Determination of multi-class pharmaceuticals in wastewater by liquid chromatography–tandem mass spectrometry (LC–MS–MS)

Review on antibiotic pollution dynamics: insights to occurrence, environmental behaviour, ecotoxicity, and management strategies

Antibiotic contamination poses a significant global concern due to its far-reaching impact on public health and the environment. This comprehensive review delves into the prevalence of various antibiotic classes in environmental pollution and their interactions with natural ecosystems. Fluoroquinolones, macrolides, tetracyclines, and sulphonamides have emerged as prevalent contaminants in environmental matrices worldwide. The concentrations of these antibiotics vary across diverse environments, influenced by production practices, consumer behaviours, and socio-economic factors. Low- and low-middle-income countries face unique challenges in managing antibiotic contamination, with dominant mechanisms like hydrolysis, sorption, and biodegradation leading to the formation of toxic byproducts. Ecotoxicity reports reveal the detrimental effects of these byproducts on aquatic and terrestrial ecosystems, further emphasizing the gravity of the issue. Notably, monitoring the antibiotic parent compound alone may be inadequate for framing effective control and management strategies for antibiotic pollution. This review underscores the imperative of a comprehensive, multi-sectoral approach to address environmental antibiotic contamination and combat antimicrobial resistance. It also advocates for the development and implementation of tailored national action plans that consider specific environmental conditions and factors. Thus, an approach is crucial for safeguarding both public health and the delicate balance of our natural ecosystems.

Distribution, fate and removal efficiency of anthelmintic drugs in wastewater treatment plants

The distribution and fate of 19 anthelmintic drugs (ADs) were investigated in two wastewater treatment plants (WWTPs) using different wastewater treatment technologies, including anaerobic-anoxic-aerobic (A2/O) biological process and cyclic activated sludge system (CASS) process. All the 19 ADs were found in the two WWTPs, with concentrations ranging from N.D. to 324.6 ng/L in the influent and from N.D. to 1579.2 ng/L in the effluent. Benzimidazoles were the primary pollutants in the wastewater and suspended particulate matter, accounting for more than half of the total concentration. The concentrations of macrocyclic lactones in the sludge were significantly higher than that of other two media. The ADs removal efficiency of A2/O ranged from -330 % (albendazole sulfoxide) to 100 % (fenbendazole, mebendazole and pyrantel). While the ADs removal efficiency of CASS process ranged from -425 % (albendazole sulfoxide) to 100 % (abamectin, moxidectin and ivermectin). There was no significant difference in the average removal efficiency of the ADs between the two processes (64 % and 63 %, except albendazole sulfoxide). The removal efficiencies of the ADs in the biodegradation stage were better than them in the sedimentation stage. The load per capita of the 19 ADs in two WWTPs ranged from 0 (moxidectin) to 36 μg.d-1.p-1 (albendazole), and the emission in the effluent ranged from 0 (moxidectin) to 163 μg.d-1.p-1 (albendazole sulfoxide). This study provided the first comprehensive data on the occurrence and fate of the 19 ADs and evaluated the removal efficiencies of the 19 ADs in two WWTPs using A2O process and CASS process in the city.

Simultaneous determination of macrolides in water samples by solid-phase extraction and capillary electrophoresis

Solid-phase extraction (SPE) coupled with capillary electrophoresis (CE) for the determination of macrolide antibiotics (azithromycin, clarithromycin, roxithromycin, tylosin) and tiamulin in water samples was described in this article. These compounds were extracted with different types of sorbents ( Oasis HLB, C18, C8, SDB, and Strata-X) and different masses of sorbents (60 mg, 200 mg, and 500 mg) using different organic solvents (methanol, ethanol, and acetonitrile) and different pH values of water samples (pH 7.00, 8.00, and 9.00). It was found that the highest extraction efficiency of the studied compounds was obtained with 200 mg/3 mL C18 cartridges with methanol as eluent at pH 9.00 of the water sample. The developed SPE-CE method for macrolide antibiotics and tiamulin was validated for linearity, precision, repeatability, the limit of detection (LOD), the limit of quantification (LOQ), and recovery. Good linearity was obtained in the range of 0.3-30 mg L-1 depending on the drug, with correlation coefficients higher than 0.9958 in all cases except clarithromycin (0.9873). Expanded measurement uncertainties were calculated for each pharmaceutical, accounting for 20.31 % (azithromycin), 38.33 % (tiamulin), 28.95 % (clarithromycin), 26.99 % (roxithromycin), and 21.09 % (tiamulin). Uncertainties associated with precision and calibration curves contributed the most to the combined measurement uncertainty. The method was successfully applied to the analysis of production waste-water from the pharmaceutical industry.

Occurrence, environmental impact and fate of pharmaceuticals in groundwater and surface water: a critical review

In many nations and locations, groundwater serves as the population's primary drinking water supply. However, pharmaceuticals found in groundwater and surface waters may affect aquatic ecosystems and public health. As a result, their existence in natural raw waters are now more widely acknowledged as a concern. This review summarises the evidence of research on pharmaceuticals' occurrence, impact and fate, considering results from different water bodies. Also, various analytical techniques were reviewed to compare different pharmaceuticals' detection frequencies in water bodies. These include liquid chromatography-mass spectrometry (LC-MS), high-performance liquid chromatography (HPLC), ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and gas chromatography-mass spectrometry (GC-MS). However, owing to LC-MS's high sensitivity and specification, it is the most reported instrument used for analysis. The PRISMA reviewing methodology was adopted based on relevant literature in order to focus on aim of the review. Among other pharmaceuticals reviewed, sulfamethoxazole was found to be the most frequently detected drug in wastewater (up to 100% detection frequency). The most reported pharmaceutical group in this review is antibiotics, with sulfamethoxazole having the highest concentration among the analysed pharmaceuticals in groundwater and freshwater (up to 5600 ng/L). Despite extensive study and analysis on the occurrence and fate of pharmaceuticals in the environment, appropriate wastewater management and disposal of pharmaceuticals in the water environment are not still monitored regularly. Therefore, there is a need for mainstream studies tailored to the surveillance of pharmaceuticals in water bodies to limit environmental risks to human and aquatic habitats in both mid and low-income nations.

