Screening of biocides, metals and antibiotics in Swedish sewage sludge and wastewater

Understanding the impact of environmentally relevant alkyl C12-16 dimethylbenzyl ammonium chloride concentrations on zebrafish health

Alkyldimethylbenzylammonium chlorides (ADBACs), classified as second-generation quaternary ammonium compounds, are extensively employed across various sectors, encompassing veterinary medicine, food production, pharmaceuticals, cosmetics, ophthalmology, and agriculture. Consequently, significant volumes of ADBAC C12-C16 are discharged into the environment, posing a threat to aquatic organisms. Regrettably, comprehensive data regarding the toxicological characteristics of these compounds remain scarce. This research aimed to determine whether or not ADBAC C12-C16, at environmentally relevant concentrations (0.4, 0.8, and 1.6 μg/L), may instigate oxidative stress and alter the expression of apoptosis-related genes in the liver, brain, gut, and gills of Danio rerio adults (5-6 months). The findings revealed that ADBAC C12-C16 elicited an oxidative stress response across all examined organs following 96 h of exposure. Nonetheless, the magnitude of this response varied among organs, with the gills exhibiting the highest degree of susceptibility, followed by the gut, liver, and brain, in descending order. Only the gut and gills of the examined organs displayed a concentration-dependent reduction in the activity of superoxide dismutase (SOD) and catalase (CAT). Akin to the oxidative stress response, all organs exhibited a marked increase in bax, blc2, casp3, and p53 expression levels. However, the gills and gut manifested a distinctive suppression in the expression of nrf1 and nrf2. Our Principal Component Analysis (PCA) confirmed that SOD, CAT, nrf1, and nrf2 were negatively correlated to oxidative damage biomarkers and apoptosis-related genes in the gills and gut; meanwhile, in the remaining organs, all biomarkers were extensively correlated. From the above, it can be concluded that ADBAC C12-C16 in low and environmental concentrations may threaten the health of freshwater fish.

Enterobacter adelaidei sp. nov. Isolation of an extensively drug resistant strain from hospital wastewater in Australia and the global distribution of the species

BACKGROUND

Enterobacter species are included among the normal human gut microflora and persist in a diverse range of other environmental niches. They have become important opportunistic nosocomial pathogens known to harbour plasmid-mediated multi-class antimicrobial resistance (AMR) determinants. Global AMR surveillance of Enterobacterales isolates shows the genus is second to Klebsiella in terms of frequency of carbapenem resistance. Enterobacter taxonomy is confusing and standard species identification methods are largely inaccurate or insufficient. There are currently 27 named species and a total of 46 taxa in the genus distinguishable via average nucleotide identity (ANI) calculation between pairs of genomic sequences. Here we describe an Enterobacter strain, ECC3473, isolated from the wastewater of an Australian hospital whose species could not be determined by standard methods nor by ribosomal RNA gene multi-locus typing.

AIM

To characterise ECC3473 in terms of phenotypic and genotypic antimicrobial resistance, biochemical characteristics and taxonomy as well as to determine the global distribution of the novel species to which it belongs.

METHODS

Standard broth dilution and disk diffusion were used to determine phenotypic AMR. The strain's complete genome, including plasmids, was obtained following long- and short read sequencing and a novel long/short read hybrid assembly and polishing, and the genomic basis of AMR was determined. Phylogenomic analysis and quantitative measures of relatedness (ANI, digital DNA-DNA hybridisation, and difference in G+C content) were used to study the taxonomic relationship between ECC3473 and Enterobacter type-strains. NCBI and PubMLST databases and the literature were searched for additional members of the novel species to determine its global distribution.

RESULTS

ECC3473 is one of 21 strains isolated globally belonging to a novel Enterobacter species for which the name, Enterobacter adelaidei sp. nov. is proposed. The novel species was found to be resilient in its capacity to persist in contaminated water and adaptable in its ability to accumulate multiple transmissible AMR determinants.

CONCLUSION

E. adelaidei sp. nov. may become increasingly important to the dissemination of AMR.

Reduced bioavailability of Au and isotopically enriched 109Ag nanoparticles transformed through a pilot wastewater treatment plant in Hyalella azteca under environmentally relevant exposure scenarios

Wastewater Treatment Plants (WWTP) are a major repository and entrance path of nanoparticles (NP) in the environment and hence play a major role in the final NP fate and toxicity. Studies on silver nanoparticles (AgNP) transport via the WWTP system and uptake by aquatic organisms have so far been carried out using unrealistically high AgNP concentrations, unlikely to be encountered in the aquatic environment. The use of high AgNP concentrations is necessitated by both the low sensitivity of the detection methods used and the need to distinguish background Ag from spiked AgNP. In this study, isotopically enriched 109AgNP were synthesized to overcome these shortcomings and characterized by a broad range of methods including transmission electron microscopy, dynamic and electrophoretic light scattering. 109AgNP and gold NP (AuNP) were spiked to a pilot wastewater treatment plant fed with municipal wastewater for up to 21 days. AuNP were used as chemically less reactive tracer. The uptake of the pristine and transformed NP present in the effluent was assessed using the benthic amphipod Hyalella azteca in fresh- and brackish water exposures at environmentally relevant concentrations of 30 to 500 ng Au/L and 39 to 260 ng Ag/L. The unique isotopic signature of the 109AgNP allowed to detect the material at environmentally relevant concentrations in the presence of a much higher natural Ag background. The results show that the transformations reduce the NP uptake at environmentally relevant exposure concentrations. For 109Ag, lower accumulation factors (AF) were obtained after exposure to transformed NP (250-350) compared to the AF values obtained for pristine 109AgNP (750-840). The reduced AF values observed for H. azteca exposed to effluent from the AuNP-spiked WWTP indicate that biological transformation processes (e.g. eco-corona formation) seem to be involved in addition to chemical transformation.

Insight into the photodegradation of methylisothiazolinone and benzoisothiazolinone in aquatic environments

Methylisothiazolinone (MIT) and Benzisothiazolinone (BIT) are two widely used non-oxidizing biocides of isothiazolinones. Their production and usage volume have sharply increased since the pandemic of COVID-19, inevitably leading to more release into water environment. However, their photochemical behaviors in water environment are still unclear. Therefore, this study investigated photodegradation properties of MIT and BIT in natural water under simulated sunlight. The results demonstrated that direct photolysis was mainly responsible for their photodegradation which occurred through their excited singlet states rather than triplet states. The quantum yields of MIT and BIT photodegradation were 11 - 13.6 × 10-4 and 2.43 - 5.79 × 10-4, respectively. pH had almost no effect on the photodegradation of MIT, while the photodegradation of BIT was significantly promoted under alkaline condition due to abundance of BIT in its deprotonated form (BIT-N-). Cl-, NO3- and dissolved organic matter (DOM) in natural water inhibited the photodegradation of both MIT and BIT, with the light screening effect of DOM being the most significantly inhibitory factor. The addition of other isothiazolinones, which possibly coexisted with MIT and BIT in actual condition, slightly inhibited the photodegradation of MIT and BIT. The estimated half-life under natural sunlight at a 30°N latitude was estimated to be approximately 1.1 days. The photodegradation pathways of MIT and BIT are similar, primarily initiated from the ring-opening at the N-S bond, with Frontier electron densities (FED) calculations suggesting the likelihood of oxidation and ·OH addition reactions at the O, N, and S sites. While the photodegradation products exhibited significantly reduced acute toxicity compared to their parent compounds, they nonetheless posed substantial chronic toxicity. These insights are vital for assessing the ecological impacts of MIT and BIT in aquatic environments.

Occurrence and source identification of the disinfectant didecyldimethylammonium chloride in a Japanese watershed receiving effluent from swine farms

Didecyldimethylammonium chloride (DDAC), a toxic quaternary ammonium compound (QAC) linked to multidrug resistance, is used widely in households and hospitals and on swine farms to prevent disease transmission. However, little is known about its occurrence in watersheds receiving livestock wastewaters or manure. We monitored DDAC and tracers (veterinary and human drugs) once a season over a year at 14 sites in a Japanese watershed where swine outnumbered humans 1.2 to 1 and where both swine and human wastewaters were largely treated on site. DDAC concentrations in sewage-treatment-plant effluent (33-52 ng/L) were close to, whereas those in river waters (3.6-16,672 ng/L) far exceeded, those reported worldwide. DDAC mass flows at the catchment outlet (1692-3816 μg/s) were higher than those of any of the drugs. DDAC concentrations were significantly correlated with total concentrations of veterinary drugs (Spearman's correlation coefficient, 0.95, P < 0.01), indicating that the major pathway of DDAC entry to surface waters was via effluent discharge from swine farms. Comparison of observed and predicted mass flows implied that a substantial percentage of DDAC was washed from the barn floor into swine excrement. To our knowledge, this is the first study to demonstrate QAC hotspots attributable to animal husbandry.

