Environmental behavior and analysis of veterinary and human drugs in soils, sediments and sludge

Interconnected environmental challenges: heavy metal-drug interactions and their impacts on ecosystems

Industrial expansion and inadequate environmental safety measures are major contributors to environmental contamination, with heavy metals (HMs) and pharmaceutical waste playing crucial roles. Their negative effects are most noticeable in aquatic species and vegetation, where they accumulate in tissues and cause harmful results. Interactions between HMs and pharmaceutical molecules result in the production of metal-drug complexes (MDCs), which have the potential to disturb diverse ecosystems and their interdependence. However, present studies frequently focus on individual pollutants and their effects on specific environmental parameters, leaving out the cumulative effects of pollutants and their processes across several environmental domains. To address this gap, this review emphasizes the environmental sources of HMs, elucidates their emission pathways during anthropogenic activities, investigates the interactions between HMs and pharmaceutical substances, and defines the mechanisms underlying the formation of MDCs across various ecosystems. Furthermore, this review underscores the simultaneous occurrence of HMs and pharmaceutical waste across diverse ecosystems, including the atmosphere, soil, and water resources, and their incorporation into biotic organisms across trophic levels. It is important to note that these complex compounds represent a higher risk than individual contaminants.

Chemometric modeling of pharmaceuticals for partitioning between sludge and aqueous phase during the wastewater treatment process

Computational techniques, such as quantitative structure-property relationships (QSPRs), can play a significant role in exploring the important chemical features essential for the degree of sorption or sludge/water partition coefficient (Kd) towards sewage sludge of wastewater treatment process to evaluate the environmental consequence and risk of pharmaceuticals. The current research work aims to construct a predictive QSPR model for the sorption of 148 diverse active pharmaceutical ingredients (APIs) in sewage sludge during wastewater treatment. For the development of the model, we employed easily computable 2D descriptors as independent variables. The model has been developed following the Organization for Economic Cooperation and Development's (OECD) guidelines. It has undergone internal and external validation using a variety of methodologies, as well as been tested for its applicability domain. A measure of hydrophobicity, i.e., MLOGP2, showed the most promising contribution in modeling the sorption coefficient of APIs. Among other parameters, the number of tertiary aromatic amines, the presence of electronegative atoms like N, O, and Cl, the size of a molecule, the number of aromatic hydroxyl groups, the presence of substituted aromatic nitrogen atoms and alkyl-substituted tertiary carbon atoms were also found to be influential for the regulation of solid water partition coefficient of APIs during the wastewater treatment process. The statistical validity tests performed on the developed partial least squares (PLS) model showed that it is statistically evident, robust, and predictive (R2Train = 0.750, Q2LOO = 0.683, Q2F1 = 0.655, Q2F2 (or R2Test) = 0.651). In addition, the predictivity of the constructed model was further inspected by using the "prediction reliability indicator" tool for 14 external APIs.

Application of UHPLC-MS/MS method to monitor the occurrence of sulfonamides and their transformation products in soil in Silesia, Poland

Sulfonamides circulating in the environment lead to disturbances in food chains and local ecosystems, but most importantly contribute to development of resistance genes, which generate problems with multidrug-resistant bacterial infections treatment. In urban areas, sources of sulfonamide distribution in soils have received comparatively less attention in contrast to rural regions, where animal-derived manure, used as a natural fertilizer, is considered the main source. The aim of this study was to determine eight sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine, sulfamethizole, sulfamethoxazole, sulfapyridine, sulfathiazole, and sulfisoxazole) in environmental soil samples collected from urbanized regions in Silesian Voivodeship with increased animal activity. These soils were grouped according to the organic carbon content. It was necessary to develop versatile and efficient extraction and determination method to analyze selected sulfonamides in various soil types. The developed LC-MS/MS method for sulfonamides analyzing was validated. The obtained recoveries exceeded 45% for soil with medium organic carbon content and 88% for sample with a very low organic carbon content (arenaceous quartz). The obtained results show the high impact of organic matter on analytes adsorption in soil, which influences recovery. All eight sulfa drugs were determined in environmental samples in the concentration range 1.5-10.5 ng g-1. The transformation products of the analytes were also identified, and 29 transformation products were detected in 24 out of 27 extracts from soil samples.

The fate of sulfamethoxazole and trimethoprim in a micro-aerated anaerobic membrane bioreactor and the occurrence of antibiotic resistance in the permeate

This study investigates the effects, conversions, and resistance induction, following the addition of 150 μg·L-1 of two antibiotics, sulfamethoxazole (SMX) and trimethoprim (TMP), in a laboratory-scale micro-aerated anaerobic membrane bioreactor (MA-AnMBR). TMP and SMX were removed at 97 and 86%, indicating that micro-aeration did not hamper their removal. These antibiotics only affected the pH and biogas composition of the process, with a significant change in pH from 7.8 to 7.5, and a decrease in biogas methane content from 84 to 78%. TMP was rapidly adsorbed onto the sludge and subsequently degraded during the long solids retention time of 27 days. SMX adsorption was minimal, but the applied hydraulic retention time of 2.6 days was sufficiently long to biodegrade SMX. The levels of three antibiotic-resistant genes (ARGs) (sul1, sul2, and dfrA1) and one mobile genetic element biomarker (intI1) were analyzed by qPCR. Additions of the antibiotics increased the relative abundances of all ARGs and intI1 in the MA-AnMBR sludge, with the sul2 gene folding 15 times after 310 days of operation. The MA-AnMBR was able to reduce the concentration of antibiotic-resistant bacteria (ARB) in the permeate by 3 log.

Uptake of Pharmaceuticals by Crops: A Systematic Review and Meta-analysis

Studies on the uptake of pharmaceuticals from soils into crops were first conducted in the 2000s. Since then a wealth of such data has been generated, but to the best of our knowledge, these studies have not been systematically reviewed. We present a quantitative, systematic review of empirical data on the uptake of pharmaceuticals into crops. We developed a custom-made relational database on plant uptake of pharmaceuticals that contained details of the experimental design and associated results from 150 articles, spanning 173 pharmaceuticals, 78 study crops, and 8048 unique measurements. Analysis of the data in the database showed clear trends in experimental design, with lettuce being the most studied crop and carbamazepine and sulfamethoxazole being the most studied pharmaceuticals. Pharmaceutical properties were found to create the greatest range in uptake concentrations of any single variable studied. Uptake concentrations were also found to vary between crops, with relatively high uptake concentrations identified in cress, lettuce, rice, and courgette crops. An understanding of the influence of soil properties on pharmaceutical uptake was limited by a lack of information on key soil properties across the published literature. The data comparisons were inhibited by differences in quality of the different studies. Moving forward, a framework for best practice in this field is needed to maximize the value and further applications of the data produced. Environ Toxicol Chem 2023;42:2091-2104. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Rapid Environmental Impact Assessment of Penicillin G in a Veterinary Product Using an Original Software Method and Monitoring by SPE-Online-UHPLC-MS/MS

Veterinary antibiotics have become a major concern due to potential environmental effects. This study presents an investigation of the exposure and environmental effects of the veterinary medicinal product in powder form, administered in the drinking water of piglets, chickens and turkeys, containing 250 mg/g penicillin G (benzylpenicillin potassium), performed according to the European Medicines Agency (EMEA) guideline and the results obtained by an analytical method based on online solid-phase extraction, ultra-high performance liquid chromatography coupled to a triple quadrupole mass spectrometer (SPE-online-UHPLC-MS/MS). The study presents the determination of the environmental risk and through an original, interactive, fast software method, created on the basis of a proprietary calculation algorithm that goes through all the prescriptions and recommendations of the EMEA guide. The results demonstrated that the concentration value for penicillin G determined in surface water by SPE-online-UHPLC-MS/MS is much lower than that predicted by calculation (predictable concentration in surface water, PECsurface water = 37.66 µg/L and the concentration SPE-online-UHPLC-MS/MS = 0.032 µg/L). Both results lead to a sub-unit risk quotient (R) indicating that the treatment carried out with the considered veterinary product does not present any risk to the environment.

