Development and validation of a sensitive and selective method using GC/MS-MS for quantification of 5-fluorouracil in hospital wastewater

Hazard assessment of antineoplastic drugs and metabolites using cytotoxicity and genotoxicity assays

Antineoplastic drugs are among the most toxic pharmaceuticals. Their release into the aquatic ecosystems has been reported, giving rise to concerns about the adverse effects, including cytotoxicity and genotoxicity, that they may have on exposed organisms. In this study, we analyzed the cytotoxicity and genotoxicity of 5-fluorouracil (5-FU) and its metabolite alpha-fluoro-beta-alanine (3-NH2-F); gemcitabine (GEM) and its metabolite 2'-deoxy-2',2'-difluorouridine (2-DOH-DiF); as well as cyclophosphamide (CP) on the HepG2 cell line. Drug concentrations were based on those previously observed in the effluent of a major cancer hospital in Brazil. The study found that GEM, 2-DOH-DiF and 5-FU resulted in reduced cell viability. No reduction in cell viability was observed for CP and 3-NH2-F. Genotoxic assessment revealed damage in the form of nucleoplasmic bridges for CP and 3-NH2-F. The tested concentrations of all compounds resulted in significantly increased MNi and NBUDs. The results showed that these compounds induced cytotoxic and genotoxic effects in HepG2 cells at concentrations found in the environment. To the best of our knowledge, this study is the first to report on the cytogenotoxic impacts of the metabolites 3-NH2-F and 2-DOH-DiF in HepG2 cells. These findings may help in the development of public policies that could minimize potential environmental contamination.

Binding mechanism and SERS spectra of 5-fluorouracil on gold clusters

The adsorption behaviour of the 5-fluorouracil (5FU) on small gold clusters Au _N with N = 6, 8, 20 was evaluated by means of density functional theory using the PBE-D3 functional in combination with a mixed basis set, i.e. cc-pVDZ-PP for gold atoms and cc-pVTZ for non-metal elements. The binding energies between 5FU and gold clusters were determined in the range of 16-24 and 11-19 kcal/mol in gas-phase and aqueous media, respectively. The corresponding Gibbs energies were found to be around -7 to -10 kcal/mol in vacum and sigificantly reduced to -1 to -6 kcal/mol in water solution, indicating that both the association and dissociation processes are likely spontaneous. An analysis on the charge density difference tends to confirm the existence of a charge transfer from the 5FU molecule to Au atoms. Analysis of the surface-enhanced Raman scattering (SERS) spectra of 5FU adsorbed on the Au surfaces shows that the stretching vibrations of N-H and C=O bonds play a major role in the SERS phenomenon. A mechanism for the drug releasing from the gold surfaces is also proposed. The process is triggered by either the low pH in cancerous tumors or the presence of cysteine residues in protein matrices.

Trends in Fenton and photo-Fenton processes for degradation of antineoplastic agents in water matrices: current knowledge and future challenges evaluation using a bibliometric and systematic analysis

Antineoplastic agents present potential hazards to human health and the environment. For this reason, these compounds have attracted a great deal of attention from researchers in the environmental sciences field. In order to help guide future research, it is important to understand the current state of investigation of the occurrence of these microcontaminants and methods for their removal, especially focusing on Fenton and photo-Fenton processes applied to various aqueous matrices in which this class of pharmaceuticals is present. For this purpose, a systematic review of these topics was performed by bibliometric analysis of articles published during the last decade and available in the Scopus and Web of Science databases. This study enables visualization of the current panorama and trends in this field, providing a guide for future collaborative research and exchange of knowledge. Various strategies have been suggested to improve the efficiency of Fenton and photo-Fenton processes, mainly by means of the application of multiples additions of iron, the use of heterogeneous catalysts, and/or the use of chelating agents. Some studies have evaluated different radiation sources employed for photo-Fenton processes, such as solar and/or artificial radiation. In turn, the identification of transformation products generated by Fenton and photo-Fenton treatments, together with their evaluation by in silico (Q)SAR predictions or experimental toxicological bioassays, are related subjects that have been less reported in published works and that should be studied in depth. These subjects can support treatment evaluations that are more realistic, considering their limitations or potentials.