Elucidating the photodegradation mechanism of octylisothiazolinone and dichlorooctylisothiazolinone in surface water: An in-depth comprehensive analysis

Octylisothiazolinone (OIT) and Dichlorooctylisothiazolinone (DCOIT), widely used antibacterial agents in coatings, have seen a sharp increase in use in response to the Coronavirus disease 2019 (Covid-19) pandemic, ultimately leading to their increase in the aquatic environment. However, their photodegradation process in surface water is still unclear. The purpose of this study is to investigate the photodegradation kinetics and mechanisms of OIT and DCOIT in natural water environments. Under simulated solar irradiation, they undergo direct photolysis in both natural freshwater and seawater mainly via their excited singlet states, while no self-sensitization photolysis was observed. The direct photolysis rate constants of OIT and DCOIT were 1.19 ± 0.07 and 0.57 ± 0.03 h-1, respectively. In addition, dissolved organic matter (DOM), NO3- and Cl- in natural waters did not contribute significantly to the photodegradation, and the light screening effect of DOM was identified as the main inhibiting factor. The photodegradation half-life of OIT was estimated to be 0.66 to 1.69 days, while the half-life of DCOIT was as high as 20.9 days during winter in surface water at 30°N latitude. Ring opening of the N-S bond and covalent bond breaking between CN are the main pathways for the photodegradation of OIT and DCOIT, which is verified by density-functional theory calculations. Ecological Structure Activity Relationships (ECOSAR) results indicate that OIT and DCOIT have "Very Toxic" biological toxicity, and the acute toxicity of their products is significantly reduced. It is noteworthy that the toxicity of the products of DCOIT is generally higher than that of OIT, and the chronic toxicity of most of the products is still above the "Toxic" level. Therefore, an in-depth understanding of the photodegradation mechanisms of OIT and DCOIT in aqueous environments is crucial for accurately assessing their ecological risks in natural water environments.

Evolution of microbial community and resistance genes in denitrification system under single and combined exposure to benzethonium chloride and methylparaben

Benzethonium chloride (BZC) and methylparaben (MeP) are commonly added into cosmetics as preservatives, which are frequently detected in wastewater treatment plants. Different response patterns of denitrification system were proposed under single and combined exposure to BZC and MeP (0, 0.5, 5 mg/L) by evaluating system performance, functional genes, extracellular polymeric substance (EPS), cytotoxicity, microbial community structure and resistance genes (RGs). The inhibition effect of BZC on denitrification system was stronger than MeP, and the co-exposure of BZC and MeP showed synergistic effect, enhancing the inhibition effect of BZC single exposure. BZC and/or MeP could promote the diffusion of RGs in sludge, including intracellular RGs (si-RGs) and extracellular RGs (se-RGs). Moreover, the single exposure of BZC and co-exposure of BZC and MeP increased the dissemination risks of RGs in water (w-RGs). IntI1 and tnpA-04, mobile genetic elements (MGEs), correlated positively with diverse RGs from different fractions. Notably, the spread of RGs through horizontal gene transfer mediated by MGEs and the flow of si-RGs into extracellular and water were observed in this study.

In Vitro Metabolism of Quaternary Ammonium Compounds and Confirmation in Human Urine by Liquid Chromatography Ion-Mobility High-Resolution Mass Spectrometry

Quaternary ammonium compounds (QACs) are high-production chemicals used as cleaning and disinfecting agents. Due to their ubiquitous presence in the environment and several toxic effects described, human exposure to these chemicals gained increasing attention in recent years. However, very limited data on the biotransformation of QACs is available, hampering exposure assessment. In this study, three QACs (dimethyl dodecyl ammonium, C10-DDAC; benzyldimethyl dodecylammonium, C12-BAC; cetyltrimethylammonium, C16-ATMAC) commonly detected in indoor microenvironments were incubated with human liver microsomes and cytosol (HLM/HLC) simulating Phase I and II metabolism. Thirty-one Phase I metabolites were annotated originating from 19 biotransformation reactions. Four metabolites of C10-DDAC were described for the first time. A detailed assessment of experimental fragmentation spectra allowed to characterize potential oxidation sites. For each annotated metabolite, drift-tube ion-mobility derived collision cross section (DTCCSN2) values were reported, serving as an additional identification parameter and allowing the characterization of changes in DTCCSN2 values following metabolism. Lastly, eight metabolites, including four metabolites of both C12-BAC and C10-DDAC, were confirmed in human urine samples showing high oxidation states through introduction of up to four oxygen atoms. This is the first report of higher oxidized C10-DDAC metabolites in human urine facilitating future biomonitoring studies on QACs.

Sewage sludge fertilization affects microbial community structure and its resistome in agricultural soils

Global sewage sludge production is rapidly increasing, and its safe disposal is becoming an increasingly serious issue. One of the main methods of municipal sewage sludge management is based on its agricultural use. The wastewater and sewage sludge contain numerous antibiotic resistance genes (ARGs), and its microbiome differs significantly from the soil microbial community. The aim of the study was to assess the changes occurring in the soil microbial community and resistome after the addition of sewage sludge from municipal wastewater treatment plant (WWTP) in central Poland, from which the sludge is used for fertilizing agricultural soils on a regular basis. This study used a high-throughput shotgun metagenomics approach to compare the microbial communities and ARGs present in two soils fertilized with sewage sludge. The two soils represented different land uses and different physicochemical and granulometric properties. Both soils were characterized by a similar taxonomic composition of the bacterial community, despite dissimilarities between soils properties. Five phyla predominated, viz. Planctomycetes, Actinobacteria, Proteobacteria, Chloroflexi and Firmicutes, and they were present in comparable proportions in both soils. Network analysis revealed that the application of sewage sludge resulted in substantial qualitative and quantitative changes in bacterial taxonomic profile, with most abundant phyla being considerably depleted and replaced by Proteobacteria and Spirochaetes. In addition, the ratio of oligotrophic to copiotrophic bacteria substantially decreased in both amended soils. Furthermore, fertilized soils demonstrated greater diversity and richness of ARGs compared to control soils. The increased abundance concerned mainly genes of resistance to antibiotics most commonly used in human and animal medicine. The level of heavy metals in sewage sludge was low and did not exceed the standards permitted in Poland for sludge used in agriculture, and their level in fertilized soils was still inconsiderable.

Exposure to zinc and dialkyldimethyl ammonium compound alters bacterial community structure and resistance gene levels in partial sulfur autotrophic denitrification coupled with the Anammox process

Dialkyldimethyl ammonium compound (DADMAC) is widely used in daily life as a typical disinfectant and often co-exists with the heavy metal zinc in sewage environments. This study investigated the effects of co-exposure to zinc (1 mg/L) and DADMAC (0.2-5 mg/L) on the performance, bacterial community, and resistance genes (RGs) in a partial sulfur autotrophic denitrification coupled with anaerobic ammonium oxidation (PSAD-Anammox) system in a sequencing batch moving bed biofilm reactor for 150 days. Co-exposure to zinc and low concentration (0.2 mg/L) DADMAC did not affect the nitrogen removal ability of the PASD-Anammox system, but increased the abundance and transmission risk of free RGs in water. Co-exposure to zinc and medium-to-high (2-5 mg/L) DADMAC led to fluctuations in and inhibition of nitrogen removal, which might be related to the enrichment of heterotrophic denitrifying bacteria dominated by Denitratisoma. Co-exposure to zinc and high concentration DADMAC (5 mg/L) stimulated the secretion of extracellular polymeric substances and increased the proliferation risk of intracellular RGs in sludge. This study provided insights into the application of PSAD-Anammox system and the ecological risks of wastewater containing zinc and DADMAC.

The influence of cationic antiseptics on the processes of light energy conversion in various photosynthetic pigment-protein complexes

The widespread use of disinfectants and antiseptics, and consequently their release into the environment, determines the relevance of studying their potential impact on the main producers of organic matter on the planet-photosynthetic organisms. The review examines the effects of some biguanides and quaternary ammonium compounds, octenidine, miramistin, chlorhexidine, and picloxidine, on the functioning of the photosynthetic apparatus of various organisms (Strakhovskaya et al. in Photosynth Res 147:197-209, 2021; Knox et al. in Photosynth Res 153:103, 2022; Paschenko et al. in Photosynth Res 155:93-105, 2023a, Photosynth Res 2023b). A common feature of these antiseptics is the combination of hydrophobic and hydrophilic regions in the molecules, the latter carrying a positive charge(s). The comparison of the results obtained with intact bacterial membrane vesicles (chromatophores) and purified pigment-protein complexes (photosystem II and I) of oxygenic organisms allows us to draw conclusions about the mechanisms of the cationic antiseptic action on the functional properties of the components of the photosynthetic apparatus.

Screening for frequently detected quaternary ammonium mixture systems in waters based on frequent itemset mining and prediction of their toxicity

Screening and prioritizing research on frequently detected mixture systems in the environment is of great significance, as conducting toxicity testing on all mixtures is impractical. Therefore, the frequent itemset mining (FIM) was introduced and applied in this paper to identify variables that commonly co-occur in a dataset. Based on the dataset of the quaternary ammonium compounds (QACs) in the water environment, the four frequent QAC mixture systems with detection rate ≥ 35 % were found, including [BDMM]+Cl--[BTMM]+Cl- (M1), [BDMM]+Cl--[BHMM]+Cl- (M2), [BTMM]+Cl- -[BHMM]+Cl- (M3), and [BDMM]+Cl--[BTMM]+Cl--[BHMM]+Cl- (M4). [BDMM]+Cl-, [BTMM]+Cl-, and [BHMM]+Cl- are benzyl dodecyl dimethyl ammonium chloride, benzyl tetradecyl dimethyl ammonium chloride, and benzyl hexadecyl dimethyl ammonium chloride, respectively. Then, the toxicity of the representative mixture rays and components for the four frequently detected mixture systems was tested using Vibrio qinghaiensis sp.-Q67 (Q67) as a luminescent indicator organism at 0.25 and 12 h. The toxicity of the mixtures was predicted using concentration addition (CA) and independent action (IA) models. It was shown that both the components and the representative mixture rays for the four frequently detected mixture systems exhibited obvious acute and chronic toxicity to Q67, and their median effective concentrations (EC50) were below 7 mg/L. Both CA and IA models predicted the toxicity of the four mixture systems well. However, the CA model had a better predictive ability for the toxicity of the M3 and M4 mixtures than IA at 12 h.

