Comparative metagenomics reveals poultry and swine farming are hotspots for multidrug and tetracycline resistance

Antibiotic misuse in livestock is a major threat to human health, as bacteria are quickly developing resistance to them. We performed a comparative analysis of 25 faecal metagenomes from swine, poultry, cattle, and humans to investigate their resistance profiles. Our analysis revealed that all genes conferring resistance to antibiotic classes assessed except tetracyclines were more prevalent in poultry manure than in the remaining species. We detected clinically relevant antibiotic resistance genes, such as mcr-1 which confers resistance to polymyxins. Among them, extended-spectrum β-lactamase blaCTX-M genes were particularly abundant in all species. Poultry manure was identified as a hotspot for multidrug resistance, which may compromise medical treatment options. Urgent actions in the livestock industry are imperative to hamper the emergence and spread of antibiotic resistance.

Hypersaline mining effluents affect the structure and function of stream biofilm

The salinisation of freshwater ecosystems is a global environmental problem that threatens biodiversity, ecosystem functioning and human welfare. The aim of this study was to investigate the potential impact of a realistic salinity gradient on the structure and functioning of freshwater biofilms. The salinity gradient was based on the real ion concentration of a mining effluent from an abandoned mine in Germany. We exposed biofilm from a pristine stream to 5 increasing salinities (3 to 100 g L^-1) under controlled conditions in artificial streams for 21 days. We evaluated its functional (photosynthetic efficiency, nutrient uptake, and microbial respiration) and structural responses (community composition, algal biomass and diatom, cyanobacteria and green algae metrics) over time. Then we compared their responses with an unexposed biofilm used as control. The functionality and structure of the biofilm exposed to the different salinities significantly decreased after short-term and long-term exposure, respectively. The community composition shifted to a new stable state where the most tolerant species increased their abundances. At the same time, we observed an increase in the community tolerance (measured as Pollution-Induced Community Tolerance) along the salinity gradient. This study provides relevant information on the salt threshold concentrations that can substantially damage algal cells (i.e., between 15 and 30 g L^-1). The results provide new insights regarding the response and adaptation of stream biofilm to salinity and its potential implications at the ecosystem level.

Nitrosation and nitration of diclofenac and structurally related nonsteroidal anti-inflammatory drugs (NSAIDs) in nitrifying activated sludge

Diclofenac (DCF) is a highly consumed non-steroidal anti-inflammatory drug that is excreted partially metabolized and is poorly removed during wastewater treatment. Previous findings demonstrated that DCF in wastewater treatment plants (WWTP) is partially removed to nitro/nitroso compounds. The reactive nitrogen species, that are microbially produced during nitrification in the activated sludge of WWTP, were suspected to be involved in the transformation of DCF. Therefore, here, we investigated the molecular features governing such biotransformation and the role played by nitrifying bacteria by biodegradation experiments at lab scale in enriched nitrifying sludge bioreactors spiked with DCF and other structurally related non-steroidal anti-inflammatory drugs (NSAIDs). We provided evidence of the incorporation of NO/NO₂ groups into DCF originated from ammonia by isotopically labelled biodegradation experiments. Nitroso and nitro-derivatives were tentatively identified for all NSAIDs studied and biotransformation mechanisms were proposed. Our findings from biodegradation experiments performed under different incubation conditions suggested that biotransformation of DCF and its related NSAIDs might not only be microbially mediated by ammonia oxidizing bacteria, but other nitrifiers co-occurring in the activated sludge as ammonia oxidizing archaea and nitrite oxidizing bacteria. Follow-up studies should be conducted to disentangle such complex behaviour in order to improve removal of these contaminants in WWTPs.