Application of duckweed (Lemna sp.) and water fern (Azolla sp.) in the removal of pharmaceutical residues in water: State of art focus on antibiotics

In recent decades, antibiotic residues in the environment have increased, affecting components of biological communities, from bacteria to plants and animals. Different methods have been used to remove these compounds, including phytoremediation with floating aquatic species such as duckweed and aquatic fern, with positive results. This study analyses information about the removal efficiency of drugs, with a focus on antibiotics, using Lemna and Azolla, which will allow a better understanding of phytoremediation processes from the perspective of plant physiology. The physiological processes of macrophytes in an environment with this type of pollutant and the phytotoxic effects on plants at high concentrations are also analysed. The metabolization of toxic compounds occurs in three phases: phase I begins with the absorption of antibiotics and the secretion of reactive oxygen species (ROS); in phase II, the effects of ROS are neutralized and minimized by conjugation with enzymes such as glutathione transferase or metabolites such as glutathione; and phase III culminates with the storage of the assimilated compounds in the vacuoles, apoplast and cell wall. In this way, plants contribute to the removal of toxic compounds. In summary, there is sufficient scientific evidence on the efficiency of the elimination of pharmaceutical compounds by these floating macrophytes at the laboratory scale, which indicates that their application under real conditions can have good results.

Sorption of cefdinir, memantine, praziquantel and trimethoprim in sediment and soil samples

The everyday use of various pharmaceuticals to treat humans or animals means that they are increasingly found in the environment. Contamination of the soil can cause the active ingredients to be strongly sorbed to the soil or sediment. In the worst case, they can also be expected to occur in the aquatic environment due to their different polarity. In this study, four drugs from different therapeutic classes (trimetoprim, memantine, cefdinir, praziquantel) were used in dissolved form in two sediment and three soil samples to obtain data that can describe their fate and behavior in the environment. The sorption affinities of the pharmaceuticals were described using linear, Freundlich and Dubinin-Radushkevich sorption isotherms. The highest K_d values were obtained for cefdinir, while memantine and praziquantel tended to be present in water due to their very low sorption coefficients. The studied influence of pH showed a negative trend for memantine and trimetoprim, while an increase in ionic strength resulted in higher K_d values for all drugs. The sorption mechanism for all tested samples was best described by the pseudo-secondary kinetic model (R² > 0.9999).

Comprehensive Characterization of 76 Pharmaceuticals and Metabolites in Wastewater by LC-MS/MS

Wastewaters are considered one of the main sources of pollution in the aquatic environment as release a large number of contaminants every day. Emerging contaminants such as pharmaceuticals have special interest due to the high levels of consumption by the global population, their bioactive properties and because actual directives do not include the monitoring of pharmaceuticals. Moreover, it is well-known that pharmaceuticals can be degraded to metabolites or transformation products (TPs), which could be more toxic than the parental compound. In this study, we have developed an analytical method based on solid-phase extraction (SPE) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) to determine 76 highly consumed pharmaceuticals, including metabolites and TPs in wastewater effluents. In the 10 wastewaters analysed, the mean concentrations were in the µg L−1 levels, being mycophenolic acid, levodopa, ibuprofen, 4-aminoantypirine, losartan, amylmetacresol, amoxicillin, fluticasone, tramadol, budesonide, chlorpheniramine and diclofenac the pharmaceuticals with the highest concentrations. This study provides a comprehensive optimization on the MS conditions to determine pharmaceutical compounds and their metabolites and provides a spectral characterization to be used for the identification of these compounds in water.

Investigation on the uptake of ciprofloxacin, chloramphenicol and praziquantel by button mushrooms

Button mushrooms are widely produced edible basidiomycetes. Commercially, they are cultivated on substrates containing fermented horse manure and chicken feces. Since pharmacologically active substances (PAS) might be introduced into the food chain via animal treatment, their residues may be present in manure used for mushroom growth. Previous studies in plants have demonstrated an uptake of PAS from the agricultural environment. The present study was performed to investigate the presence of PAS in button mushrooms. For analysis, a multi-analyte method for the detection of 21 selected PAS using liquid chromatography tandem-mass spectrometry was developed, successfully validated and applied to commercially available button mushrooms. Traces of chloramphenicol were detected in two of 20 samples. Additionally, in a mushroom cultivation experiment an uptake of ciprofloxacin, chloramphenicol and praziquantel was conducted. Throughout the whole experiment, praziquantel was present in quantifiable amounts in mushrooms and in high quantities in soil.

Solid-phase optimisation for simultaneous determination of thirteen pharmaceuticals in Ethiopian water samples with HPLC-DAD detection: an initial assessment

Pharmaceutical consumption is increasing worldwide as it is essential to treat and prevent health issues but they end up in the environment. However, in many African countries like Ethiopia, the status of these compounds in various environmental samples is not very well known. In this study, a simple method for the extraction and determination of thirteen pharmaceutical compounds of different therapeutic classes in water samples using solid-phase extraction and HPLC-DAD was developed. Different parameters affecting extraction were optimised and obtained as hydrophilic-lipophilic balance (HLB) extraction cartridge, water sample pH of 5, elution solvent of 2% formic acid in water with methanol (20:80%, v/v), a sample volume of 150 mL and addition of 0.5% w/v EDTA in the sample. The limits of detection and quantification of the optimised method were in the range of 0.1-0.8 µg/L and 0.2-2.6 µg/L, respectively. The relative recovery in the spiked environmental water sample was in the range of 70-117% except for amoxicillin and acetylsalicylic acid in influent wastewater. The precision for all ranged from 0.3 to 11%. The proposed method was successfully tested for the detection and quantification of different environmental water samples collected from Addis Ababa, Ethiopia. Trimethoprim, caffeine and albendazole concentrations of 7.8 (1.1), 3.2 (0.4) and 2.1 (0.1) µg/L were quantified in hospital wastewater, respectively. The concentration of norfloxacin was found to be below the limit of quantification in the same water. Trimethoprim and ciprofloxacin were also found in the sewage treatment plant influent sample at a concentration of 0.5 (0.02) and 0.3 (0.01) µg/L, respectively.