Impact of benzalkonium chloride on anaerobic granules and its long-term effects on reactor performance

This study assessed the inhibitory and performance-degrading effects induced by the cationic surfactant benzalkonium chloride (BAC) on anaerobic granules during the long-term operation of a laboratory-scale expanded granular sludge bed (EGSB) reactor. To address the critical scientific problem of how BAC affects the efficiency of EGSB reactors, this research uniquely evaluated the long-term stress response to BAC by systematically comparing continuous and discontinuous inhibitor exposure scenarios. The novel comparison demonstrated that inhibitor concentration is of minor relevance compared to the biomass-specific cumulative inhibitor load in the reactor. After exceeding a critical biomass-specific cumulative inhibitor load of 6.1-6.5 mg BAC/g VS, continuous and discontinuous exposure to BAC caused comparable significant deterioration in reactor performance, including accumulation of volatile fatty acids (VFA), decreased removal efficiency, reduced methane production, as well as the wash-out, flotation, and disintegration of anaerobic granules. BAC exposures had a more detrimental effect on methanogenesis than on acidogenesis. Moreover, long-term stress by BAC led to an inhibition of protein production, resulting in a decreased protein-to-polysaccharide ratio of extracellular polymeric substances (EPS) that promoted destabilizing effects on the granules. Finally, hydrogenotrophic methanogenesis was triggered. Reactor performance could not be restored due to the severe loss of granular sludge.

Assessing antibiotic residues in sediments from mangrove ecosystems: A review

Antibiotics' widespread and abusive use in aquaculture and livestock leads to extensive environmental dissemination and dispersion, consequently increasing antibiotic-resistant bacteria in marine ecosystems. Hence, there is an increased need for efficient methods for identifying and quantifying antibiotic residues in soils and sediments. From a review of the last 20 years, we propose and compare different chromatographic techniques for detecting and quantifying antibiotics in sediment samples from marine ecosystems, particularly in mangrove forest sediments. The methods typically include three stages: extraction of antibiotics from the solid matrix, cleaning, and concentration of samples before quantification. We address the leading causes of the occurrence of antibiotics in marine ecosystem sediments and analyze the most appropriate methods for each analytical stage. Ultimately, selecting a method for identifying antibiotic residues depends on multiple factors, ranging from the nature and physicochemical properties of the analytes to the availability of the necessary equipment and the available resources.

Analysis of chlorhexidine, antibiotics and bacterial community composition in water environments from Brazil, Cameroon and Madagascar during the COVID-19 pandemic

The widespread of chlorhexidine and antibiotics in the water bodies, which grew during the global COVID-19 pandemic, can increase the dispersion of antibiotic resistance. We assessed the occurrence of these pharmaceutical compounds as well as SARS-CoV-2 and analysed the bacterial community structure of hospital and urban wastewaters from Brazil, Cameroon, and Madagascar. Water and wastewater samples (n = 59) were collected between January-June 2022. Chlorhexidine, azithromycin, levofloxacin, ceftriaxone, gentamicin and meropenem were screened by Ultra-High-Performance Liquid Chromatography coupled with mass spectrometer. SARS-CoV-2 was detected based on the nucleocapsid gene (in Cameroon and Madagascar), and envelope and spike protein-encoding genes (in Brazil). The total community-DNA was extracted and used for bacterial community analysis based on the 16S rRNA gene. To unravel likely interaction between pharmaceutical compounds and/or SARS-CoV-2 with the water bacterial community, multivariate statistics were performed. Chlorhexidine was found in hospital wastewater effluent from Brazil with a maximum concentration value of 89.28 μg/L. Additionally, antibiotic residues such as azithromycin and levofloxacin were also present at concentrations between 0.32-7.37 μg/L and 0.11-118.91 μg/L, respectively. In Cameroon, azithromycin was the most found antibiotic present at concentrations from 1.14 to 1.21 μg/L. In Madagascar instead, ceftriaxone (0.68-11.53 μg/L) and levofloxacin (0.15-0.30 μg/L) were commonly found. The bacterial phyla statistically significant different (P < 0,05) among participating countries were Proteobacteria, Patescibacteria and Dependentiae which were mainly abundant in waters sampled in Africa and, other phyla such as Firmicutes, Campylobacterota and Fusobacteriota were more abundant in Brazil. The phylum Caldisericota was only found in raw hospital wastewater samples from Madagascar. The canonical correspondence analysis results suggest significant correlation of azithromycin, meropenem and levofloxacin with bacteria families such as Enterococcaceae, Flavobacteriaceae, Deinococcaceae, Thermacetogeniaceae and Desulfomonilaceae, Spirochaetaceae, Methanosaetaceae, Synergistaceae, respectively. Water samples were also positive for SARS-CoV-2 with the lowest number of hospitalized COVID-19 patients in Madagascar (n = 7) and Brazil (n = 30). Our work provides new data about the bacterial community profile and the presence of pharmaceutical compounds in the hospital effluents from Brazil, Cameroon, and Madagascar, whose limited information is available. These compounds can exacerbate the spreading of antibiotic resistance and therefore pose a risk to public health.

Current insights into the effects of cationic biocides exposure on Enterococcus spp

Cationic biocides (CBs), such as quaternary ammonium compounds and biguanides, are critical for controlling the spread of bacterial pathogens like Enterococcus spp., a leading cause of multidrug-resistant healthcare-associated infections. The widespread use of CBs in recent decades has prompted concerns about the potential emergence of Enterococcus spp. populations exhibiting resistance to both biocides and antibiotics. Such concerns arise from their frequent exposure to subinhibitory concentrations of CBs in clinical, food chain and diverse environmental settings. This comprehensive narrative review aimed to explore the complexity of the Enterococcus' response to CBs and of their possible evolution toward resistance. To that end, CBs' activity against diverse Enterococcus spp. collections, the prevalence and roles of genes associated with decreased susceptibility to CBs, and the potential for co- and cross-resistance between CBs and antibiotics are reviewed. Significant methodological and knowledge gaps are identified, highlighting areas that future studies should address to enhance our comprehension of the impact of exposure to CBs on Enterococcus spp. populations' epidemiology. This knowledge is essential for developing effective One Health strategies that ensure the continued efficacy of these critical agents in safeguarding Public Health.

Quantitative Non-targeted Screening to Profile Micropollutants in Sewage Sludge Used for Agricultural Field Amendments

A considerable number of micropollutants from human activities enter the wastewater network for removal. However, at the wastewater treatment plant (WWTP), some proportion of these compounds is retained in the sewage sludge (biosolids), and due to its high content of nutrients, sludge is widely applied as an agricultural fertilizer and becomes a means for the micropollutants to be introduced to the environment. Accordingly, a holistic semiquantitative nontarget screening was performed on sewage sludges from five different WWTPs using nanoflow liquid chromatography coupled to high-resolution Orbitrap mass spectrometry. Sixty-one inorganic elements were measured using inductively coupled plasma mass spectrometry. Across all sludges, the nontarget analysis workflow annotated >21,000 features with chemical structures, and after strict prioritization and filtering, 120 organic micropollutants with diverse chemical structures and applications such as pharmaceuticals, pesticides, flame retardants, and industrial and natural compounds were identified. None of the tested sludges were free from organic micropollutants. Pharmaceuticals contributed the largest share followed by pesticides and natural products. The predicted concentration of identified contaminants ranged between 0.2 and 10,881 ng/g dry matter. Through quantitative nontarget analysis, this study comprehensively demonstrated the occurrence of cocktails of micropollutants in sewage sludges.

Quantification of quaternary ammonium compounds by liquid chromatography-mass spectrometry: Minimizing losses from the field to the laboratory

Quaternary Ammonium Compounds (QACs) are widely used in household, medical and industrial settings. As a consequence, they are ubiquitously found in the environment. Although significant efforts have been put into the development of sensitive and reproducible analytical methods, much less effort has been dedicated to the monitoring of QACs upon sample storage and sample preparation. Here we studied the effect of storage, concentration, and extraction procedures on the concentrations of QACs in samples. Thirteen QACs selected amongst benzalkonium compounds (BACs), dialkyldimethylammonium compounds (DADMACs) and alkyltrimethylammonium compounds (ATMACs) were quantified in aqueous and solid samples using LC-MS/MS. Most QACs adsorbed on container walls could be recovered using a short washing step with MeOH containing 2 % v/v formic acid. Concentrations of QACs from aqueous solutions using solid phase extraction (SPE) with Strata-X cartridges and elution with acidified MeOH utilized to wash the emptied containers gave highly satisfactory recoveries (101-111 %). Good recoveries (89-116 %) were also obtained when extracting a spiked organic-rich synthetic soil using accelerated solvent extraction (ASE) with acidified MeOH at low solid/solvent ratio (0.4 g/20 mL). Applying the recommended methodologies to real samples collected from a Canadian wastewater treatment plant (WWTP) gave QAC concentrations in the ranges of 0.01-30 µg/L, < 1.2 µg/L, and 0.05-27 mg/kg for the influent, effluent and biosolids samples, respectively.

Occurrence and distribution of antibiotics and antibiotic resistance genes from the land to ocean in Daliao River-Liaodong Bay, China

In this study, the pollution status of antibiotics and ARGs in sediments from the land-sea intersection of Liaodong Bay was analyzed. The results showed that the level of antibiotic pollution ranged from ND to 433.27 ng/kg, with quinolones and tetracycline as the dominant antibiotics. The relative abundance of ARGs ranged from 3.62 × 10-3 to 1.32 × 10-1 copies/16SrRNA copies, with aminoglycoside and MLSB resistance genes being dominant. Regarding spatial distribution, the land and estuary areas showed higher antibiotic pollution levels than the offshore areas. Similarly, the land and estuary areas exhibited higher antibiotic diversity than the offshore areas. The ARGs were widely distributed on land, and their abundance gradually decreased to the downstream estuary area. Land and coastal areas exhibited higher ARG diversity than estuary areas. Analysis of environmental factors revealed a significant correlation between ARGs and non-corresponding antibiotics, and some ARGs were affected by heavy metals Cu and Pb.

