lagoon or runoff pond waters and solid animal manures compared to surface waters, which these compounds are used in veterinary applications.

Pharmaceuticals in the aquatic environments: Evidence of emerged threat and future challenges for marine organisms

Pharmaceuticals are nowadays recognized as a threat for aquatic ecosystems. The growing consumption of these compounds and the enhancement of human health in the past two decades have been paralleled by the continuous input of such biologically active molecules in natural environments. Waste water treatment plants (WWTPs) have been identified as a major route for release of pharmaceuticals in aquatic bodies where concentrations ranging from ng/L to μg/L are ubiquitously detected. Since medicines principles are designed to be effective at very low concentrations, they have the potential to interfere with biochemical and physiological processes of aquatic species over their entire life cycle. Investigations on occurrence, bioaccumulation and effects in non target organisms are fragmentary, particularly for marine ecosystems, and related to only a limited number over the 4000 substances classified as pharmaceuticals: hence, there is a urgent need to prioritize the environmental sustainability of the most relevant compounds. The aim of this review is to summarize the main adverse effects documented for marine species exposed in both field and laboratory conditions to different classes of pharmaceuticals including non-steroidal anti-inflammatory drugs, psychiatric, cardiovascular, hypocholesterolaemic drugs, steroid hormones and antibiotics. Despite a great scientific advancement has been achieved, our knowledge is still limited on pharmaceuticals behavior in chemical mixtures, as well as their interactions with other environmental stressors. Complex ecotoxicological effects are increasingly documented and multidisciplinary, integrated approaches will be helpful to clarify the environmental hazard of these "emerged" pollutants in marine environment.

A review of analytical procedures for the simultaneous determination of medically important veterinary antibiotics in environmental water: Sample preparation, liquid chromatography, and mass spectrometry

Medically important (MI) antibiotics are defined by the United States Food and Drug Administration as drugs containing certain active antimicrobial ingredients that are used for the treatment of human diseases or enteric pathogens causing food-borne diseases. The presence of MI antibiotic residues in environmental water is a major concern for both aquatic ecosystems and public health, particularly because of their potential to contribute to the development of antimicrobial-resistant microorganisms. In this article, we present a review of global trends in the sales of veterinary MI antibiotics and the analytical methodologies used for the simultaneous determination of antibiotic residues in environmental water. According to recently published government reports, sales volumes have increased steadily, despite many countries having adopted strategies for reducing the consumption of antibiotics. Global attention needs to be directed urgently at establishing new management strategies for reducing the use of MI antimicrobial products in the livestock industry. The development of standardized analytical methods for the detection of multiple residues is required to monitor and understand the fate of antibiotics in the environment. Simultaneous analyses of antibiotics have mostly been conducted using high-performance liquid chromatography-tandem mass spectrometry with a solid-phase extraction (SPE) pretreatment step. Currently, on-line SPE protocols are used for the rapid and sensitive detection of antibiotics in water samples. On-line detection protocols must be established for the monitoring and screening of unknown metabolites and transformation products of antibiotics in environmental water.

Rapid and Concomitant Analysis of Pharmaceuticals in Treated Wastewater by Coated Blade Spray Mass Spectrometry

The widespread use of pharmaceuticals in both human and animal populations, and the resultant contamination of surface waters from the outflow of water treatment facilities is an issue of growing concern. This has raised the need for analytical methods that can both perform rapid sample analysis and overcome the limitations of conventional analysis procedures, such as multistep workflows and tedious procedures. Coated blade spray (CBS) is a solid-phase microextraction based technique that enables the direct-to-mass-spectrometry analysis of extracted compounds via the use of limited organic solvent to desorb analytes and perform electrospray ionization. This paper documents how CBS can be applied for the concomitant tandem mass spectrometric (MS/MS) analysis of nine pharmaceuticals in treated wastewater. The total analysis times of less than 11 min provided limits of detection lower than 50 ng L^-1 for all target compounds in river water. The CBS methodology was then compared to a conventional solid-phase extraction technique for the analysis of the final effluent of six wastewater treatment facilities. The experimental results strongly suggest that CBS offers scientists a viable alternative method for analyzing water samples that is both rapid and relatively solvent-free.