GC Determination of Fluorouracil in Serum by Using Hexafluroroacetylacetone as Derivatizing Reagent

A gas chromatographic (GC) procedure has been developed for the determination of fluorouracil (5-FU) after pre-column derivatization with hexafluoroacetylacetone. GC separation was from column DB-1 (30 m × 0.32 mm id) and the determination was by flame-ionization detection. The derivatization conditions were optimized at pH 4, heating at 90°C for 40 min and extraction of the derivative was in chloroform. Using the conditions nucleobases cytosine, uracil, thymine, adenine and guanine separated completely from fluorouracil. The linear calibration range and LOD for 5-fluorouracil were 0.5-40.0 and 0.2 μg/mL, respectively. The derivatization, elution and separation were repeatable in terms of retention time and peak height/peak area (n = 5) and relative standard deviations (RSD) were within 3.5%. The method was applied for the analysis of serum spiked with 5-FU with recovery of 95.5-97.5% with RSD 1.5-3.1%.

Detection of anti-cancer drugs and metabolites in the effluents from a large Brazilian cancer hospital and an evaluation of ecotoxicology

The use of chemotherapy agents has been growing worldwide, due to the increase number of cancer cases. In several countries, mainly in Europe countries, these drugs have been detected in hospitals and municipal wastewaters. In Brazil this issue is poorly explored. The main goal of this study was to assess the presence of three anti-cancer drugs, 5-fluorouracil (5-FU), gemcitabine (GEM) and cyclophosphamide (CP), and two metabolites, alpha-fluoro-beta-alanine (3-NH₂-F) and 2'-deoxy-2',2'-difluorouridine (2-DOH-DiF), in effluents from a large cancer hospital, in the municipal wastewater treatment plant (WWTP) influent and effluent, and also to evaluate toxicity of the mixtures of these compounds by ecotoxicological testing in zebrafish. The sample collections were performed in Barretos Cancer Hospital of the large cancer center in Brazil. After each collection, the samples were filtered for subsequent Liquid Chromatography Mass Spectrometry analysis. The presence of CP, GEM, and both metabolites (3-NH₂-F and 2-DOH-DiF) were detected in the hospital wastewater and the WWTP influent. Three drugs, GEM, 2-DOH-DiF and CP, were detected in the WWTP effluent. Two drugs were detected below the limit of quantification, 2-DOH-DiF: <LOQ (above 1400 ng L^-1) and CP: <LOQ (above 300 ng L^-1), and GEM was quantified at 420 ng L^-1. Furthermore, 2-DOH-DiF (116,000 ng L^-1) was detected at the highest level in the hospital wastewater. There were no zebrafish deaths at any of the concentrations of the compounds used. However, we observed histological changes, including aneurysms and edema in the gills and areas of necrosis of the liver. In summary, we found higher concentrations of CP, GEM and both metabolites (3-NH₂-F and 2-DOH-DiF) were detected for the first time. There is currently no legislation regarding the discharge of anti-cancer drugs in effluents in Brazil. This study is first to focus on effluents from specific treatments from a large cancer hospital located in small city in Brazil.