Towards sorptive eradication of pharmaceutical micro-pollutant ciprofloxacin from aquatic environment: A comprehensive review

Antibiotics are widely prioritized pharmaceuticals frequently adopted in medication for addressing numerous ailments of humans and animals. However, the non-judicious disposal of ciprofloxacin (CIP) with concentration levels exceeding threshold limit in an aqueous environment has been the matter of growing concern nowadays. CIP is found in various waterways with appreciable mobility due to its limited decay in solidified form. Hence, the effective eradication strategy of this non-steroidal anti-inflammatory antibiotic from aqueous media is pivotal for preventing the users and the biosphere from their hazardous impacts. Reportedly several customary techniques like reverse osmosis, precipitation, cross-filtration, nano-filtration, ion exchange, microbial remediation, and adsorption have been employed to eliminate CIP from water. Out of them, adsorption is ascertained to be a potential method because of lesser preliminary investment costs, ease of operation, greater efficiency, less energy usage, reduced chemical and biological slurry production, and ready availability of precursor materials. Towards remediation of ciprofloxacin-laden water, plenty of researchers have used different adsorbents. However, the present-day challenge is opting the promising sorbent and its application towards industrial scale-up which is vital to get reviewed. In this article, adsorbents of diverse origins are reviewed in terms of their performances in CIP removal. The review stresses the impact of various factors on sorptive assimilation of CIP, adsorption kinetics, isotherms, mechanism of ionic interaction, contrivances for CIP detection, cost estimation and reusability assessments of adsorbents also that may endorse the next-generation investigators to decide the efficacious, environmental appealing and cost-competitive adsorbents for effective riddance of CIP from wastewater.

A perspective of spatial variability and ecological risks of antibiotics in the agricultural-pastoral ecotone soils in eastern Inner Mongolia

Antibiotics have garnered growing attention as pharmaceuticals ubiquitously present in human society. Within the soil environment, antibiotics exhibit a propensity for high environmental persistence, thereby posing a potential threat to the ecosystem. However, research on antibiotics in agricultural-pastoral ecotone soils is scarce. This study investigates the occurrence, distribution and risk of 11 common antibiotics in agricultural soils of the agro-pastoral transition zone in Horqin Left Middle Banner, eastern Inner Mongolia. The total concentration varies from not detectable to 609.62 μg/kg. Tetracyclines are the dominant antibiotic, with a higher detection frequency than Macrolides and Sulfonamides. The detection rates of the three types of antibiotics differ significantly. The study also finds that soil properties (organic matter content, pH, bulk density, clay, cation exchange capacity have no significant correlation with antibiotics in soil. Moreover, spatial regression analysis reveals that population density is the primary factor influencing the spatial distribution of antibiotics in soil. Ecological risk assessment shows that clarithromycin and erythromycin are the two most harmful factors in the ecological risk of agricultural soil.

Antifungal drugs in the aquatic environment: A review on sources, occurrence, toxicity, health effects, removal strategies and future challenges

Fungal infections pose a significant global health burden, resulting in millions of severe cases and deaths annually. The escalating demand for effective antifungal treatments has led to a rise in the wholesale distribution of antifungal drugs, which consequently has led to their release into the environment, posing a threat to ecosystems and human health. This article aims to provide a comprehensive review of the presence and distribution of antifungal drugs in the environment, evaluate their potential ecological and health risks, and assess current methods for their removal. Reviewed studies from 2010 to 2023 period have revealed the widespread occurrence of 19 various antifungals in natural waters and other matrices at alarmingly high concentrations. Due to the inefficiency of conventional water treatment in removing these compounds, advanced oxidation processes, membrane filtration, and adsorption techniques have been developed as promising decontamination methods.In conclusion, this review emphasizes the urgent need for a comprehensive understanding of the presence, fate, and removal of antifungal drugs in the environment. By addressing the current knowledge gaps and exploring future prospects, this study contributes to the development of strategies for mitigating the environmental impact of antifungal drugs and protecting ecosystems and human health.

Benzethonium chloride affects short chain fatty acids produced from anaerobic fermentation of waste activated sludge: Performance, biodegradation and mechanisms

Benzethonium chloride (BZC) is viewed as a promising disinfectant and widely applied in daily life. While studies related to its effect on waste activated sludge (WAS) anaerobic fermentation (AF) were seldom mentioned before. To understand how BZC affects AF of WAS, production of short chain fatty acids (SCFAs), characteristics of WAS as well as microbial community were evaluated during AF. Results manifested a dose-specific relationship of dosages between BZC and SCFAs and the optimum yield arrived at 2441.01 mg COD/L with the addition of 0.030 g/g TSS BZC. Spectral results and protein secondary structure variation indicated that BZC denatured proteins in the solid phase into smaller proteins or amino acids with unstable structures. It was also found that BZC could stimulate the extracellular polymeric substances secretion and reduce the surface tension of WAS, leading to the enhancement of solubilization. Beside, BZC promoted the hydrolysis stage (increased by 7.09 % to 0.030 g/g TSS BZC), but inhibited acetogenesis and methanogenesis stages (decreased by 6.85 % and 14.75 % to 0.030 g/g TSS BZC). The microbial community was also regulated by BZC to facilitate the enrichment of hydrolytic and acidizing microorganisms (i.e. Firmicutes). All these variations caused by BZC were conducive to the accumulation of SCFAs. The findings contributed to investigating the effect of BZC on AF of WAS and provided a new idea for the future study of AF mechanism.

Promising bioprocesses for the efficient removal of antibiotics and antibiotic-resistance genes from urban and hospital wastewaters: Potentialities of aerobic granular systems

The use, overuse, and improper use of antibiotics have resulted in higher levels of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs), which have profoundly disturbed the equilibrium of the environment. Furthermore, once antibiotic agents are excreted in urine and feces, these substances often can reach wastewater treatment plants (WWTPs), in which improper treatments have been highlighted as the main reason for stronger dissemination of antibiotics, ARB, and ARGs to the receiving bodies. Hence, achieving better antibiotic removal capacities in WWTPs is proposed as an adequate approach to limit the spread of antibiotics, ARB, and ARGs into the environment. In this review, we highlight hospital wastewater (WW) as a critical hotspot for the dissemination of antibiotic resistance due to its high level of antibiotics and pathogens. Hence, monitoring the composition and structure of the bacterial communities related to hospital WW is a key factor in controlling the spread of ARGs. In addition, we discuss the advantages and drawbacks of the current biological WW treatments regarding the antibiotic-resistance phenomenon. Widely used conventional activated sludge technology has proved to be ineffective in mitigating the dissemination of ARB and ARGs to the environment. However, aerobic granular sludge (AGS) technology is a promising technology-with broad adaptability and excellent performance-that could successfully reduce antibiotics, ARB, and ARGs in the generated effluents. We also outline the main operational parameters involved in mitigating antibiotics, ARB, and ARGs in WWTPs. In this regard, WW operation under long hydraulic and solid retention times allows better removal of antibiotics, ARB, and ARGs independently of the WW technology employed. Finally, we address the current knowledge of the adsorption and degradation of antibiotics and their importance in removing ARB and ARGs. Notably, AGS can enhance the removal of antibiotics, ARB, and ARGs due to the complex microbial metabolism within the granular biomass.

Quaternary Ammonium Compounds (QACs) in Wastewater Influent and Effluent Throughout the COVID-19 Pandemic

Quaternary ammonium compounds (QACs) are used in consumer and industrial products, including disinfectants. Due to the COVID-19 pandemic, disinfectant use has increased, purportedly increasing loads to wastewater treatment plants and the environment. To understand how the increased usage has affected QAC loadings to treatment plants and to determine how effectively plants remove QACs from liquid effluent that is discharged to surface and groundwaters, influent and effluent wastewater samples were collected from four treatment plants (treatment capacities < 5 MGD to > 100 MGD) for 21 months beginning in May 2020. Influent QAC concentrations were hundreds of μg/L and effluent QAC concentrations were < 1 μg/L, corresponding to an average removal of 98% from all four plants. The most prevalent QACs in influent were those used most commonly in disinfectants, specifically benzylalkyldimethylammonium compounds (BACs) and short-chain dialkyldimethylammonium compounds (DADMACs), and influent levels of these compounds were correlated with QAC sales. Prior to this study, ethylbenzylalkyldimethylammonium compounds (EtBACs) had not been studied, and they comprised 13 ± 6% of QACs in influent. While removal was high at all plants, low μg/L concentrations were still continuously discharged into the environment. For QACs with equivalent alkyl chain lengths, those with aromatic substituents (BACs and EtBACs) appear to be removed more effectively than those with only alkyl chains (DADMACs).