Simultaneous determination of seven multiclass veterinary antibiotics in surface water samples in the Republic of Korea using liquid chromatography with tandem mass spectrometry

A simultaneous determination method using solid-phase extraction and liquid chromatography with tandem mass spectrometry was developed to detect and quantify the presence of seven multiclass veterinary antibiotics (13 compounds in total) in surface water samples, which included the effluents of livestock wastewater and sewage treatment plants, as well as the reservoir drainage areas from dense animal farms. The pH of all water samples was adjusted to 2 or 6 before solid-phase extraction using Oasis HLB cartridges. The developed method was fully validated in terms of linearity, method detection limit, method quantitation limit, accuracy, and precision. The linearity of all tested drugs was good, with R² determination coefficients ≥ 0.9931. The method detection limits and method quantitation limits were 0.1-74.3 and 0.5-236.6 ng/L, respectively. Accuracy and precision values were 71-120 and 1-17%, respectively. The determination method was successfully applied for monitoring water samples obtained from the Yeongsan River in 2015. The most frequently detected antibiotics were lincomycin (96%), sulfamethazine (90%), sulfamethoxazole (88%), and sulfathiazole (50%); the maximum concentrations of which were 398.9, 1151.3, 533.1, and 307.4 ng/L, respectively. Overall, the greatest numbers and concentrations of detected antibiotics were found in samples from the effluents of livestock wastewater, sewage treatment plants, and reservoir drainage areas. Diverse veterinary antibiotics were present, and their presence was dependent upon the commercial sales and environmental properties of the analytes, the geographical positions of the sampling points, and the origin of the water.

Environmental concentration of carbamazepine accelerates fish embryonic development and disturbs larvae behavior

Environmental pollution caused by pharmaceuticals has been recognized as a major threat to the aquatic ecosystems. Carbamazepine, as the widely prescribed antiepileptic drug, has been frequently detected in the aquatic environment and has created concerns about its potential impacts in the aquatic organisms. The effects of carbamazepine on zebrafish embryos were studied by examining their phenotype, behavior and molecular responses. The results showed that carbamazepine disturbed the normal growth and development of exposed zebrafish embryos and larvae. Upon exposure to carbamazepine at 1 μg/L, the hatching rate, body length, swim bladder appearance and yolk sac absorption rate were significantly increased. Embryos in treatment groups were more sensitive to touch and light stimulation. At molecular level, exposure to an environmentally relevant concentration (1 μg/L) of carbamazepine disturbed the expression pattern of neural-related genes of zebrafish embryos and larvae. This study suggests that the exposure of fish embryo to antiepileptic drugs, at environmentally relevant concentrations, affects their early development and impairs their behavior. Such impacts may have future repercussions by affecting fish population structure.

The effect of composting on the persistence of four ionophores in dairy manure and poultry litter

Manure composting is a well-described approach for stabilization of nutrients and reduction of pathogens and odors. Although composting studies have shown that thermophilic temperatures and aerobic conditions can increase removal rates of selected antibiotics, comparable information is lacking for many other compounds in untreated or composted manure. The objective of this study was to determine the relative effectiveness of composting conditions to reduce concentrations of four widely used ionophore feed supplements in dairy manure and poultry litter. Replicate aliquots of fresh poultry litter and dairy manure were amended with monensin, lasalocid, salinomycin, or amprolium to 10mgkg(-1)DW. Non-amended and amended dairy manure and poultry litter aliquots were incubated at 22, 45, 55, or 65°C under moist, aerobic conditions. Residue concentrations were determined from aliquots removed after 1, 2, 4, 6, 8, and 12weeks. Results suggest that the effectiveness of composting for contaminant reduction is compound and matrix specific. Composting temperatures were not any more effective than ambient temperature in increasing the rate or extent of monensin removal in either poultry litter or dairy manure. Composting was effective for lasalocid removal in poultry litter, but is likely to be too slow to be useful in practice (8-12weeks at 65°C for >90% residue removal). Composting was effective for amprolium removal from poultry litter and salinomycin in dairy manure but both required 4-6weeks for >90% removal. However, composting did not increase the removal rates or salinomycin in poultry litter or the removal rates of lasalocid or amprolium in dairy manure.