Wastewater monitoring by means of e-nose, VE-tongue, TD-GC-MS, and SPME-GC-MS

The presence of wastewater and air pollution has become an important risk factor for citizens, not only in terms of problems related to health risks, but also because of its negative impact on the country's image. For this reason, malodorous emission monitoring and control techniques are in high demand in urban areas and industries. The aim of this work is first to build an electronic nose (e-nose) and a Voltammetric Electronic tongue (VE-tongue) in order to study their ability to discriminate between polluted and clean environmental samples. Secondly, Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS), and Solid Phase Micro Extraction-Gas Chromatography-Mass Spectrometry (SPME-GC-MS) are utilized to explain this discrimination by identifying specific compounds from these samples. Indeed, the e-nose, consisted of metal oxide semiconductor gas sensors, is used for the assessment of the studied odorous air and headspace samples from water and wastewater sites. Moreover, the VE-tongue, based on metal electrodes, is utilized to determine the patterns of the sensor array responses, which serve as fingerprints profiles of the analyzed liquid samples. Chemometric tools, such as Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), and Support Vector Machines (SVMs) are operated for the processing of data from the e-nose and the VE-tongue. By using the both systems, the analyses of headspace and liquid samples from the seven sites allow better discrimination. To explain the cause of the obtained discrimination, TD-GC-MS and SPME-GC-MS analyses are well performed to identify compounds related sites. According to these outcomes, the proposed e-nose and VE-tongue are proved to be rapid and valuable tools for analysis of environmental polluted matrices.

Determination of 5-fluorocytosine, 5-fluorouracil, and 5-fluorouridine in hospital wastewater by liquid chromatography-mass spectrometry

Chemotherapeutics are pharmaceutical compounds the occurrence of which in the environment is of growing concern because of the increase in treatments against cancer diseases. They can reach the aquatic ecosystems after passing through wastewater treatment plants without complete removal. One of the most frequently used chemotherapeutics is 5-fluorouracil which exhibits a strong cytostatic effect. In this paper, an analytical methodology was developed, validated, and applied to determine 5-fluorouracil, its precursor, 5-fluorocytosine, and its major active metabolite, 5-fluorouridine, in hospital wastewater samples. Due to the expected low concentrations after dilution and interferences present in such a complex matrix, a very selective and sensitive detection method is required. Moreover, an extraction method must be implemented prior to the determination in order to purify the sample extract and preconcentrate the target analytes at micrograms per liter concentration levels. Solid-phase extraction followed by liquid chromatography with tandem mass spectrometry was the combination of choice and all included parameters were studied. Under optimized conditions for wastewater samples analysis, recoveries from 63 to 108% were obtained, while intraday and interday relative standard deviations never exceeded 20 and 25%, respectively. Limits of detection between 61 and 620 ng/L were achieved. Finally, the optimized method was applied to samples from hospital wastewater effluents.

Development of an analytical methodology for the analysis of priority cytostatics in water

The consumption of cytostatics has remarkably increased over the last years due to the high cancer incidence worldwide. In previous studies, seven cytostatics were already recognized to potentially induce chronic effects in aquatic organisms, taking into account their estimated concentrations in surface waters: cyclophosphamide (CYC), capecitabine (CAP), mycophenolic acid (MPA), imatinib (IMA), bicalutamide (BICA), prednisone (PRED) and 5-fluorouracil (5FU). The objective of the present study was to simultaneously analyse these 7 prioritized compounds, which have the highest chances to be found in surface and wastewaters. The analytical challenge relies in the determination of these very polar compounds, which have different chemical and structural properties. Solid-phase extraction with an Ultra Performance Liquid Chromatograph-Mass Spectrometer in electrospray ionization mixed mode (5-fluorouracil and bicalutamide in negative mode and the others in positive one) was developed to determine seven cytostatics in wastewater and surface water. Among eight tested cartridges with different sorbents and conditions, the best extraction performance was attained with Oasis WAX at pH 10, with recoveries ranging from 31 ± 4 (5FU) and 103 ± 17% (MPA). Regarding the chromatographic analysis, the best results were achieved with an XBridge amide column. The final analytical methodology was successfully applied for the analysis of real water samples, confirming the presence of risky cytostatics in surface and wastewaters.