Biofabricated yeast: super-soldier for detoxification of heavy metals

The advances in nanotechnology have shown enormous impacts in environmental technology as a potent weapon for degradation of toxic organic pollutants and detoxification of heavy metals. It is either by in-situ or ex-situ adaptive strategies. Mycoremediation of environmental pollutants has been a success story of the past decade, by employing the wide arsenal of biological capabilities of fungi. Recently, the proficiency and uniqueness of yeast cell surface alterations have encouraged the generation of engineered yeast cells as dye degraders, heavy metal reduction and its recovery, and also as detoxifiers of various hazardous xenobiotic compounds. As a step forward, recent trends in research are towards developing biologically engineered living materials as potent, biocompatible and reusable hybrid nanomaterials. They include chitosan-yeast nanofibers, nanomats, nanopaper, biosilica hybrids, and TiO₂-yeast nanocomposites. The nano-hybrid materials contribute significantly as supportive stabilizer, and entrappers, which enhances the biofabricated yeast cells' functionality. This field serves as an eco-friendly cutting-edge cocktail research area. In this review, we highlight recent research on biofabricated yeast cells and yeast-based biofabricated molecules, as potent heavy metals, toxic chemical detoxifiers, and their probable mechanistic properties with future application perspectives.

Domestic Waste and Wastewaters as Potential Sources of Pharmaceuticals in Nestling White Storks (Ciconia ciconia)

Information on the exposure of wild birds to pharmaceuticals from wastewater and urban refuse is scarce despite the enormous amount of drugs consumed and discarded by human populations. We tested for the presence of a battery of antibiotics, NSAIDs, and analgesics in the blood of white stork (Ciconia ciconia) nestlings in the vicinity of urban waste dumps and contaminated rivers in Madrid, central Spain. We also carried out a literature review on the occurrence and concentration of the tested compounds in other wild bird species to further evaluate possible shared exposure routes with white storks. The presence of two pharmaceutical drugs (the analgesic acetaminophen and the antibiotic marbofloxacin) out of fourteen analysed in the blood of nestlings was confirmed in 15% of individuals (n = 20) and in 30% of the nests (n = 10). The apparently low occurrence and concentration (acetaminophen: 9.45 ng mL−1; marbofloxacin: 7.21 ng mL−1) in nestlings from different nests suggests the uptake through food acquired in rubbish dumps rather than through contaminated flowing water provided by parents to offspring. As with other synthetic materials, different administration forms (tablets, capsules, and gels) of acetaminophen discarded in household waste could be accidentally ingested when parent storks forage on rubbish to provide meat scraps to their nestlings. The presence of the fluoroquinolone marbofloxacin, exclusively used in veterinary medicine, suggests exposure via consumption of meat residues of treated animals for human consumption found in rubbish dumps, as documented previously at higher concentrations in vultures consuming entire carcasses of large livestock. Control measures and ecopharmacovigilance frameworks are needed to minimize the release of pharmaceutical compounds from the human population into the environment.

Determination of pharmaceuticals and metabolites in sludge and hydrochar after hydrothermal carbonization using sonication-QuEChERS extraction method and UHPLC LTQ/Orbitrap MS

Pharmaceuticals (PhACs) are an important group of emerging contaminants that are released continuously in the environment from wastewater treatments plants (WWTPs). They can produce biological effects even though at very low concentrations. Conventional WWTPs are not able to remove or degrade completely emerging pollutants resulting in the presence of PhACs in sewage sludge after wastewater treatment. PhACs are found in sludge at low ppb-ppt levels, and their analysis and detection is a difficult task due to the complexity of sewage sludge matrices. Hydrothermal carbonization is currently being proposed as a suitable conversion technology for sewage sludge management to recover valuable products and to be used for soil amendment. In this work, a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based methodology with a dispersive solid-phase extraction (d-SPE) clean-up followed by ultra-high-performance liquid chromatography coupled with high-resolution linear ion trap-Orbitrap mass spectrometry (UHPLC-LTQ/Orbitrap MS), operated in positive ionization mode, was adopted to investigate 33 multiclass pharmaceuticals in sewage sludge and in hydrochar produced after hydrothermal carbonization. The analytical method was first optimized studying various extraction parameters and finally validated in terms of linearity, recovery, intra and inter-day precisions, expanded uncertainty (%U)/Horrat ratio at three spiking levels, matrix-effects (ME), process efficiency (PE), and limits of detection and quantification. The developed methodology fulfilled all analytical requirements and was finally applied to sludge samples from the WWTP of Ioannina city where a group of antibiotics was detected at concentrations up to 15 ng g^-1 and psychiatric drugs such as amisulpride, clozapine, and citalopram were detected at higher concentration levels up to 205, 87.4 and 63.2 ng g^-1, respectively. The method was also applied to hydrothermally treated sludge sample under different reaction conditions. Most of the antibiotic compounds were not detected, and several psychiatric drugs such as mirtazapine, bupropion, valsartan, diazepam, and caffeine were found at concentrations below the LOQ.

Influence of Organic Matter on the Sorption of Cefdinir, Memantine and Praziquantel on Different Soil and Sediment Samples

Pharmaceuticals are known for their great effects and applications in the treatment and suppression of various diseases in human and veterinary medicine. The development and modernization of science and technologies have led to a constant increase in the production and consumption of various classes of pharmaceuticals, so they pose a threat to the environment, which can be subjected to the sorption process on the solid phase. The efficiency of sorption is determined by various parameters, of which the physicochemical properties of the compound and the sorbent are very important. One of these parameters that determine pharmaceutical mobility in soil or sediment is the soil−water partition coefficient normalized to organic carbon (Koc), whose determination was the purpose of this study. The influence of organic matter, suspended in an aqueous solution of pharmaceutical (more precisely: cefdinir, memantine, and praziquantel), was studied for five different types of soil and sediment samples from Croatia. The linear, Freundlich, and Dubinin−Raduskevich sorption isotherms were used to determine specific constants such as the partition coefficient Kd, which directly describes the strength of sorbate and sorbent binding. The linear model proved to be the best with the highest correlation coefficients, R2 > 0.99. For all three pharmaceuticals, a positive correlation between sorption affinity described by Kd and Koc and the amount of organic matter was demonstrated.

Effects of florfenicol on methane accumulation and changes in the structure of the prokaryotic community in a water-sediment system

Florfenicol has been widely used in the veterinary and aquaculture to control bacterial diseases because of its high efficacy, quick effect, and low cost. The water-sediment system has become an important sink for florfenicol, and the anaerobic environment of lake sediments is favorable for methane (CH₄) production. Although antibiotics may impact methanogenesis under anaerobic conditions, the influence of florfenicol on CH₄ accumulation in anaerobic water-sediment system remains uncertain. This study evaluated how florfenicol affects CH₄ accumulation and the structure of the prokaryotic community in a water-sediment system. Anaerobic systems with different florfenicol concentrations (0, 0.2, 1, 5 and 10 mg/L) were incubated and CH₄ accumulation, pH, total organic carbon content, degradation ratio of florfenicol, and structure of the prokaryotic community were monitored. It was found that CH₄ accumulation raised in low florfenicol (0.2 and 1 mg/L) systems during the growth period, while CH₄ accumulation declined in high florfenicol (5 and 10 mg/L) systems. In the first 13 d, 83.67-99.30 % of florfenicol degraded in different treatments. The addition of florfenicol also influenced the structure of the prokaryotic community of the sediments. Proteobacteria and Chloroflexi were dominant at the phylum level. The dominant taxa at the order level gradually changed from Methanomicrobiales to Methanobacteriales, and finally to Methanosarcinales, indicating the dynamic transformation of methanogens in the reactor. This study reveals the effects of florfenicol on CH₄ production under anaerobic conditions and provides a theoretical basis for further research on the underlying mechanisms. The findings also provide some basic data on the impact of new pollutants on the global carbon cycle and greenhouse gas emission.

