Veterinary pharmaceuticals and antibiotics in manure and slurry and their fate in amended agricultural soils: Findings from an experimental field site (Baix Empordà, NE Catalonia)

Escherichia coli isolates from vegetable farms in Addis Ababa, Ethiopia: Antimicrobial susceptibility profile and associated resistance genetic markers

The use of animal manure to fertilize soil is an emerging concern contributing to the transfer of antimicrobial-resistant pathogens to vegetables. Hence, assessing antimicrobial susceptibility profile of Escherichia coli in vegetable farms is essential to design appropriate interventions against antimicrobial resistance (AMR) in the food chain. This study assessed antimicrobial resistance profile and associated genetic markers among E. coli isolated from vegetable farms fertilized with animal manure in Addis Ababa, Ethiopia. A total of 1044 samples were collected using convenience sampling: soil (n = 271), manure (n = 375), and vegetables (n = 398) from 81 vegetable farms in Addis Ababa, Ethiopia. Antimicrobial susceptibility test was conducted for 100 E. coli isolates and antimicrobial resistance genes (ARGs) were tested by polymerase chain reaction (PCR). Of the 1044 collected samples, 25.3% were positive for E. coli, with significantly higher prevalence in the manure sample and samples collected from Akaki Kality sub-city (p < .05). The highest resistance rate was recorded for tetracycline (72%), followed by streptomycin (63%), and sulfamethoxazole +trimethoprim (56%). Multidrug resistance was detected in 61% of the E. coli isolates. The aac(3)-IV (76.9%), bla TEM (65.4%), aadA (60.3%), tet(A) (58.3%), and sulI (51.7%) were the commonly detected resistance genes. The current study showed a high burden of antimicrobial resistance among E. coli isolated from manure-amended vegetable farms, with potential of playing a significant role in the dissemination of antimicrobial resistance in the food chain. Efforts should be made to reduce the burden of resistant organisms and ARGs through prudent use of antimicrobials in livestock and application of appropriate composting techniques before using manure as fertilizer.

Optimization and validation of multiresidual extraction methods for pharmaceuticals in Soil, Lettuce, and Earthworms

The presence of human and veterinary pharmaceuticals (PhACs) in the environment poses potential risks. To comprehensively assess these risks, robust multiresidual analytical methods are essential for determining a broad spectrum of PhAC classes in various environmental compartments (soil, plants, and soil organisms). This study optimized extraction methods for analyzing over 40 PhACs from various matrices, including soil, lettuce, and earthworms. A four-step ultrasonic extraction method with varying extraction conditions and subsequent solid phase extraction was developed for soil samples. QuEChERS methods were optimized for extracting PhACs from lettuce and earthworm samples, addressing a literature gap in these less-studied matrices. The quantification of PhACs in soil, lettuce, and earthworm extracts was performed using a single LC-MS/MS method. Following thorough method validation, earthworms and lettuce were exposed to a mixture of 27 pharmaceuticals in a soil environment. The method validation results demonstrated the robustness of these methods for a broad spectrum of PhACs. Specifically, 29 out of 42 PhACs were extracted with an average efficiency > 50% and RSD < 30% from the soil; 40 out of 42 PhACs exhibited average efficiency > 50% and %RSD < 30% from the earthworms, while 39 out of 42 PhACs showed average efficiency > 50% and RSD < 30% from the lettuce. Exposure experiments confirmed the viability of these methods for quantifying a diverse range of PhACs in different environmental compartments. This study presents three thoroughly validated methods for determining more than 40 PhACs in diverse matrices, enabling a comprehensive assessment of PhAC dissemination in the environment.

Evaluating antibiotic occurrence, degradation, and environmental risks in poultry litter within Argentina's agricultural hub

This study explores the relationship between poultry farming's antibiotic administration practices and residual antibiotic levels in the litter before its application onto agricultural soils. Twenty-three antibiotics were performed across 19 Argentinean farms representing diverse antibiotic management practices. Analysis revealed up to 20 antibiotics from eight chemical classes in poultry litter samples, with tylosin, enrofloxacin, and salinomycin being the most relevant drugs. Farms with restricted antibiotic use in feed exhibited lower residual concentrations. A self-heating treatment was tested to reduce litter antibiotic levels. Although a 60 % reduction of antibiotics was found after treatment, prevalent compounds persisted at residual levels. Regulatory measures and comprehensive litter treatments pre-application are crucial to mitigate environmental risks. This is the first study that provides insight on the occurrence of >20 drugs in real poultry production scenarios from Latin America and demonstrates how relatively simple treatments can be readily applied to decrease the associated environmental risks.

Selection of pharmaceuticals of concern in reclaimed water for crop irrigation in the Mediterranean area

The reuse of reclaimed water in agriculture is being fostered in areas suffering from water scarcity. However, water pollutants can compromise food safety and pose a risk for the environment. This study aims to select the pharmaceutical compounds worth monitoring and investigating when reclaimed water is used for tomato and lettuce irrigation. A comprehensive study was first conducted to identify the pharmaceuticals frequently detected in secondary wastewater effluents in Catalonia (Northeast Spain). Priority pharmaceuticals were further selected based on their occurrence in secondary effluents, persistence (removal in conventional treatment), bioaccumulation potential, toxicity for aquatic organisms, and the risks they pose to the terrestrial environment and human health (through the consumption of crops). Out of the 47 preselected priority compounds, six could pose a risk to organisms living in soil irrigated with reclaimed water and seven could be potentially taken up by the crops. Nonetheless, no risk for human consumption was foreseen.

Fate of fluoroquinolones in field soil environment after incorporation of poultry litter from a farm with enrofloxacin administration via drinking water

The practice of incorporating animal manure into soil is supported within the European Circular economy as a possible substitute for mineral fertilizers and will become crucial for the sustainability of agriculture. However, this practice may indirectly contribute to the dissemination of antibiotics, resistance bacteria, and resistance genes. In this study, medicated drinking water and poultry litter samples were obtained from a broiler-chick farm. The obtained poultry litter was incorporated into the soil at the experimental field site. The objectives of this research project were first to develop analytical methods able to quantify fluoroquinolones (FQs) in medicated drinking water, poultry litter, and soil samples by LC-MS; second to study the fate of these FQs in the soil environment after incorporation of poultry litter from flock medicated by enrofloxacin (ENR); and third to screen the occurrence of selected fluoroquinolone resistance encoding genes in poultry litter and soil samples (PCR analysis). FQs were quantified in the broiler farm's medicated drinking water (41.0 ± 0.3 mg∙L-1 of ENR) and poultry litter (up to 70 mg∙kg-1 of FQs). The persistence of FQs in the soil environment over 112 days was monitored and evaluated (ENR concentrations ranged from 36 μg∙kg-1 to 9 μg∙kg-1 after 100 days). The presence of resistance genes was confirmed in both poultry litter and soil samples, in agreement with the risk assessment for the selection of AMR in soil based on ENR concentrations. This work provides a new, comprehensive perspective on the entry and long-term fate of antimicrobials in the terrestrial environment and their consequences after the incorporation of poultry litter into agricultural fields.

Prioritized regional management for antibiotics and heavy metals in animal manure across China

High levels of antibiotics and heavy metals in animal manure pose a potential threat to both the ecological environment and public health. A regional knowledge of their distribution and risk assessment across China remains unclear. A dataset containing 4082 records covering a total of forty-two antibiotics and eight heavy metals was established for animal manure across China. The results showed that the residual concentration of antibiotics was in the order of tetracyclines > aminoglycosides > fluoroquinolones > macrolides > sulfonamides > β-lactams, and that of heavy metals is Zn > Cu > Cr > Pb > Ni > As > Cd > Hg. The mean concentration of antibiotics and heavy metals was higher in pig manure compared to chicken and cow manure (Kruskal-Wallis test). The lowest level of antibiotics was observed in Northwest China based on geographic distribution characteristics. It was related to the high ratio of cow and sheep farming that less antibiotics were administered to. The pollution status of heavy metals was more severe in East China. Furthermore, high correlations were observed between antibiotics (tetracyclines) and heavy metals (Cu, Zn, and As). Especially, tetracycline in North China and Cd in Northeast China exhibited a high risk in manure; thus, they were priority regions for antibiotics/heavy metals pollution control. This study identified risk assessment of typical antibiotics and heavy metals in animal manure and emphasized the necessity of regional management across China.