Investigating the formation and toxicity of nitrogen transformation products of diclofenac and sulfamethoxazole in wastewater treatment plants

Diclofenac (DCF) and sulfamethoxazole (SMX) are highly consumed pharmaceuticals and concentrated in effluents from conventional wastewater treatment plants (WWTPs) since they are not completely eliminated. Under microbial mediated nitrification/denitrification processes occurring in nitrifying activated sludge DCF biotransformed into its nitroso and nitro derivatives (NO-DCF and NO2-DCF, respectively). SMX was biotransformed under denitrification conditions in water/sediment batch reactors into its nitro and desamino derivatives (NO2-SMX and Des-SMX, respectively). Four transformation products (TPs) from DCF and SMX were analized in wastewaters (WW) and receiving surface waters (SW). Nitrifying/denitrifying-derivatives of DCF and SMX were detected for the first time in WW and SW at one order of magnitude lower than their parent compounds. Relationships observed among levels of NO-DCF, NO2-DCF and nitrogen-species tentatively suggested that nitrification/denitrification processes are involved in nitration and nitrosation of DCF during biological WW treatment. Acute toxicity of analytes to Daphnia magna and Vibrio fischeri was assessed individually and in mixtures with other relevant micropollutants. Individual effects showed these compounds as not harmful and not toxic. However, synergism effects observed in mixtures evidenced that contribution of these compounds to overall toxicity of complex environmental samples, should not be dismissed.

Pesticide Mixture Toxicity in Surface Water Extracts in Snails (Lymnaea stagnalis) by an in Vitro Acetylcholinesterase Inhibition Assay and Metabolomics

Many chemicals in use end up in the aquatic environment. The toxicity of water samples can be tested with bioassays, but a metabolomic approach has the advantage that multiple end points can be measured simultaneously and the affected metabolic pathways can be revealed. A current challenge in metabolomics is the study of mixture effects. This study aims at investigating the toxicity of an environmental extract and its most abundant chemicals identified by target chemical analysis of >100 organic micropollutants and effect-directed analysis (EDA) using the acetylcholinesterase (AChE) bioassay and metabolomics. Surface water from an agricultural area was sampled with a large volume solid phase extraction (LVSPE) device using three cartridges containing neutral, anionic, and cationic sorbents able to trap several pollutants classes like pharmaceuticals, pesticides, PAHs, PCBs, and perfluorinated surfactants. Targeted chemical analysis and AChE bioassay were performed on the cartridge extracts. The extract of the neutral sorbent cartridge contained most of the targeted chemicals, mainly imidacloprid, thiacloprid, and pirimicarb, and was the most potent AChE inhibitor. Using an EDA approach, other AChE inhibiting candidates were identified in the neutral extract, such as carbendazim and esprocarb. Additionally, a metabolomics experiment on the central nervous system (CNS) of the freshwater snail Lymnaea stagnalis was conducted. The snails were exposed to the extract, the three most abundant chemicals individually, and a mixture of these. The extract disturbed more metabolic pathways than the three most abundant chemicals individually, indicating the contribution of other chemicals. Most pathways perturbed by the extract exposure overlapped with those related to exposure to neonicotinoids, like the polyamine metabolism involved in CNS injuries. Metabolomics for the straightforward comparison between a complex mixture and single compound toxicity is still challenging but, compared to traditional biotesting, is a promising tool due to its increased sensitivity.

Concentration and risk of pharmaceuticals in freshwater systems are related to the population density and the livestock units in Iberian Rivers

Considerable amounts of pharmaceuticals are used in human and veterinary medicine, which are not efficiently removed during wastewater and slurries treatment and subsequently entering continuously into freshwater systems. The intrinsic biological activity of these non-regulated pollutants turns their presence in the aquatic environment into an ecological matter of concern. We present the first quantitative study relating the presence of pharmaceuticals and their predicted ecotoxicological effects with human population and livestock units. Four representative Iberian River basins (Spain) were studied: Llobregat, Ebro, Júcar and Guadalquivir. The levels of pharmaceuticals were determined in surface water and sediment samples collected from 77 locations along their stream networks. Predicted total toxic units to algae, Daphnia and fish were estimated for pharmaceuticals detected in surface waters. The use of chemometrics enabled the study of pharmaceuticals for: their spatial distribution along the rivers in two consecutive years; their potential ecotoxicological risk to aquatic organisms; and the relationships among their occurrence and predicted ecotoxicity with human population and animal farming pressure. The Llobregat and the Ebro River basins were characterized as the most polluted and at highest ecotoxicological risk, followed by Júcar and Guadalquivir. No significant acute risks of pharmaceuticals to aquatic organisms were observed. However potential chronic ecotoxicological effects on algae could be expected at two hot spots of pharmaceuticals pollution identified in the Llobregat and Ebro basins. Analgesics/antiinflammatories, antibiotics and diuretics were the most relevant therapeutic groups across the four river basins. Among them, hydrochlorothiazide and gemfibrozil, as well as azithromycin and ibuprofen were widely spread and concentrated pharmaceuticals in surface waters and sediments, respectively. Regarding their predicted ecotoxicity, sertraline, gemfibrozil and loratidine were identified as the more concerning compounds. Significantly positive relationships were found among levels of pharmaceuticals and toxic units and population density and livestock units in both surface water and sediment matrices.