Risks of benzalkonium chlorides as emerging contaminants in the environment and possible control strategies from the perspective of ecopharmacovigilance

An unprecedented increase in the use of disinfection products triggered by the coronavirus disease 2019 (COVID-19) pandemic is resulting in aggravating environmental loads of disinfectants as emerging contaminants, which has been considered a cause for worldwide secondary disasters. This review analyzed the literature published in the last decade about occurrence, bioaccumulation, and possible environmental risks of benzalkonium chlorides (BKCs) as emerging contaminants. Results indicated that BKCs globally occurred in municipal wastewater, surface water, groundwater, reclaimed water, sludge, sediment, soil, roof runoff, and residential dust samples across 13 countries. The maximum residual levels of 30 mg/L and 421 μg/g were reported in water and solid environmental samples, respectively. Emerging evidences suggested possible bioaccumulation of BKCs in plants, even perhaps humans. Environmentally relevant concentrations of BKCs exert potential adverse impacts on aquatic and terrestrial species, including genotoxicity, respiratory toxicity, behavioural effects and neurotoxicity, endocrine disruption and reproductive impairment, phytotoxicity, etc. Given the intrinsic biocidal and preservative properties of disinfectants, the inductive effects of residual BKCs in environment in terms of resistance and imbalance of microorganisms have been paid special attention. Considering the similarities of disinfectants to pharmaceuticals, from the perspective of ecopharmacovigilance (EPV), a well-established strategy for pharmaceutical emerging contaminants, we use the control of BKC pollution as a case, and provide some recommendations for employing the EPV measures to manage environmental risks posed by disinfectant emerging contaminants.

In vitro evaluation for estrogenic mechanisms of the disinfectant benzalkonium chloride as an emerging contaminant

This study aimed to evaluate in vitro the possible mechanisms underlying the estrogenic potential of benzalkonium chloride (BAC) as a disinfectant emerging contaminant. Effects of BAC at the environmentally-relevant concentrations on estrogen synthesis and estrogen receptor (ER) signaling were assessed using the H295R steroidogenesis assay and the MCF-7 proliferation assay, respectively. Results showed that exposure to BAC at concentrations of 1.0-1.5 mg/L for 48 h significantly increased estradiol production of H295R cells in a concentration-dependent manner. Transcription of steroidogenic genes 3β-HSD2, 17β-HSD1, 17β-HSD4, and CYP19A were significantly enhanced by BAC. In ER-positive MCF-7 cells, exposure to 0.5-1.5 mg/L BAC for 48 h significantly promoted cell proliferation and increased the expressions of ERα and G-protein coupled estrogen receptor 1. Flow cytometry analysis showed that 0.5-1.5 mg/L BAC significantly decreased the percentage of cells in G0/G1 phase, increased the percentage in S phase, and BAC at concentrations of 1.0 and 1.5 mg/L increased the G2/M phase cells. Findings of the study suggested that BAC at environmentally-relevant concentrations might act as a xenoestrogen through its inhibitory effect on steroidogenesis and ER-mediated mechanism.

Detection of SARS-CoV-2 RNA in wastewater from an enclosed college campus serves as an early warning surveillance system

SARS-CoV-2, the causative agent of Covid-19, is shed from infected persons in respiratory droplets, feces, and urine. Using quantitative PCR (qPCR), our group hypothesized that we could detect SARS-CoV-2 in wastewater samples collected on a university campus prior to the detection of the virus in individuals on campus. Wastewater samples were collected 3 times a week from 5 locations on the main campus of the University of North Carolina Wilmington (UNCW) from July 24, 2020 to December 21, 2020. Post-collection, total RNA was extracted and SARS-CoV-2 RNA in the samples was detected by qPCR. SARS-CoV-2 signal was detected on campus beginning on August 19 as classes began and the signal increased in both intensity and breadth as the Fall semester progressed. A comparison of two RNA extraction methods from wastewater showed that SARS-CoV-2 was detected more frequently on filter samples versus the direct extracts. Aligning our wastewater data with the reported SARS-CoV-2 cases on the campus Covid-19 dashboard showed the virus signal was routinely detected in the wastewater prior to clusters of individual cases being reported. These data support the testing of wastewater for the presence of SARS-CoV-2 and may be used as part of a surveillance program for detecting the virus in a community prior to an outbreak occurring and could ultimately be incorporated with other SARS-CoV-2 metrics to better inform public health enabling a quick response to contain or mitigating spread of the virus.

Deciphering the interaction impacts between antiseptic benzethonium chloride and biofilm nitrification system: Performance, resistance mechanisms and biodegradation

Benzethonium chloride (BEC) is one of emerging bacteriostatic agents. BEC-bearing wastewater generated during sanitary applications in food and medication is easily combined with other wastewater streams to flow into wastewater treatment plants. This study focused on the long-term (231 days) impacts of BEC on the sequencing moving bed biofilm nitrification system. Nitrification performance was tolerant to low concentration of BEC (≤ 0.2 mg/L), but the nitrite oxidation was severely inhibited when the concentration of BEC was 1.0-2.0 mg/L. Partial nitrification maintained about 140 days with nitrite accumulation ratio over 80%, mainly caused by the inhibition of Nitrospira, Nitrotoga and Comammox. Notably, BEC exposure in the system might cause the co-selection of antibiotic resistance genes (ARGs) and disinfectant resistance genes (DRGs), and the resistance of biofilm system to BEC was strengthened by efflux pumps mechanism (qacEdelta1 and qacH) and antibiotic deactivation mechanism (aadA, aac(6')-Ib and blaTEM). Extracellular polymeric substances secretion and BEC biodegradation were also contributed to the system microorganisms resisting BEC exposure. In addition, Klebsiella, Enterobacter, Citrobacter and Pseudomonas were isolated and identified as BEC degrading bacteria. The metabolites of N,N-dimethylbenzylamine, N-benzylmethylamine and benzoic acid were identified, and the biodegradation pathway of BEC was proposed. This study brought new knowledge about the fate of BEC in biological treatment units and laid a foundation for its elimination from wastewater.

Identification and characterization of quaternary ammonium compounds in Flemish indoor dust by ion-mobility high-resolution mass spectrometry

Quaternary ammonium compounds (QACs) are a class of surfactants commonly used in disinfecting and cleaning products. Their use has substantially increased during the COVID-19 pandemic leading to increasing human exposure. QACs have been associated with hypersensitivity reactions and an increased risk of asthma. This study introduces the first identification, characterization and semi-quantification of QACs in European indoor dust using ion-mobility high-resolution mass spectrometry (IM-HRMS), including the acquisition of collision cross section values (^DTCCS_N2) for targeted and suspect QACs. A total of 46 indoor dust samples collected in Belgium were analyzed using target and suspect screening. Targeted QACs (n = 21) were detected with detection frequencies ranging between 4.2 and 100 %, while 15 QACs showed detection frequencies > 90 %. Semi-quantified concentrations of individual QACs showed a maximum of 32.23 µg/g with a median ∑QAC concentration of 13.05 µg/g and allowed the calculation of Estimated Daily Intakes for adults and toddlers. Most abundant QACs matched the patterns reported in indoor dust collected in the United States. Suspect screening allowed the identification of 17 additional QACs. A dialkyl dimethyl ammonium compound with mixed chain lengths (C16:C18) was characterized as a major QAC homologue with a maximum semi-quantified concentration of 24.90 µg/g. The high detection frequencies and structural variabilities observed call for more European studies on potential human exposure to these compounds. For all targeted QACs, drift tube IM-HRMS derived collision cross section values (^DTCCS_N2) are reported. Reference ^DTCCS_N2 values allowed the characterization of CCS-m/z trendlines for each of the targeted QAC classes. Experimental CCS-m/z ratios of suspect QACs were compared with the CCS-m/z trendlines. The alignment between the two datasets served as an additional confirmation of the assigned suspect QACs. The use of the 4bit multiplexing acquisition mode with consecutive high-resolution demultiplexing confirmed the presence of isomers for two of the suspect QACs.

Antifungal medicines in the terrestrial environment: Levels in biosolids from England and Wales

Antifungals are used widely in clinical and agricultural practice to control fungal growth, either treating or preventing infection. There are reports of increasing prevalence of resistance to antifungals in human pathogens and concern that their use in agriculture is driving clinical resistance in patients. While crop protection products are the most obvious source in agriculture, a further source may be biosolids from wastewater treatment. In the UK, these are applied to land to provide nutrients and improve soil structure for crops. In this study, biosolids from ten sites in England and one in Wales were analysed for clinical antifungals. Ketoconazole and miconazole were detected in all samples with a median concentration of 0.87 and 0.54 mg kg^-1 dry weight (DW), respectively. Clotrimazole was detected at seven of eleven sites at a median level of 1.32 mg kg^-1 DW and its absence at four others was considered treatment related. Two prescription-only and systemic medications, itraconazole and posaconazole, were frequently detected with median concentrations of 0.14 mg kg^-1 DW and 0.09 mg kg^-1 DW, respectively. The biosolid levels of itraconazole found in this study were two orders of magnitude higher than an indicative Predicted No Effect Concentration for resistance selection (PNEC-R) in soil. Neither fluconazole, griseofulvin, and voriconazole nor flucytosine and nystatin were found above the limit of detection of 0.01 or 0.1 mg kg^-1 as received, respectively. The findings show that biosolids represent a viable pathway for antifungal agents to reach soil.

Evidence for wastewaters as environments where mobile antibiotic resistance genes emerge

The emergence and spread of mobile antibiotic resistance genes (ARGs) in pathogens have become a serious threat to global health. Still little is known about where ARGs gain mobility in the first place. Here, we aimed to collect evidence indicating where such initial mobilization events of clinically relevant ARGs may have occurred. We found that the majority of previously identified origin species did not carry the mobilizing elements that likely enabled intracellular mobility of the ARGs, suggesting a necessary interplay between different bacteria. Analyses of a broad range of metagenomes revealed that wastewaters and wastewater-impacted environments had by far the highest abundance of both origin species and corresponding mobilizing elements. Most origin species were only occasionally detected in other environments. Co-occurrence of origin species and corresponding mobilizing elements were rare in human microbiota. Our results identify wastewaters and wastewater-impacted environments as plausible arenas for the initial mobilization of resistance genes.