A novel approach to the application of hexagonal mesoporous silica in solid-phase extraction of drugs

Mesoporous silica with hexagonal type structure containing amine functional group was introduced. Firstly, aminopropyl hexagonal mesoporous silica was synthetized in a co-condensation process, via templating route of n-dodecylamine. Then synthesized mesoporous material were characterized, and FT-IR spectrum confirmed the presence of amine group and CHN analysis determined the amount of organic layer. The high surface area (750 m²/g) was determined by applying nitrogen adsorption-desorption technique. The morphology was examined by scanning electron microscopy which proved hexagonal structure. The crystallinity of mesoporous material was observed in XRD pattern of this material. According to previous background of such material in adsorbing drug, herein, the efficiency of this material in adsorbing of 5-fluorouracil was evaluated through solid phase extraction method in aqueous and plasma media with high performance liquid chromatography. The extraction efficiency was evaluated for drug concentrations of 500-2000 ng/ml by means of 5-20 mg/ml hexagonal mesoporous silica in both media. The results showed good to excellent recovery rate of in both aqueous and plasma medium which confirmed that the aminopropyl functionalized hexagonal mesoporous silica could be considered as promising device for drug bioanalysis.

Distribution of Anticancer Drugs in River Waters and Sediments of the Yodo River Basin, Japan

This article reviews the pollution status of anticancer drugs present in the Yodo River basin located in the Kansai district of Japan, covering both the soluble and insoluble (adsorbed on the river sediments and suspended solids) levels. Procedures ranging from sampling in the field and instrumental analytical methods to the data processing for mass balance estimation of the target basin are also described. All anticancer drugs concerned with this article were detected in sewage and river waters, where the presence of bicalutamide (BLT) was identified at considerably high concentrations (maximum 254 ng/L in the main stream, 151 ng/L in tributaries, and 1032 ng/L in sewage treatment plant (STP) effluents). In addition, sorption distribution coefficient (logKd) values showed a tendency to become higher in the silty sediments at Suita Bridge than in the sandy sediments at Hirakata Bridge; these trends were supported by the results of the laboratory-scale sorption experiment. STPs were concluded to be the main sources of the anticancer drug load in the river, and a mass flux evaluation revealed that the effect of attenuation in the river environment was small. The effectiveness of ozonation in the sewage treatment process for removal of these anticancer drugs was further confirmed. The present article should be of value for facilitating the environmental risk assessment of a wide range of drugs in a broader geographical area.

Degradation of 5-FU by means of advanced (photo)oxidation processes: UV/H2O2, UV/Fe2+/H2O2 and UV/TiO2--Comparison of transformation products, ready biodegradability and toxicity

The present study investigates the degradation of the antimetabolite 5-fluorouracil (5-FU) by three different advanced photo oxidation processes: UV/H2O2, UV/Fe(2+)/H2O2 and UV/TiO2. Prescreening experiments varying the H2O2 and TiO2 concentrations were performed in order to set the best catalyst concentrations in the UV/H2O2 and UV/TiO2 experiments, whereas the UV/Fe(2+)/H2O2 process was optimized varying the pH, Fe(2+) and H2O2 concentrations by means of the Box-Behnken design (BBD). 5-FU was quickly removed in all the irradiation experiments. The UV/Fe(2+)/H2O2 and UV/TiO2 processes achieved the highest degree of mineralization, whereas the lowest one resulted from the UV/H2O2 treatment. Six transformation products were formed during the advanced (photo)oxidation processes and identified using low and high resolution mass spectrometry. Most of them were formed and further eliminated during the reactions. The parent compound of 5-FU was not biodegraded, whereas the photolytic mixture formed in the UV/H2O2 treatment after 256 min showed a noticeable improvement of the biodegradability in the closed bottle test (CBT) and was nontoxic towards Vibrio fischeri. In silico predictions showed positive alerts for mutagenic and genotoxic effects of 5-FU. In contrast, several of the transformation products (TPs) generated along the processes did not provide indications for mutagenic or genotoxic activity. One exception was TP with m/z 146 with positive alerts in several models of bacterial mutagenicity which could demand further experimental testing. Results demonstrate that advanced treatment can eliminate parent compounds and its toxicity. However, transformation products formed can still be toxic. Therefore toxicity screening after advanced treatment is recommendable.