Transcriptomic, biochemical and individual markers in transplanted Daphnia magna to characterize impacts in the field

Daphnia magna individuals were transplanted across 12 sites from three Spanish river basins (Llobregat, Ebro, Jucar) showing different sources of pollution. Gene transcription, feeding and biochemical responses in the field were assessed and compared with those obtained in re-constituted water treatments spiked with organic eluates obtained from water samples collected at the same locations and sampling periods. Up to 166 trace contaminants were detected in water and classified by their mode of action into 45 groups that included metals, pharmaceuticals, pesticides, illicit drugs, and other industrial compounds. Physicochemical water parameters differentiated the three river basins with Llobregat having the highest levels of conductivity, metals and pharmaceuticals, followed by Ebro, whereas the Jucar river had the greatest levels of illicit drugs. D. magna grazing rates and cholinesterase activity responded similarly than the diversity of riparian benthic communities. Transcription patterns of 13 different genes encoding for general stress, metabolism and energy processes, molting and xenobiotic transporters corroborate phenotypic responses differentiated sites within and across river basins. Principal Component Analysis and Partial Least Square Projections to Latent Structures regression analyses indicated that measured in situ responses of most genes and biomarkers and that of benthic macroinvertebrate diversity indexes were affected by distinct environmental factors. Conductivity, suspended solids and fungicides were negatively related with the diversity of macroinvertebrates cholinesterase, and feeding responses. Gene transcripts of heat shock protein and metallothionein were positively related with 11 classes of organic contaminants and 6 metals. Gene transcripts related with signaling paths of molting and reproduction, sugar, protein and xenobiotic metabolism responded similarly in field and lab exposures and were related with high residue concentrations of analgesics, diuretics, psychiatric drugs, β blockers, illicit drugs, trizoles, bisphenol A, caffeine and pesticides. These results indicate that application of omic technologies in the field is a promising subject in water management.

Hydrological variation modulates pharmaceutical levels and biofilm responses in a Mediterranean river

The Llobregat is a Mediterranean river that is severely impacted by anthropogenic pressures. It is characterized by high flow variability which modulates its chemical and biological status. The present work evaluates the effects of flow changes on the concentration of pharmaceutically active compounds (PhACs) and their relationship to cellular parameters of river biofilms. To this end, at two selected sampling sites at the lower course of the Llobregat river, surface water samples were collected twice a week over two hydrologically different periods exhibiting low and high river flows. Higher levels of PhACs were detected at the downstream sampling site. Irrespective of the flow regime, analgesics, anti-inflammatories and lipid regulators were the most abundant substances at both sampling sites with total concentrations of up to 1,000 ng/L and 550 ng/L at the upstream and downstream sites, respectively. Antibiotics (fluoroquinolones) and psychiatric treatment drugs were also detected at high levels in the second campaign achieving concentrations of up to 500 ng/L. The principal component analysis (PCA) performed with the PhACs concentrations of the two campaigns revealed differences in the various therapeutic groups depending on sampling site and period. After a flash flood event during the second sampling period, dilution of PhACs occurred, but their average concentrations measured before the flood were restored within two weeks. For the majority of compounds, PhAC concentrations displayed an inverse relationship with river discharge The effects of water containing different concentrations of PhACs on biofilm communities were evaluated and related to flow regime variations. Translocation of biofilm communities from a less to a more polluted site of the river demonstrated an increase in bacteria mortality in the translocated biofilms. After the flood, extracellular peptidase activity and chlorophyll-a concentration were significantly reduced, and biofilm growth rate was significantly lower.