Degradation kinetics of veterinary antibiotics and estrogenic hormones in a claypan soil

Veterinary antibiotics and estrogens are excreted in livestock waste before being applied to agricultural lands as fertilizer, resulting in contamination of soil and adjacent waterways. The objectives of this study were to 1) investigate the degradation kinetics of the VAs sulfamethazine and lincomycin and the estrogens estrone and 17β-estradiol in soil mesocosms, and 2) assess the effect of the phytochemical DIBOA-Glu, secreted in eastern gamagrass (Tripsacum dactyloides) roots, on antibiotic degradation due to the ability of DIBOA-Glu to facilitate hydrolysis of atrazine in solution assays. Mesocosm soil was a silt loam representing a typical claypan soil in portions of Missouri and the Central United States. Mesocosms (n = 133) were treated with a single target compound (antibiotic concentrations at 125 ng g-1 dw, estrogen concentrations at 1250 ng g-1 dw); a subset of mesocosms treated with antibiotics were also treated with DIBOA-Glu (12,500 ng g-1 dw); all mesocosms were kept at 60% water-filled pore space and incubated at 25 °C in darkness. Randomly chosen mesocosms were destructively sampled in triplicate for up to 96 days. All targeted compounds followed pseudo first-order degradation kinetics in soil. The soil half-life (t0.5) of sulfamethazine ranged between 17.8 and 30.1 d and ranged between 9.37 and 9.90 d for lincomycin. The antibiotics results showed no significant differences in degradation kinetics between treatments with or without DIBOA-Glu. For estrogens, degradation rates of estrone (t0.5 = 4.71-6.08 d) and 17β-estradiol (t0.5 = 5.59-6.03 d) were very similar; however, results showed that estrone was present as a metabolite in the 17β-estradiol treated mesocosms and vice-versa within 24 h. The antibiotics results suggest that sulfamethazine has a greater potential to persist in soil than lincomycin. The interconversion of 17β-estradiol and estrone in soil increased their overall persistence and sustained soil estrogenicity. This study demonstrates the persistence of these compounds in a typical claypan soil representing portions of the Central United States.

Optimization and validation of an extraction method for the analysis of multi-class emerging contaminants in soil and sediment

Analytical methods for the determination of multi-class emerging contaminants are limited for soil and sediment while they are essential to provide a more complete picture of their distribution in the environment and to understand their fate in different environmental compartments. In this paper, we present the development and optimization of an analytical strategy that combines reliable extraction, purification and the analysis using ultra-pressure liquid chromatography triple quadrupole mass spectrometry (UPLC-MS/MS) of 90 emerging organic contaminants including pesticides, pharmaceuticals and personal care products, flame retardants, per- and polyfluoroalkyl substances (PFASs) and plasticizers in soil and sediment. To extract a wide range of chemicals, the extraction strategy is based on the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach. A number of different options were investigated (buffer, acidification, addition of EDTA, different types and combinations of dispersive SPE etc.) and the effectiveness of the chemical extraction procedure and the clean-up was assessed for two matrices: soil (organic matter content of 9%) and sediment (organic matter content of 1.9%). The method was fully validated for both matrices, in terms of accuracy, linearity, repeatability (intra-day), reproducibility (inter-day), method limits of detection and quantification (LODs and MLOQs, respectively). The final performance showed good accuracy and precision (mean recoveries were between 70 and 120% with relative standard deviations (RSD) less than 20% in most cases), low matrix effects, good linearity for the matrix-matched calibration curve (R2≥0.991) and MLOQs ranged from 0.25 and 10 µg/kg. To demonstrate the applicability and suitability of the validated method, soil and sediment samples from Vietnam, France, Sweden and Mexico were analyzed. The results showed that of the 90 target compounds, a total of 33 were quantified in the sediment and soil samples analyzed. In addition to multi-target analysis, this strategy could be suitable for non-target screening, to provide a more comprehensive view of the contaminants present in the samples.

Simultaneous detection of pesticides and pharmaceuticals in three types of bio-based fertilizers by an improved QuEChERS method coupled with UHPLC-q-ToF-MS/MS

Bio-based fertilizers (BBFs) have the potential to contain both pesticides and pharmaceutical residues, which may pose a threat to soils, crops, and human health. However, no analytical screening method is available currently to simultaneously analyze a wide range of contaminants in the complex origin-dependent matrices of BBFs. To fill this gap, our study tested and improved an original QuEChERS method (OQM) for simultaneously analyzing 78 pesticides and 18 pharmaceuticals in BBFs of animal, plant, and ashed sewage sludge origin. In spiked recovery experiments, 34-58 pharmaceuticals and pesticides were well recovered (recovery of 70-120%) via OQM at spiking concentrations levels of 10 ng/g and 50 ng/g in these three different types of BBFs. To improve the extraction efficiency further, ultrasonication and end-over-end rotation were added based on OQM, resulting in the improved QuEChERS method (IQM) that could recover 57-79 pesticides and pharmaceuticals, in the range of 70-120%. The detection limits of this method were of 0.16-4.32/0.48-12.97 ng/g, 0.03-11.02/0.10-33.06 ng/g, and 0.06-5.18/0.18-15.54 ng/g for animal, plant, and ash-based BBF, respectively. Finally, the IQM was employed to screen 15 BBF samples of various origins. 15 BBFs contained at least one pesticide or pharmaceutical with ibuprofen being frequently detected in at concentration levels of 4.1-181 ng/g. No compounds were detected in ash-based BBFs.

Effects of diclofenac, sulfamethoxazole, and wastewater from constructed wetlands on Eisenia fetida: impacts on mortality, fertility, and oxidative stress

Soil contamination with micropollutants is an important global problem and the impact of these pollutants on living organisms cannot be underestimated. The effects of diclofenac (DCF) and sulfamethoxazole (SMX), their mixture (MIX), and wastewater containing these drugs on the mortality and reproduction of Eisenia fetida were investigated. The impact on the activities of antioxidant enzymes in earthworm cells was also assessed. Furthermore, the influence of the following parameters of the vertical flow constructed wetlands on wastewater toxicity was investigated: the dosing system, the presence of pharmaceuticals and the plants Miscanthus giganteus. The compounds and their mixture significantly affected the reproduction and mortality of earthworms. The calculated values of LC50,28 days values were 3.4 ± 0.3 mg kg-1 for DCF, 1.6 ± 0.3 mg kg-1 for SMX, and 0.9 ± 0.1 mg kg-1 for MIX. The EC50 (reproduction assay) for DCF was 1.2 ± 0.2 mg kg-1, whereas for SMX, it was 0.4 ± 0.1 mg kg-1, and for MIX, it was 0.3 ± 0.1 mg kg-1, respectively. The mixture toxicity index (MTI) was calculated to determine drug interactions. For both E. fetida mortality (MTI = 3.29) and reproduction (MTI = 3.41), the index was greater than 1, suggesting a synergistic effect of the mixture. We also observed a negative effect of wastewater (raw and treated) on mortality (32% for raw and 8% for treated wastewater) and fertility (66% and 39%, respectively) of E. fetida. It is extremely important to analyze the harmfulness of microcontaminants to organisms inhabiting natural environments, especially in the case of wastewater for irrigation of agricultural fields.

Pharmaceutical-contaminated irrigation water: implications for ornamental plant production and phytoremediation using enrofloxacin-accumulating species

Enrofloxacin (Enro) has been widely encountered in natural water sources, and that water is often used for irrigation in crop production systems. Due to its phytotoxicity and accumulation in plant tissues, the presence of Enro in water used for crop irrigation may represent economical and toxicological concerns. Here, we irrigated two ornamental plant species (Zantedeschia rehmannii Engl. and Spathiphyllum wallisii Regel.) with water artificially contaminated with the antimicrobial enrofloxacin (Enro; 0, 5, 10, 100, and 1000 μg L-1) to evaluate its effects on ornamental plant production, as well as its accumulation and distribution among different plant organs (roots, leaves, bulbs, and flower stems), and examined the economic and environmental safety of commercializing plants produced under conditions of pharmaceutical contamination. The presence of Enro in irrigation water was not found to disrupt plant growth (biomass) or flower production. Both species accumulated Enro, with its internal concentrations distributed as the following: roots > leaves > bulbs > flower stems. In addition to plant tolerance, the content of Enro in plant organs indicated that both Z. rehmannii and S. wallisii could be safety produced under Enro-contaminated conditions and would not significantly contribute to contaminant transfer. The high capacity of those plants to accumulate Enro in their tissues, associated with their tolerance to it, indicates them for use in Enro-phytoremediation programs.