Eco-friendly multivariate curve resolution-alternating least squares and chromatographic quantifications of some veterinary drug residues in pharmaceutical industrial wastewater

Three eco-friendly and cost-effective analytical methods were developed and optimized for quantitative analysis of some veterinary drug residues in production wastewater samples. The studied drugs were ivermectin, rafoxanide and sulfadimidine. A solid-phase extraction procedure was employed using Bond Elut C18 cartridges, prior to analysis. The first method was a chemometric approach called multivariate curve resolution - alternating least squares (MCR-ALS). A calibration model was developed and several figures of merit (RMSEP, SEP, bias, RE%) were calculated. The second method was a thin layer chromatography followed by densitometric measurements at 245 nm. The separation was performed using silica gel 60 F254 plates and ethyl acetate : acetonitrile : toluene : ammonia (20 : 3 : 2 : 1, by volume) as a developing system. The third method was a high performance liquid chromatographic separation on HiQsil C18 HS column with UV detection at 245 nm. The mobile phase consisted of acetonitrile : methanol : water (60 : 25 : 15, by volume), with a flow rate of 1.5 mL min-1. The proposed methods were validated according to ICH guidelines. The described procedures were applied to quantify the studied drug residues in synthetic and real industrial wastewater samples. The proposed methods were statistically compared with the official and the reported methods, showing no significant difference with respect to accuracy and precision at P = 0.05.

Development and Validation of a LC-MS/MS Method for Determination of Multi-Class Antibiotic Residues in Aquaculture and River Waters, and Photocatalytic Degradation of Antibiotics by TiO2 Nanomaterials

This study presents a multi-residue method for simultaneous qualitative and quantitative analysis of eight antibiotics from some common classes, including beta-lactam, tetracyclines, lincosamides, glycopeptides, and sulfonamides in 39 aquaculture and river water samples from the Mekong Delta (Vietnam) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). As a result, doxycycline (DXC), oxytetracycline (OTC), lincomycin (LCM), sulfamethoxazole (SMX), and sulfamethazine (SMZ) were detected with high frequency over 65% and an average concentration of 22.6–76.8 ng·mL−1. The result suggests that antibiotic residues in the aquaculture and river waters are considered as an emerging environmental problem of the region. To address this issue, we fabricated the well-defined TiO2 nanotube arrays (TNAs) and nanowires on nanotube arrays (TNWs/TNAs) using the anodization method. The TNAs had an inner tube diameter of ~95 nm and a wall thickness of ~25 nm. Meanwhile, the TNWs/TNAs had a layer of TiO2 nanowires with a length of ~6 µm partially covering the TNAs. In addition, both TNAs and TNWs/TNAs had pure anatase phase TiO2 with (101) and (112) dominant preferred orientations. Moreover, the TNAs and TNWs/TNAs effectively and rapidly degraded the antibiotic residues under UV-VIS irradiation at 120 mW/cm2 and obtained over 95% removal at 20 min. Indeed, the photocatalytic reaction rate constants (k) were in the range of 0.14–0.36 min−1 for TNAs, and 0.15–0.38 min−1 for TNWs/TNAs. Noticeably, the k values of TNWs/TNAs were slightly higher than those of TNAs for LCM, DXC, OTC, SMZ, and SMX that could be attributed to the larger surface area of TNWs/TNAs than TNAs when TNWs/TNAs had an additional ~6μm TNWs top layer.

Determination of Praziquantel in Sparus aurata L. after Administration of Medicated Animal Feed

Simple Summary

The present study aimed to determine the praziquantel concentration in Sparus aurata muscle after oral administration of medicated feed. The in-feed treatment is commonly used in aquaculture breeding because it allows the treatment of a large fish population without stress. However, no residue limit exists for praziquantel in fish for human consumption, so the purpose of this work was to verify if this drug was able to accumulate in fish tissues after this treatment. The high-sensitivity analytical method developed in this work permitted to identify and quantify low concentrations of the drug in gilthead sea bream muscle, after the above-mentioned treatment. This method can be useful to competent authorities in evaluating the appropriate withdrawal time in fish treated with praziquantel and intended for human consumption.

Abstract

Praziquantel (PZQ) is an anthelmintic drug used in humans and animals against Platyhelminthes and in aquaculture in the Far East. Medicated feed is one of the most convenient forms of oral administration of drugs in aquaculture because it allows to treat a large population of fish in an easy way. However, this treatment may lead to residues in fish intended for human consumption. In this study, a liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was developed in order to verify the presence of PZQ in samples of Sparus aurata after oral administration of feed treated with PZQ. The method was validated according to international guidelines. It showed good recoveries, selectivity and sensitivity (LOD and LOQ were 3.0 and 9.3 ng/g, respectively), with precision and matrix effect values ≤ 15%. This method could also be applied to determine PZQ residue in other fish species and thus to evaluate the appropriate withdrawal time in treated fish intended for human consumption.