Sewage sludge treatment methods and P-recovery possibilities: Current state-of-the-art

With the growing emphasis on environmental protection, the ways of sewage sludge treatment are changing. In this review, we analyse different methods of sewage sludge treatment in terms of potential environmental risk and raw materials recovery. The review begins with a comparison and assessment of existing reviews on this topic. Then, it focuses on the properties and current utilisation of sewage sludge in agriculture and a brief description of sludge thermal treatment methods (mono- and co-incineration, pyrolysis, and gasification). The final part of the review is devoted to technologies for treating sludge ash from mono-incinerators to recover phosphorus, a substance listed as a critical raw material by the EU. Our results show that direct use of sewage sludge likewise composts containing sewage sludge should no longer be considered as a direct source of nutrients and organic matter in agriculture, because of its pollutant content. Co-incineration and landfilling represent a dead-end in sludge treatment due to the loss of raw materials, whereas pyrolysis is sustainable for remote locations with low heavy metal content sludge. Heavy metals also pose a problem for the direct use of sludge ash and must be therefore removed. There are already sludge ash processing technologies that are capable of processing ash to form a variety of raw materials such as phosphorus. These regeneration approaches are currently in their infancy, but are gradually being introduced. The sewage sludge treatment industry is rapidly evolving, and we have attempted to summarise and discuss the current state of knowledge in this review, which will provide a baseline towards the future of sewage sludge suitable treatment.

Relevance of sorption in bio-reduction of amoxicillin taking place in forest and crop soils

The fate of antibiotics reaching soils is a matter of concern, given its potential repercussions on public health and the environment. In this work, the potential bio-reduction of the antibiotic amoxicillin (AMX), affected by sorption and desorption, is studied for 17 soils with clearly different characteristics. To carry out these studies, batch-type tests were performed, adding increasing concentrations of AMX (0, 2.5, 5, 10, 20, 30, 40, and 50 μmol L^-1) to the soils. For the highest concentration added (50 μmol L^-1), the adsorption values for forest soils ranged from 90.97 to 102.54 μmol kg^-1 (74.21-82.41% of the amounts of antibiotic added), while the range was 69.96-94.87 μmol kg^-1 (68.31-92.56%) for maize soils, and 52.72-85.40 μmol kg^-1 (50.96-82.55%) for vineyard soils. When comparing the results for all soils, the highest adsorption corresponded to those more acidic and with high organic matter and non-crystalline minerals contents. The best adjustment to adsorption models corresponded to Freundlich's. AMX desorption was generally <10%; specifically, the maximum was 6.5% in forest soils, and 16.9% in agricultural soils. These results can be considered relevant since they cover agricultural and forest soils with a wide range of pH and organic matter contents, for an antibiotic that, reaching the environment as a contaminant, can pose a potential danger to human and environmental health.

Sporopollenin based materials as a versatile choice for the detoxification of environmental pollutants - A review

Before making the transfer to land, plants survive in water for millions of years to avoid the severe circumstances that prevail on lands, such as drought and UV radiation. All land plant spores are coated in sporopollenin, a substance that has developed to endow pollen and spore shells with exceptional, one-of-a-kind qualities. In a nutshell, sporopollenin-coated spores are a unique invention only seen in land plants. Sporopollenin, discovered in the outer exine layer of pollen walls, is a lipid and phenolic-based polymer with high carbon, hydrogen, and oxygen cross-linking. Products based on sporopollenin can remediate toxic pollutant contamination in the aquatic environment. This research and development are now underway. In this review, we show how sporopollenin-based adsorbents act in environmental challenges and their immense promise for this application via remarkable physical and chemical characteristics. A comparison is made of the benefits of various sporopollenin-modified structures. This strategy will further our understanding of how a biopolymer's structure can be accommodated to address emerging environmental challenges, revealing more about sporopollenin's dynamical nature.

Occurrence, detection and ecotoxicity studies of selected pharmaceuticals in aqueous ecosystems- a systematic appraisal

Pharmaceutical compounds (PCs) have globally emerged as a significant group of environmental contaminants due to the constant detection of their residues in the environment. The main scope of this review is to fill the void of information on the knowledge on the African occurrence of selected PCs in environmental matrices in comparison with those outside Africa and their respective toxic actions on both aquatic and non-aquatic biota through ecotoxicity bioassays. To achieve this objective, the study focused on commonly used and detected pharmaceutical drugs (residues). Based on the conducted literature survey, Africa has the highest levels of ciprofloxacin, sulfamethoxazole, lamivudine, acetaminophen, and diclofenac while Europe has the lowest of all these PC residues in her physical environments. For ecotoxicity bioassays, the few data available are mostly on individual groups of pharmaceuticals whereas there is sparsely available data on their combined forms.

Assessment of the occurrence of 455 pharmaceutical compounds in sludge according to their physical and chemical properties: A review

Sludge agronomical reuse is of major interest due to the beneficial contribution of nutrients. However, it implies the introduction of unregulated pharmaceuticals into amended-soils and creates a controversial issue about sludge management. To limit their dissemination, it is essential to identify the compounds of interest and understand their attenuation mechanisms through the sludge processes. This paper summarizes the knowledge on 455 investigated pharmaceuticals among 32 therapeutical categories in amendable sludge matrices. It contributes to enlarging the list of commonly quantified compounds to 305 residues including 84 additional compounds compared to previous reviews. It highlights that sorption appears as the main mechanism controlling the occurrence of pharmaceuticals in sludge matrices and shows the considerable residual levels of pharmaceuticals reaching several mg/kg in dry weight. Antibiotics, stimulants, and antidepressants show the highest concentrations up to 232 mg/kg, while diuretics, anti-anxieties or anticoagulants present the lowest concentrations reaching up to 686 µg/kg. Collected data show the increase in investigated compounds as antifungals or antihistamines, and underline emerging categories like antidiabetics, antivirals, or antiarrhythmics. The in-depth analysis of the substantial database guides onto the pharmaceuticals that are the most likely to occur in these amendable matrices to assist future research.

The electrospun polyacrylonitrile/covalent organic framework nanofibers for efficient enrichment of trace sulfonamides residues in food samples

In this work, the electrospun polyacrylonitrile/covalent organic frameworks Tp-BD nanofibers (PAN/Tp-BD) were synthesized and applied as an adsorbent for thin film microextraction (TFME) of seven sulfonamides in animal derived food samples. The morphology, structure, porosity, and stability of the prepared nanofibers were investigated. The PAN/Tp-BD nanofibers exhibited good chemical stability, high flexibility, porous fibrous structure, and excellent extraction efficiency. Based on the PAN/Tp-BD nanofibers as the adsorbent, a thin film microextraction-high performance liquid chromatography (TFME-HPLC) method for the determination of seven sulfonamides (SAs) in food samples was developed. Under the optimal conditions, the TFME-HPLC exhibited the low limit of detection (0.10-0.18 ng·mL^-1), the low limit of quantitation (0.33-0.60 ng·mL^-1), the wide linear range (0.5-50 ng·mL^-1) with correlation coefficients between 0.994 and 0.998, and good enrichment factors between 39.7 to 170.1 towards 20 ng/mL SAs solution. The relative standard deviation (RSD) was lower than 11% in the interday and intraday analysis. Furthermore, the applicability of PAN/Tp-BD nanofibers was demonstrated for measuring trace SAs residues in the spiked food samples with recoveries ranging from 85.3% to 115.2%. The results demonstrated that the PAN/Tp-BD nanofibers have great potential for the efficient extraction of sulfonamides from complex food samples.