A Critical Review on Clinical Application of Separation Techniques for Selective Recognition of Uracil and 5-Fluorouracil

The most important objectives that are frequently found in bio-analytical chemistry involve applying tools to relevant medical/biological problems and refining these applications. Developing a reliable sample preparation step, for the medical and biological fields is another primary objective in analytical chemistry, in order to extract and isolate the analytes of interest from complex biological matrices. Since, main inborn errors of metabolism (IEM) diagnosable through uracil analysis and the therapeutic monitoring of toxic 5-fluoruracil (an important anti-cancerous drug) in dihydropyrimidine dehydrogenase deficient patients, require an ultra-sensitive, reproducible, selective, and accurate analytical techniques for their measurements. Therefore, keeping in view, the diagnostic value of uracil and 5-fluoruracil measurements, this article refines several analytical techniques involved in selective recognition and quantification of uracil and 5-fluoruracil from biological and pharmaceutical samples. The prospective study revealed that implementation of molecularly imprinted polymer as a solid-phase material for sample preparation and preconcentration of uracil and 5-fluoruracil had proven to be effective as it could obviates problems related to tedious separation techniques, owing to protein binding and drastic interferences, from the complex matrices in real samples such as blood plasma, serum samples.

Removal of antineoplastic drugs cyclophosphamide, ifosfamide, and 5-fluorouracil and a vasodilator drug pentoxifylline from wastewaters by ozonation

We investigated the ozonation of the antineoplastic drugs cyclophosphamide (CP), ifosfamide (IF), and 5-fluorouracil (5-FU) and of the vasodilator pentoxifylline (PEN) in distilled water, in pharmaceutical wastewater, and in hospital effluent at pH 5-11. Under an alkaline pH of 11, all of the target compounds rapidly degraded through the attack of hydroxyl radicals, which resulted in their complete removal within 5 min at an ozone supply rate of 3 g O3/h. Under acidic pH conditions, such as pH 5.6, CP and IF exhibited slower removal rates; however, compounds with unsaturated C-C bonds, such as 5-FU and PEN, were still removed at rapid rates under acidic conditions. Although the parent compounds were removed within minutes, the resulting ozonation byproducts were resistant to further ozonation and possessed increased Microtox acute toxicity. In distilled water, the resulting ozonation products exhibited minimal mineralization but high acute toxicity, whereas in naturally buffered pharmaceutical and hospital effluents, the byproducts were more amenable to removal and detoxification.

Cytostatic drugs and metabolites in municipal and hospital wastewaters in Spain: filtration, occurrence, and environmental risk

Concerns about cytostatic anticancer drugs in the environment are increasing, mainly due to the lack of knowledge about the fate and impact of these cytotoxic compounds in the water cycle. In this context, the present work investigated the occurrence of 13 cytostatics and 4 metabolites in wastewater samples from various wastewater treatment plants (WWTPs) and from a large hospital from Spain. The target compounds belong to five different classes according to the Anatomical Therapeutic Classification (ATC), namely, alkylating agents, antimetabolites, plant alkaloids and other natural products, cytotoxic antibiotics and related substances, and other antineoplastic agents. Some of them have been classified as carcinogens in humans by the International Agency for Research on Cancer (IARC). These compounds were determined by an automated on line solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) method. Results showed the presence of methotrexate (MET), ifosfamide (IF), cyclophosphamide (CP), irinotecan (IRI), doxorubicin (DOX), capecitabine (CAP), tamoxifen (TAM) and the metabolites endoxifen (OH-D-TAM), hydroxytamoxifen (OH-TAM) and hydroxypaclitaxel (OH-PAC) at levels ranging from 2 ng L(-1) (for MET) to 180 ng L(-1) (for TAM). Some of these compounds were found to be efficiently removed after wastewater treatment, e.g. MET, DOX and IRI, whereas other compounds, such as TAM, CP and IF remained largely unaltered. The behaviour of the target compounds during the common filtration step of the water samples was also investigated with the finding that some compounds are strongly adsorbed to nylon filters, while cellulose acetate appears as the best choice for the filter material. The aquatic environmental risk associated to the detected compounds was also assessed. To the best of the authors' knowledge, this is the first report of the presence of the metabolites OH-D-TAM and OH-TAM in the water cycle.