Effects of co-selection of antibiotic-resistance and metal-resistance genes on antibiotic-resistance potency of environmental bacteria and related ecological risk factors

The inadequate elimination of micropollutants in wastewater treatment plants (WWTP), cause to increase in the incidence of antibiotic resistant bacterial strains. Growth of microbial pathogens in WWTP is one of the serious public health problems. The widespread and simultaneous emergence of antibiotic resistance genes (ARGs) and heavy metal resistance genes (HMRGs) in the environment with heavy metals create persistent and selective pressure for co-selection of both genes on environmental microorganisms. Co-localization of ARGs and HMRGs on the same horizontal mobile genetic elements (MGEs) allows the spreading of numerous antibiotic-resistant strains of bacteria in aquatic and terrestrial environment. The biofilm formation and colonization potential of environmental bacteria leads to the co-selection of multi-antibiotic resistance and multi-metal tolerance. Horizontal gene transfer (HGT), co-localization of both ARGs and HMRGs on the same MGEs, and the shared resistomes are important bacteria-associated ecological risks factors, which reduce the effectiveness of antibiotics against bacterial infections.

Sewage-based surveillance shows presence of Klebsiella pneumoniae resistant against last resort antibiotics in the population in Bergen, Norway

The aim of this study was to understand the prevalence of antibiotic resistance in Klebsiella pneumoniae present in the population in Bergen city, Norway using city-scale sewage-based surveillance, as well as the potential spread of K. pneumoniae into the marine environment through treated sewage. From a total of 30 sewage samples collected from five different sewage treatment plants (STPs), 563 presumptive K. pneumoniae isolates were obtained on Simmons Citrate Agar with myo-Inositol (SCAI) plates, and 44 presumptive K. pneumoniae isolates on SCAI plates with cefotaxime. Colistin resistance was observed in 35 isolates, while cefotaxime resistance and tigecycline resistance was observed in only five isolates each, out of 563 presumptive K. pneumoniae isolates. All 44 isolates obtained on cefotaxime-containing plates were multidrug-resistant, with 25% (n = 11) showing resistance against tigecycline. Clinically important acquired antibiotic resistance genes (ARGs), like bla_CTX-M-14, bla_CTX-M-15, qnrS1, aac(3)-IIe, tet(A), and sul1, were detected in several sequenced Klebsiella spp. isolates (n = 53). All sequenced colistin-resistant isolates (n = 13) had a mutation in the mgrB gene with nucleotide substitution at position C88T creating a premature stop codon. All sequenced tigecycline-resistant isolates (n = 4) harbored a Tet(A) variant with 22 amino acid (aa) substitutions compared to the reference protein. The sequenced K. pneumoniae isolates (n = 44) belonged to 22 different sequence types (STs) with ST730 (29.5%) as most prevalent, followed by pathogenic ST307 (11.4%). Virulence factors, including aerobactin (iutA), enterobactin (entABCDEFS and fepABCDG), salmochelin (iro), and yersiniabactin (ybt) were detected in several sequenced K. pneumoniae isolates, suggesting pathogenicity potential. Heavy metal resistance genes were common in sequenced K. pneumoniae isolates (n = 44) with silver (silABCEFPRS) and copper (pcoABDRS) resistance genes present in 79.5% of the isolates. Sewage-based surveillance can be a useful tool for understanding antibiotic resistance in pathogens present within a population and to provide up-to date information on the current resistance situation. Our study presents a framework for population-based surveillance of resistance in K. pneumoniae.

Assessing the Potential Ecotoxicological Risk of Different Organic Amendments Used in Agriculture: Approach Using Acute Toxicity Tests on Plants and Earthworms

In Europe, spreading organic wastes to fertilize soils is an alternative commonly used instead of chemical fertilizers. Through their contributions of nutrients and organic matter, these wastes promote plant growth and thus agricultural production. However, these organic amendments can also contain mineral and organic pollutants requiring chemical and ecotoxicological analyses to guarantee their harmlessness on soil and its organisms during spreading. The purpose of this study was to assess the potential toxicity of three organic amendments from different sources (sewage sludge, dairy cow manure, dairy cow slurry) by performing chemical analyses and acute toxicity tests on three types of organism: earthworms, plants, soil microbial communities. Chemical analysis revealed a higher content of certain pharmaceuticals, polycyclic aromatic hydrocarbons and metals in sewage sludge in comparison with the two other types of organic wastes. The ecotoxicological assessment showed a dose-dependent effect on soil organisms for the three organic amendments with higher toxic effects during the exposure tests with a soil amended with dairy cow slurry. However, at realistic spreading doses (10 and 20 g kg^-1 dry weight of organic amendments) on a representative exposed soil, organic amendment did not show any toxicity in the three organisms studied and had positive effects such as increased earthworm biomass, increased plant root growth and earthworm behavior showing attraction for organic amendment. On the contrary, exposure assays carried out on a limited substrate like sandy soil showed increased toxicity of organic amendments on plant germination and root growth. Overall, the ecotoxicological analysis revealed greater toxicity for soil organisms during the amendment of cow slurry, contrary to the chemical analysis which showed the potential high risk of spreading sewage sludge due to the presence of a higher quantity of pollutants. The analysis of the chemical composition and use of acute toxicity tests is the first essential step for assessing the ecotoxicological risk of spreading organic amendments on soil organisms. In addition to standard tests, the study suggests using a representative soil in acute toxicity tests to avoid overestimating the toxic effects of these organic amendments.

Data-driven discoveries on widespread contamination of freshwater reservoirs by dominant antibiotic resistance genes

The propagation of antibiotic resistance genes (ARGs) in freshwater reservoirs threatens ecosystem security and human health, and has attracted increasing attention. A series of recent research articles on ARGs provides a unique opportunity for data-driven discoveries in this emerging field. Here, we mined data from a total of 290 samples from 60 reservoirs worldwide with a data-driven framework (DD) developed to discover geographical distribution, influencing factors and pollution hotspots of ARGs in freshwater reservoirs. Most data came from Asia and Europe where nine classes of ARGs were most frequently detected in reservoirs with multi-drug resistance and sulfonamide resistance genes prevailing. Factors driving distribution of reservoir ARGs differed between reservoir waters and sediments, and interactions among these factors had linear or nonlinear enhancement effects on the explanatory power of ARG distribution. During the cold season, small-sized reservoir waters rich in organic carbon, mobile genetic elements (MGEs) and antibiotics had a higher pollution potential of ARGs; during the spring drought, sediments in large reservoirs located in densely populated areas were more conducive to dissemination of ARGs due to their richness in antibiotics and MGEs. Thus, distribution pattern of ARG pollution hotspots in reservoir waters and sediments varies greatly depending on the differences of internal and external factors. From the "One Health" perspective, this widespread contamination of freshwater reservoirs by ARGs we discovered through the DD framework should be a push to promote integrated research across regions and disciplines. Especially the human - food-chain - ecosystem interface needs an improved understanding of ARG contamination mechanisms and targeted monitoring and evaluation systems should be developed to maintain all ecosystem services in freshwater reservoirs as well as to safeguard human health.

Widespread occurrence of quaternary alkylammonium disinfectants in soils of Hesse, Germany

Quaternary alkylammonium compounds (QAACs) are cationic organic compounds with amphiphilic properties that are widely used as surfactants and disinfectants in industry, households and agriculture. Several studies suggest that QAACs co-select for antibiotic resistant microorganisms and thus may contribute to the spread of antibiotic resistance in the environment. Data on QAAC occurrence in soil are scarce and limited to soils that are prone to direct exposure to QAACs. Therefore, we conducted a comprehensive study on the occurrence of QAACs in soils of Hesse, a federal state in Germany, covering an area of 21,115 km². Sixty-five soil samples that comprised different land uses (arable, grassland, forest, vineyard) and area types (rural, agglomeration) were analysed for concentrations of alkyltrimethylammonium (ATMACs, with alkyl chain lengths C8-C16), benzylalkyldimethylammonium (BACs, C8-C18) and dialkyldimethylammonium compounds (DADMACs, C8-C18) via HPLC-MS/MS after ultrasonic-assisted extraction with acidified acetonitrile. QAACs were detected in 97 % of the soil samples irrespective of land use and area type. The most abundant QAAC homologues were DADMACs > BACs > ATMACs. The highest total QAAC concentrations were detected in alluvial soils influenced by the deposition of suspended particles during flood events, with DADMAC-C16 and -C18 as the dominant homologues. The high abundance of long-chain DADMACs suggests that legacy pollution and accumulation govern QAAC concentrations in soils. The presence of QAACs in forest soils points to a potential input via atmospheric deposition. Our work highlights the widespread occurrence of QAACs in soils of Hesse and the need for more research on their entry paths and fate in the soil ecosystem.

Occurrence, effects, and ecological risks of chemicals in sanitizers and disinfectants: A review

In response to the novel coronavirus referred to as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) – a virus that causes COVID-19 disease has led to wide use of sanitizers and disinfectants. This, in turn, triggered concerns on their potential deleterious effects to human health and the environment due to numerous chemicals incorporated in both product categories. Here, the current state of science regarding the occurrence and ecological effects of different classes of chemicals in these products (e.g., ultraviolent filters, fragrances, etc.) are summarized in different natural (e.g., rivers) and engineered (e.g., wastewater treatment plants) systems. Data collected in the literature suggests chemicals incorporated in sanitizers and disinfectants are present in the environment, and a large portion are toxic to fish, algae, and daphnia. Using the risk quotient approach based on occurrence data, we found eight chemicals that posed the highest risk to aquatic organisms in freshwater systems were benzalkonium chloride, 4-chloro-m-cresol, sodium ortho phenyl phenate, hydrogen peroxide, 1, 2-propanediol, 4-Methyl-benzilidine-camphor, ethylhexyl methoxy cinnamate, and octocrylene. Considering limited occurrence and effects information for most chemicals, further studies on environmental monitoring and potential consequences of long-term exposure in aquatic ecosystems are recommended.