Calibration and validation of a microporous polyethylene passive sampler for quantitative estimation of illicit drug and pharmaceutical and personal care product (PPCP) concentrations in wastewater influent

Wastewater-based epidemiology (WBE), the per capita normalised measurement of drugs, chemicals or metabolites in wastewater influent, relies on sampling and quantitative analysis to evaluate temporal and spatial trends of chemical consumption. Continuous, high-resolution, flow proportional composite sampling is optimal for accurate representations of chemical mass loads, but is rarely implemented, with conventional autosamplers providing relatively low frequency time or volume proportional samples. However, due to equipment or resource constraints at many wastewater treatment plants (WWTPs), even this may not be feasible. Passive sampling may provide an alternative sampling strategy. To investigate this, samplers comprising hollow, cylindrical Microporous Polyethylene Tubes (MPTs) containing polymeric sorbent phases of Strata-X and Strata-X in agarose were simultaneously deployed in a municipal WWTP influent stream. Samplers were extracted, analysed and evaluated for a range of illicit drugs and pharmaceuticals and personal care products (PPCPs) after 4, 7, 15, 21, and 29 day deployments. The MPT samplers were calibrated against 24-hour time proportional composite grab samples that were collected in parallel. Diffusion through the MPT governed uptake, reducing or eliminating the influence of external flow rates that may fluctuate unpredictably in a WWTP environment. Calibration data for six illicit drugs and fourteen PPCPs, including methamphetamine, benzoylecgonine, MDMA, codeine and carbamazepine, demonstrated linear accumulation in the samplers (R² ≥ 0.84). Derived sampling rates for these analytes ranged from 0.25 to 17 mL d^-1 for ibuprofen and verapamil, respectively. A validation study using this sampling rate data showed the MPT could effectively quantify concentrations (≥0.1 ng mL^-1) of a range of amphetamine-type stimulants, opioids and metabolites as well as nicotine, accounting for 95% of the variance in parallel composite grab sample concentrations of these compounds. The MPT sampler shows promise for providing essential monitoring data for WBE, informing future intervention and research strategies.

Materials for Solid-Phase Extraction of Organic Compounds

This review provides an overview of the most recent developments involving materials for solid-phase extraction applied to determine organic contaminants. It mainly concerns polymer-based sorbents that include high-capacity, as well as selective sorbents, inorganic-based sorbents that include those prepared using sol-gel technology along with structured porous materials based on inorganic species, and carbon nanomaterials, such as graphene and carbon nanotubes. Different types of magnetic nanoparticles coated with these materials are also reviewed. Such materials, together with their main morphological and chemical features, are described, as are some representative examples of their application as solid-phase extraction materials to extract organic compounds from different types of samples, including environmental water, biological fluids, and food.

Coating magnetic biochar with humic acid for high efficient removal of fluoroquinolone antibiotics in water

As antibiotics are widely consumed, fluoroquinolones (FQs) behave to have huge hidden danger to human health. Various agricultural residues have potential to produce biochar rich in porous structure for adsorption of contaminants. In this study, potato leaves and stems were pyrolyzed at 500 °C under anoxic condition for biochar (BC) preparation. At the same conditions, magnetic biochar (MBC) and humic acid (HA) coated magnetic biochar (HAB) were also prepared. In particular, characterizations of HAB showed the extensive coating of HA on MBC surface and introducing more oxygen-containing groups, which may promote the adsorption capacity of biochar. Three typical FQs (ciprofloxacin (CIP), norfloxacin (NOR) and enrofloxacin (ENR)) were used as target contaminants to further investigate the adsorption property of HAB. Compared with BC and MBC, novel adsorbent HAB due to introduction of HA exhibited better FQs adsorption ability, and its maximum adsorption capacity for CIP, NOR and ENR were 1.80, 1.67 and 1.70 times higher than those of MBC and were 3.40, 2.88, 2.96 times higher than those of raw BC, respectively. Pseudo-second-order kinetic model and Langmuir isotherm model could describe the process of FQs adsorbed on HAB more appropriately, and thermodynamic results illustrated that the sorption process was spontaneous and endothermic. In addition, FQs adsorption by HAB was increased with initial solution pH from 3.0 to 10.0, while it was slightly decreased with ionic strength rising (0.001-0.1 M CaCl₂). Combined with FTIR results, high FQs removal efficiency could be attributed to electrostatic, hydrophobic, H-bond and π-π EDA interactions.

Bacteria-assisted removal of fluoroquinolones from wheat rhizospheres in an agricultural soil

Extensive fluoroquinolone antibiotics use results in their widespread occurrence in various environments including soil, which threatens the soil ecology and public health. The fate of fluoroquinolones in agricultural soil and the efficacy of enhanced degradation in the presence of an agricultural crops and antibiotic degrading bacteria could be better understood. The current study examined ciprofloxacin (CIP), enrofloxacin (ENR), and levofloxacin (LEV) biodegradation in a Maury Silt Loam soil in greenhouse conditions by bacterial-assisted removal of individual and mixed antibiotics in wheat rhizospheres. Fluoroquinolones were added at rates of 5, 50, and 100 mg kg^-1. Three bacterial isolates were applied at 10⁶ CFU g^-1 soil individually and in consortium. Antibiotics appeared in wheat tissue, with more accumulation in roots than shoots. Low recoveries (<50%) of CIP, ENR, and LEV were observed at all levels and treatments in a bacteria and wheat-free control compared to the initial concentrations applied Contaminated soil with wheat had greater antibiotic recovery than the wheat-free control. Antibiotic recovery with bacterial inoculum was less than that of the indigenous bacteria. The least antibiotic recovery occurred with wheat and bacterial inoculum together. At concentrations of 5 and 50 mg kg^-1, but not at 100 mg kg^-1, CIP, ENR, and LEV were below detection limits in soil after 30 days through the combination of wheat and bacteria compared to the control. This synergistic removal of the fluoroquinolone antibiotics is proposed to be due to enhanced antibiotic bioavailability, which suggests it as an environment-friendly approach to biodegradation.

Development and Optimisation of a Multiresidue Method for the Determination of 40 Anthelmintic Compounds in Environmental Water Samples by Solid Phase Extraction (SPE) with LC-MS/MS Detection

A comprehensive multiresidue method was developed and validated for the determination of 40 anthelmintic compounds, including 13 transformation products, in surface and groundwater samples at sub nanogram per litre (ng L-1) levels. Anthelmintic residues were extracted from unfiltered water samples using polymeric divinylbenzene solid phase extraction (SPE) cartridges, and eluted with methanol: acetone (50:50, v/v). Purified extracts were concentrated, filtered and injected for UHPLC-MS/MS determination. The method recovery (at a concentration representative of realistic expected environmental water levels based on literature review) ranged from 83-113%. The method was validated, at three concentration levels, in accordance to Commission Decision 2002/657/EC and SANTE/11813/2017 guidelines. Trueness and precision, under within-laboratory reproducibility conditions, ranged from 88-114% and 1.1-19.4%, respectively. The applicability of the method was assessed in a pilot study whereby 72 different surface and groundwater samples were collected and analysed for the determination of these 40 compounds for the first time in Ireland. This is the most comprehensive method available for the investigation of the occurrence of both anthelmintic parent compounds and their transformation products in raw, unfiltered environmental waters.