Evaluation of Monensin Transport to Shallow Groundwater after Irrigation with Dairy Lagoon Water

Animal waste products from concentrated animal feeding operations are a significant source of antibiotics to the environment. Monensin, an ionophore antibiotic commonly used to increase feed efficiency in livestock, is known to have varied toxicological effects on nontarget species. The current study builds on prior studies evaluating the impact of dairy management on groundwater quality by examining the transport of monensin in an agricultural field with coarse-textured soils during irrigation with lagoon wastewater. The dairy is located in California's San Joaquin Valley, where groundwater can be encountered <5 m below the surface. Groundwater samples were collected from a network of monitoring wells installed throughout the dairy and adjacent to irrigated fields before and after an irrigation event, which allowed for measurement of monensin potentially reaching the shallow groundwater as a direct result of irrigation with lagoon water. Monensin was extracted from water samples via hydrophilic-lipophilic balance solid-phase extraction and quantified with liquid chromatography-mass spectrometry. Irrigation water was found to contain up to 1.6 μg L monensin, but monensin was only detected in monitoring wells surrounding the waste storage lagoon. Water chemistry changes in the wells bordering the irrigated field suggest that up to 7% of irrigation water reached groundwater within days of irrigation. The study suggests that contamination of groundwater with monensin can occur primarily by compromised waste storage systems and that rapid transport of monensin to groundwater is not likely to occur from a single irrigation event.

Removal of ciprofloxacin from aqueous solution using long TiO2 nanotubes with a high specific surface area

Long TiO₂ nanotubes (TNs) were successfully prepared by the reaction of TiO₂ and NaOH.

Ultra-high performance liquid chromatography-electrospray tandem mass spectrometry for the analysis of antibiotic residues in environmental waters

An optimized solid-phase extraction (SPE) and ultra-high performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS) method was developed for the effective analysis of 35 antibiotics including sulfonamides (SAs), quinolones (QLs), tetracyclines (TCs), macrolides (MALs), lincomycin (LIN), and chloramphenicol (CAP). The addition of 0.1% formic acid to the mobile phase was favorable for the formation of [M + H](+) and the enhancement in the detection signals, but using ammonium formate decreased [M + H](+) with a corresponding reduction in the response of CAP. The optimal pH range for the SPE was 4.5 ∼ 5.0 with 6 mL aqueous ammonia/methanol (5/95, v/v) as the optimized eluent. An internal standard (IS) was selected for each type of analytes based on similarities in classification and retention time. The detection was completed in less than 10 min and was excellent with method detection limits (MDL) of 0.29 ∼ 4.03 ng/L. The recoveries of the antibiotics in samples from ultrapure water and groundwater were 67.13 ∼ 93.00% and 68.91 ∼ 92.67%, respectively. The antibiotics in samples collected from wastewater, surface water, and groundwater were also effectively detected. This newly developed method has the advantages of short detection times, small sample consumption, excellent reproducibility, and high sensitivity. This provides a reliable and promising technique for the simultaneous detection and monitoring of various residual antibiotics in aqueous environmental samples.

Stacking Time and Aluminum Sulfate Effects on Polyether Ionophores in Broiler Litter

The use of ionophores as antiparasitic drugs plays an important role in US poultry production, especially in the broiler () industry. However, administered ionophores can pass through the bird's digestive system and appear in broiler litter, which, when applied to agricultural fields, can present an environmental hazard. Stacking (storing or stockpiling) broiler litter for some time might decrease the litter ionophore concentrations before land application. Because ionophores undergo abiotic hydrolysis at low pH, decreasing litter pH with acidic aluminum sulfate (alum) might also decrease ionophore concentrations. We assessed the change in ionophore concentrations in broiler litter in response to the length of time broiler litter was stored (stacking time) and alum addition. We spiked broiler litter with monensin and salinomycin, placed alum-amended litter (∼pH 4-5) and unamended litter (∼pH 8-9) into 1.8-m bins, and repeatedly sampled each bin for 112 d. Our findings showed that stacking broiler litter alone did not have an impact on monensin concentration, but it did slowly reduce salinomycin concentration by 55%. Adding alum to broiler litter reduced monensin concentration by approximately 20% relative to unamended litter, but it did not change salinomycin concentration. These results call for continued search for alternative strategies that could potentially reduce the concentration of ionophores in broiler litter before their application to agricultural soils.