Ketoprofen as an emerging contaminant: occurrence, ecotoxicity and (bio)removal

Ketoprofen, a bicyclic non-steroidal anti-inflammatory drug commonly used in human and veterinary medicine, has recently been cited as an environmental contaminant that raises concerns for ecological well-being. It poses a growing threat due to its racemic mixture, enantiomers, and transformation products, which have ecotoxicological effects on various organisms, including invertebrates, vertebrates, plants, and microorganisms. Furthermore, ketoprofen is bioaccumulated and biomagnified throughout the food chain, threatening the ecosystem function. Surprisingly, despite these concerns, ketoprofen is not currently considered a priority substance. While targeted eco-pharmacovigilance for ketoprofen has been proposed, data on ketoprofen as a pharmaceutical contaminant are limited and incomplete. This review aims to provide a comprehensive summary of the most recent findings (from 2017 to March 2023) regarding the global distribution of ketoprofen in the environment, its ecotoxicity towards aquatic animals and plants, and available removal methods. Special emphasis is placed on understanding how ketoprofen affects microorganisms that play a pivotal role in Earth's ecosystems. The review broadly covers various approaches to ketoprofen biodegradation, including whole-cell fungal and bacterial systems as well as enzyme biocatalysts. Additionally, it explores the potential of adsorption by algae and phytoremediation for removing ketoprofen. This review will be of interest to a wide range of readers, including ecologists, microbiologists, policymakers, and those concerned about pharmaceutical pollution.

Wide-scope screening of multi-class contaminants in seafood using a novel sample preparation (QuEChUP) procedure coupled with UHPLC-Q-TOF-MS: Application for semi-quantitation of real seafood samples

A high-resolution mass spectrometry screening method was developed and validated based on EU SANTE/11312/2021 guidelines for the analysis of 850 multi-class contaminants in commercial seafood samples. Samples were extracted using a novel sequential QuEChUP preparation method that combines the QuEChERS and QuPPe procedures. The screening detection limits (SDLs) and limits of identification (LOIs) were equal to or lower than 0.01 mg·kg^-1 for 92% and 78% of contaminants, respectively. This screening procedure was ultimately applied for a target screening analysis of 24 seafood samples. The concentrations of identified contaminants were assessed using semi-quantitative approach. Two identified contaminants, diuron and diclofenac, showed the highest estimated average concentrations: 0.076 and 0.068 mg·kg^-1 respectively in mussel samples. Suspect screening was also performed. Target and suspect screening led to the identification of mixtures of contaminants (pesticides, veterinary products, industrial chemicals and personal care products) and the assessment of their frequencies of appearance (FoA).

Advancements in the dominion of fate and transport of pharmaceuticals and personal care products in the environment-a bibliometric study

The study on the fate and transport of Pharmaceuticals and Personal Care Products, PPCPs (FTP) in the environment, has received particular attention for over two decades. The PPCPs threaten ecology and human health even at low concentrations due to their synergistic effects and long-range transport. The research aims to provide an inclusive map of the scientific background of FTP research over the last 25 years, from 1996 to 2020, to identify the main characteristics, evolution, salient research themes, trends, and research hotspots in the field of interest. Bibliometric networks were synthesized and analyzed for 577 journal articles extracted from the Scopus database. Consequently, seven major themes of FTP research were identified as follows: (i) PPCPs category; (ii) hazardous effects; (iii) occurrence of PPCPs; (iv) PPCPs in organisms; (v) remediation; (vi) FTP-governing processes; and (vii) assessment in the environment. The themes gave an in-depth picture of the sources of PPCPs and their transport and fate processes in the environment, which originated from sewage treatment plants and transported further to sediment/soils/groundwater/oceans that act as the PPCPs' major sink. The article provided a rigorous analysis of the research landscape in the FTP study conducted during the specified years. The prominent research themes, content analysis, and research hotspots identified in the study may serve as the basis of real-time guidance to lead future research areas and a prior review for policymakers and practitioners.

Impact of antibiotics on microbial community in aquatic environment and biodegradation mechanism: a review and bibliometric analysis

Antibiotic residues in aquatic environments pose a potential hazard, and microbes, which play important roles in aquatic ecosystems, are vulnerable to the impacts of antibiotics. This study aimed to analyze the research progress, trends, and hot topics of the impact of antibiotics on microbial community and biodegradation mechanism using bibliometric analysis. An in-depth analysis of the publication characteristics of 6143 articles published between 1990 and 2021 revealed that the number of articles published increased exponentially. The research sites have been mainly concentrated in the Yamuna River, Pearl River, Lake Taihu, Lake Michigan, Danjiangkou Reservoir, etc., illustrating that research around the world is not even. Antibiotics could change the diversity, structure, and ecological functions of bacterial communities, stimulate a widespread abundance of antibiotic-resistant bacteria and antibiotic-resistant genes, and increase the diversity of eukaryotes, thus triggering the shift of food web structure to predatory and pathogenic. Latent Dirichlet allocation theme model analysis showed three clusters, and the research hotspots mainly included the effect of antibiotics on the denitrification process, microplastics combined with antibiotics, and methods for removing antibiotics. Furthermore, the mechanisms of microbe-mediated antibiotic degradation were unraveled, and importantly, we provided bottlenecks and future research perspectives on antibiotics and microbial diversity research.

Potential output and risk of commonly administered veterinary antibiotics from small-scale livestock farms to surrounding areas in Northwest China

The concern over antibiotic pollution from animal husbandry has significantly increased over recent years. However, few studies on output and environmental risk of veterinary antibiotics (VAs) throughout different exposure matrices from small-scale livestock farms (SSLFs) have been explored. This study explored the output and environmental risk of three classes of VAs (sulfonamides (SAs), tetracyclines (TCs), fluoroquinolones (FQs)) in three different types of environmental media (manure, soil, and plants/vegetables) derived from four livestock feedlots in the Hexi Corridor of Northwest China. Following, a risk assessment was conducted to identify the hazardous potential of these VAs on the ecological health of the surrounding environment. A total of 108 soil, 36 manure, 12 plants/vegetables, and 15 animal product samples were collected from the animal feedlots for analysis. The results showed that each of the three groups of VAs were detected in the soil, manure and plant samples derived from all four feedlots in varying levels. In the soil samples, the detection rate of SAs (68%) was higher than the TCs (57%) and the FQs (27%). The total concentration of VAs ranged from not detected (n.d.) to 275 ng/g, while chlortetracycline (CTC) was the most abundant (275 ng/g) of the VAs in soil samples. The SAs had the highest detection rate (100%), followed by TCs (89%), and FQs (78%) in manure samples. The total concentration of VAs residues ranged from n. d. to 105 ng/g, of which CTC was as high as 91 ng/g in manures. In the plant/vegetable samples, the TCs had the highest detection rate (58%), while sulfamethazine (SDM) was the most abundant (32 ng/g). The total concentration of the VAs ranged from n. d. to 65 ng/g in the plant/vegetable samples. The target VAs were not detected in animal products. Measurements of the composition of VAs in soil samples at different vertical depths as well as horizontal distances from the manure accumulation sites showed that VAs were partially retained in the soil of the feedlots and were distributed into the surrounding environment both horizontally and vertically. It is suspected that the detected VAs could be accumulated in agricultural soils since they could be found in most of the sampled manures and soils in SSLFs. These results highlighted the necessity of considering SSLF practices to mange the accumulation and disposal of manure mitigating and controlling VA pollution.

Graphene oxide addition to anaerobic digestion of waste activated sludge: Impact on methane production and removal of emerging contaminants

The effect of graphene oxide on the anaerobic digestion of waste activated sludge was investigated at two graphene oxide concentrations (0.025 and 0.075 g graphene oxide per g volatile solids) using biochemical methane potential tests. The occurrence of 36 pharmaceuticals was monitored in the solid and liquid phases before and after the anaerobic treatment. The addition of graphene oxide improved the removal of most pharmaceuticals detected, even those that are considered persistent to biological degradation, such as azithromycin, carbamazepine, and diclofenac. No significant differences were observed in the final specific methane production without graphene oxide and with the lowest graphene oxide concentration, yet the highest graphene oxide concentration partially inhibited methane production. The relative abundance of antibiotic resistance genes was not affected by the graphene oxide addition. Finally, significant changes in the microbial community including bacteria and archaea were detected with graphene oxide addition.

Acetaminophen induced antioxidant and detoxification responses in a stygobitic crustacean

A variety of veterinary and human medicinal products (VHMPs) are found in groundwater, an often-neglected habitat inhabited by species with unique traits, stygobitic species. It is crucial to understand the effect of VHMPs on stygobitic species because they may respond differently to stressors than surface species. Our hypothesis is that groundwater species may be more susceptible to environmental contaminants due to less plasticity in their detoxification response and acquisition of energy because subterranean habitats are more stable and isolated from anthropogenic activities. We performed a battery of biomarkers associated with important physiological functions on the stygobitic asellid crustacean Proasellus lusitanicus, after a 14-day exposure to acetaminophen, a commonly used pharmaceutical and pollutant of groundwaters. Our results show an decrease in total glutathione levels and an increase in glutathione S-transferase activity, suggesting a successful detoxification response. This helps explaining why acetaminophen did not cause oxidative damage, as well as had no effect cholinesterase activity nor in aerobic production of energy. This study shows the remarkable capacity of P. lusitanicus to tolerate sublethal concentrations of VHMP acetaminophen. Most ecotoxicological studies on stygobitic species focused on the lethal effects of these compound. The present study focus on consequences at sublethal concentrations. Future studies should assess the stress levels induced to better predict and estimate the impacts of contaminants on groundwater ecosystems.

