Human pharmaceuticals in the aquatic environment: a challenge to Green Chemistry

Effects of levofloxacin hydrochloride on photosystem II activity and heterogeneity of Synechocystis sp

Effects of LH on photosynthesis of Synechocystis sp. were investigated by a variety of in vivo chlorophyll fluorescence. O2 evolution and the photosystem II (PSII) activity were clearly inhibited by LH. Exposure to LH increased the proportion of PSIIbeta and this weakened the connectivity between PSII units and hindered excitation energy-transfer between PSII units. LH decreased the density of the active photosynthetic reaction centers, inhibited electron transport, and increased the dissipated energy flux per reaction center. The inhibitory effect of LH on Q(A)(-) reoxidation process could be divided into several stages. LH first inhibited the electron transfer from Q(A)(-) to Q(B) by weakening the connectivity between Q(A)(-) and Q(B), and PQ binding began taking part in Q(A)(-) reoxidation. At the second stage, the connectivity between Q(A)(-) and PQ pool was broken and inhibition on PQ binding occurred. At this stage, some Q(A)(-) began to be oxidized by S2(Q(A)Q(B))(-). Finally, when the connectivity between Q(A)(-) and Q(B) and PQ was completely broken, all Q(A)(-) was oxidized through charge recombination.

Environmental exposure of pharmaceuticals and musk fragrances in the Somes River before and after upgrading the municipal wastewater treatment plant Cluj-Napoca, Romania

BACKGROUND, AIM, AND SCOPE

Pharmaceutically active substances are a class of emerging contaminants, which has led to increasing concern about potential environmental risks. After excretion, substantial amounts of unchanged pharmaceuticals and their metabolites are discharged into domestic wastewaters. The absence of data on the environmental exposure in Eastern Europe is significant, since use patterns and volumes differ from country to country. In Romania, the majority of wastewater, from highly populated cities and industrial complex zones, is still discharged into surface waters without proper treatment or after inefficient treatment. In respect to this, it is important to determine the environmental occurrence and behavior of pharmaceuticals and personal care products (PPCPs) in wastewaters and surface waters. The objective of the present study was to investigate the occurrence of selected PPCPs during the transport in the Somes River by mass flow analysis before and after upgrading a municipal wastewater treatment plant (WWTP) in Cluj-Napoca, which serves 350,000 inhabitants and is the largest plant discharging into the Somes River. The concentrations of PPCPs at Cluj-Napoca can be correlated with the high population and a high number of hospitals located in the catchment area leading to higher mass flows. The results of this study are expected to provide information, with respect to the Romanian conditions, for environmental scientists, WWTP operators, and legal authorities. The data should support the improvement of existing WWTPs and implementation of new ones where necessary and, therefore, minimize the input of contaminants into ambient waters.

MATERIALS AND METHODS

The PPCPs were selected on the basis of consumption at the regional scale, reported aquatic toxicity, and the suitability of the gas chromatography/mass spectrometry (GC/MS) method for the determination of the compounds at trace levels. The studied PPCPs, caffeine (stimulant), carbamazepine (antiepileptic), pentoxifylline (anticoagulant), cyclophosphamide (cytostatic), ibuprofen (analgesic), and galaxolide (musk fragrance), were determined in samples of the Somes River. The analytes were enriched by solid-phase extraction and subsequently determined by GC/MS. Caffeine, pentoxifylline, and galaxolide were determined underivatized, whereas the acidic pharmaceuticals carbamazepine, cyclophosphamide, and ibuprofen were determined after derivatization with N-methyl-N-(trimethylsilyl)-trifluoroacetamide.