Alum and Rainfall Effects on Ionophores in Runoff from Surface-Applied Broiler Litter

Polyether ionophores, monensin, and salinomycin are commonly used as antiparasitic drugs in broiler production and may be present in broiler litter (bird excreta plus bedding material). Long-term application of broiler litter to pastures may lead to ionophore contamination of surface waters. Because polyether ionophores break down at low pH, we hypothesized that decreasing litter pH with an acidic material such as aluminum sulfate (alum) would reduce ionophore losses to runoff (i.e., monensin and salinomycin concentrations, loads, or amounts lost). We quantified ionophore loss to runoff in response to (i) addition of alum to broiler litter and (ii) length of time between litter application and the first simulated rainfall event. The factorial experiment consisted of unamended (∼pH 9) vs. alum-amended litters (∼pH 6), each combined with simulated rainfall at 0, 2, or 4 wk after litter application. Runoff from alum-amended broiler litter had 33% lower monensin concentration ( < 0.01), 57% lower monensin load ( < 0.01), 48% lower salinomycin concentration ( < 0.01), and 66% lower salinomycin load ( < 0.01) than runoff from unamended broiler litter when averaged across all events of rainfall. Ionophore losses to runoff were also less when rainfall was delayed for 2 or 4 wk after litter application relative to applying rainfall immediately after litter application. While the weather is difficult to predict, our data suggest that ionophore losses in runoff can be reduced if broiler litter applications are made to maximize dry time after application.

Photodegradation of veterinary ionophore antibiotics under UV and solar irradiation

The veterinary ionophore antibiotics (IPAs) are extensively used as coccidiostats and growth promoters and are released to the environment via land application of animal waste. Due to their propensity to be transported with runoff, IPAs likely end up in surface waters where they are subject to photodegradation. This study is among the first to investigate the photodegradation of three commonly used IPAs, monensin (MON), salinomycin (SAL) and narasin (NAR), under UV and solar irradiation. Results showed that MON was persistent in a deionized (DI) water matrix when exposed to UV and sunlight, whereas SAL and NAR could undergo direct photolysis with a high quantum yield. Water components including nitrate and dissolved organic matter had a great impact on the photodegradation of IPAs. A pseudosteady state kinetic model was successfully applied to predict IPAs' photodegradation rates in real water matrices. Applying LC/MS/MS, multiple photolytic transformation products of IPAs were observed and their structures were proposed. The direct photolysis of SAL and NAR occurred via cleavage on the ketone moiety and self-sensitized photolysis. With the presence of nitrate, MON was primarily degraded by hydroxyl radicals, whereas SAL showed reactivity toward both hydroxyl and nitrogen-dioxide radicals. Additionally, toxicity tests showed that photodegradation of SAL eliminated its antibiotic properties against Bacillus subtilis.

Occurrence of Ionophores in the Danish Environment

Antibiotics in the environment are a potential threat to environmental ecosystems as well as human health and safety. Antibiotics are designed to have a biological effect at low doses, and the low levels detected in the environment have turned focus on the need for more research on environmental occurrence and fate, to assess the risk and requirement for future regulation. This article describes the first occurrence study of the antibiotic polyether ionophores (lasalocid, monensin, narasin, and salinomycin) in the Danish environment. Various environmental matrices (river water, sediment, and soil) have been evaluated during two different sampling campaigns carried out in July 2011 and October 2012 in an agricultural area of Zealand, Denmark. Lasalocid was not detected in any of the samples. Monensin was measured at a concentration up to 20 ng·L⁻¹ in river water and 13 µg·kg⁻¹ dry weight in the sediment as well as being the most frequently detected ionophore in the soil samples with concentrations up to 8 µg·kg⁻¹ dry weight. Narasin was measured in sediment samples at 2 µg·kg⁻¹ dry weight and in soil between 1 and 18 µg·kg⁻¹ dry weight. Salinomycin was detected in a single soil sample at a concentration of 30 µg·kg⁻¹ dry weight.