Adaptation of Rhizosphere Microbial Communities to Continuous Exposure to Multiple Residual Antibiotics in Vegetable Farms

The constant application of manure-based fertilizers in vegetable farms leads to antibiotic residue accumulation in soils, which has become a major stressor affecting agroecosystem stability. The present study investigated the adaptation profiles of rhizosphere microbial communities in different vegetable farms to multiple residual antibiotics. Multiple antibiotics, including trimethoprim, sulfonamides, quinolones, tetracyclines, macrolides, lincomycins, and chloramphenicols, were detected in the vegetable farms; the dominant antibiotic (trimethoprim) had a maximum concentration of 36.7 ng/g. Quinolones and tetracyclines were the most prevalent antibiotics in the vegetable farms. The five most abundant phyla in soil samples were Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi and Firmicutes, while the five most abundant phyla in root samples were Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Myxococcota. Macrolides were significantly correlated with microbial community composition changes in soil samples, while sulfonamides were significantly correlated with microbial community composition changes in root samples. Soil properties (total carbon and nitrogen contents and pH) influenced the shifts in microbial communities in rhizosphere soils and roots. This study provides evidence that low residual antibiotic levels in vegetable farms can shift microbial community structures, potentially affecting agroecosystem stability. However, the degree to which the shift occurs could be regulated by environmental factors, such as soil nutrient conditions.

New insights into lincomycin biodegradation by Conexibacter sp. LD01: Genomics characterization, biodegradation kinetics and pathways

The aerobic, lincomycin-degrading bacterial strain Conexibacter sp. LD01, belonging to the phylum Actinobacteria, was isolated from activated sludge. Both second- and third-generation sequencing technologies were applied to uncover the genomic characterization and high-quality genome with 99.2% completeness and 2.2% contamination was obtained. The biodegradation kinetics of lincomycin fit well with the modified Gompertz model (R² > 0.97). Conexibacter sp. LD01 could subsist with lincomycin as the sole source of carbon, nitrogen, and energy. When 500 mg/L of glucose was added as a co-substrate, the biodegradation rate improved significantly, whereas the addition of 500 mg/L sodium pyruvate had a slight inhibitory effect. Ammonia nitrogen was the best nitrogen source for Conexibacter sp. LD01 when growing and degrading lincomycin. In total, 17 metabolic products consisting of nine novel products were detected, and five biodegradation pathways, including N-demethylation, breakage of the amido bond, sulfoxidation, and oxidation of the pyrrolidine ring and propylamino chain, were proposed. This study significantly expands our understanding of the functional microorganisms and mechanism involved in lincomycin biodegradation at the phylum level.

Determination of contaminants of emerging concern in raw pig manure as a whole: difference with the analysis of solid and liquid phases separately

The content of veterinary drugs in manure is usually estimated by the amount of residues determined in its solid or liquid phase, individually, which previously required a separation step. As an alternative, a multiresidue method for the analysis of 48 veterinary drugs and other contaminants of emerging concern (CECs) in swine raw manure as a whole has been developed and in-house validated in this work. The impact of several experimental factors during ultrasound assisted extraction was assessed. Hence, the use of alumina seemed to especially decrease the matrix effect and improve the overall recovery of drugs, mainly those with a high octanol-water partition coefficient. CECs in the extracts were analyzed by ultra-high performance liquid chromatography coupled to mass spectrometry in tandem. A standard addition-matrix matched calibration was used for quantification. Application of the method to two related samples (raw manure and farm centrifuged raw manure) from a facility revealed that the concentrations of CECs determined in the raw manure by the comprehensive methodology were higher than those calculated by adding the concentrations measured in the solid and liquid phases, separately. This was attributed to the loss of CECs adsorbed on fine particles in the suspension during the sample preparation procedure of the liquid-phase. Furthermore, the decrease of residues in the raw manure when this is centrifuged in the farm to yield compost is shown.

Quantifying Antibiotic Distribution in Solid and Liquid Fractions of Manure Using a Two-Step, Multi-Residue Antibiotic Extraction

Antibiotic distribution and analysis within liquid and solid fractions of manure are highly variable due to each compound’s respective physiochemical properties. This study developed and evaluated a uniform method extracting 10 antibiotics from 4 antibiotic classes (tetracycline, sulfonamides, macrolides, and β-lactam) from unprocessed manure, solid−liquid separated manure, and composted solids. Through systematic manipulation of previously published liquid chromatography tandem mass spectrometry methods; this study developed an extraction protocol with optimized recovery efficiencies for varied manure substrates. The method includes a two-step, liquid-solid extraction using 10 mL of 0.1 M EDTA-McIlviane buffer followed by 10 mL of methanol. Antibiotics recoveries from unprocessed manure, separated liquids, separated solids, and heat-treated solids using the two-step extraction method had relative standard deviations < 30% for all but ceftiofur. Total antibiotic recoveries were 67−131% for tetracyclines, 56% for sulfonamide, 49−53% for macrolides, and 1.3−66% for β-lactams. This is the first study to use one protocol to assess four classes of antibiotics in liquid and solid manure fractions. This study allowed for more precise risk assessment of antibiotic transport in manure waste stream applied to fields as a liquid or solid compost.

An exhaustive investigation on antibiotics contamination from livestock farms within sensitive reservoir water area: Spatial density, source apportionment and risk assessment

Although the studies on antibiotic contamination are common at present, large-scale sampling studies drawing highly representative conclusions are still scarce. This study conducted a comprehensive investigation on a total of 1183 samples from 70 livestock farms within a sensitive area around reservoir waters. 45 types of antibiotics belonging to 5 different classes were monitored. This is the first analysis to comprehensively investigate the density distribution, source apportionment, ecological and health risk of antibiotics in an entire area of sensitive waters. The results showed that the layer manure samples had highest detection rate of antibiotics (0.0 %-96.1 %, average value = 30.7 %) followed by pig manure samples. Oxytetracycline had the highest concentration of 712.16 mg/kg in a pig manure sample. Different from using antibiotic concentration as a proxy for pollution level, the spatial density was calculated by averaging antibiotic concentration to area and converting different livestock to pig equivalent. The spatial density of pig equivalent can more realistically reflect the pollution caused by different breeds of livestocks. It was shown that the pig farms contributed higher to total antibiotic density than the layer and cattle farms did. After assessed, a few antibiotics (oxytetracycline, chlorotetracycline and tetracycline) have posed high ecological risks to soil around the farms. However, none of them caused hazard quotient (HQ) risk and carcinogenic risk (CR) to human health in the water of reservoir. Children were more likely to be at hazard risk than adults. Antibiotic mass fluctuation rules were analyzed along the chain (feed → livestock waste → soil → surface water). Feed, livestock waste and soil had similar diversity, but the antibiotic concentrations continued to decline, implying the possible sources of antibiotic residues were similar. Thus, it is important to reduce unnecessary antibiotic use to prevent the potential long-term risk of antibiotics.

Differential response of N2O emissions, N2O-producing and N2O-reducing bacteria to varying tetracycline doses in fertilized soil

Tetracyclines are the most widely used antibiotics worldwide. Their presence in soils could affect nutrient cycling, but our knowledge regarding how they affect soil microbial communities involved in greenhouse gas emissions is limited. The objective of the current study was to evaluate how tetracycline is affecting N₂O emissions and the abundance of denitrifiers in fertilized soil. For this purpose, soil mesocosms were treated with only NH₄NO₃ (100 mg/kg) or NH₄NO₃ (100 mg/kg) plus three different doses of tetracycline (0.1, 0.5 and 2 mg/kg). Soils that did not receive tetracycline or NH₄NO₃ were used as controls. Nitrous oxide fluxes were monitored daily for 16 days. The total bacterial (16S rRNA), the abundance of N₂O-reducing and -producing bacteria were quantified by qPCR at the end of the experiment. The application of NH₄NO₃ caused a significant increase of N₂O emissions and AOB abundance but did not affect the abundance of denitrifiers and AOA compared to control soils. Different doses of tetracycline in fertilized soils did not mitigate these N₂O emissions; instead, higher cumulative emissions were noticed in soils treated with the lowest dose. In these soils the total bacterial abundance was higher compared to soils received higher tetracycline concentration. The abundances of the N₂O-producing and N₂O-reducing communities were also differently affected by the addition of tetracycline, which was dose-dependent. Higher doses of tetracycline favored N₂O-reducers within the total bacterial community, which could be important for mitigating N₂O emissions in the long term.