RESULTS AND DISCUSSION

The concentrations in the Somes River varied from below 10 ng/L up to 10 microg/L. A substantial decrease of the exposure in the Somes River could be observed due to the upgrade of the municipal WWTP in Cluj-Napoca. The loads in the river stretch between Cluj-Napoca and Dej (Somes Mic) varied strongly: caffeine (400-2,000 g/day), carbamazepine (78-213 g/day), galaxolide (140-684 g/day), ibuprofen (84-108 g/day). After the upgrade of the WWTP Cluj-Napoca, the concentrations in the Somes of caffeine, pentoxifylline, cyclophosphamide, galaxolide, and tonalide were significantly reduced (over 75%). One might be cautious comparing both studies because the relative efficiency of the WWTP's removal of PPCP was not evaluated. However, the significantly lower concentrations of most compounds after the upgrade of the WWTP Cluj-Napoca allow one to infer that the technical measures at the source substantially reduced inputs of contaminants to the receiving river. Dej loads of the poorly biodegradable substance carbamazepine increased by a factor of 2-3 as a result of wastewater discharges into the river. The disproportionate increase in caffeine loads by a factor of 4 below Cluj-Napoca indicates inputs of untreated wastewater from the Somes Mare due to the discharge of untreated wastewater derived from Bistrita, Nasaud, and Beclean (115,000 inhabitants).

CONCLUSIONS

The relative contribution of treated and untreated wastewater in surface water might be assessed by measuring chemical markers. Recalcitrant pharmaceuticals like carbamazepine are suitable as chemical markers for estimating the relative contribution of wastewater in surface water. The easily degradable caffeine might be a good indicator for raw sewage and hardly treated wastewaters.

RECOMMENDATIONS AND PERSPECTIVES

Municipal WWTPs have the potential of a significant contribution in reducing the load of contaminants to ambient waters. The efficiency of the wastewater treatment in Cluj-Napoca improved considerably after the upgrade of the WWTP. Therefore, it is crucial that several WWTPs must be implemented or improved in the Somes Valley Watershed in order to reduce the discharge of contaminants in the Somes River from these point sources.

Occurrence and fate of pharmaceutical products and by-products, from resource to drinking water

Among all emerging substances in water, pharmaceutical products (PPs) and residues are a lot of concern. These last two years, the number of studies has increased drastically, however much less for water resources and drinking water than for wastewater. This literature review based on recent works, deals with water resources (surface or groundwater), focusing on characteristics, occurrence and fate of numerous PPs studied, and drinking water including water quality. Through this review, it appears that the pharmaceutical risk must be considered even in drinking water where concentrations are very low. Moreover, there is a lack of research for by-products (metabolites and transformation products) characterization, occurrence and fate in all water types and especially in drinking water.

Analysis for estrogens as environmental pollutants--a review

The approaches to the analysis for estrogen compounds as environmental pollutants are critically reviewed and evaluated on the basis of significant, recent original publications. The importance of sample pretreatment and analyte preconcentration techniques is pointed out, with an emphasis on SPE and on the use of highly selective interactions such as molecular recognition. The hyphenated systems of high-performance gas or liquid chromatography and mass spectrometric techniques are discussed as the basic methods of determination of estrogens in environmental samples. Immunochemical procedures are shown to be useful in semiquantitative screening of estrogen pollutants (e.g. ELISA kits). Classical HPLC and GC with common UV/Vis, fluorescence and electrochemical detection are useful in routine checking on higher pollutant concentrations.

Free-radical-induced oxidative and reductive degradation of fibrate pharmaceuticals: kinetic studies and degradation mechanisms

The presence of pharmaceutically active compounds (PhACs) in aquatic systems is an emerging environmental issue and poses a potential threat to ecosystems and human health. Unfortunately, current water treatment techniques do not efficiently remove all of the PhACs, which results in the occurrence of such compounds in surface and ground waters. Advanced oxidation/reduction processes (AO/RPs) which utilize free radical reactions to directly degrade chemical contaminants are alternatives to traditional water treatment methods. This study reports the absolute bimolecular reaction rate constants for three pharmaceutical compounds (fibrates), clofibric acid, bezafibrate, and gemfibrozil, with the hydroxyl radical (*OH) and hydrated electron (e(-)(aq)). The bimolecular reaction rate constants for *OH were (6.98 +/- 0.12) x 10(9), (8.00 +/- 0.22) x 10(9), and (10.0 +/- 0.6) x 10(9), and for e(-)(aq) were (6.59 +/- 0.43) x 10(8), (112 +/- 3) x 10(8), and (6.26 +/- 0.58) x 10(8), for clofibric acid, bezafibrate, and gemfibrozil, respectively. Transient spectra were obtained for the intermediate radicals produced by the hydroxyl radical reactions. In addition, preliminary degradation mechanisms and major products were elucidated using (137)Cs gamma-irradiation and LC-MS. These data are required for evaluating the potential use of AO/RPs for the destruction of these compounds in treating water for various purposes.