Fate and transport of monensin in the presence of nonionic surfactant Brij35 in soil

As fresh water is a limited resource in many parts of the world, the use of wastewater for irrigation has become an important alternative. Therefore, many countries facing a water deficit, use partially treated, or even untreated, wastewater. This may increase the input of many contaminants into the environment. In the present study, we investigated the effect of using surfactant rich water in irrigation on the mobility of the most commonly-used veterinary antibiotic, monensin. Nine PVC lysimeters, 1.0m long×0.45 m diameter, were packed with a sandy soil to a bulk density of 1.35 Mg m(-3). Cattle manure, containing monensin, was applied at the surface of the lysimeters at the recommended rate of 10t/ha. Each of three aqueous Brij 35 solutions, 0, 0.5 and 5 g L(-1), was applied to the lysimeters in triplicate. Over a 90 day period, soil and leachate samples were collected and analyzed. The results of the laboratory sorption experiment showed that when the nonionic surfactant Brij 35 is present, the sorption coefficient of monensin was reduced significantly from 120.22 mL g(-1) in the aqueous medium to 112.20, 100 and 63.09 mL g(-1) with Brij35 concentrations of 0.25, 2.5 and 5 g L(-1), respectively. The lysimeter results indicated a significant downward movement of monensin at depths of 60 cm in the soil profile and leachate in the presence of the surfactant. Thus, the continuous use of poor quality water could influence the transport of monensin in agricultural soils, and consequently, pose a risk for groundwater pollution.

Monitoring the presence of 13 active compounds in surface water collected from rural areas in northwestern Spain

Drug residues are considered environmental contaminants, and their occurrence has recently become a matter of concern. Analytical methods and monitoring systems are therefore required to control the continuous input of these drug residues into the environment. This article presents a suitable HPLC-ESI-MS/MS method for the simultaneous extraction, detection and quantification of residues of 13 drugs (antimicrobials, glucocorticosteroids, anti-inflammatories, anti-hypertensives, anti-cancer drugs and triphenylmethane dyes) in surface water. A monitoring study with 549 water samples was carried out in northwestern Spain to detect the presence of drug residues over two sampling periods during 2010, 2011 and 2012. Samples were collected from rural areas with and without farming activity and from urban areas. The 13 analytes were detected, and 18% of the samples collected showed positive results for the presence of at least one analyte. More collection sites were located in rural areas than in urban areas. However, more positive samples with higher concentrations and a larger number of analytes were detected in samples collected from sites located after the discharge of a WWTP. Results indicated that the WWTPs seems to act as a concentration point. Positive samples were also detected at a site located near a drinking water treatment plant.

Anthropogenic impacts on a bedrock aquifer at the village scale

This study focuses on assessing groundwater potability in a highly complex and heterogeneous fractured bedrock aquifer having variable overburden cover. Eight monitoring wells were installed in a privately serviced lakeside village, and groundwater was routinely sampled over a 2-year timeframe for concentration analysis of nitrate, fecal indicator bacteria, stable isotopes, and a total of 41 pharmaceutical compounds. While pollutant concentrations remained low throughout the study, the presence of fecal indicator bacteria and pharmaceuticals was noted at least once (but not always consistently) in most sampling intervals. An interpretation based on the integration of chemical, bacterial, and site characterization datasets suggests that: (1) the fracture network is complex and heterogeneous with limited vertical connectivity; (2) existing pathways are sufficient for the quick and widespread migration of surface contaminants to depth; (3) anthropogenic contaminants from both septic systems and agriculture are likely sourced in the surrounding uplands where overburden is thin; and (4) fecal contamination, as observed over the long term, is ubiquitous at the village scale. Groundwater quality is continually changing in this hydrogeologic environment and the determination of potability on the larger scale is not likely to be adequately captured with infrequent domestic well sampling (i.e., voluntary annual sampling by homeowners).