The influence of antibiotics on the anammox process - a review

Anaerobic ammonium oxidation (anammox) is one of the most promising processes for the treatment of ammonium-rich wastewater. It is more effective, cheaper, and more environmentally friendly than the conventional process currently in use for nitrogen removal. Unfortunately, anammox bacteria are sensitive to various substances, including heavy metals and organic matter commonly found in the wastewater treatment plants (WWTPs). Of these deleterious substances, antibiotics are recognized to be important. For decades, the increasing consumption of antibiotics has led to the increased occurrence of antibiotics in the aquatic environment, including wastewater. One of the most important issues related to antibiotic pollution is the generation and transfer of antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs). Here, we will discuss the effect of short- and long-term exposure of the anammox process to antibiotic pollutants; with a special focus on the activity of the anammox bacteria, biomass properties, community structures, the presence of antibiotic resistance genes and combined effect of antibiotics with other substances commonly found in wastewater. Further, the defense mechanisms according to which bacteria adapt against antibiotic stress are speculated upon. This review aims to facilitate a better understanding of the influence of antibiotics and other co-pollutants on the anammox process and to highlight future avenues of research to target gaps in the knowledge.

Occurrence of antibiotics and antibiotic-resistant bacteria (ARB) in the Nervión river

The main hydrometeorological, microbiological and physico-chemical characteristics of the Nervión river were monitored during a year, including 10 antibiotics and the presence of bacteria resistant to these antibiotics among faecal coliforms (FC) and total aerobic bacteria at 22 °C (TAB₂₂). The characteristics of the river water were variable without a clear seasonal component, strongly influenced by rainfall, with a good quality for drinking water production throughout the year according to the physico-chemical parameters. The antibiotic resistant bacteria isolated from the water of the Nervión river were especially resistant to β-lactams and macrolide antibiotics, highlighting the absence of resistance to derivatives of tetracyclines among strains of TAB₂₂. A third of the isolated strains were multi-resistant to antibiotics with a seasonal component in its presence, with multi-resistant FC more abundant during summer and multi-resistant TAB₂₂ more abundant during winter. The presence of antibiotics in the waters of the Nervión river was not very significant, with total absence of β-lactams, minocycline and ciprofloxacin. Erythromycin and clarithromycin can be considered ubiquitous with mean concentrations of 2.5 ± 2.3 ngL^-1 and 5.7 ± 4.6 ngL^-1 respectively, and the presence of sulfamethoxazole and trimethoprim was also noticeable with maximum concentrations of 78.3 ngL^-1 for sulfamethoxazole. Dilution due to the increase of rainfall was observed for several analysed antibiotics, but without significant seasonal differences.

Ethnoveterinary Survey Conducted in Baiku Yao Communities in Southwest China

Baiku Yao is a branch of the Yao ethnic group mainly living in Guangxi and Guizhou provinces of China. They are recognized by UNESCO as an ethnic group with an intact ethnic culture. The Baiku Yao people have extensive ethnoveterinary knowledge, which they used to prevent and control various animal diseases. During the African swine fever outbreak, the livestock of the Baiku Yao community remained unaffected. We investigated ethnoveterinary knowledge among local Baiku Yao villagers. A total of 39 ethnoveterinary plant species are utilized for the treatment of various diseases. Five species, namely, Stephania kwangsiensis, Aristolochia kwangsiensis, Clerodendrum bungei, Paederia foetida, and Tetradium ruticarpum, had the highest relative frequency values. Strobilanthes cusia, Tetradium ruticarpum, and Stephania kwangsiensis are highly valued locally for treating animal plagues. The existing traditional ethnoveterinary knowledge needs to be conserved and validated scientifically.

Assessment of micropollutants toxicity by using a modified Saccharomyces cerevisiae model

Environment can be affected by a variety of micropollutants. In this paper, we develop a system to assess the toxicity on an environmental sample, based on the expression of a nanoluciferase under the control of the STB5 promotor in a yeast. The STB5 gene encodes for a transcription factor involved in a pleiotropic drug resistance and in the oxidative stress response. The response of the modified yeast was assessed using 42 micropollutants belonging to different families (antibiotics, pain killers, hormones, plasticizers, pesticides, etc.). Among them, 26 induced an increase of the bioluminescence for concentration ranges from pg.L^-1 to ng.L^-1. Surprisingly, for concentrations higher than 100 ng.L^-1, no response can be observed, suggesting that other mechanisms are involved when the stress increases. Analyzing the different responses obtained, we highlighted six nonmonotonic types of responses. The type of response seems to be independent of the properties of the compounds (polarity, toxicology, molecular weight) and of their family. In conclusion, we highlighted that a cellular response exists for very low exposition to environmental concentration of micropollutants and that it was necessary to explore the cellular mechanisms involved at very low concentration to provide a better risk assessment.

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.

Leaching of benzimidazole antiparasitics in soil columns and in soil columns amended with sheep excreta

Benzimidazoles are anthelmintics frequently used in sheep farming due to the high susceptibility of these animals to parasitic diseases. Sheep excreta are often disposed onto soils as a fertilizer, and they may contain benzimidazole residues that can contaminate soil and water. This work aimed to assess the leaching behavior of benzimidazole drugs (albendazole, fenbendazole, and thiabendazole) and their metabolites in two Brazilian soils of different textural classifications (sandy and clay), as well as sheep excreta-amended soils, following the OECD 312 Guidelines. Ewes received a single oral dose of 10 mg kg^-1 b.w. of either albendazole or fenbendazole. The feces were collected at 24, 48, 72, 96, and 120 h post-dose, and the parent drugs and their metabolites extracted using the QuEChERS approach and quantified by UHPLC-MS/MS. For the leaching assays, a benzimidazole solution was directly applied onto the soil columns, or an amount of 5 g of the medicated sheep feces was distributed over the top of the soil columns. In soil samples, benzimidazoles were extracted by solid-liquid extraction and quantified by UHPLC-MS/MS. For the leaching studies, atrazine was used as a reference substance to determine the relative mobility factor of the analytes of interest. Benzimidazoles were considered slightly to moderately mobile in both soils tested, with a leaching distance of up to 25 cm in a 30-cm soil column. Approximately 3 to 6% of the benzimidazoles present in ewe feces were able to leach into the soil columns. This finding is of concern since benzimidazoles are persistent in soil and may pose a risk to soil biota and induce the development of resistant strains of parasites.

Environmental risk assessment of pharmaceuticals at a seasonal holiday destination in the largest freshwater shallow lake in Central Europe

The presence of pharmacologically active compounds (PhACs) in surface waters poses an environmental risk of chronic exposure to nontarget organisms, which is a well-established and serious concern worldwide. Our aim was to determine the temporal changes in ecological risk quotient (RQ) based on the concentrations of 42 PhACs from six sampling sites on seven sampling dates in the water of a freshwater lake in Central Europe preferentially visited by tourists. Our hypothesis was that the environmental risk increases during the summer holiday season due to the influence of tourists. Different experimental toxicological threshold concentrations and seasonal measured environmental concentrations of 16 PhACs were applied to ecological risk assessment. RQs of 4 dominant PhACs (diclofenac, estrone [E1], estradiol [E2], and caffeine) indicated high ecological risk (RQ > 1) for freshwater ecosystems. Additionally, our results confirmed the assumptions that the high tourist season had a significant impact on the calculated RQ; however, these results are mainly due to the concentration and temporal change of particular PhACs, including diclofenac (5.3-419.4 ng/L), E1 (0.1-5.5 ng/L), and E2 (0.1-19.6 ng/L). The seasonal dependent highest RQs changed as follows: 9.80 (June 2017; E2), 1.23 (August 2017; E1), 0.43 (November 2017; E1), 0.51 (April 2018; E1), 5.58 (June 2018, diclofenac), 39.50 (August 2018; diclofenac), and 30.60 (October 2018; diclofenac).