Determination of antimicrobial agents and their transformation products in an agricultural water-soil system modified with manure

Manure fertilization is the primary source of veterinary antimicrobials in the water-soil system. The research gap is the fate of antimicrobials after their release into the environment. This study aimed to provide a detailed and multi-faceted examination of fertilized cultivated fields using two types of manure (poultry and bovine) enriched with selected antimicrobials. The research focused on assessing the mobility and stability of antimicrobials in the water-soil system. Additionally, transformation products of antimicrobials in the environment were identified. The extraction (solid-phase extraction and/or solid-liquid extraction) and LC-MS/MS analysis procedures were developed to determine 14 antimicrobials in the soil and pore water samples. Ten out of fourteen antimicrobials were detected in manure-amended soil and pore water samples. The highest concentration in the soil was 109.1 ng g^-1 (doxycycline), while in pore water, it was 186.6 ng L^-1 (ciprofloxacin). Sixteen transformation products of antimicrobials were identified in the soil and soil-related pore water. The same transformation products were detected in both soil and soil pore water extracts, with significantly higher signal intensities observed in soil extracts than in water. Transformation products were formed in oxidation, carbonylation, and ring-opening reactions.

Global review of macrolide antibiotics in the aquatic environment: Sources, occurrence, fate, ecotoxicity, and risk assessment

The extensive use of macrolide antibiotics (MCLs) has led to their frequent detection in aquatic environments, affecting water quality and ecological health. In this study, the sources, global distribution, environmental fate, ecotoxicity and global risk assessment of MCLs were analyzed based on recently published literature. The results revealed that there are eight main sources of MCLs in the water environment. These pollution sources resulted in MCL detection at average or median concentrations of up to 3847 ng/L, and the most polluted water bodies were the receiving waters of wastewater treatment plants (WWTPs) and densely inhabited areas. Considering the environmental fate, adsorption, indirect photodegradation, and bioremoval may be the main attenuation mechanisms in natural water environments. N-demethylation, O-demethylation, sugar and side chain loss from MCL molecules were the main pathways of MCLs photodegradation. Demethylation, phosphorylation, N-oxidation, lactone ring hydrolysis, and sugar loss were the main biodegradation pathways. The median effective concentration values of MCLs for microalgae, crustaceans, fish, and invertebrates were 0.21, 39.30, 106.42, and 28.00 mg/L, respectively. MCLs induced the generation of reactive oxygen species, that caused oxidative stress to biomolecules, and affected gene expression related to photosynthesis, energy metabolism, DNA replication, and repair. Moreover, over 50% of the reported water bodies represented a medium to high risk to microalgae. Further studies on the development of tertiary treatment technologies for antibiotic removal in WWTPs, the combined ecotoxicity of antibiotic mixtures at environmental concentration levels, and the development of accurate ecological risk assessment models should be encouraged.

Prioritized antibiotics screening based on comprehensive risk assessments and related management strategy in various animal farms

Antibiotic pollution in the environment caused by animal breeding has become a serious issue. The persistent release of antibiotics with animal waste may lead to antibiotic resistances in the environment, which poses a threat to human health. This study tries to provides a practical method for screening prioritized antibiotics via a comprehensive risk assessment and determination of their major sources, and put forward corresponding regulatory measures for animal industries. We investigated the occurrence and distribution of 20 antibiotics belonging to eight classes, spanning the areas of animal feed, drinking water, and animal feces on 59 animal farms in Shandong Province, China. The results showed that antibiotic contamination was prevalent in different environmental mediums (feed, feces, and drinking water) on these farms. Tetracyclines typically exhibited higher concentrations than the other classes in all samples, and the majority of antibiotics had greater concentrations in cattle feces than in pig- or chicken feces. For the antibiotic ecological risks in feces, doxycycline, tetracycline, and enrofloxacin exhibited much more toxic effects on terrestrial organisms (e.g., wheat, cucumber, and rice). Ciprofloxacin, enrofloxacin, ofloxacin, and tetracycline levels in drinking water samples can lead to high risk of antibiotic resistance, while no antibiotic posed obvious risks to human health. Based on compressive risk assessments, 11 antibiotics were prioritized to control in the animal breeding environment. Based on the survey of feeds, drinking water and animal waste from the farm, roxithromycin in the feces mainly originated from the feeds, while most prioritized antibiotics, were from extra addition in the animal breeding process (including injection and other oral routes). The key point of local antibiotic management in animal farms should be adjusted from the feed factory to the extra addition of antibiotics in animal breeding processes.

Environmental risks caused by livestock and poultry farms to the soils: Comparison of swine, chicken, and cattle farms

The lack of treatment systems for pollutants in family-livestock and poultry sites results in large amounts of untreated manure and urine being directly discharged to environment. The risks from veterinary antibiotic (VA) and heavy metal (HM) exposure in the rural environment require further research. In this investigation, 221 samples (feed, manure, surface soil, soil profiles, water, and plant) were collected from 41 livestock and poultry farms (swine, chichen, and cattle). Copper (Cu), zinc (Zn), oxytetracycline (OTC), and enrofloxacin (ENR) were frequently detected in the samples. Metals and VAs in sandy loam soils were more inclined to migrate to deep layers than those in loam soils. Copper and Zn in the polluted soils mainly existed in available forms, which facilitated their migration to deep soil layers. In this study, OTC was also observed to migrate more easily to deeper soil layers than ENR due to its relatively high pKa value. Eighteen antibiotic resistance genes (ARGs) and 5 metal resistance genes (MRGs) along with one mobile genetic element (MGE) occurred in the soils at 80 cm depth. Luteimonas, Clostridium_sensu_stricto_1, and Rhodanobacter were dominant genera detected in the soil samples from different sites, which might increase migration of ARGs or degradation of VAs. An ecological risk assessment suggested that VAs posed threats to the growth of Triticum aestivum L, Cucumis sativus L, and Brassiaca chinensis L. Remediation techniques including biochar/modified biochar, anaerobic digestion, and manure composting should be developed urgently for joint HM and VA pollution.

Dispersal of antibiotic resistance genes in an agricultural influenced multi-branch river network

Rivers in agricultural regions serve as an important sink for livestock and poultry farm runoff, fertilizer runoff, and country living sewage, which could bring antibiotic resistance genes (ARGs) contaminations. However, the diversity and distribution of ARGs has not been well documented in the agricultural influenced river. Here, the diversity of ARGs, and their relationship with biochemical factors were determined in the surface water in an agricultural region of the Jialing River and its five rural branches. The 218 unique ARGs encoding resistance to eight major antibiotic classes have been detected using high-throughput quantitative PCR. The branches of the river had a remarkably higher abundance of ARGs than the mainstream. The aminoglycoside, beta_Lactamase, MLSB, and Multidrug resistance genes were significantly enriched in the branches compared to the mainstream. Compared with the mainstream, the ARGs profiles in the branches showed obvious higher spatial variability. Significant correlation between ARGs profiles and bacterial community structures were observed, and network analysis further showed that the ARGs were associated with their potential hosts, such as Ottowia and Novosphingobium. Redundancy discrimination analysis revealed that Cu content has a significant contribution to the increase of ARGs in the river. The microbial diversity index was negatively correlated with the abundance of the ARGs. These results provide evidence for the enrichment of ARGs in the agricultural influenced river and branches due to the joint influence of chemical and microbial variables.

Disposal of Unused and Expired Medicines within the Sunyani Municipality of Ghana: A Cross-Sectional Survey

The occurrence of pharmaceuticals in the environment is a global challenge. Pharmaceuticals such as antibiotics and analgesics have been reported in various environmental matrices at varying concentrations. The major disposal route for unused and expired pharmaceuticals in Ghana is throwing them into dustbins. Although there are laws on the proper disposal patterns of drugs, these laws are poorly implemented. Sunyani is a fast-growing community with several health facilities that dispense medications daily. The purchase and use of medications among households are also high. However, no data exist on the disposal patterns of pharmaceuticals within the Sunyani Municipality. This study aims to identify the disposal patterns for unused and expired medications by households and pharmacies within the Sunyani Municipality, Ghana. A descriptive cross-sectional study was conducted among 400 persons in homes and 35 persons from randomly selected pharmacies and over-the-counter medication shops (OTCMs) within the Sunyani Municipality. A face-to-face interview approach using structured questionnaires for each respondent was employed. Household respondents disposed of unused and expired medications mainly through dumping in garbage cans (70.8%), incineration (11.5%), and flushing down the sink (9%). Pharmaceutical shop respondents also disposed of unused and expired medications into dump cans, by incineration, through the Food and Drugs Authority of Ghana, and took back to pharmaceutical wholesalers. Disposal practices observed in this study by households and pharmacy respondents were largely inappropriate. This could be due to the lack of education on the proper disposal patterns available to these respondents. It is recommended that guidelines on safe disposal be put in place, and a structured procedure for collecting unused and expired pharmaceuticals should be introduced.