Salting-out assisted liquid-liquid extraction for the determination of ciprofloxacin residues in water samples by high performance liquid chromatography-diode array detector

Background

The occurrence of emerging pollutants like pharmaceuticals and related compounds in the aquatic and terrestrial environments is of increasing concern. Ciprofloxacin is one of the pharmaceuticals which is active against a wide range of bacteria. The main objective of this research is to develop a simple method for the extraction and determination of ciprofloxacin residues in environmental water samples.

Results

A salting-out assisted liquid-liquid extraction (SALLE) method for the determination of ciprofloxacin in water samples by high-performance liquid chromatography with diode array detector (HPLC-DAD) was developed. The calibration curve was linear over the range of 0.1-100 μg/L with coefficient of determination (r²) of 0.9976. The limits of detection (LOD) and quantification (LOQ) of the method were 0.075 and 0.25 µg/L, respectively. The reproducibility in terms of relative standard deviation (% RSD) was less than 10%. The applicability of the developed method was investigated by analyzing tap water, bottled mineral water and waste water and demonstrated satisfactory recoveries in the ranges of 86.4-120%.

Conclusion

The method offered a number of features including wide linear range, good recovery, short analysis time, simple operation process and environmental friendly. The developed method can be utilized as an attractive alternative for the determination of ciprofloxacin residues in environmental water matrices.

Removal of veterinary antibiotics in constructed wetland microcosms - Response of bacterial communities

This study aimed to evaluate the response of bacteria, in terms of microbial community structure, from constructed wetland (CW) microcosms exposed to two veterinary antibiotics, enrofloxacin (ENR) and ceftiofur (CEF), alone or in a mixture, identifying which bacterial groups were dominant in CWs substrate during livestock wastewater treatment. Wastewater, not-doped or doped with ENR and/or CEF (100 µg/L each), was treated during 18 one-week cycles. Systems showed removal percentages > 85% for the added antibiotics, showing also high removal percentages for nutrients and organic matter and confirming CWs systems were working properly. However, both time of exposure and presence of antibiotics influenced significantly CWs substrate bacterial community structure. Pyrosequencing results showed bacterial communities were dominated by phyla Proteobacteria (38-48%), Firmicutes (20-27%), Bacteroidetes (12-15%) and Actinobacteria (4-9%), and that their relative abundance was clearly affected by the presence of the antibiotics. Results suggest the applicability of CWs for the removal of veterinary antibiotics from livestock wastewaters and provide new knowledge about the bacteria within the system, which can potentially be involved in removal processes. This information could in the future be used to improve CWs removal rates of pharmaceuticals from livestock wastewaters.

Benzimidazoles in wastewater: Analytical method development, monitoring and degradation by photolysis and ozonation

Pharmaceutical residues are constantly released into natural waters, mainly from wastewater treatment plants (WWTPs) whose processes are unable to completely eliminate them. Among these drugs, the occurrence of benzimidazoles, a class of antiparasitics for human and veterinary use, has been reported in WWTP effluents and surface waters. In this study, an SPE-UHPLC-MS/MS method was developed and optimized for extraction and quantitation of benzimidazoles in influents and effluents of a local WWTP and in hospital wastewater. The extraction procedure was optimized using response surface methodology (Box-Behnken design) and the optimal parameters were as follows: 2.0 mL of loading solvent consisting of a mixture of water:methanol (95:5, v/v) and temperature at 43 °C. In hospital wastewater, albendazole (ABZ) and its principal metabolite ricobendazole (RBZ) were the main benzimidazole-related contaminants and were found at concentrations of up to 3810 and 3894 ng L^-1, respectively. The WWTP system was able to remove from 46% to 95% of the ABZ quantified in the influent, discharging an effluent with 16-441 ng L^-1 of ABZ. The concentrations of other benzimidazoles and metabolites in the WWTP effluents remained below 350 ng L^-1. WWTP effluents fortified with 50 μg L^-1 of ABZ required 26.7 mg_O3 L^-1 to remove ABZ and RBZ. After ozonation, the COD and BOD₅ of the effluents were reduced by 27%. Photolysis by UVA radiation was not effective to remove ABZ and FBZ from the effluent samples.

Bacteria That Make a Meal of Sulfonamide Antibiotics: Blind Spots and Emerging Opportunities

The release of sulfonamide antibiotics into the environment is alarming because the existence of these antibiotics in the environment may promote resistance in clinically relevant microorganisms, which is a potential threat to the effectiveness of antibiotic therapies. Controllable biodegradation processes are of particular significance for the inexpensive yet effective restoration of sulfonamide-contaminated environments. Cultivation-based techniques have already made great strides in successfully isolating bacteria with promising sulfonamide degradation abilities, but the implementation of these isolates in bioremediation has been limited by unknown microbial diversity, vast population responsiveness, and the impact of perturbations from open and complex environments. Advances in DNA sequencing technologies and metagenomic analyses are being used to complement the information derived from cultivation-based procedures. In this Review, we provide an overview of the growing understanding of isolated sulfonamide degraders and identify shortcomings of the prevalent literature in this field. In addition, we propose a technical paradigm that integrates experimental testing with metagenomic analysis to pave the way for improved understanding and exploitation of these ecologically important isolates. Overall, this Review aims to outline how metagenomic studies of isolated sulfonamide degraders are being applied for the advancement of bioremediation strategies for sulfonamide contamination.