Quantitative analysis of polyethylene terephthalate and polycarbonate microplastics in sediment collected from South Korea, Japan and the USA

Microplastics (MPs) have emerged as contaminants of public health and environmental concern. Although studies have reported the occurrence of MPs in sediment, quantitative determination of polyethylene terephthalate (PET) and polycarbonate (PC) concentrations is limited. In this study, marine coastal and freshwater sediment collected from various locations in South Korea, Japan and the United States were analyzed for PET and PC MPs using a depolymerization method of sample preparation followed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) detection. PET MPs were found in surface sediments from South Korea (n = 20), Japan (n = 4) and the United States (n = 43) at concentrations (dry weight) in the ranges of <MQL-13,000,000 ng/g (median: 6600 ng/g), 3600-5400 ng/g (4400 ng/g) and <MQL-10,000 ng/g (<MQL), respectively. Similarly, PC MPs were found in the concentration ranges of <MQL-140,000 ng/g (median: 290 ng/g, South Korea), 150-510 ng/g (100 ng/g, Japan) and <MQL-110,000 ng/g (160 ng/g, the United States). Spatial analysis of concentrations of PET and PC MPs in sediment from Lake Shihwa watershed in South Korea showed a decreasing trend with increasing distance from inland point source areas (Ansan industrial area). No distinct vertical profiles were recorded for PET or PC MPs in sediment cores collected from Tokyo Bay (Japan) or inland lakes in Michigan (the United States). The measured concentrations of MPs in sediment provide baseline data to evaluate future trends and for ecological risk assessment.

Alteration of antibiotic-resistant phenotypes and minimal inhibitory concentration of Escherichia coli in pig farming: Comparison between closed and open farming systems

The prevalence of antibiotic residues and antibiotic-resistant Escherichia coli (ARE) in closed (CSF) and open (OSF) pig farming systems was analysed. Results showed that a high level of E. coli populations, antibiotic contamination in supplied water, and additional antibiotics used, such as neomycin (NEO) or colistin (CLT), were observed in OSF. Similar ARE resistance to five antibiotics, including NEO, was observed in the water source, dung, and wastewater/sludge but were different from those of CLT. An increased occurrence of ARE was found in the sludge of anaerobic digestion (AD) and the waste stabilisation pond (WSP), but they were not well correlated with their residual antibiotic concentrations. CLT administration yielded higher ARE prevalence in pig excreta and wastewater in OSF, but its absence in CSF also resulted in ARE occurrence with increased minimal inhibitory concentration (MIC) levels in the anaerobic digester/waste stabilisation ponds. This study revealed that ARE prevalence and MIC levels of CLT could be developed during the wastewater treatment process in the pig farm, although none of the AREs were found in the original excreta/wastewater.

Sorption of selected antiparasitics in soils and sediments

BACKGROUND

Veterinary pharmaceuticals can enter the environment when excreted after application and burden terrestrial and aquatic ecosystems. However, knowledge about the basic process of sorption in soils and sediments is limited, complicating regulatory decisions. Therefore, batch equilibrium studies were conducted for the widely used antiparasitics abamectin, doramectin, ivermectin, and moxidectin to add to the assessment of their environmental fate.

RESULTS

We examined 20 soil samples and six sediments from Germany and Morocco. Analysis was based on HPLC-fluorescence detection after derivatization. For soils, this resulted in distribution coefficients K D of 38-642 mL/g for abamectin, doramectin, and ivermectin. Moxidectin displayed K D between 166 and 3123 mL/g. Normalized to soil organic carbon, log K OC coefficients were 3.63, 3.93, 4.12, and 4.74 mL/g, respectively, revealing high affinity to organic matter of soils and sediments. Within sediments, distribution resulted in higher log K OC of 4.03, 4.13, 4.61, and 4.97 mL/g for the four substances. This emphasizes the diverse nature of organic matter in both environmental media. The results also confirm a newly reported log KOW for ivermectin which is higher than longstanding assumptions. Linear sorption models facilitate comparison with other studies and help establish universal distribution coefficients for the environmental risk assessment of veterinary antiparasitics.

CONCLUSIONS

Since environmental exposure affects soils and sediments, future sorption studies should aim to include both matrices to review these essential pharmaceuticals and mitigate environmental risks from their use. The addition of soils and sediments from the African continent (Morocco) touches upon possible broader applications of ivermectin for human use. Especially for ivermectin and moxidectin, strong sorption further indicates high hydrophobicity and provides initial concern for potential aquatic or terrestrial ecotoxicological effects such as bioaccumulation. Our derived K OW estimates also urge to re-assess this important regulatory parameter with contemporary techniques for all four substances.

GRAPHIC ABSTRACT

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s12302-021-00513-y.

Overview of Sample Preparation and Chromatographic Methods to Analysis Pharmaceutical Active Compounds in Waters Matrices

In the environment, pharmaceutical residues are a field of particular interest due to the adverse effects to either human health or aquatic and soil environment. Because of the diversity of these compounds, at least 3000 substances were identified and categorized into 49 different therapeutic classes, and several actions are urgently required at multiple steps, the main ones: (i) occurrence studies of pharmaceutical active compounds (PhACs) in the water cycle; (ii) the analysis of the potential impact of their introduction into the aquatic environment; (iii) the removal/degradation of the pharmaceutical compounds; and, (iv) the development of more sensible and selective analytical methods to their monitorization. This review aims to present the current state-of-the-art sample preparation methods and chromatographic analysis applied to the study of PhACs in water matrices by pinpointing their advantages and drawbacks. Because it is almost impossible to be comprehensive in all PhACs, instruments, extraction techniques, and applications, this overview focuses on works that were published in the last ten years, mainly those applicable to water matrices.

Contamination, distribution, and risk assessment of antibiotics in the urban surface water of the Pearl River in Guangzhou, South China

To assess the impact of antibiotic pollution to the ecosystem in urban water, the occurrence, seasonal, and spatial distributions, potential sources, and ecological risks of 18 targeted antibiotics in urban river, Pearl River located in Guangzhou city, were investigated. Surface water samples were sampled from 24 sites in Guangzhou center of Pearl River during dry and wet seasons. The results indicated that the concentrations of antibiotic residues were at the nanogram per liter level, except sulfamethazine (SMD) (μg/L). Sulfonamides (SAs) were the dominant antibiotics, contributing 60.4-65.0% to the total antibiotics. The concentrations of SAs, fluoroquinolones (QUs), macrolides (MLs), tetracyclines (TCs), and lincosamides (LCs) were higher in dry season than those in wet season at most sampling sites, which possibly resulted from the dilution effect of heavy rainfall. The concentrations of the antibiotic residues in Guangzhou were comparable or higher than other urban rivers. The calculation on risk quotients indicated that erythromycin-H₂O (ETM-H₂O) and tetracycline (TC) were of high risks. The source identification by the Pearson correlation analysis and principal component analysis-multiple linear regression (PCA-MLR) method suggested that municipal wastewater treatment plants were primary sources of antibiotics. These results would provide important information for the environmental protect.