The effect of disinfectants and antiseptics on co- and cross-selection of resistance to antibiotics in aquatic environments and wastewater treatment plants

The outbreak of the SARS-CoV-2 pandemic led to increased use of disinfectants and antiseptics (DAs), resulting in higher concentrations of these compounds in wastewaters, wastewater treatment plant (WWTP) effluents and receiving water bodies. Their constant presence in water bodies may lead to development and acquisition of resistance against the DAs. In addition, they may also promote antibiotic resistance (AR) due to cross- and co-selection of AR among bacteria that are exposed to the DAs, which is a highly important issue with regards to human and environmental health. This review addresses this issue and provides an overview of DAs structure together with their modes of action against microorganisms. Relevant examples of the most effective treatment techniques to increase the DAs removal efficiency from wastewater are discussed. Moreover, insight on the resistance mechanisms to DAs and the mechanism of DAs enhancement of cross- and co-selection of ARs are presented. Furthermore, this review discusses the impact of DAs on resistance against antibiotics, the occurrence of DAs in aquatic systems, and DA removal mechanisms in WWTPs, which in principle serve as the final barrier before releasing these compounds into the receiving environment. By recognition of important research gaps, research needs to determine the impact of the majority of DAs in WWTPs and the consequences of their presence and spread of antibiotic resistance were identified.

Antibiotics and antimycotics in waste water treatment plants: Concentrations, removal efficiency, spatial and temporal variations, prediction, and ecological risk assessment

For investigating the spatial, temporal variations and assessing ecological risk of 10 antibiotics and 6 antimycotics, influent sewage water and treated effluent were collected during three different seasons in 19 waste water treatment plants of Tianjin. High performance liquid chromatography tandem mass spectrometry was used to analyze 16 substances. The concentration range of influent samples was not detected (nd) -547.94 ng/L and the concentration range of effluent samples was nd-52.97 ng/L. By calculating the removal efficiency, it was found that Ciprofloxacin (CIP), Ofloxacin (OFL) and Clotrimazole (CTR) were effectively removed. There were significant spatial and temporal differences, the concentration in the dry season was evidently higher than that in the wet and normal seasons, and the northeast was lower than that in the northwest and southeast. By establishing a data set of influent and effluent, the priority features were extracted by feature engineering, which were temperature and NH₃-N. Under the condition of ensuring the best performance of the models, the influent model with 9 features and the effluent model with 4 features were established, and the quantitative relationship between the above features and concentration was obtained through partial dependence analysis. Except for Moxifloxacin (MOX), Norfloxacin (NOR) and OFL in the influent samples, the RQ values for other antibiotics and antimycotics were less than 0.1. Among the effluent samples, only NOR had an RQ value greater than 0.1, and OFL, MOX, and Pefloxacin (PEF) had RQ values between 0.01 and 0.1. Comparing the observations and predictions individual RQ values, the predictions were ideal and matched the observations. This work effectively assessed environmental impact and provided a valuable reference for evaluating antibiotics and antimycotics ecological toxicity.

Antibiotic concentrations in raw hospital wastewater surpass minimal selective and minimum inhibitory concentrations of resistant Acinetobacter baylyi strains

Antibiotics are essential for modern medicine, they are employed frequently in hospitals and, therefore, present in hospital wastewater. Even in concentrations, that are lower than the minimum inhibitory concentrations (MICs) of susceptible bacteria, antibiotics may exert an influence and select resistant bacteria, if they exceed the MSCs (minimal selective concentrations) of resistant strains. Here, we compare the MSCs of fluorescently labelled Acinetobacter baylyi strains harboring spontaneous resistance mutations or a resistance plasmid with antibiotic concentrations determined in hospital wastewater. Low MSCs in the μg/L range were measured for the quinolone ciprofloxacin (17 μg/L) and for the carbapenem meropenem (30 μg/L). A 24 h continuous analysis of hospital wastewater showed daily fluctuations of the concentrations of these antibiotics with distinctive peaks at 7-8 p.m. and 5-6 a.m. The meropenem concentrations were always above the MSC and MIC values of A. baylyi. In addition, the ciprofloxacin concentrations were in the range of the lowest MSC for about half the time. These results explain the abundance of strains with meropenem and ciprofloxacin resistance in hospital wastewater and drains.

Ecological Risk Analysis for Benzalkonium Chloride, Benzethonium Chloride, and Chloroxylenol in US Disinfecting and Sanitizing Products

Use of three topical antiseptic compounds-benzalkonium chloride (BAC), benzethonium chloride (BZT), and chloroxylenol (PCMX)-has recently increased because of the phaseout of other antimicrobial ingredients (such as triclosan) in soaps and other disinfecting and sanitizing products. Further, use of sanitizing products in general increased during the coronavirus (COVID-19) pandemic. We assessed the environmental safety of BAC, BZT, and PCMX based on best available environmental fate and effects data from the scientific literature and privately held sources. The ecological exposure assessment focused on aquatic systems receiving effluent from wastewater-treatment plants (WWTPs) and terrestrial systems receiving land-applied WWTP biosolids. Recent exposure levels were characterized based on environmental monitoring data supplemented by modeling, while future exposures were modeled based on a hypothetical triclosan replacement scenario. Hazard profiles were developed based on acute and chronic studies examining toxicity to aquatic life (fish, invertebrates, algae, vascular plants) and terrestrial endpoints (plants, soil invertebrates, and microbial functions related to soil fertility). Risks to higher trophic levels were not assessed because these compounds are not appreciably bioaccumulative. The risk analysis indicated that neither BZT nor PCMX in any exposure media is likely to cause adverse ecological effects under the exposure scenarios assessed in the present study. Under these scenarios, total BAC exposures are at least three times less than estimated effect thresholds, while margins of safety for freely dissolved BAC are estimated to be greater than an order of magnitude. Because the modeling did not specifically account for COVID-19 pandemic-related usage, further environmental monitoring is anticipated to understand potential changes in environmental exposures as a result of increased antiseptic use. The analysis presented provides a framework to interpret future antiseptic monitoring results, including monitoring parameters and modeling approaches to address bioavailability of the chemicals of interest. Environ Toxicol Chem 2022;41:3095-3115. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Cosmetic Preservatives: Hazardous Micropollutants in Need of Greater Attention?

In recent years, personal care products (PCPs) have surfaced as a novel class of pollutants due to their release into wastewater treatment plants (WWTPs) and receiving environments by sewage effluent and biosolid-augmentation soil, which poses potential risks to non-target organisms. Among PCPs, there are preservatives that are added to cosmetics for protection against microbial spoilage. This paper presents a review of the occurrence in different environmental matrices, toxicological effects, and mechanisms of microbial degradation of four selected preservatives (triclocarban, chloroxylenol, methylisothiazolinone, and benzalkonium chloride). Due to the insufficient removal from WWTPs, cosmetic preservatives have been widely detected in aquatic environments and sewage sludge at concentrations mainly below tens of µg L-1. These compounds are toxic to aquatic organisms, such as fish, algae, daphnids, and rotifers, as well as terrestrial organisms. A summary of the mechanisms of preservative biodegradation by micro-organisms and analysis of emerging intermediates is also provided. Formed metabolites are often characterized by lower toxicity compared to the parent compounds. Further studies are needed for an evaluation of environmental concentrations of preservatives in diverse matrices and toxicity to more species of aquatic and terrestrial organisms, and for an understanding of the mechanisms of microbial degradation. The research should focus on chloroxylenol and methylisothiazolinone because these compounds are the least understood.

Phosphorus recovery as K-struvite from a waste stream: A review of influencing factors, advantages, disadvantages and challenges

Currently, the depletion of natural resources and contamination of the surrounding environment demand a paradigm shift to resource recycling and reuse. In this regard, phosphorus (P) is a model nutrient that possesses the negative traits of depletion (will be exhausted in the next 100 years) and environmental degradation (causes eutrophication and climate change), and this has prompted the scientific community to search for options to solve P-related problems. To date, P recovery in the form of struvite from wastewater is one viable solution suggested by many scholars. Struvite can be recovered either in the form of NH₄-struvite (MgNH₄PO₄•6H₂O) or K-struvite (MgKPO₄•6H₂O). From struvite, K (MgKPO₄•6H₂O) and N (MgNH₄PO₄•6H₂O) are important nutrients for plant growth, but N is more abundant in the environment than K (the soil's most limited nutrient), which requires a systematic approach during P recovery. Although K-struvite recovery is a promising approach, information related to its crystallization is deficient. Here, we present the general concept of P recovery as struvite and details about K-struvite, such as the source of nutrients, factors (pH, molar ratio, supersaturation, temperature, and seeding), advantages (environmental, economic, and social), disadvantages (heavy metals, pathogenic organisms, and antibiotic resistance genes), and challenges (scale-up and acceptance). Overall, this study provides insights into state-of-the-art K-struvite recovery from wastewater as a potential slow-release fertilizer that can be used as a macronutrient (P-K-Mg) source for plants as commercial grade-fertilizers.