Fluoroquinolones (FQs) in the environment: A review on their abundance, sorption and toxicity in soil

The use of fluoroquinolones (FQs) antibiotics as therapeutic agents and growth promoters is increasing worldwide; however their extensive uses are also resulting in antibiotic resistance among world communities. FQs have also become one of the major contaminants in the waste water bodies, which are not even completely removed during the treatment processes. Furthermore, their abundance in agricultural resources, such as the irrigation water, the bio-solids and the livestock manure can also affect the soil micro-environment. These antibiotics in soil tend to interact in several different ways to affect soil flora and fauna. The current review endeavors to highlight the some critical aspects of FQs prevalence in the environment. The review presents a detailed discussion on the pathways and abundance of FQs in soil. The discussion further spans the issue of sorption and FQs transformation into the soil better understand of their behavior and their toxicity to soil flora and fauna.

Environmental behavior of sulfadiazine, sulfamethazine, and their metabolites

Sulfonamides are one of the most frequently used antibiotics worldwide. Therefore, processes that determine their fate in the environment are of great interest. In the present work, biodegradation as biotic process and hydrolysis and photolysis as abiotic processes were investigated. In biodegradation experiments, it was found out that sulfonamides (sulfadiazine and sulfamethazine) and their N ⁴-acetylated metabolites were not readily biodegradable. The results showed that decrease of concentrations were in the range from 4% for sulfadiazine to 22% for N ⁴-acetylsulfamethazine. Hydrolytic experiments examined at pH values normally found in the environment also showed their resistance. However, photolysis proved to be significant process for decreasing concentrations of sulfonamides and their metabolites in three various aqueous matrices (Milli-Q water, river water, and synthetic wastewater). In addition, influence of ubiquitous water constituents (Cl^-, NO₃^-, SO₄^2-, PO₄^3-, and humic acids) was also investigated, showing their different impact on photolysis of investigated pharmaceuticals. The results showed that photolysis followed first-order kinetics in all cases. The obtained results are very important for assesing the environmental fate of sulfonamides and their metabolites in the aquatic environment.

Constructed wetlands for the removal of metals from livestock wastewater - Can the presence of veterinary antibiotics affect removals?

The presence of emergent antibiotics, in livestock wastewater may affect constructed wetlands (CWs) performance in the removal of other pollutants. The main objective of this study was to evaluate the influence of two antibiotics commonly used in livestock industry, enrofloxacin and ceftiofur, on metal removal by CWs. Microcosms (0.4m×0.3m×0.3m), simulating CWs, were constructed with Phragmites australis to treat livestock wastewater spiked or not with 100µg/L of enrofloxacin or ceftiofur (individually or in mixture). Wastewater was treated during 20 one-week cycles. After one-week cycle wastewater was removed and replaced by new wastewater (with or without spiking). At weeks 1, 2, 4, 8, 14, 18 and 20, treated wastewater was analysed to determine the removal rates of metals (Zn, Cu, Fe and Mn) and of each antibiotic. At weeks 1, 8 and 20 portions of the plant root substrate were collected and metals determined. At the end of the experiment metal levels were also determined in plant tissues. Removal rate of Fe from wastewater was 99%. Removal rates of Cu and Zn were higher than 85% and 89%, respectively, whereas for Mn removal rates up to 75% were obtained. In general, no significant differences were observed through time in the removals of the different metals, indicating that the systems maintained their functionality during the experimental period. Antibiotics did not interfere with the system depuration capacity, in terms of metals removals from wastewater, and ceftiofur even promoted metal uptake by P. australis. Therefore, CWs seem to be a valuable alternative to remove pollutants, including antibiotics and metals, from livestock wastewaters, reducing the risk the release of these wastewaters might pose into the environment, although more research should be conducted with other antibiotics in CWs.

Kinetics and degradation pathways of photolytic and photocatalytic oxidation of the anthelmintic drug praziquantel

In this study, an anthelmintic drug, praziquantel(PZQ), was degraded using the direct photolysis, photocatalysis, and oxidation processes including UV radiation, TiO₂ film, and hydrogen peroxide. The photolytic degradation with predominant wavelengths of 185/254nm (UV-C) proved to be more efficient with a half-life of 3.13min compared to the radiation of 365nm (UV-A) where the degradation did not occur. In order to enhance the rate of PZQ photolytic degradation, H₂O₂ was added, which resulted in two to three times higher degradation rates. In the photocatalytic degradation, TiO₂ film was used as catalyst. The degradation was ten times faster in the photocatalytic experiments where UV-C light (k=0.2390min^-1) was used than in those with UV-A (k=0.0201min^-1). Comparing the results from all performed experiments it can be concluded that the UV-C/TiO₂/H₂O₂ process yielded the highest degradation rate and complete degradation of PZQ was obtained in less than 7min. The degradation of PZQ followed the first order kinetics in all the experiments. The photo degradation was inhibited in the presence of methanol. The degradation pathways and the structural formulae of five degradation products (m/z 273, 269, 189, 147, 132) were proposed based on the liquid chromatography tandem mass spectrometry analysis.

The effects of ciprofloxacin on early life stages of common carp (Cyprinus carpio)