Usage of pharmaceutical contraceptive drug for controlling Eobania vermiculata snails by baits technique

The present study focused on evaluating the effects of oral administration of three different concentrations of Yasmin® combined contraceptive pills (estrogen and progesterone) on reproductive hormones levels, histology of the ovotestis and rate of oviposition of E. vermiculata for two months using baits technique. The levels of anti-müllerian hormone (AMH), Follicle stimulating hormone (FSH), Luteinizing hormone (LH), Estradiol (E2), Progesterone(PRG), Thyroid-stimulating hormone (TSH) and Testesterone (T) of treated snails were decreased with increasing the drug concentrations by percentages of -83.3%, -78.9%, - 59.6%,- 98.3 %, - 79.6 %, - 86.7% and 8.2%, respectively. Prolactin (PRL) level was significantly increased (86.9%) compared to control snails after 8 weeks of exposure. Histological investigations on the hermaphrodite glands of snails treated with 909 μg/gm. showed glandular hyperplasia, sloughing of germinal epithelium, acini sizes reduction, suppression of follicular growths, decreased luteinization and vasodilation. Male acini revealed histolytic of spermatogonia and mature sperms. The lowest concentration (303 μg/gm.) caused gradual decrease of the total egg counts that reach 50% at the 8^th week of treatment. Higher doses (606 and 909 μg/gm.) resulted in dramatic dwindling of egg numbers and inspiring complete egg cessation at the 7^th and 3^rd weeks of treatments, respectively. The applications of combined contraceptive drugs as baits give promising results for controlling high population densities of E. vermiculata snails at Sharkia Governorate, Egypt.

Multivariate optimization of a dispersive liquid-liquid microextraction method for the determination of six antiparasite drugs in kennel effluent waters by using second-order chromatographic data

Six veterinary active ingredients (imidacloprid, albendazole, fenbendazole, praziquantel, fipronil and permethrin) were extracted and quantified by liquid chromatography with diode array detection in water samples from a wetland system used for the treatment of waste from a dog breeding plant. Response surface methodology, based on least-squares and artificial neural networks modelling, was applied for the optimization of a dispersive liquid-liquid microextraction (DLLME) procedure. Firstly, two experimental designs were built for screening and optimization, respectively. Then, the desirability function was implemented for the simultaneous optimization of the six recoveries (chromatographic areas of the six compounds). The optimum conditions were: 600 μL of acetone (dispersive solvent), 670 μL of dichloromethane (extractant solvent) and 0.6 min of vortex mixing. The preconcentration factor was 37.5. Then, in order to identify and quantify the six drugs, second-order calibration with MCR-ALS modeling of HPLC-DAD data was implemented attaining successful results. The limits of quantification were 4 ng mL^-1 for imidaclopril, albendazole and fenbendazole; 8 ng mL^-1 for praziquantel and fipronil; and 26 ng mL^-1 for permethrin. The developed method allowed the quantitation of the target analytes, even in the presence of unexpected compounds from dirty water samples. The following maximum levels of veterinary drugs were found (in ng mL^-1): imidaclopril, 7; albendazole, 46; fenbendazole, 21; praziquantel, 29; fipronil, 29 and permethrin, 217.

Monitoring of Water Quality, Antibiotic Residues, and Antibiotic-Resistant Escherichia coli in the Kshipra River in India over a 3-Year Period

The emergence of antibiotic resistance is a major global and environmental health issue, yet the presence of antibiotic residues and resistance in the water and sediment of a river subjected to excessive anthropogenic activities and their relationship with water quality of the river are not well studied. The objectives of the present study were a) to investigate the occurrence of antibiotic residues and antibiotic-resistant Escherichia coli (E. coli) in the water and sediment of the Kshipra river in India at seven selected sites during different seasons of the years 2014, 2015, and 2016 and b) to investigate the association between antibiotic residues and antibiotic-resistant E. coli in water and sediment and measured water quality parameters of the river. Antibiotic residues and resistant E. coli were present in the water and sediment and were associated with the measured water quality parameters. Sulfamethoxazole was the most frequently detected antibiotic in water at the highest concentration of 4.66 µg/L and was positively correlated with the water quality parameters. Significant (p < 0.05) seasonal and spatial variations of antibiotic-resistant E. coli in water and sediment were found. The resistance of E. coli to antibiotics (e.g., sulfamethiazole, norfloxacin, ciprofloxacine, cefotaxime, co-trimoxazole, ceftazidime, meropenem, ampicillin, amikacin, metronidazole, tetracycline, and tigecycline) had varying associations with the measured water and sediment quality parameters. Based on the results of this study, it is suggested that regular monitoring and surveillance of water quality, including antibiotic residues and antibiotic resistance, of all rivers should be taken up as a key priority, in national and Global Action Plans as these can have implications for the buildup of antibiotic resistance.

Effects of clay colloids on ciprofloxacin transport in saturated quartz sand porous media under different solution chemistry conditions

Antibiotics, a highly prevalent class of environmental organic pollutants, are becoming a matter of global concern. Clay minerals that are ubiquitous in subsurface environments may play an important role in the fate and transport of antibiotics. Taking ciprofloxacin (CIP) as a model antibiotic, this work explored the role of clay colloids (kaolinite and montmorillonite) on the adsorption and transport of CIP under different chemical solution conditions. The adsorption isotherms showed that montmorillonite colloids had a larger CIP sorption capacity than kaolinite colloids. The results of transport experiments indicated that montmorillonite colloids could promote CIP transport in saturated sand columns, but the addition of kaolinite colloids affected CIP mobility to a much smaller extent. The much stronger transport-enhancement effect of montmorillonite colloids was due to CIP adsorbed strongly to the colloids and desorption hysteresis of colloid-adsorbed CIP, likely stemming from the intercalation of this antibiotic in the interlayer of montmorillonite. Interestingly, transport of clay colloids increased with the increasing pH from 5.0 to 9.0; however, CIP transport decreased with the increasing pH in the presence of clay colloids. The observations were likely attributable to pH-dependent ciprofloxacin adsorption/desorption to clay minerals. Increasing the concentrations of NaCl and CaCl₂ generally decreased the contaminant-mobilizing ability of montmorillonite colloids, mainly by increasing the aggregation of colloids and thus, decreasing the transport of colloid-adsorbed CIP. Moreover, under the test conditions (1 mM NaCl and pH 7.0), the presence of CIP inhibited the transport of clay colloids due to the increase in aggregate size of clay colloids with the addition of CIP. Overall, these findings suggest that clay colloids with high adsorption abilities for antibiotics in the subsurface environment may act as a carrier for certain antibiotic compounds.