Study of the stability of 26 cytostatic drugs and metabolites in wastewater under different conditions

The stability of 26 cytostatic drugs (21 parent compounds and 5 metabolites) in wastewater was studied using liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS). Wastewater aliquots were spiked with the target compounds at 1000μg L(-1) and stored in the dark under different temperature (-20, 4 and 25°C) and pH (acid and neutral) conditions for different periods of time (up to 3 months). The influence of these factors (temperature, pH and time) on the stability of the compounds was evaluated through an experimental design. The most negative factor was the time of storage, but temperature also exerted a very important influence. Acidification of the samples is a good option for some cytostatics (e.g., temozolomide, tamoxifen and its metabolites, and chlorambucil) but it may have a negative effect on others (e.g. ifosfamide). The design also showed correlations between factors indicating that an increase of the storage time is more relevant at high temperatures, while an increase of the temperature is more detrimental in non-acidified samples. After 3 months at -20°C, all compounds with the exception of temozolomide, vinorelbine, imatinib and erlotinib presented recoveries below 80%. The most unstable compounds were oxaliplatin, 5-(3-N-methyltriazen-1-yl)-imidazole-4-carboxamide and chlorambucil. To the authors' knowledge, the stability data reported in the present study is the first ever published for most of the target compounds in wastewater. The results obtained point out storage at -20°C from collection to analysis as the best storage option.

Is the phototransformation of pharmaceuticals a natural purification process that decreases ecological and human health risks?

Sunlight photodegradation has long been considered a significant process in lowering the concentrations of pharmaceuticals in surface waters and thus decreasing the ecological risk. For the first time, this study identified the significance of investigating the environmental photodegradation of a pharmaceutical residue mixture (rather than a single compound) and the associated toxicity of transformation byproducts in environmental waters, including rivers, hospital wastewaters, and effluents from wastewater treatment plants and pharmaceutical production facilities. Pharmaceuticals undergo phototransformation rather than mineralization (11-23% in 34 h). Pharmaceutical mixtures could possibly act as dissolved organic matter for each individual compound and subsequently affect the photolysis rates. The increased toxicity of irradiated pharmaceutical mixtures challenges the validity of the current understanding of sunlight photolysis. The implications of this work suggest that current knowledge concerning the occurrence, natural attenuation, ecotoxicity, and human health risks of pharmaceuticals is far from complete; photolysis is not necessarily a purification process.

Photocatalytic oxidation of 5-fluorouracil and cyclophosphamide via UV/TiO2 in an aqueous environment

Cytostatic drugs are a class of pharmaceuticals that are increasingly used in cancer therapies; 5-fluorouracil is one of the most commonly used cytostatic (antineoplastic) drugs in the world. This study applied photocatalytic oxidation to remove 5-fluorouracil. Degussa P25 showed a higher photocatalytic degradation efficiency for 5-fluorouracil removal than Aldrich TiO2 and ZnO. Under optimal conditions (20 mg L(-1) TiO2 at pH 5.8), 200 μg L(-1) 5-fluorouracil can be removed within 2 h (k = 0.0375 min(-1)). 5-fluorouracil was found to be decomposed by near-surface OH free radicals produced from valence holes (hvb(+)). At a relatively high concentration, 5-fluorouracil (27.6 mg L(-1)) is >99.9% removed within 4 h by 300 mg L(-1) Degussa P25, while 24 h is required to reach complete mineralization with 96.7% fluoride recovery. Cyclophosphamide is another widely used cancer drug that follows a similar decomposition pathway. Cyclophosphamide (27.6 mg L(-1)) was also >99.9% eliminated within 4 h, but dechlorination and mineralization reached only 79.9% and 55.1%, respectively, after 16 h of irradiation. Together with the results for Microtox(®), it is suggested that the oxidation products of cyclophosphamide are even more recalcitrant and toxic. For engineering practices, despite the fact that photocatalytic oxidation can rapidly remove target antineoplastic, it is also important to further evaluate the treatment efficiency of the photoproducts.