Modelling the emerging pollutant diclofenac with the GREAT-ER model: application to the Llobregat River Basin

The present research aims at giving an insight into the increasingly important issue of water pollution due to emerging contaminants. In particular, the source and fate of the non-steroidal anti-inflammatory drug diclofenac have been analyzed at catchment scale for the Llobregat River in Catalonia (Spain). In fact, water from the Llobregat River is used to supply a significant part of the Metropolitan Area of Barcelona. At the same time, 59 wastewater treatment plants discharge into this basin. GREAT-ER model has been implemented in this basin in order to reproduce a static balance for this pollutant for two field campaigns data set. The results highlighted the ability of GREAT-ER to simulate the diclofenac concentrations in the Llobregat Catchment; however, this study also pointed out the urgent need for longer time series of observed data and a better knowledge of wastewater plants outputs and their parameterization in order to obtain more reliable results.

Response of biofilm bacterial communities to antibiotic pollutants in a Mediterranean river

Antibiotics are emerging contaminants, which wing to their bioactivity, may lead to short-term and long-term alterations of natural microbial communities in aquatic environment. We investigated the effects of antibiotics on biofilm bacterial communities in the Llobregat River (Northeast Spain). Three sampling sites were selected: two less polluted sites and one hotspot. River water was collected from each site and used both as inoculum and medium for growing biofilms in independent mesocosms. After 25d of biofilm colonization, we exposed the colonized biofilms to river waters from the downstream sites (progressively contaminated by antibiotics). A control from each site was maintained where the growing biofilm was always exposed to water from the same site. The bacterial community composition, bacterial live/dead ratio and extracellular enzyme activities of the biofilms were measured before and 9d after exposing the biofilms to increasing contaminated waters. Sixteen antibiotic compounds were detected in the water from the three sampling sites. At each site, the antibiotics present in the highest concentrations were sulfonamides, followed by quinolones and macrolides. Bacterial communities of biofilms grown with the three river waters differed markedly in their structure, but less so in terms of functional descriptors. After switching the medium water to increasing pollution, biofilms exhibited increased levels of actinobacteria (HGC), a trend that was associated to the higher antibiotic concentrations in the water. These biofilms also showed increased bacterial mortality, and decreased extracellular leucine-aminopeptidase and alkaline phosphatase. There was a significant correlation between antibiotic concentrations and biofilm responses. Our results indicate that the continuous entrance of antibiotics in running waters cause significant structural and functional changes in microbial attached communities.

Effects of pesticides and pharmaceuticals on biofilms in a highly impacted river

We investigated the effects of pharmaceuticals and pesticides detected in a Mediterranean river, on fluvial biofilms by translocation experiments performed under controlled conditions. Water was sampled from three sites along a pollution gradient. Biofilms grown in mesocosms containing relatively clean water were translocated to heavily polluted water. Several biofilm descriptors were measured before and after translocations. Fifty-seven pharmaceuticals and sixteen pesticides compounds were detected in river waters. The translocation from less to more polluted site was the most effective. Autotrophic biomass and peptidase increased while phosphatase and photosynthetic efficiency decreased. Multivariate analysis revealed that analgesics and anti-inflammatories significantly affected biofilm responses. Ibuprofen and paracetamol were associated with negative effects on photosynthesis, and with the decrease of the green algae/cyanobacteria ratio, while diclofenac was associated with phosphatase activity. The effects of these emerging compounds on biofilms structure and function may cause important alterations in river ecosystem functioning.