A One Health Comparative Assessment of Antimicrobial Resistance in Generic and Extended-Spectrum Cephalosporin-Resistant Escherichia coli from Beef Production, Sewage and Clinical Settings

This study aimed to compare antimicrobial resistance (AMR) in extended-spectrum cephalosporin-resistant and generic Escherichia coli from a One Health continuum of the beef production system in Alberta, Canada. A total of 705 extended-spectrum cephalosporin-resistant E. coli (ESC^r) were obtained from: cattle feces (CFeces, n = 382), catch basins (CBasins, n = 137), surrounding streams (SStreams, n = 59), beef processing plants (BProcessing, n = 4), municipal sewage (MSewage; n = 98) and human clinical specimens (CHumans, n = 25). Generic isolates (663) included: CFeces (n = 142), CBasins (n = 185), SStreams (n = 81), BProcessing (n = 159) and MSewage (n = 96). All isolates were screened for antimicrobial susceptibility to 9 antimicrobials and two clavulanic acid combinations. In ESC^r, oxytetracycline (87.7%), ampicillin (84.4%) and streptomycin (73.8%) resistance phenotypes were the most common, with source influencing AMR prevalence (p < 0.001). In generic E. coli, oxytetracycline (51.1%), streptomycin (22.6%), ampicillin (22.5%) and sulfisoxazole (14.3%) resistance were most common. Overall, 88.8% of ESC^r, and 26.7% of generic isolates exhibited multi-drug resistance (MDR). MDR in ESC^r was high from all sources: CFeces (97.1%), MSewage (96.9%), CHumans (96%), BProcessing (100%), CBasins (70.5%) and SStreams (61.4%). MDR in generic E. coli was lower with CFeces (45.1%), CBasins (34.6%), SStreams (23.5%), MSewage (13.6%) and BProcessing (10.7%). ESBL phenotypes were confirmed in 24.7% (n = 174) ESC^r and 0.6% of generic E. coli. Prevalence of bla genes in ESC^r were bla_CTXM (30.1%), bla_CTXM-1 (21.6%), bla_TEM (20%), bla_CTXM-9 (7.9%), bla_OXA (3.0%), bla_CTXM-2 (6.4%), bla_SHV (1.4%) and AmpC β-lactamase bla_CMY (81.3%). The lower AMR in ESC^r from SStreams and BProcessing and higher AMR in CHumans and CFeces likely reflects antimicrobial use in these environments. Although MDR levels were higher in ESC^r as compared to generic E. coli, AMR to the same antimicrobials ranked high in both ESC^r and generic E. coli sub-populations. This suggests that both sub-populations reflect similar AMR trends and are equally useful for AMR surveillance. Considering that MDR ESC^r MSewage isolates were obtained without enrichment, while those from CFeces were obtained with enrichment, MSewage may serve as a hot spot for MDR emergence and dissemination.

Quinolone Complexes with Lanthanide Ions: An Insight into their Analytical Applications and Biological Activity

Quinolones comprise a series of synthetic bactericidal agents with a broad spectrum of activity and good bioavailability. An important feature of these molecules is their capacity to bind metal ions in complexes with relevant biological and analytical applications. Interestingly, lanthanide ions possess extremely attractive properties that result from the behavior of the internal 4f electrons, behavior which is not lost upon ionization, nor after coordination. Subsequently, a more detailed discussion about metal complexes of quinolones with lanthanide ions in terms of chemical and biological properties is made. These complexes present a series of characteristics, such as narrow and highly structured emission bands; large gaps between absorption and emission wavelengths (Stokes shifts); and long excited-state lifetimes, which render them suitable for highly sensitive and selective analytical methods of quantitation. Moreover, quinolones have been widely prescribed in both human and animal treatments, which has led to an increase in their impact on the environment, and therefore to a growing interest in the development of new methods for their quantitative determination. Therefore, analytical applications for the quantitative determination of quinolones, lanthanide and miscellaneous ions and nucleic acids, along with other applications, are reviewed here.

Structural annotation of electro- and photochemically generated transformation products of moxidectin using high-resolution mass spectrometry

Moxidectin (MOX) is a widely used anthelmintic drug for the treatment of internal and external parasites in food-producing and companion animals. Transformation products (TPs) of MOX, formed through metabolic degradation or acid hydrolysis, may pose a potential environmental risk, but only few were identified so far. In this study, we therefore systematically characterized electro- and photochemically generated MOX TPs using high-resolution mass spectrometry (HRMS). Oxidative electrochemical (EC) TPs were generated in an electrochemical reactor and photochemical (PC) TPs by irradiation with UV-C light. Subsequent HRMS measurements were performed to identify accurate masses and deduce occurring modification reactions of derived TPs in a suspected target analysis. In total, 26 EC TPs and 59 PC TPs were found. The main modification reactions were hydroxylation, (de-)hydration, and derivative formation with methanol for EC experiments and isomeric changes, (de-)hydration, and changes at the methoxime moiety for PC experiments. In addition, several combinations of different modification reactions were identified. For 17 TPs, we could predict chemical structures through interpretation of acquired MS/MS data. Most modifications could be linked to two specific regions of MOX. Some previously described metabolic reactions like hydroxylation or O-demethylation were confirmed in our EC and PC experiments as reaction type, but the corresponding TPs were not identical to known metabolites or degradation products. The obtained knowledge regarding novel TPs and reactions will aid to elucidate the degradation pathway of MOX which is currently unknown. Graphical abstract.

Adsorption Characteristics of Oxytetracycline by Different Fractions of the Organic Matter from Humus Soil: Insight from Internal Structure and Composition

For minimizing the transport of antibiotics to groundwater, the migration of antibiotics in soils should be investigated. Soil organic matter can affect the migration of antibiotics. To date, the influence of aromatics and aliphatic content of organic matter on the adsorption of antibiotics has been controversial. To better understand the reaction mechanism of soil organic matter with antibiotics, this study investigated the adsorption of oxytetracycline (OTC) by humus soils (HOS) and their fractions. HOS were sequentially fractionated into four organic fractions, including the removal of dissolved organic matter (HRDOM), removal of minerals (HRM), removal of free fat (HRLF), and nonhydrolyzable organic carbon (HNHC). Moreover, batch experiments revealed that adsorption capacity was ordered by HNHC > HOS > HRDOM > HRLF > HRM. SEM images and N₂ adsorption/desorption isotherms indicate that adsorption capacity is independent of the external structure. However, adsorption capacity is related to the internal structure and composition. Combination analysis with elemental composition and infrared spectroscopy showed that the adsorption capacity of HRM, HRLF, and HNHC had a good positive correlation with aromaticity, but a negative correlation with polarity and hydrophilicity. Additionally, the rule of binding affinity between OTC and functional groups with different properties was summarized as aromatic > polarity > hydrophilic.

Inhibition of anaerobic ammonium oxidation (anammox) bacteria by addition of high and low concentrations of chloramphenicol and comparison of attached- and suspended-growth

Inhibition of anammox activities was tested with two ranges of chloramphenicol (CAP) concentration (5, 10, 20, 50, and 100 mg L^-1) and (100, 500, and 1000 μg L^-1). In a short-term study, strong inhibition of activity was dependent of CAP concentration in both attached-growth (SBR-A) and suspended-growth (SBR-S) systems. The activities of attached-growth cultures at all CAP concentrations were reversible after 1 day, while activities for suspended-growth cultures were only gradually reversible dependent on the CAP concentrations. In long-term studies with daily additions of 6 mg L^-1 CAP, the anammox activity on day 41 in SBR-A had decreased to 18% baseline (SAA reduced from 0.528 to 0.096 mg N mg^-1 VSS d^-1). More rapid reduction of anammox activity was observed in SBR-S, down to 17% baseline after only 27 days (SAA decreased from 0.576 to 0.096 mg N mg^-1 VSS d^-1). Inhibition was irreversible in both SBR-S and SBR-A after the long-term study. With lower CAP additions (100-1000 μg L^-1), the activities in both reactors were stable during daily CAP addition for two weeks. Attached-growth cultures tended to be more tolerant of CAP addition than suspended-growth cultures. Both un-competitive and non-competitive models could be used to compare anammox activities with the higher CAP concentrations. The SAA_max [fx] (the maximum specific anammox activity) and _hK_i (the inhibition constant) of SBR-A were 0.48 mg N mg^-1 VSS d^-1 and 98.3 mg L^-1, respectively. The SAA_max[fx] and K_i of SBR-S were 1.25 mg N mg^-1 VSS d^-1and 71.1 mg L^-1, respectively.