Phototransformation determines the fate of 5-fluorouracil and cyclophosphamide in natural surface waters

The use of cytotoxic substances, such as 5-fluorouracil and cyclophosphamide, is carefully controlled; however, these medications may still enter bodies of water through wastewater discharge. These substances may pose risks to stream and river life, as well as to humans via drinking water. In this study, the photochemical fate of 5-fluorouracil and cyclophosphamide was investigated in synthetic waters and four river waters and was found to be the most important attenuation process for each entity in natural surface waters. Bicarbonate alone was found to react with the excited states of 5-fluorouracil, thus enhancing direct photolysis rates. In the presence of nitrate and significant amounts of bicarbonate (close to 2 mM), 5-fluorouracil was rapidly removed (within 1 day) through indirect photolysis. In contrast, natural attenuation was of low importance for cyclophosphamide in most surface waters studied. A long, shallow river or lake with a long residence time (>7 days), very low alkalinity, and significant nitrate levels (>5 mg-N L(-1)) may be an exception. The phototransformation product of 5-fluorouracil was also identified. However, the total organic carbon experiments yielded important results: photolysis resulted in quick transformation of 5-fluorouracil but minimal mineralization. Additional studies of the toxicity of photobyproducts of 5-fluorouracil are needed to determine the true risk to human health of 5-fluorouracil contamination of surface water, given its near-total photodegradation and resultant, deceptively low detection rate in surface waters.

Potential environmental implications of nano-enabled medical applications: critical review

The application of nanotechnology and nanoscience for medical purposes is anticipated to make significant contributions to enhance human health in the coming decades. However, the possible future mass production and use of these medical innovations exhibiting novel and multifunctional properties will very likely lead to discharges into the environment giving rise to potentially new environmental hazards and risks. To date, the sources, the release form and environmental fate and exposure of nano-enabled medical products have not been investigated and little or no data exists, although there are a small number of currently approved medical applications and a number in clinical trials. This paper discusses the current technological and regulatory landscape and potential hazards and risks to the environment of nano-enabled medical products, data gaps and gives tentative suggestions relating to possible environmental hotspots.

Hospital wastewater treatment by membrane bioreactor: performance and efficiency for organic micropollutant elimination

A pilot-scale membrane bioreactor (MBR) was installed and operated for one year at a Swiss hospital. It was fed an influent directly from the hospital's sanitary collection system. To study the efficiency of micropollutant elimination in raw hospital wastewater that comprises a complex matrix with micropollutant concentrations ranging from low ng/L to low mg/L, an automated online SPE-HPLC-MS/MS analytical method was developed. Among the 68 target analytes were the following: 56 pharmaceuticals (antibiotics, antimycotics, antivirals, iodinated X-ray contrast media, antiinflamatory, cytostatics, diuretics, beta blockers, anesthetics, analgesics, antiepileptics, antidepressants, and others), 10 metabolites, and 2 corrosion inhibitors. The MBR influent contained the majority of those target analytes. The micropollutant elimination efficiency was assessed through continuous flow-proportional sampling of the MBR influent and continuous time-proportional sampling of the MBR effluent. An overall load elimination of all pharmaceuticals and metabolites in the MBR was 22%, as over 80% of the load was due to persistent iodinated contrast media. No inhibition by antibacterial agents or disinfectants from the hospital was observed in the MBR. The hospital wastewater was found to be a dynamic system in which conjugates of pharmaceuticals deconjugate and biological transformation products are formed, which in some cases are pharmaceuticals themselves.