The authors performed a toxicity test with ciprofloxacin in fertilized eggs of common carp according to guideline 210 of the Organisation for Economic Co-operation and Development. The tested concentrations were 1 μg L(-1) , 100 μg L(-1) , 500 μg L(-1) , 1000 μg L(-1) , and 3000 μg L(-1) . Accelerated hatching was found in all groups exposed to ciprofloxacin, but significant growth reduction was found only in the group exposed to the highest concentration (3000 μg L(-1) ). Increased numbers of macroscopic morphological anomalies were observed on day 6 of the test (after hatching). The highest numbers of macroscopic morphological anomalies were observed in the groups of free embryos and larvae exposed to ciprofloxacin concentrations of 100 μg L(-1) , 500 μg L(-1) , 1000 μg L(-1) , and 3000 μg L(-1) (20-23% of tested samples). A gradual decrease in glutathione S-transferase activity was detected in all experimental groups exposed to ciprofloxacin, but significant differences (p < 0.01) were found only in groups treated with 500 μg L(-1) and 3000 μg L(-1) . Glutathione peroxidase and catalase exhibited increased activity in most of the tested concentrations (p < 0.01 and <0.05, respectively), whereas decreased glutathione reductase activity was found in the groups exposed to ciprofloxacin concentrations of 500 μg L(-1) and 3000 μg L(-1) (p < 0.05). The concentration of thiobarbituric acid-reactive substances was significantly lower (p < 0.01) in all experimental groups exposed to ciprofloxacin. The lowest-observed-effect concentration of ciprofloxacin was 1 μg L(-1) . These results suggest that hatching, early ontogeny, occurrence of morphological anomalies, antioxidant and biotransformation enzyme activity, and lipid peroxidation in fish can be affected by ciprofloxacin. Environ Toxicol Chem 2016;35:1733-1740. © 2015 SETAC.

Aspects of decontamination of ivermectin and praziquantel from environmental waters using advanced oxidation technology

Recently performed environmental risk assessments of ivermectin demonstrated the need to complete the information regarding the fate of ivermectin in environment. There is also a lack of information concerning the fate and stability of praziquantel. The forced degradation study and photocatalytic degradation pathways in aqueous TiO2 suspensions of the two anthelmintics ivermectin and praziquantel were investigated and compared. The degradation efficiency increased for both compounds with the increase in the TiO2 concentration from 0.25 to 2.00 g L(-1), and then remained constant. The estimated k-values were from 0.36 h(-1) to 0.64 h(-1) for IVE and from 0.29 h(-1) to 0.47 h(-1) for PZQ, respectively. The degradation rate was not significantly impacted by the change of the pH value (pH 3, 5, 7, and 9) at 2.0 g L(-1) of TiO2. The photo degradation was about 90% for both compounds after 5 h of irradiation and it was significantly inhibited in the presence of iodide anion and isopropyl alcohol, which indicated, that hydroxyl radicals as well as holes contributed to the degradation of both anthelmintics. The contribution of hydroxyl radicals and holes was 92.1% for IVE and 93.2% for PZQ, respectively. Photocatalytic process of ivermectin resulted in three degradation intermediates; another two were formed during acidic and basic hydrolysis. Praziquantel underwent degradation to six degradation intermediates; four of them were formed under photocatalytic irradiation. The intermediates were identified using UHPLC-MS/MS. UV/TiO2 photolysis has been found as an effective advanced oxidation technology for the decontamination of ivermectin and praziquantel.

Microbial community dynamics associated with veterinary antibiotics removal in constructed wetlands microcosms

This study aimed to evaluate the response of the microbial community from CWs microcosms tested for the removal of two veterinary antibiotics, enrofloxacin (ENR) and tetracycline (TET), from livestock industry wastewater. Three treatments were tested (control, ENR or TET (100 μg L(-1))) over 12 weeks in microcosms unplanted and planted with Phragmites australis. CWs removal efficiency was relatively stable along time, with removals higher than 98% for ENR and 94% for TET. In addition, CWs were able to reduce wastewater toxicity, independently of antibiotics presence. Despite no significant differences were observed in terms of microbial abundance, bacterial richness or diversity, analysis of similarities (two-way crossed ANOSIM) showed a significant effect of both time and treatments in bacterial community structure. This study points to CWs applicability for veterinary antibiotics removal from livestock wastewaters, showing that CWs microbial communities were able to adapt without significant changes in their diversity or depuration capacity.

Fluoroquinolone antibiotics: an emerging class of environmental micropollutants

The aim of this review paper is to provide a comprehensive overview of different chemical and environmental aspects concerning fluoroquinolone antibiotics as emerging contaminants. A literature survey has been performed based on 204 papers from 1998 to mid-2013, resulting in a dataset consisting out of 4100 data points related to physical-chemical properties, environmental occurrence, removal efficiencies, and ecotoxicological data. In a first part, an overview is given on relevant physical-chemical parameters to better understand the behavior of fluoroquinolones during wastewater treatment and in the environment. Secondly, the route of these antibiotics after their application in both human and veterinary surroundings is discussed. Thirdly, the occurrence of fluoroquinolone residues is discussed for different environmental matrices. The final part of this review provides a tentative risk assessment of fluoroquinolone compounds and their transformation products in surface waters by means of hazard quotients. Overall, this review shows that fluoroquinolone antibiotics have a wide spread use and that their behavior during wastewater treatment is complex with an incomplete removal. As a result, it is observed that these biorecalcitrant compounds are present in different environmental matrices at potentially hazardous concentrations for the aquatic environment. The latter calls for actions on both the consumption as well as the wastewater treatment aspect to diminish the discharge of these biological active compounds.

Occurrence and behaviour of 105 active pharmaceutical ingredients in sewage waters of a municipal sewer collection system

The concentrations and behaviour of 105 different active pharmaceutical ingredients (APIs) in the aqueous phase of sewage water within a municipal sewer collection system have been investigated. Sewage water samples were gathered from seven pump stations (one of which was located within a university hospital) and from sewage water treatment influent and effluent. The targeted APIs were quantified using a multi-residue method based on online solid phase extraction liquid chromatography tandem mass spectrometry. The method was thoroughly validated and complies with EU regulations on sample handling, limits of quantification, quality control and selectivity. 51 APIs, including antibiotics, antidepressants, hypertension drugs, analgesics, NSAIDs and psycholeptics, were found frequently within the sewer collection system. API concentrations and mass flows were evaluated in terms of their frequency of detection, daily variation, median/minimum/maximum/average concentrations, demographic dissimilarities, removal efficiencies, and mass flow profiles relative to municipal sales data. Our results suggest that some APIs are removed from, or introduced to, the aqueous phase of sewage waters within the studied municipal collection system.