Simultaneous determination of tetracyclines and their degradation products in environmental waters by liquid chromatography-electrospray tandem mass spectrometry

A sensitive method was developed for the trace determination of six tetracyclines and ten of their degradation products in influent, effluent, and river waters using liquid chromatography-electrospray tandem mass spectrometry detection, combined with Oasis hydrophilic-lipophilic balance (HLB) cartridge extraction and Oasis mixed-mode strong anion exchange (MAX) cartridge cleanup. Tetracyclines and their products were separated by liquid chromatography in 9.5min, and the instrument detection limits were generally between 0.03 and 0.1microg/L except for minocycline (0.5microg/L). The chromatograms were improved through the MAX cleanup and no apparent matrix effect was found. The recoveries of all the target compounds except for 4-epianhydrochlortetracycline and anhydrochlortetracycline (34-52%) were 75-120% for influent, 61-103% for effluent, and 64-113% for river waters. The method detection limits (MDLs) of the analytes varied in the range of 0.8-17.5ng/L in all studied matrices. The method was applied for the determination of tetracyclines and their products in a sewage treatment plant (STP) and surface waters in Beijing, China. Oxytetracycline (3.8-72.5ng/L), tetracycline (1.9-16.5ng/L), and five products including 4-epitetracycline, 4-epioxytetracycline, isochlortetracycline, anhydrotetracycline, and 4-epianhydrochlortetracycline (5.7-25.3ng/L) were detected in wastewater, while only oxytetracycline and tetracycline (2.2 and 2.1ng/L) were detected in surface water samples.

The afterlife of drugs and the role of pharmEcovigilance

The prescribing and usage of medications (for both humans and domestic animals) have ramifications extending far beyond the traditional objectives of conventional medical care. The healthcare industry has an environmental footprint that includes the active pharmaceutical ingredients (APIs) from medications, residues of which can establish themselves as environmental pollutants. This occurs by a variety of routes, but primarily from excretion, bathing and disposal. Many parallels exist between healthcare and the protection and remediation of the environment, spanning the stages from symptomology and diagnosis to treatment. The critical role played by pharmacovigilance in healthcare has a counterpart with the ecological environment. The term ecopharmacovigilance has been used with respect to the unforeseen consequences APIs can have once they enter the environment. We propose that conventional pharmacovigilance could be expanded to encompass environmental concerns--a concept we term pharmEcovigilance--as a way to unify the parallel but interconnected needs for protecting both human and ecological health.To convey the scope of a pharmEcovigilance programme, we provide an overview of the occurrence of APIs as environmental pollutants, their ramifications for human health and the environment and some of the ways in which their impact could be reduced or minimized. The major areas discussed include: (i) the routes by which APIs become contaminants in the environment; (ii) the hazards of leftover drugs as a result of stockpiling and from disposal to sewage, which can also eventually contribute to the contamination of drinking water; (iii) why drugs accumulate unused; and (iv) the benefits for humans and the environment that could accrue from reducing the accumulation of leftover drugs and the subsequent introduction of APIs into the environment. A broad spectrum of actions could be taken by prescribers (including veterinarians) and the healthcare industry at large (including manufacturers and insurers) to reduce the release or introduction of APIs to the environment. Most significantly, however, a major reason to consider implementing a pharmEcovigilance programme--beyond reducing the environmental footprint of healthcare--is the previously unforeseen collateral benefit in making further progress in optimizing the delivery, effectiveness, outcomes and cost of healthcare, as well as improving safety for humans, pets and wildlife. For this reason, the relationships that healthcare professionals and patients have with medications might also include consideration of pharmEcovigilance. Like any profession that deals with chemicals, perhaps a major challenge to be faced is how to ensure the sustainability (and minimize the life cycle exposure hazards) of a chemical-based, chemical-centric society in the most cost-effective and safest manner. Given that the medical community is a major source of numerous 'exotic' chemical pollutants in the environment (with thousands of chemically distinct APIs in current use), albeit at very low levels, an imperative could be created for designing and implementing approaches for reducing and controlling this source of pollution. With reduced wastage of medications, in part driven by appropriate or rational prescribing and dispensing, the ecological footprint of medicine could be greatly reduced, with concomitant improvements in many aspects of healthcare.