Occurrence of veterinary drugs and resistance genes during anaerobic digestion of poultry and cattle manures

In the present paper, the mesophilic (35 °C) and thermophilic (55 °C) biomethanization of poultry and cattle manures were investigated using biochemical methane potential (BMP) tests. Specific methane production (SMP), 24 pharmaceutical compounds (PhACs), and five antibiotic resistance genes (ARGs) (bla_KPC, ermB, qnrS, sul1 and tetW) together with the microbial community were analyzed. Mesophilic BMP tests resulted in the highest SMP when poultry manure was used (285.5 mL CH₄/g VSS with poultry vs 239.6 mL CH₄/g VSS with cattle manure) while thermophilic temperatures led to the highest SMP with cattle manure (231.2 mL CH₄/g VSS with poultry vs 238.0 mL CH₄/g VSS with cattle manure). Higher removals of veterinary pharmaceuticals were detected at 55 °C with both manures indicating that thermophilic digestion is better suited for the removal of these compounds. Tylosin, tilmicosin, chlortetracycline, and sulfamethoxazole presented removals higher than 50%, being the first two completely removed under mesophilic and thermophilic conditions. When comparing the relative abundance of ARGs at the end of each treatment, the most significant removal was found for qnrS which was not detected after the anaerobic treatment. The remaining ARGs did not suffer significant changes. Finally, microbial composition analysis showed that temperature affected the final microbial population more than the microorganisms present in the substrate or inoculum.

Understanding flow patterns from the field - Controlled laboratory experiments on the transport behavior of veterinary antibiotics in the presence of liquid manure

The main entry path of veterinary antibiotics to the environment is the application of liquid manure on agricultural land. Along with the manure, they can infiltrate into soils and leach into groundwater. As the environmental behavior of veterinary antibiotics is strongly affected by the process of sorption, the comprehensive knowledge regarding their sorption behavior is key to a reliable risk assessment. However, the flow patterns in field experiments are influenced by several factors that can hardly be distinguished, while most of the sorption studies on veterinary antibiotics were designed without manure or as batch experiments, which means that the effects of manure on the transport behavior of the antibiotic substances remained unaccounted for. In order to understand the results from a previous field experiment and concurrently fill the identified knowledge gap, a column experiment was performed to investigate the effects of manure on the transport of sulfamethazine, sulfadiazine, tetracycline, and lincomycin in soil. Results show that sulfamethazine and sulfadiazine were highly mobile in both the presence and absence of manure, while tetracycline did not appear at the outlet of any column. Despite their high mobility, in the presence of manure the sulfonamides were slightly delayed compared to the conservative tracer as was also seen during the previous field experiment. Lincomycin transport was already delayed in the absence of manure. Furthermore, in the presence of manure, lincomycin was delayed by 4.5 times relative to the tracer, which clearly underlined the influence of manure on the transport of lincomycin and offers an explanation why lincomycin has barely been detected in the long-term field experiment. However, in contrast to the results obtained in the field experiment, the recovery rates were the same in presence and absence of manure for both sulfonamides and lincomycin, probably due to reduced degradation at the applied concentration level.

Occurrence of veterinary antibiotics in animal manure, compost, and agricultural soil, originating from different feedlots in suburbs of Shanghai, East China

The present study aims to monitor and assess the occurrence of veterinary antibiotics (VAs) in animal manure, compost, and fertilized soil, originating from different large-scale feedlots. The corresponding concentrations of 39 types of VAs in 8 large-scale feedlots of pig, dairy cow, and poultry were sampled in different seasons and analyzed using LC-MS. The results indicated that 17 types, 16 types, and 5 types of VAs were detected in the swine manure, compost, and fertilized soil with the concentrations of 0.003-17.82, 0.002-9.59, and 0.004-0.007 mg kg^-1 (dry matter), respectively; 3 types, 2 types, and 1 type of VAs were detected in the dairy manure, compost, and fertilized soil with the concentrations of 0.003-1.94, 0.014-0.044, and 0.025 mg kg^-1 (dry matter), respectively; 7 types, 5 types, and 1 type of VAs were detected in the poultry manure, compost, and fertilized soil with the concentrations of 0.035-1.06, 0.018-0.049, and 0.019 mg kg^-1 (dry matter), respectively. The main antibiotic classes persisted in the animal manure and their composting product and fertilized soil were sulfonamides (SAs), macrolides (MAs), and tetracyclines (TCs). Thus, this study would help to adopt strategies in pollution control of VAs and environmental protection of agriculture.

Using highly stabilized digestate and digestate-derived ammonium sulphate to replace synthetic fertilizers: The effects on soil, environment, and crop production

Recovered fertilizers (a highly stabilized digestate and ammonium sulphate) obtained from anaerobic digestion of sewage sludge, were used on plot trials with a maize crop, in a comparison with synthetic fertilizers. After three consecutive cropping seasons, the soils fertilized with the recovered fertilizers (RF), compared to those fertilized with synthetic fertilizers (SF), did not show significant differences either in their chemical characteristics or in the accumulation of inorganic and organic pollutants (POPs). The RF ensured an ammonia N availability in the soil equal to that of the soil fertilized with SF, during the whole period of the experiment. Furthermore, no risks of N leaching were detected, and the use of RF did not result in a greater emission of ammonia or greenhouse gases than the use of SF. The agronomic results obtained using RF were equivalent to those obtained with SF (fertilizer use efficiency of 85.3 ± 10 and 93.6 ± 4.4% for RF and SF respectively). The data show that utilising a very stable digestate can be a good strategy to produce a bio-based fertilizer with similar performance to that of a synthetic fertilizer, without environmental risks.

Implications of the use of organic fertilizers for antibiotic resistance gene distribution in agricultural soils and fresh food products. A plot-scale study

The spread of antibiotic resistance genes (ARG) into agricultural soils, products, and foods severely limits the use of organic fertilizers in agriculture. In order to help designing agricultural practices that minimize the spread of ARG, we fertilized, sown, and harvested lettuces and radish plants in experimental land plots for two consecutive agricultural cycles using four types of fertilizers: mineral fertilization, sewage sludge, pig slurry, or composted organic fraction of municipal solid waste. The analysis of the relative abundances of more than 200,000 ASV (Amplicon Sequence Variants) identified a small, but significant overlap (<10%) between soil's and fertilizer microbiomes. Clinically relevant ARG were found in higher loads (up to 100 fold) in fertilized soils than in the initial soil, particularly in those treated with organic fertilizers, and their loads grossly correlated to the amount of antibiotic residues found in the corresponding fertilizer. Similarly, low, but measurable ARG loads were found in lettuce (tetM, sul1) and radish (sul1), corresponding the lowest values to samples collected from minerally fertilized fields. Comparison of soil samples collected along the total period of the experiment indicated a relatively year-round stability of soil microbiomes in amended soils, whereas ARG loads appeared as unstable and transient. The results indicate that ARG loads in soils and foodstuffs were likely linked to the contribution of bacteria from organic fertilizer to the soil microbiomes, suggesting that an adequate waste management and good pharmacological and veterinarian practices may significantly reduce the presence of these ARGs in agricultural soils and plant products.

Effect of low levels of oxytetracycline on anaerobic digestion of cattle manure

Cattle manure is rich in organic matter and nutrients, but it may also contain harmful substances such as residual antibiotics and other toxic compounds. Oxytetracycline (OTC) is a widely used veterinary antibiotic and its presence in manure can affect the subsequent anaerobic digestion process. This study evaluated the effect of OTC concentrations viz. 0.12, 0.3, 0.6, 1.2, 3, 6 and 12 mg L^-1 on batch mesophilic anaerobic digestion of cattle manure. The results showed that cumulative biogas yield decreased by 25, 29 and 55% at 3, 6 and 12 mg OTC L^-1 in contrast to control. Volatile solids removal was 39% for control which reduced to 13% in 12 mg L^-1 OTC spiked reactor. Effect on stability parameters was significant at OTC concentrations from 1.2 to 12 mg L^-1. Two different kinetic models were used for biogas data validation and the modified Gompertz model best fitted to the experimental data.

Emission estimation and prioritization of veterinary pharmaceuticals in manure slurries applied to soil

Veterinary pharmaceuticals (VPs) are emitted into the environment and transfer to groundwater and surface water is diffuse and complex, whereas actual information on the fate is frequently limited. For 17 VPs of potential concern in the Netherlands, we assessed sources and emission due to animal slurry applications to soil. Hence, we examined the use of VPs in four livestock sectors in the Netherlands for 2015-2018, and quantified animal excretion rates and dissipation during slurry storage. For almost all VPs, administrated quantities to the animals during the period 2015-2018 decreased. VP concentrations during a storage period of six months could decrease between 10 and 98% depending on the compound. Predicted concentrations of VPs in slurries after storage compared well with measured concentrations in the literature. Based on the storage model outcomes, we developed a residue indicator, that quantifies the potential for residues in applied slurry. This indicator agrees well with the most frequently detected VPs in the Dutch slurries, and is therefore useful to prioritize measures aiming at reducing VP emissions into the environment.