Occurrence and modeling of pharmaceuticals on a sewage-impacted Mediterranean river and their dynamics under different hydrological conditions

The occurrence of 73 representative pharmacologically active compounds (PhACs) was assessed in a sewage-impacted section of the Llobregat River (NE Catalonia, Spain). This Mediterranean river is characterized by flow rate fluctuations strongly influenced by seasonal rainfall. River flow variations increase the potential environmental risk posed by organic micro-pollutants as their concentrations may increase substantially under low flow conditions. Little is known about the transport behavior of emerging contaminants in surface waters once they are discharged from waste water treatment plants (WWTP) into rivers. This research aimed to study the presence and fate of emerging contaminants under different hydrological conditions by sampling two different sites along the river in different seasons. The highest levels of pharmaceuticals were determined during cold and dry periods. The impact of the flow changes on the concentration of the pharmaceuticals in the river was assessed with the relative sensitive coefficients. Due to expected dilution effects, the response of pharmaceuticals to river flow was negative. Only in a few cases, positive relationships between drug concentrations and flow were detected, suggesting an important role of other hydrological phenomena like sediment re-suspension as well as the source of pollutants. To evaluate the role of other factors influencing PhAC concentrations, a plug-flow model was applied to obtain disappearance constants "k" for a set of selected compounds. Erythromycin presented k values of -0.15 h(-1) in both sites being the compound more efficiently removed from the water column. The k values for ibuprofen, furosemide, enrofloxacin, enalapril, acetaminophen, diclofenac and Ketoprofen were between -0.04 and -0.10 h(-1) showing less disappearance than erythromycin in the water column. However, other compounds presented k values<0.06, which suggested conservative behavior of these compounds in the water column. This study supports the reliability of the calculated k values for the disappearance of compounds in river waters.

Solar photocatalytic treatment of trimethoprim in four environmental matrices at a pilot scale: transformation products and ecotoxicity evaluation

The pilot-scale solar degradation of trimethoprim (TMP) in different water matrices (demineralized water: DW, simulated natural freshwater: SW; simulated wastewater: SWW; and real effluent: RE) was investigated in this study. DOC removal was lower in the case of SW compared to DW, which can be attributed to the presence of inorganic anions which may act as scavengers of the HO·. Furthermore, the presence of organic carbon and higher salt content in SWW and RE led to lower mineralization per dose of hydrogen peroxide compared to DW and SW. Toxicity assays in SWW and RE were also performed indicating that toxicity is attributed to the compounds present in RE and their by-products formed during solar Fenton treatment and not to the intermediates formed by the oxidation of TMP. A large number of compounds generated by the photocatalytic transformation of TMP were identified by UPLC-QToF/MS. The degradation pathway revealed differences among the four matrices; however hydroxylation, demethylation and cleavage reactions were observed in all matrices. To the best of our knowledge this is the first time that TMP degradation products have been identified by adopting a solar Fenton process at a pilot-scale set-up, using four different aqueous matrices.

Formation of diclofenac and sulfamethoxazole reversible transformation products in aquifer material under denitrifying conditions: batch experiments

Soil-aquifer processes have proven to work as a natural treatment for the attenuation of numerous contaminants during artificial recharge of groundwater. Nowadays, significant scientific effort is being devoted to understanding the fate of pharmaceuticals in subsurface environments, and to verify if such semipersistent organic micropollutants could also be efficiently removed from water. In this context we carried out a series of batch experiments involving aquifer material, selected drugs (initial concentration of 1 μg/L and 1 mg/L), and denitrifying conditions. Diclofenac and sulfamethoxazole exhibited an unreported and peculiar behavior. Their concentrations consistently dropped in the middle of the tests but recovered toward the end, which suggest a complex effect of denitrifying conditions on aromatic amines. The transformation products Nitro-Diclofenac and 4-Nitro-Sulfamethoxazole were detected in the biotic experiments, while nitrite was present in the water. Their concentrations developed almost opposite to those of their respective parent compounds. We conjecture that this temporal and reversible effect of denitrifying conditions on the studied aromatic amines could have significant environmental implications, and could explain at least partially the wide range of removals in subsurface environments reported in literature for DCF and SMX, as well as some apparent discrepancies on SMX behavior.