The development of a microwave-assisted extraction method for the determination of sulfonamide antibiotics in sediments and soils

A microwave-assisted extraction technique was developed for the determination of nine sulfonamide antibiotics (sulfaguanidine, sulfacetamide, sulfadiazine, sulfathiazole, sulfapyridine, sulfamethazine, sulfamerazine, sulfamethoxazole, and sulfadimethoxine) in six sediments and soils of varying organic carbon content. Method optimization was performed using Lake Erie sediment and revealed the optimum extraction solvent to be methanol, with an extraction time of 45 min. After extraction, samples were “cleaned up” via filtration and quantified using LC-MS/MS spectroscopy. Method calibration curves were constructed in each environmental solid with sulfonamides ranging from 10 to 2000 ng/g; method detection limits were typically in the sub- to low nanograms per gram range. Method validation entailed spiking each solid at three different concentrations spanning the calibration curve (40, 300, and 800 ng/g); generally, method accuracy for spiked solids exceeded 80%, with precision being within 20%. Finally, we extracted sulfonamides from environmental solids (two sediments and one soil) that had been aged for 21 days and found that our method accuracy remained in excess of 80%. Moreover, absolute recoveries generally agreed with method accuracies (at the 95% confidence interval) in all environmental solids, demonstrating the efficiency of our microwave-assisted extraction procedure and its suitability for application to environmental samples.

Acid-catalyzed transformation of ionophore veterinary antibiotics: reaction mechanism and product implications

Ionophore antibiotics (IPAs) are polyether antimicrobials widely used in the livestock industry and may enter the environment via land application of animal waste and agricultural runoff. Information is scarce regarding potential transformation of IPAs under environmental conditions. This study is among the first to identify the propensity of IPAs to undergo acid-catalyzed transformation in mildly acidic aquatic systems and characterize the reactions in depth. The study focused on the most widely used monensin (MON) and salinomycin (SAL), and also included narasin (NAR) in the investigation. All three IPAs are susceptible to acid-catalyzed transformation. MON reacts much more slowly than SAL and NAR and exhibits a different kinetic behavior that is further evaluated by a reversible reaction kinetic model. Extensive product characterization identifies that the spiro-ketal group of IPAs is the reactive site for the acid-catalyzed hydrolytic transformation, yielding predominantly isomeric and other products. Toxicity evaluation of the transformation products shows that the products retain some antimicrobial properties. The occurrence of IPAs and isomeric transformation products is also observed in poultry litter and agricultural runoff samples. Considering the common presence of mildly acidic environments (pH 4-7) in soils and waters, the acid-catalyzed transformation identified in this study likely plays an important role in the environmental fate of IPAs.

Global synthesis and critical evaluation of pharmaceutical data sets collected from river systems

Pharmaceuticals have emerged as a major group of environmental contaminants over the past decade but relatively little is known about their occurrence in freshwaters compared to other pollutants. We present a global-scale analysis of the presence of 203 pharmaceuticals across 41 countries and show that contamination is extensive due to widespread consumption and subsequent disposal to rivers. There are clear regional biases in current understanding with little work outside North America, Europe, and China, and no work within Africa. Within individual countries, research is biased around a small number of populated provinces/states and the majority of research effort has focused upon just 14 compounds. Most research has adopted sampling techniques that are unlikely to provide reliable and representative data. This analysis highlights locations where concentrations of antibiotics, cardiovascular drugs, painkillers, contrast media, and antiepileptic drugs have been recorded well above thresholds known to cause toxic effects in aquatic biota. Studies of pharmaceutical occurrence and effects need to be seen as a global research priority due to increasing consumption, particularly among societies with aging populations. Researchers in all fields of environmental management need to work together more effectively to identify high risk compounds, improve the reliability and coverage of future monitoring studies, and develop new mitigation measures.