Metal speciation in sludges: a tool to evaluate risks of land application and to track heavy metal contamination in sewage network

The agricultural spreading of dehydrated sewage sludge from urban sewage treatment plants is economically profitable provided that the soil agronomic quality and the absence of contamination, in particular of heavy metals, are maintained. We evaluated the variability of sludge between five treatment plants in northern Algeria. We determined parameters that account for their agronomic quality and total content of Ag, Cd, Co, Cr, Cu, Ni, Pb, Ti and Zn. The speciation of metals, which determines their bioavailability, was characterized by sequential extraction into five fractions: easily exchangeable, acid-soluble, bound to carbonates and Fe-sulphides, bound to Fe-Mn oxides, bound to organic matter or sulphides, residual. All the sludges analysed showed satisfactory properties for plant growth. High total Ni contents for three of the sludges indicated that they were not landfillable under French or Chinese regulations. Ni, however, was contained in poorly bioavailable fractions and therefore presented a low risk to soils. In contrast, the total Cu was lower than the regulatory limit values, but mainly contained in very bioavailable fractions whose accumulation over time could reach toxic levels for plants over a period of 3 to 11 years depending on the sludges. These results showed that regulations are not adapted and must take into account the bioavailability with regard to the characteristics of the soils on which to spread. The speciation of metals in the sludge has also, on the one hand, made it possible to identify the zone of the sewerage network in which the sources of contamination must be sought and, on the other hand, has given indications on the possible nature of these sources.

Chlorination of isothiazolinone biocides: kinetics, reactive species, pathway, and toxicity evolution

Due to the Covid-19 pandemic, the worldwide biocides application has been increased, which will eventually result in enhanced residuals in treated wastewater. At the same time, chlorine disinfection of secondary effluents and hospital wastewaters has been intensified. With respect to predicted elevated exposure in wastewater, the chlorination kinetics, transformation pathways and toxicity evolution were investigated in this study for two typical isothiazolinone biocides, methyl-isothiazolinone (MIT) and chloro-methyl-isothiazolinone (CMIT). Second-order rate constants of 0.13 M^-1·s^-1, 1.95 × 10⁵ M^-1·s^-1 and 5.14 × 10⁵ M^-1·s^-1 were determined for the reaction of MIT with HOCl, Cl₂O and Cl₂, respectively, while reactivity of CMIT was around 1-2 orders of magnitude lower. While chlorination of isothiazolinone biocides at pH 7.1 was dominated by Cl₂O-oxidation, acidic pH and elevated Cl^- concentration favored free active chlorine (FAC) speciation into Cl₂ and increased overall isothiazolinone removal. Regardless of the dominant FAC species, the elimination of MIT and CMIT resulted in an immediate loss of acute toxicity under all experimental conditions, which was attributed to a preferential attack at the S-atom resulting in subsequent formation of sulfoxides and sulfones and eventually an S-elimination. However, chlorination of isothiazolinone biocides in secondary effluent only achieved <10% elimination at typical disinfection chlorine exposure 200 mg·L^-1·min, but was predicted to be remarkably increased by acidizing solution to pH 5.5. Alternative measures might be needed to minimize the discharge of these toxic chemicals into the aquatic environment.

Evolution of Chlorhexidine Susceptibility and of the EfrEF Operon among Enterococcus faecalis from Diverse Environments, Clones, and Time Spans

Chlorhexidine (CHX) is widely used to control the spread of pathogens (e.g., human/animal clinical settings, ambulatory care, food industry). Enterococcus faecalis, a major nosocomial pathogen, is broadly distributed in diverse hosts and environments facilitating its exposure to CHX over the years. Nevertheless, CHX activity against E. faecalis is understudied. Our goal was to assess CHX activity and the variability of ChlR-EfrEF proteins (associated with CHX tolerance) among 673 field isolates and 1,784 E. faecalis genomes from the PATRIC database from different sources, time spans, clonal lineages, and antibiotic-resistance profiles. The CHX MIC (MICCHX) and minimum bactericidal concentration (MBCCHX) against E. faecalis presented normal distributions (0.5 to 64 mg/L). However, more CHX-tolerant isolates were detected in the food chain and recent human infections, suggesting an adaptability of E. faecalis populations in settings where CHX is heavily used. Heterogeneity in ChlR-EfrEF sequences was identified, with isolates harboring incomplete ChlR-EfrEF proteins, particularly the EfrE identified in the ST40 clonal lineage, showing low MICCHX (≤1mg/L). Distinct ST40-E. faecalis subpopulations carrying truncated and nontruncated EfrE were detected, with the former being predominant in human isolates. This study provides a new insight about CHX susceptibility and ChlR-EfrEF variability within diverse E. faecalis populations. The MICCHX/MBCCHX of more tolerant E. faecalis (MICCHX = 8 mg/L; MBCCHX = 64 mg/L) remain lower than in-use concentrations of CHX (≥500 mg/L). However, increased CHX use, combined with concentration gradients occurring in diverse environments, potentially selecting multidrug-resistant strains with different CHX susceptibilities, signals the importance of monitoring the trends of E. faecalis CHX tolerance within a One Health approach. IMPORTANCE Chlorhexidine (CHX) is a disinfectant and antiseptic used since the 1950s and included in the World Health Organization's list of essential medicines. It has been widely applied in hospitals, the community, the food industry, animal husbandry and pets. CHX tolerance in Enterococcus faecalis, a ubiquitous bacterium and one of the leading causes of human hospital-acquired infections, remains underexplored. Our study provides novel and comprehensive insights about CHX susceptibility within the E. faecalis population structure context, revealing more CHX-tolerant subpopulations from the food chain and recent human infections. We further show a detailed analysis of the genetic diversity of the efrEF operon (previously associated with E. faecalis CHX tolerance) and its correlation with CHX phenotypes. The recent strains with a higher tolerance to CHX and the multiple sources where bacteria are exposed to this biocide alert us to the need for the continuous monitoring of E. faecalis adaptation toward CHX tolerance within a One Health approach.

Chlorhexidine residues in sludge from municipal wastewater treatment plants: analytical determination and toxicity evaluation

In this work, a procedure for the sensitive and selective determination of chlorhexidine in sludge from municipal sewage treatment plants (STPs) based on matrix solid-phase dispersion (MSPD) and liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) was optimized and validated. Analysis of sewage sludge samples, obtained from different STPs in Northwest Spain from 2018 to 2021, showed that chlorhexidine was ubiquitous in this environmental compartment with concentrations between 0.3 and 16 µg g⁻¹. The toxicity of this pollutant was assessed in in vitro assays considering three different model organisms: Candida albicans, Escherichia coli, and Staphylococcus aureus. C. albicans was the most sensitive of the tested microorganisms to chlorhexidine with a lethal threshold concentration of 0.1 mg L⁻¹. Thus, the lowest observed sludge residue was 3 times higher than the acute toxicity threshold measured for C. albicans. Moreover, E. coli and S. aureus were also affected at chlorhexidine concentrations around 1.8 mg L⁻¹ and 0.5 mg L⁻¹, respectively. So, chlorhexidine residues might affect the population of microorganisms existing in STPs. In addition, the potential phytotoxicity of the compound was evaluated with germination experiments using different model seeds. At the evaluated dose (10 µg g⁻¹ dried soil), chlorhexidine did not affect the germination of Sorghum saccharatum, Lepidium sativum, or Sinapis alba seeds. Thus, amending agriculture soils with chlorhexidine containing sludge is unlikely to affect the germination of plants.

Occurrence of antibiotics and bacterial resistance genes in wastewater: resistance mechanisms and antimicrobial resistance control approaches

Antimicrobial pharmaceuticals are classified as emergent micropollutants of concern, implying that even at low concentrations, long-term exposure to the environment can have significant eco-toxicological effects. There is a lack of a standardized regulatory framework governing the permissible antibiotic content for monitoring environmental water quality standards. Therefore, indiscriminate discharge of antimicrobials at potentially active concentrations into urban wastewater treatment facilities is rampant. Antimicrobials may exert selective pressure on bacteria, leading to resistance development and eventual health consequences. The emergence of clinically important multiple antibiotic-resistant bacteria in untreated hospital effluents and wastewater treatment plants (WWTPs) has been linked to the continuous exposure of bacteria to antimicrobials. The levels of environmental exposure to antibiotics and their correlation to the evolution and spread of resistant bacteria need to be elucidated to help in the formulation of mitigation measures. This review explores frequently detected antimicrobials in wastewater and gives a comprehensive coverage of bacterial resistance mechanisms to different antibiotic classes through the expression of a wide variety of antibiotic resistance genes either inherent and/or exchanged among bacteria or acquired from the reservoir of antibiotic resistance genes (ARGs) in wastewater systems. To complement the removal of antibiotics and ARGs from WWTPs, upscaling the implementation of prospective interventions such as vaccines, phage therapy, and natural compounds as alternatives to widespread antibiotic use provides a multifaceted approach to minimize the spread of antimicrobial resistance.

Influence of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) on Photosynthetic Parameters and Secondary Metabolites of Plants from Fabaceae Family

Nonsteroidal anti-inflammatory medications (NSAIDs) are commonly used painkillers, anti-inflammatory agents, and fever reducers. They arrive in the environment from municipal wastewater and/or agriculture waste, affecting growing plants. In our study, the impact of NSAIDs, namely, diclofenac, indomethacin, naproxen, and paracetamol, on four plant species from the Fabaceae family (Cicer arietinum, Pisum sativum, Lens culinaris, and Vicia faba) was tested. The assimilation rate and stomatal conductance decreased for all plants treated with NSAIDs. Chlorophyll and carotenoid contents in the leaves of plants under stress declined by more than 15% compared with the control plants, while the flavonoids and total phenols decreased to a lesser extent. In contrast, the plants treated with NSAIDs emit terpenes and green leaf were volatile, at a level of some nmol m−2 s−1, which could influence the atmospheric reaction and ozone formation.