Ecotoxicity and genotoxicity assessment of cytotoxic antineoplastic drugs and their metabolites

In spite of growing scientific concern about pharmaceuticals in the environment, there is still a lack of information especially with regard to their metabolites. The present study investigated ecotoxicity and genotoxicity of three widely used cytostatic agents 5-fluorouracil (5-FU), cytarabine (CYT) and gemcitabine (GemC) and their major human metabolites, i.e. alpha-fluoro-beta-alanine (FBAL), uracil-1-beta-D-arabinofuranoside (AraU) and 2',2'-difluorodeoxyuridine (dFdU), respectively. Effects were studied in acute immobilization and reproduction assays with crustacean Daphnia magna and growth inhibition tests with alga Desmodesmus subspicatus and bacteria Pseudomonas putida. Genotoxicity was tested with umu-test employing Salmonella choleraesius subsp. chol. Toxicity was relatively high at parent compounds with EC(50) values ranging from 44 microg L(-1) (5-fluorouracil in the P. putida test) to 200 mg L(-1) (cytarabine in D. magna acute test). In general, the most toxic compound was 5-FU. Studied metabolites showed low or no toxicity; only FBAL (metabolite of 5-FU) showed low toxicity to D. subspicatus and P. putida with EC(50) values 80 and 140 mg L(-1), respectively. All parent cytostatics showed genotoxicity with minimum genotoxic concentrations (MGC) ranging from 40 to 330 mg L(-1). From metabolites, only FBAL was genotoxic in high concentrations. To our knowledge, the present study provides some of the first ecotoxicity data for both cytostatics and their metabolites, which might further serve for serious evaluation of ecological risks. The observed EC(50) values within the microg L(-1) range were fairly close to concentrations reported in hospital sewage water, which indicates further research needs, especially studies of chronic toxicity.

Sampling for pharmaceuticals and personal care products (PPCPs) and illicit drugs in wastewater systems: are your conclusions valid? A critical review

The analysis of 87 peer-reviewed journal articles reveals that sampling for pharmaceuticals and personal care products (PPCPs) and illicit drugs in sewers and sewage treatment plant influents is mostly carried out according to existing tradition or standard laboratory protocols. Less than 5% of all studies explicitly consider internationally acknowledged guidelines or methods for the experimental design of monitoring campaigns. In the absence of a proper analysis of the system under investigation, the importance of short-term pollutant variations was typically not addressed. Therefore, due to relatively long sampling intervals, potentially inadequate sampling modes, or insufficient documentation, it remains unclear for the majority of reviewed studies whether observed variations can be attributed to "real" variations or if they simply reflect sampling artifacts. Based on results from previous and current work, the present paper demonstrates that sampling errors can lead to overinterpretation of measured data and ultimately, wrong conclusions. Depending on catchment size, sewer type, sampling setup, substance of interest, and accuracy of analytical method, avoidable sampling artifacts can range from "not significant" to "100% or more" for different compounds even within the same study. However, in most situations sampling errors can be reduced greatly, and sampling biases can be eliminated completely, by choosing an appropriate sampling mode and frequency. This is crucial, because proper sampling will help to maximize the value of measured data for the experimental assessment of the fate of PPCPs as well as for the formulation and validation of mathematical models. The trend from reporting presence or absence of a compound in "clean" water samples toward the quantification of PPCPs in raw wastewater requires not only sophisticated analytical methods but also adapted sampling methods. With increasing accuracy of chemical analyses, inappropriate sampling increasingly represents the major source of inaccuracy. A condensed step-by-step Sampling Guide is proposed as a starting point for future studies.