Antibiotics mineralization by electrochemical and UV-based hybrid processes: evaluation of the synergistic effect

Antibiotics are not efficiently removed in conventional wastewater treatments. In fact, different advanced oxidation process (AOPs), including ozone, peroxide, UV radiation, among others, are being investigated in the elimination of microcontaminants. Most of AOPs proved to be efficient on the degradation of antibiotics, but the mineralization is on the one hand not evaluated or on the other hand not high. At this work, the UV-based hybrid process, namely Photo-assisted electrochemical oxidation (PEO), was applied, aiming the mineralization of microcontaminants such as the antibiotics Amoxicillin (AMX), Norfloxacin (NOR) and Azithromycin (AZI). The influence of the individual contributions of electrochemical oxidation (EO) and the UV-base processes on the hybrid process (PEO) was analysed. Results showed that AMX and NOR presented higher mineralization rate under direct photolysis than AZI due to the high absorption of UV radiation. For the EO processes, a low mineralization was found for all antibiotics, what was associated to a mass-transport limitation related to the low concentration of contaminants (200 µg/L). Besides that, an increase in mineralization was found, when heterogeneous photocatalysis and EO are compared, due to the influence of UV radiation, which overcomes the mass-transport limitations. Although the UV-based processes control the reaction pathway that leads to mineralization, the best results to mineralize the antibiotics were achieved by PEO hybrid process. This can be explained by the synergistic effect of the processes that constitute them. A higher mineralization was achieved, which is an important and useful finding to avoid the discharge of microcontaminants in the environment.

Distribution and co-occurrence of antibiotic and metal resistance genes in biofilms of an anthropogenically impacted stream

Urban stream biofilms are potential hotspots for resistomes and antibiotic resistance genes (ARGs). Biofilm communities that harbor resistance genes may be influenced by contaminant input (e.g., metals and antibiotics) from urban drainage (i.e., Wastewater Treatment Plant effluent and stormwater runoff); understanding the ecology of these communities and their resistome is needed. Given the potential importance of the co-occurrence of ARGs and metal resistance genes (MRGs), we investigated the spatial and temporal distribution of three ARGs (tetracycline [tetW] and sulfonamides [sulI and sulII]), four MRGs (lead [pbrT], copper [copA], and cadmium/cobalt/zinc [czcA and czcC]) via quantitative PCR and biofilm bacterial community composition via MiSeq 16S sequencing at four time points along an urbanization gradient (i.e., developed, agriculture, and forested sites) in a stream's watershed. Our results revealed that ARG and MRG abundances were significantly affected by land use-time interaction, with greater resistance abundances occurring in more urban locations during particular times of the year. It was also observed that changes in ARG and MRG profiles were influenced by differences in community composition among land use types, and that these differences were in response to changes in stream physicochemical parameters (pH, redox, temperature, nutrient availability, and metal concentration) that were driven by sub-watershed land use. Moreover, the dynamics between ARGs and MRGs within these communities correlated strongly and positively with one another. Taken altogether, our results demonstrate that changes in environmental properties due to human activity may drive the ARG-MRG profiles of biofilm communities by modulating community structure over time and space.

Occurrence, fate and toxic effects of the industrial endocrine disrupter, nonylphenol, on plants - A review

Nonylphenol (NP) and its detrimental effects on the environment, humans, wildlife, fish and birds is an increasingly important global research focus. The number of investigations on the toxicity and metabolic fate of NP in plants is however limited. This paper reviews the prevalence and source of NP in plants and the effect it has on its morphological, physiological and ultrastructural status. Fruit and vegetables have been found to contain levels of NP that is twenty-fold exceeding the no observable effect level (NOEL) of freshwater algae. Apart from the potential risk this poses to the health of consumers, it can overburden the plant's natural defence system, leading to growth disorders. Plants exposed to NP show signs of overall growth reduction, changes in organelle structure and oxidative damage. These adverse effects may exacerbate the food security dilemma faced by many countries and impede their progress towards attaining the sustainable development goals.

Assessment of the Sulfamethoxazole mobility in natural soils and of the risk of contamination of water resources at the catchment scale

Sulfamethoxazole (SMX) is one of the antibiotics most commonly detected in aquatic and terrestrial environments and is still widely used, especially in low income countries. SMX is assumed to be highly mobile in soils due to its intrinsic molecular properties. Ten soils with contrasting properties and representative of the catchment soil types and land uses were collected throughout the watershed, which undergoes very rapid urban development. SMX displacement experiments were carried out in repacked columns of the 10 soils to explore SMX reactive transfer (mobility and reactivity) in order to assess the contamination risk of water resources in the context of the Bolivian Altiplano. Relevant sorption processes were identified by modelling (HYDRUS-1D) considering different sorption concepts. SMX mobility was best simulated when considering irreversible sorption as well as instantaneous and rate-limited reversible sorption, depending on the soil type. SMX mobility appeared lower in soils located upstream of the watershed (organic and acidic soils - Regosol) in relation with a higher adsorption capacity compared to the soils located downstream (lower organic carbon content - Cambisol). By combining soil column experiments and soil profiles description, this study suggests that SMX can be classified as a moderately to highly mobile compound in the studied watershed, depending principally on soil properties such as pH and OC. Potential risks of surface and groundwater pollution by SMX were thus identified in the lower part of the studied catchment, threatening Lake Titicaca water quality.

Characterization and source identification of tetracycline antibiotics in the drinking water sources of the lower Yangtze River

The occurrence and spatio-temporal patterns of five tetracyclines (TCs) and six of their degradation products were investigated in twenty-eight drinking water sources along the lower Yangtze River (LYR) over dry, normal and flood seasons. Tetracycline (TC), oxytetracycline (OTC) and doxytetracycline (DXC) were the dominant antibiotics detected with the highest occurrence. The maximum concentrations of TC, OTC and DXC were found in dry season as 11.16, 18.98, and 56.09 ng/L, respectively, because of the low dilution, low degradation, and high consumption in this season. Cluster analysis indicated distinct variations in the TCs' compositional profiles in both space and time. OTC and its metabolites contributed 18.5-59.6% of the TC load in dry season, possibly due to the seasonally increased release of pharmaceutical OTCs from sewage effluents, but they were seldom detected in other seasons. Pollution load index analysis showed that tributaries carrying large amounts of veterinary TCs derived from breeding wastewater and untreated rural sewage contributed larger proportions of the TC load for most drinking water sources than sewage outlets. The contribution ratio of the TC load from tributaries (74.5%) was approximately three times higher than that from sewage discharges (25.5%). The study demonstrated that the control of load from tributaries is the key to mitigating TC pollution of the drinking water sources in the LYR. An effective source tracking method for evaluating the contribution of antibiotic load from multiple diffuse pollution origins and identifying the high-risk contamination sources was established for antibiotic management and control.

Behaviour and cardiac response to stress in signal crayfish exposed to environmental concentrations of tramadol

Evidence of the ecological and biological impact of pharmaceuticals in surface waters on aquatic organisms is increasing. Tramadol is a synthetic opioid analgesic used to treat chronic and acute pain. To investigate its long-term effects at environmentally relevant levels, we evaluated heart rate (HR) and locomotion of signal crayfish Pacifastacus leniusculus during a 21-day exposure to 1 μg L-1 tramadol followed by 14 days depuration. Locomotion and HR were recorded over a period 30 min before and 30 min after exposure to physiological fluids of an injured conspecific, a natural stressor, four times during the tramadol exposure and four times during depuration. A significant increase in HR following stress induction was found in the majority of tramadol-exposed and control crayfish, as well as significant group-specific HR changes between both groups. Locomotor activity during tramadol treatment differed from that during depuration, in general showing less time spent in locomotion and lower distance moved. The tramadol exposed crayfish exhibited higher velocity during depuration than during the exposure period. Results may suggest a potential shift in prey-predator relationships.