Application of comprehensive two-dimensional gas chromatography with mass spectrometric detection for the analysis of selected drug residues in wastewater and surface water

Pharmaceutical residues have become tightly controlled environmental contaminants in recent years, due to their increasing concentration in environmental components. This is mainly caused by their high level of production and everyday consumption. Therefore there is a need to apply new and sufficiently sensitive analytical methods, which can detect the presence of these contaminants even in very low concentrations. This study is focused on the application of a reliable analytical method for the analysis of 10 selected drug residues, mainly from the group of non-steroidal anti-inflammatory drugs (salicylic acid, acetylsalicylic acid, clofibric acid, ibuprofen, acetaminophen, caffeine, naproxen, mefenamic acid, ketoprofen, and dicofenac), in wastewaters and surface waters. This analytical method is based on solid phase extraction, derivatization by N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) and finally analysis by comprehensive two-dimensional gas chromatography with Time-of-Flight mass spectrometric detection (GCxGC-TOF MS). Detection limits ranged from 0.18 to 5 ng/L depending on the compound and selected matrix. The method was successfully applied for detection of the presence of selected pharmaceuticals in the Svratka River and in wastewater from the wastewater treatment plant in Brno-Modrice, Czech Republic. The concentration of pharmaceuticals varied from one to several hundreds of ng/L in surface water and from one to several tens of isg/L in wastewater.

Fate of citalopram during water treatment with O3, ClO2, UV and Fenton oxidation

In the present study we investigate the fate of citalopram (CIT) at neutral pH using advanced water treatment technologies that include O(3), ClO(2) oxidation, UV irradiation and Fenton oxidation. The ozonation resulted in 80% reduction after 30 min treatment. Oxidation with ClO(2) removed>90% CIT at a dosage of 0.1 mg L(-1). During UV irradiation 85% reduction was achieved after 5 min, while Fenton with addition of 14 mg L(-1) (Fe(2+)) resulted in 90% reduction of CIT. During these treatment experiments transformation products (TPs) were formed from CIT, where five compounds were identified by using high resolution and tandem mass spectrometry. Among these desmethyl-citalopram and citalopram N-oxide have been previously identified as human metabolites, while three are novel and published here for the first time. The three TPs are a hydroxylated dimethylamino-side chain derivative, a butyrolactone derivative and a defluorinated derivative of CIT.

Detection and quantitative analysis of 21 veterinary drugs in river water using high-pressure liquid chromatography coupled to tandem mass spectrometry

INTRODUCTION

The use of veterinary drugs in food production focuses on the control and improvement of animal health. The disadvantage of this practice is that pharmaceuticals and their metabolites are released into the environment, finding their way to natural water systems and becoming a potential risk to non-target organism.

METHODS

This paper reports the development and validation of a quantitative method, based on high-performance liquid chromatography coupled to tandem mass spectrometry, for the simultaneous analysis of 21 veterinary drugs, antimicrobials, corticosteroids, coccidiostats and antifungal agents, in surface water.

RESULTS

The precision of the method was established by calculating the mean recoveries, which were in the range of 94-101%. The developed method was employed to conduct the first monitoring study on the presence of veterinary drugs in the Galicia region, Northwest of Spain and was applied to 235 surface water samples. Eleven veterinary drugs were detected at concentrations from below the limit of quantification to 2,978.6 ng L(-1). Limits of detection and quantification were in the range of 6.2 (betamethasone, cortisone, decoquinate, dexamethasone, maduramycin, monensin, narasin, salinomycin, sulfachloropyridazine, sulfamethoxypyridazine and trimethoprim) to 12.5 ng L(-1) (for the rest of the selected drugs) and 12.5 (betamethasone, cortisone, decoquinate, dexamethasone, maduramycin, monensin, narasin, salinomycin, sulfachloropyridazine, sulfamethoxypyridazine and trimethoprim) to 25.0 ng L(-1) (for the remaining pharmaceuticals), respectively.

CONCLUSION

Sulfonamides were the group most frequently found, which are widely used in veterinary medicine.