Assessing the effects of fluoxetine on Physa acuta (Gastropoda, Pulmonata) and Chironomus riparius (Insecta, Diptera) using a two-species water-sediment test

Fluoxetine has been tested in a two-species water-sediment system, which allowed a two-generation study with Chironomus riparius and a partial life-cycle with the freshwater snail Physa acuta to be performed at the same time. The design considered the continuous application of fluoxetine to overlaying water for nominal concentrations of 31.25, 62.5, 125 and 250 microg/L. A fifth treatment (87.5 microg/L) level consisted of pulse applications once a week. Measures of water and sediment concentrations were determined once a week and at the end of experiment (day 44), respectively. The fate study demonstrated that water dissipation can be explained by partitioning of fluoxetine to sediment. At the end of experiment, the percentage of detected fluoxetine was up to 10-fold higher in sediment than in overlaying water. The employed two-species test allowed distinguishing, in the same exposure conditions, effects due to waterborne exposure together ingestion at the sediment surface (freshwater grazing snail P. acuta) and exposure by burrowing activities (sediment-dwelling insect larvae C. riparius). The effect assessment showed a stimulation of P. acuta reproduction at lower concentrations (31.25 and 62.5 microg/L), while the opposite effect was observed at the highest treatment (250 microg/L). Additional studies should be conducted to establish if the statistically significant differences observed in F0 sex ratio at the 62.5 microg/L and F1 adult emergence at 31.25 microg/L of C. riparius have a toxicological significance. This study showed that fluoxetine can affect reproduction of freshwater molluscs. The results of the present study may contribute to knowledge on ecotoxicology of pharmaceuticals, about which little data is available. The possible consequences and implications for targeting the environmental risk assessment of fluoxetine are discussed.

Removal of residual pharmaceuticals from aqueous systems by advanced oxidation processes

Over the past few years, pharmaceuticals are considered as an emerging environmental problem due to their continuous input and persistence to the aquatic ecosystem even at low concentrations. Advanced oxidation processes (AOPs) are technologies based on the intermediacy of hydroxyl and other radicals to oxidize recalcitrant, toxic and non-biodegradable compounds to various by-products and eventually to inert end-products. The environmental applications of AOPs are numerous, including water and wastewater treatment (i.e. removal of organic and inorganic pollutants and pathogens), air pollution abatement and soil remediation. AOPs are applied for the abatement of pollution caused by the presence of residual pharmaceuticals in waters for the last decade. In this light, this paper reviews and assesses the effectiveness of various AOPs for pharmaceutical removal from aqueous systems.