Veterinary antibiotics can reduce crop yields by modifying soil bacterial community and earthworm population in agro-ecosystems

Veterinary antibiotics are intensively and widely used in animal farming to treat or prevent diseases, as well as improve growth rate and feed efficiency. Animal manure is an important reservoir of veterinary antibiotics due to their high excretion rates, and thus manure application has been a critical source of veterinary antibiotics in agro-ecosystems. However, how veterinary antibiotics affect agroecosystem functions is still unclearly understood. In this study, we evaluated the effects of veterinary antibiotics on soil bacteria and earthworms in agricultural land with long-term manure application. The potential mechanisms of antibiotic-induced changes in crop yields were also revealed. The results showed that the increasing prevalence of veterinary antibiotics in agro-ecosystems inhibited earthworm abundance and bacterial diversity, and then decreased the bioavailability of soil nutrients. Furthermore, high-dose exposure to veterinary antibiotics improved the abundance of plant pathogenic bacteria. Analysis indicated that veterinary antibiotics played an important underlying role in driving the negative effects on peanut grain yields via disturbing microbe- and earthworm-mediated soil available nutrient contents. The direct toxicity effects of antibiotics on peanut relative yields were stronger than their indirect mediating effects. Additionally, the tradeoffs between antibiotics and agroecosystem functions increased at low exposure levels and then decreased at high exposure levels, which indicated the effects of antibiotics on agroecosystem functions were dose-dependent, except for earthworm biomass. Antibiotic contamination which will impose threats to agricultural sustainability was highlighted and should be paid more attention.

Determination of multiple antibiotics in agricultural soil using a quick, easy, cheap, effective, rugged, and safe method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry

In this study, we combined ultra-high performance liquid chromatography with tandem mass spectrometry to establish a quick, easy, cheap, effective, rugged, and safe method of detecting 21 target antibiotics in agricultural soil samples. Antibiotics were extracted with mixed solvents consisting of ethylenediaminetetraacetic acid disodium salt dihydrate and phosphoric acid citric acid buffer and acetonitrile which were purified with octadecylsilyl as an adsorbent and anhydrous sodium sulfate as a desiccant. This method was able to effectively extract all of the target antibiotics from agricultural soils, with recovery efficiencies ranging from 55 to 108% and limits of detection between 0.09-0.68 μg/kg. We also validated this new method for selectivity, sensitivity, and reliability of detecting multiple antibiotics in 12 samples. Considering the potential environmental and public health effects of antibiotics in agricultural soils, our new method can help analyze the degree of antibiotic contamination and provide valuable information for soil quality and risk assessment.

Interaction of pig manure-derived dissolved organic matter with soil affects sorption of sulfadiazine, caffeine and atenolol pharmaceuticals

Pharmaceutically active compounds (PhACs) released into the environment have an adverse impact on the soil and water ecosystem as well as human health. Sorption of PhACs by soils and its potential modification through introduced DOM in the applied animal manure or treated wastewater (TWW) determines the mobility and environmental relevance of PhACs. Sulfadiazine, caffeine and atenolol were selected as target PhACs to investigate their sorption behaviors by five selected arable soils in the absence and presence of pig manure DOM. Sulfadiazine was least sorbed, followed by caffeine and atenolol according to the Freundlich sorption isotherm fit (soil average K_f [μg^(1-n) mLⁿ g^-1] 4.07, 9.06, 18.92, respectively). The addition of manure DOM (31.34 mg C L^-1) decreased the sorption of sulfadiazine and especially of caffeine and atenolol (average K_f 3.04, 6.17, 5.79, respectively). Freundlich sorption isotherms of the PhACs became more nonlinear in the presence of manure DOM (Freundlich exponent n changed from 0.74-1.40 to 0.62-1.12), implying more heterogeneous sorption of PhACs in soil-DOM binary systems. Sorption competition of DOM molecules with sulfadiazine and caffeine mostly contributed to their decreased soil sorption when DOM was present. In contrast, the formation of DOM-atenolol associates in the solution phase caused the largely decreased soil sorption of atenolol in the presence of DOM. It is suggested that DOM concentration (e.g., ≥ 60 mg C L^-1) and its interaction with PhACs should be taken into consideration when assessing the environmental impact of land application of animal manure or irrigation with TWW.

The role of chemotaxis and efflux pumps on nitrate reduction in the toxic regions of a ciprofloxacin concentration gradient

Spatial concentration gradients of antibiotics are prevalent in the natural environment. Yet, the microbial response in these heterogeneous systems remains poorly understood. We used a microfluidic reactor to create an artificial microscopic ecosystem that generates diffusive gradients of solutes across interconnected microenvironments. With this reactor, we showed that chemotaxis toward a soluble electron acceptor (nitrate) allowed Shewanella oneidensis MR-1 to inhabit and sustain metabolic activity in highly toxic regions of the antibiotic ciprofloxacin (>80× minimum inhibitory concentration, MIC). Acquired antibiotic resistance was not observed for cells extracted from the reactor, so we explored the role of transient adaptive resistance by probing multidrug resistance (MDR) efflux pumps, ancient elements that are important for bacterial physiology and virulence. Accordingly, we constructed an efflux pump deficient mutant (∆mexF) and used resistance-nodulation-division (RND) efflux pump inhibitors (EPIs). While batch results showed the importance of RND efflux pumps for microbial survival, microfluidic studies indicated that these pumps were not necessary for survival in antibiotic gradients. Our work contributes to an emerging body of knowledge deciphering the effects of antibiotic spatial heterogeneity on microorganisms and highlights differences of microbial response in these systems versus well-mixed batch conditions.

Effects of Partial Organic Substitution for Chemical Fertilizer on Antibiotic Residues in Peri-Urban Agricultural Soil in China

Recycling of organic wastes in agricultural ecosystems to partially substitute chemical fertilizer is recommended to improve soil productivity and alleviate environmental degradation. However, livestock manure- and sewage sludge-derived amendments are widely known to potentially carry antibiotic residues. The aim of this study is to investigate how substituting organic fertilizer for chemical fertilizer affects soil quality and antibiotic residues in agricultural soil, as well as their tradeoffs. A field experiment was conducted with the different treatments of pig manure and sewage sludge as typical organic fertilizers at equal total nitrogen application rates. The analysis of variance showed that the increments on the levels of residual antibiotics in the agricultural soils due to organic substitution for chemical fertilizer by pig manure and sewage sludge were observed. The antibiotic residues ranged from 13.73 to 76.83 ng/g for all treatments. Partial organic substitution significantly increased the sequestration of antibiotics in agricultural soil by 138.1~332.5%. Organic substitution will also significantly improve soil quality, especially for nutrient availability. Based on principal component analysis, organic substitution will strongly affected soil quality and antibiotic contamination. Pearson's correlation showed that soil physicochemical properties had significant correlations with concentrations of antibiotics in soil, indicating organic fertilizers can promote the persistence of antibiotics in soil by modifying soil quality. To balance the benefits and risks, appropriate management practices of organic fertilizers should be adopted.

Antibiotic residues in substrates and output materials from biogas plants - Implications for agriculture

Bio-based fertilizers including farmyard manure, sewage sludge, meat and bone meal, composts, digestates and derived products are nutrient-rich fertilizers. They deliver organic matter but may pose the risk to contaminate soils by pollutants such as pharmaceuticals, heavy metals, resistance genes or pathogens. Manure and sewage sludge are increasingly used in biogas plants for energy production with the residue being used as fertilizer. It is therefore important to understand the fate of pharmaceuticals during anaerobic digestion. In the present study, 29 biogas plants from three countries were studied. The different input materials and output after digestion were analyzed for selected examples of antibiotics from three different classes, namely tetracyclines (TCs), sulfonamides (SAs) and fluoroquinolones (FQs). These classes are frequently found in animal manures and sewage sludge and display differing mobility and persistence. The results revealed that antibiotics could be detected in 81% of the substrates derived from animal manures and sewage sludge and in 83% of the digestates. Antibiotics were determined with the highest frequency of 100% in sewage sludge where especially ciprofloxacin and tetracycline were found. Highest concentrations were analyzed in poultry dung with in maximum of 8.6 and 8.2 mg/kg DW of enrofloxacin and tetracycline, respectively. After digestion, slightly lower concentrations of antibiotics were determined for most substrates. However, in one biogas plant using poultry dung as an input material a maximum concentration of 15.2 mg/kg DW of tetracycline was determined in the digestate, which after separation accounted for 29.8 mg/kg DW of tetracycline in the liquid phase.