Chemometric quality inspection control of pyrantel pamoate, febantel and praziquantel in veterinary tablets by mid infrared spectroscopy

This paper describes the development and validation of a new multivariate calibration method based on diffuse reflectance mid infrared spectroscopy for direct and simultaneous determination of three veterinary pharmaceutical drugs, pyrantel pamoate, praziquantel and febantel, in commercial tablets. The best synergy interval partial least squares (siPLS) model was obtained by selecting three spectral regions, 3715-3150, 2865-2583, and 2298-1733 cm(-1), preprocessed by first derivative and Savitzky-Golay smoothing followed by mean centering. This model was built with five latent variables and provided root mean square errors of prediction (RMSEP) equal or lower than 0.69 mg per 100 mg of powder for the three analytes. The method was validated according the appropriate regulations through the estimate of figures of merit, such as trueness, precision, linearity, analytical sensitivity, bias and residual prediction deviation (RPD). Then, it was applied to three different veterinary pharmaceutical formulations found in the Brazilian market, in a situation of multi-product calibration, since the excipient composition of these commercial products, which was not known a priori, was modeled by an experimental design that scanned the likely content range of the possible constituents. The results were verified with high performance liquid chromatography with diode array detection (HPLC-DAD) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and were in agreement with the predicted values at 95% confidence level. The developed method presented the advantages of being simple, rapid, solvent free, and about ten times faster than the HPLC ones.

Analysis of anthelmintics in surface water by ultra high performance liquid chromatography coupled to quadrupole linear ion trap tandem mass spectrometry

A method based on ultra high performance liquid chromatography coupled to quadrupole linear ion trap mass spectrometry (UHPLC-QqLIT-MS) has been developed to investigate occurrence of 10 anthelmintic drugs from different structural groups (moxidectin, flubendazole, fenbendazole, levamisol, mebendazole, oxibendazole, albendazole, triclabendazole, febantel and praziquantel) in surface water. Analytes were pre-concentrated by solid phase extraction (SPE) using hydrophilic-lipophilic polymeric based sorbent. Quantification of investigated analytes was done using deuterated compounds as internal standards in order to minimize matrix effect. Analyte recoveries from spiked samples at two concentration levels were above 75% for most of the analytes. The main advantages of developed method are fast separation using UHPLC and therefore short analysis time, combined with good sensitivity which is demonstrated by low ngL(-1) detection limits. The developed method was applied for analysis of anthelmintics in the Llobregat River (NE Spain) and its main tributaries (rivers Anoia and Cardener). Eight out of ten anthelmintics were detected in all analyzed samples with the concentrations in low ngL(-1) level. The method fills the gap on analytical methodologies for determination of anthelmintic drugs in the environment.

Photodegradation of sulfonamides and their N (4)-acetylated metabolites in water by simulated sunlight irradiation: kinetics and identification of photoproducts

Once released into the aquatic environment, pharmaceuticals may undergo different degradation processes. Photodegradation, for example, might be an important elimination process for light-sensitive pharmaceuticals, such as antibiotics. In this study, the fate of sulfonamides (sulfamethazine, sulfadiazine, and sulfamethoxazole) and their N (4)-acetylated metabolites (N (4)-acetylsulfadiazine, N (4)-acetylsulfamethazine, and N (4)-acetylsulfamethoxazole) under simulated sunlight irradiation was investigated. The irradiation resulted in total or almost total degradation (88 to 98 %) of the pharmaceuticals tested, except for sulfamethazine (52 %), during 24 h of irradiation. The photoproducts of all investigated pharmaceuticals have been analyzed using high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. Structure elucidation performed from photodegradation products of both, sulfonamides and their N (4)-acetylated metabolites, clearly showed two major formation pathways. These were cleavage of the sulfonamide bond as well as SO2 extrusion. In total, nine photoproducts were elucidated. Among these photoproducts, the tautomers of sulfamethoxazole and desulfonated products of sulfadiazine and sulfamethazine were also present. Tautomers of sulfadiazine and sulfamethazine have been characterized here for the first time as well as some photoproducts of sulfadiazine, sulfametoxazole, and their metabolites N (4)-acetylsulfadiazine and N (4)-acetylsulfametoxazole. The obtained results are an important piece in the complex puzzle for assessing the environmental fate of sulfonamides and their metabolites in the environment.

Activated sludge systems removal efficiency of veterinary pharmaceuticals from slaughterhouse wastewater

The knowledge on the efficiency of wastewater treatment plants (WWTPs) from animal food production industry for the removal of both hormones and antibiotics of veterinary application is still very limited. These compounds have already been reported in different environmental compartments at levels that could have potential impacts on the ecosystems. This work aimed to evaluate the role of activated sludge in the removal of commonly used veterinary drugs, enrofloxacin (ENR), tetracycline (TET), and ceftiofur, from wastewater during a conventional treatment process. For that, a series of laboratory-controlled experiments using activated sludge were carried out in batch reactors. Sludge reactors with 100 μg/L initial drug charge presented removal rates of 68 % for ENR and 77 % for TET from the aqueous phase. Results indicated that sorption to sludge and to the wastewater organic matter was responsible for a significant percentage of drugs removal. Nevertheless, these removal rates still result in considerable concentrations in the aqueous phase that will pass through the WWTP to the receiving environment. Measuring only the dissolved fraction of pharmaceuticals in the WWTP effluents may underestimate the loading and risks to the aquatic environment.

Potential of constructed wetlands microcosms for the removal of veterinary pharmaceuticals from livestock wastewater

The aim of the present work was to evaluate, at microcosm level, the capacity of constructed wetlands (CWs) to remove veterinary pharmaceutical compounds, from wastewater. Results indicated that CWs have potential to mitigate the release of veterinary drugs, namely enrofloxacin (ENR, a fluoroquinolone) and tetracycline (TET, tetracyclines family). Removal efficiencies of 94% and 98% where achieved for TET and ENR, respectively, when treating pigfarm wastewater effluent doped at 100 μg L(-1) drug level, along twelve weeks. Occurrence of adsorption of the drugs to CWs substrate may be the predominant mechanism for ENR, although for TET there are signs that degradation is also occurring.