Pharmaceuticals on a sewage impacted section of a Mediterranean River (Llobregat River, NE Spain) and their relationship with hydrological conditions

INTRODUCTION

Mediterranean rivers are characterized by a high flow variability, which is strongly influenced by the seasonal rainfall. When water scarcity periods occur, water flow, and dilution capacity of the river is reduced, increasing the potential environmental risk of pollutants. On the other hand, floods contribute to remobilization of pollutants from sediments. Contamination levels in Mediterranean rivers are frequently higher than in other European river basins, including pollution by pharmaceutical residues. Little attention has been paid to the transport behavior of emerging contaminants in surface waters once they are discharged from WWTP into a river. In this context, this work aimed to relate presence and fate of emerging contaminants with hydrological conditions of a typical Mediterranean River (Llobregat, NE Spain).

METHODS

River fresh water samples were collected twice a week over a period of 5 weeks at three sampling points. Sixty-six pharmaceutical compounds belonging to different therapeutical classes were analyzed by LC-MS/MS.

RESULTS AND DISCUSSION

Positive and negative correlations between the concentrations of the target analytes and hydrological variables like river flow and dissolved organic matter were observed pointing out the relevance of different hydrological phenomena like dilution effects or sediment re-suspension. Sensitivity calculations showed that the majority of compounds were sensitive to flow variations.

Photofate of oseltamivir (Tamiflu) and oseltamivir carboxylate under natural and simulated solar irradiation: kinetics, identification of the transformation products, and environmental occurrence

In this work the photodegradation pathways and rates of oseltamivir ester (OE) and oseltamivir carboxylate (OC) were studied under artificial and natural solar irradiation with the goal of assessing the potential of photolysis as a removal mechanism in aquatic environments. The structures of the photoproducts of OE, elucidated by ultra performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-QToF-MS), were proposed to originate from hydration of the cyclohexene ring (TP330), ester hydrolysis (TP284), a combination thereof (TP302), intramolecular cyclization involving the ester (TP312), and cleavage of the ethylpropoxy side chain (TP226). The only photoproduct detected in case of OC was postulated to correspond to the hydration of the α,β-unsaturated acid (TP302). Under simulated solar irradiation the degradation rate of OC was approximately 10 times slower than that of OE, with half-lives ranging from 48 h in ultrapure water to 12 h in surface water from Sant Joan Despi, Llobregat river. The photodegradation under natural solar irradiation during the season of pandemic Influenza peak incidence was about 150 days for OC and 15 days for OE. In general, the photoproducts proved to be more resistant toward further photodegradation than the parent antivirals. In a monitoring survey of surface waters from the Ebro river (NE Spain), OC and OE were detected along with the photoproducts TP330 and 312.

Pilot study on the application of computerised glow curve analysis in TL based personal dosimetry services

Preliminary results of an inter-laboratory collaborative work on the application of computerised glow curve analysis to TL personal dosimetry are presented. Very simple analysis methods have proved to be useful for the evaluation of glow curves similar to those encountered in the dosimetric control of radiation workers. A first result obtained in the study has been the possibility of simplifying the TL working procedures by eliminating pre-annealing or pre-heating steps employed in conventional systems to avoid low temperature peaks. The presence of these unwanted peaks can be detected by the computerised evaluation methods, discriminating their contribution to the dosimetric TL data.

[Nutritional status of Guatemalan preschool children hospitalized for acute respiratory infections]

Nutritional status (weight-for-age, length-for-age, and weight-for-length) was determined in 678 children aged 0-59 months, admitted to the San Juan de Dios General Hospital in Guatemala City with signs and symptoms of acute respiratory infections. Five hundred and fifty seven (82.2%) cases were bronchopneumoniae; 62 (9.1%) were pneumoniae, and 43 (6.3%) were bronchiolitis. Five hundred and seventy (82.6%) children lived in the urban zones of the capital city and 118 (17.4%) in the municipalities of the Department of Guatemala. Deficit in weight-for-age was found in 188 (27.8%) cases, while 176 (25.9%) showed a deficiency in length-for-age. In terms of weight-for-length, 84 (12.4%) were below -2.00 standard deviations of the reference curve. The children from out of the city showed the highest proportions of malnutrition. Monitoring of nutritional status of hospitalized children with infectious diseases can provide valuable information, not only for their management, but also for parental health education.