Microbial and chemical pollutants on the manure-crops pathway in the perspective of "One Health" holistic approach

This study determined the impact of poultry and bovine manure fertilization on the content of antibiotics, heavy metals (HMs), and the quantitative and qualitative composition of integrase and antibiotic resistance genes in soil, groundwater, and crops cultivated on manure-amended plots. Antibiotic concentration levels were analyzed using the HPLC-MS/MS, heavy metal concentration level were measured by HGAAS and ICP-OES, while the integrase genes and ARGs were quantified using Real-Time PCR (qPCR) method. Manure, soil, and crops samples contained the highest concentration of Zn (10⁴-10⁵ ng g_dm^-1) and Cu (10³-10⁵ ng g_dm^-1) of all HMs tested. Manure-supplemented soil was characterised by a high concentration of doxycycline and enrofloxacin. A high abundance of integrase genes was noted in samples of manure (10⁹-10¹⁰ copies g_dm^-1) and soil (10⁷-10⁸ copies g_dm^-1). Among all the analyzed genes, sul1, sul2, bla_TEM, and integrase genes were the most common. Results of the study demonstrate the selective character of ARGs transfer from poultry and bovine manure to plants. The only gene to occur in all studied environmental compartments was sul1 (from 10² - groundwater to 10¹¹ - poultry manure). It was also found that animal manure may cause an increase in the HMs concentration in soil and their accumulation in crops, which may influence the health of humans and animals consuming crops grown on manure-amended soil. The high abundance of integrase genes and ARGs and their reciprocal correlations with HMs pose a serious risk of the rapid spread of antibiotic resistance in the environment. Moreover, unusual dependencies between integrase genes and selected ARGs indicate the possibility of changes in the mobility nature of genetic elements.

Proliferation of antibiotic-resistant microorganisms and associated genes during composting: An overview of the potential impacts on public health, management and future

Antibiotic residues together with non-antibiotic drugs and heavy metals act as a selective pressure for the spread of antibiotic-resistant microorganisms (ARMs), antibiotic-resistant genes (ARGs), and mobile genetic elements (MGEs) during composting of livestock manure. ARMs, ARGs and MGEs have become emerging contaminants since they are regularly implicated in the majority of compost produced from livestock manure. The prevalence of these contaminants in agricultural soil receiving compost has drawn huge attention globally due to the risks they pose to the total environment. Although a large body of literature exists on the application of composting methods in minimizing the relative abundance of these contaminants, there is a paucity of information on the robustness, limitations and opportunities and threats of various composting protocols currently deployed. To address this knowledge gap, the current review compiled literature on the origin and mechanisms of the proliferation of ARMs, ARGs, and MGEs during composting of livestock manure. The effectiveness of current composting protocols in the reduction or removal of emerging contaminants was evaluated. Furthermore, the potential environmental impacts and human health risks of these contaminants following land application of compost were also presented. Finally, we propose some strategic approaches for the reduction of ARGs and MGEs during composting of livestock manure.

Qualitative Risk Analysis for Contents of Dry Toilets Used to Produce Novel Recycling Fertilizers

Human excreta are a sustainable, economical source of nutrients, and can be used to produce recycling fertilizer for horticulture by collecting and processing the contents of dry toilets. Herein, we discuss the key categories of risk associated with the main groups of materials commonly found in dry toilets. The study was part of the development of a German product standard for marketable and quality-assured recycling fertilizers from human excreta for use in horticulture. Particular attention is paid to ensuring that the fertilizer is epidemiologically and environmentally harmless and that the quality of the recycling fertilizer is adequate in terms of low pollution and nutrient availability. In sum, the risk of transmissible human pathogens lies within the human excreta, particularly feces; plant materials added during composting are of particular phytosanitary relevance; pharmaceutical residues in excrements and chemical additives are potential sources of pollutants; non-biodegradable contaminants can cause pollution and injury; and the horticultural risks involve mainly the ammonia emission potential and in some cases the salinity effects of urine. These risks can be reduced significantly (i) with education of users around proper operation of dry toilets and the consequences of adding inappropriate waste, (ii) with facilitation of proper use with general waste bins and clear instructions, and importantly (iii) by using modern sanitization and cleaning processes and testing for harmful substances under the guidance of local laws and regulations, ensuring safe and high-quality fertilizers. In conclusion, the benefits of using dry toilet contents to produce fertilizers for use in horticulture are unquestionable. Our analysis highlights the need to support recycling optimization and awareness for the purpose of a sustainable circular economy and to minimize the risk of harm to humans and the environment overall.

Occurrence, effects and behaviour of the antibiotic lincomycin in the agricultural and aquatic environment - A review

Lincomycin, an antibiotic commonly used in veterinary medicine, is frequently detected within the agricultural environment. The active compound enters the aquatic environment after manure application via infiltration or surface run-off, where it may negatively affect non-target organisms and contribute to the development and spread of resistant genes. However, a review on the fate of lincomycin within the agricultural and aquatic environment is lacking. Hence, to provide an overview, the main part of this paper summarizes the current literature on the occurrence, effects and behaviour of lincomycin in all relevant environmental compartments, including manure, soil, surface water and groundwater. Lincomycin was regularly detected in all environmental compartments and even in the food chain, appeared to sorb temporarily and mainly in its cationic microspecies, and dissipated after time periods that could cover days, months, or years, depending on the compartment and conditions. As noticed during the literature research conducted, information on the attenuation of lincomycin in terms of biological degradation in the aquatic environment is widely lacking, although it seems that biodegradation is the major removal mechanism. Therefore, a laboratory study, implemented by means of batch experiments, was carried out in order to evaluate the biological degradation of lincomycin in the aquatic environment. First order degradation started after a start-up phase of 10-14 days with a degradation rate constant of 0.55 d^-1 and a half-life time of 30 h. Further, the degradation rate constant was found to be independent of initial concentrations as long as concentrations did not exceed a concentration level at which the bacteria were inhibited, as it was the case in this study at a concentration of 10 mg L^-1. Biodegradation was confirmed as an important degradation pathway for LIN in the aquatic environment.

Determination of antibiotics and other veterinary drugs in the solid phase of pig manure

The presence of residues of veterinary pharmaceuticals in farm wastewaters such as pig slurry represents a problem that needs to be tackled to avoid further contamination of environmental waters and the development of resistant bacteria. For their monitoring and control, it is necessary the existence of reliable analytical tools. The present paper describes for the first time the development and optimization by statistical experimental design of a specifically designed analytical method for the analysis of 21 veterinary drugs, including 18 antibiotics of several families (β-lactams, tetracyclines, fluoroquinolones, sulfonamides, macrolides, among others), 1 antiparasitic, 1 analgesic and 1 hormone, in a complex environmental matrix such as the fresh solid phase of pig slurry. The resulting method, consisted of an ultrasound assisted extraction (UAE) combined with in-situ dispersive solid phase extraction (d-SPE) from a 0.3 g of freeze-dried sample aliquot followed by a preconcentration step by compact solid phase extraction (c-SPE) and subsequent instrumental analysis by ultra-high-performance-liquid-chromatography (UHPLC) coupled to mass spectrometry in tandem (MS/MS) by a triple quadrupole, was successfully validated as a very sensitive (method limit of quantification in the low ng g^-1) and reliable method (relative recoveries around 100% and method repeatability featured by a general relative standard deviation below 20%). Provided raw data was intended to be processed by matrix-matched quantification approach. The resulting methodology was applied to the characterization of several pig manures from different Spanish farms sampled across breeding season between 2018 and 2019. Sample precedence showed to have a high impact in the positives, its frequency and concentration.

Veterinary antibiotics and estrogen hormones in manures from concentrated animal feedlots and their potential ecological risks

The spread of pharmaceutically active chemicals (PACs), such as antibiotics and estrogenic hormones from animal manures can pose threats to the ecologic environment. In this work, animal manure samples were collected from 71 concentrated animal feedlots in Northern China and investigated for 24 antibiotics and 4 estrogenic hormones. Results showed that these micropollutants were ubiquitous in manures with the concentration ranges of undetectable (ND)-543,445 μg/kg (mean: 44,568 μg/kg) for antibiotics and ND-249.8 μg/kg (mean: 24.78 μg/kg) for estrogens. There was a significant variation in the amounts of PACs in different animal manures. The amounts of antibiotics in manures had following order: swine (83,177 μg/kg) >chicken (52,932 μg/kg) >beef (37,120 μg/kg) >dairy (305 μg/kg), while the estrogens in dairy (mean: 39.27 μg/kg) and chicken manures (mean: 40.08 μg/kg) were higher than those in beef (2.7 μg/kg) and swine manures (1.8 μg/kg). Based on the estimated farmland application rate of manure, antibiotics and estrogens may cause high ecological risks to terrestrial organisms according to the risk quotient evaluation. Estrogens could pose a relatively higher risk than antibiotics. The toxicological effects of antibiotics and estrogens to the terrestrial environment should receive more intensive study.