Actor modelling and its contribution to the development of integrative strategies for management of pharmaceuticals in drinking water

Widespread presence of human pharmaceuticals in water resources across the globe is documented. While some, but certainly not enough, research on the occurrence, fate and effect of pharmaceuticals in water resources has been carried out, a holistic risk management strategy is missing. The transdisciplinary research project "start" aimed to develop an integrative strategy by the participation of experts representing key actors in the problem field "pharmaceuticals in drinking water". In this paper, we describe a novel modelling method, actor modelling with the semi-quantitative software DANA (Dynamic Actor Network Analysis), and its application in support of identifying an integrative risk management strategy. Based on the individual perceptions of different actors, the approach allows the identification of optimal strategies. Actors' perceptions were elicited by participatory model building and interviews, and were then modelled in perception graphs. Actor modelling indicated that an integrative strategy that targets environmentally-responsible prescription, therapy, and disposal of pharmaceuticals on one hand, and the development of environmentally-friendly pharmaceuticals on the other hand, will likely be most effective for reducing the occurrence of pharmaceuticals in drinking water (at least in Germany where the study was performed). However, unlike most other actors, the pharmaceutical industry itself does not perceive that the production of environmentally-friendly pharmaceuticals is an action that helps to achieve its goals, but contends that continued development of highly active pharmaceutical ingredients will help to reduce the occurrence of pharmaceuticals in the water cycle. Investment in advanced waste or drinking water treatment is opposed by both the wastewater treatment company and the drinking water supplier, and is not mentioned as appropriate by the other actors. According to our experience, actor modelling is a useful method to suggest effective and realisable integrative risk management strategies in complex problem fields that involve many societal actors.

Reduction of pharmaceutically active compounds by a lagoon wetland wastewater treatment system in Southeast Louisiana

A number of pharmaceutically active compounds (PhACs) have been detected in the aquatic environment as a result of discharges of municipal wastewater. In the state of Louisiana, USA, many municipalities treat wastewater using natural systems, such as lagoons and wetlands, rather than conventional wastewater treatment technologies. Nearly all research to date has focused on the fate of PhACs in conventional treatment plants, not constructed and natural wetlands. In the wastewater treatment plant (WWTP) for Mandeville, Louisiana, USA, wastewater flows of 7600 m(3)d(-1) are treated in a series of aeration lagoons (basins), followed by a constructed wetland and UV disinfection, before being discharged into a natural forested wetland (i.e. Bayou Chinchuba) and eventually, Lake Pontchartrain. Thirteen out of the 15PhACs investigated were detected in the wastewater inflow to the treatment plant. Only 9 of the 13 compounds were above the detection limits at the treatment plant effluent. The concentrations of most compounds were reduced by greater than 90% within the plant, while carbamazepine and sotalol were only reduced by 51% and 82%, respectively. The percent reductions observed in the Mandeville system were greater than reduction rates reported for conventional WWTPs; perhaps due to the longer treatment time ( approximately 30 days). Most target PhACs were not completely removed before discharge into Lake Pontchartrain, although their collective annual loading was reduced to less than 1kg and down to ppb with significant potential for dilution in the large lake.

Oxidative transformations of environmental pharmaceuticals by Cl₂, ClO₂, O₃, and Fe(VI): kinetics assessment

Several pharmaceuticals have been detected globally in surface water and drinking water, which indicate their insufficient removal from water and wastewater using conventional treatment methods. This paper reviews the kinetics of oxidative transformations of pharmaceuticals (antibiotics, lipid regulators, antipyretics, anticonvulsants, and beta-blockers) by Cl(2), ClO(2), O(3), and ferrate(VI) (Fe(VI)O(4)(2-),Fe(VI)) under treatment conditions. In the chlorination of sulfonamide antibiotics, HOCl is the major reactive Cl(2) species whereas in the oxidation by Fe(VI), HFeO(4)(-) is the dominant reactive species. Both oxidation processes can oxidize sulfonamides in seconds at a neutral pH (t(1/2)≤ 220 s; 1 mg L(-1) HOCl or K(2)FeO(4)). The reactivity of O(3) with pharmaceuticals is generally higher than that of HOCl (k(app,pH 7) (O(3))=1-10(7)M(-1)s(-1); k(app,pH 7) (HOCl)=10(-2)-10(5)M(-1)s(-1)). Ozone selectively oxidizes pharmaceuticals and reacts mainly with activated aromatic systems and non-protonated amines. Oxidative transformation of most pharmaceuticals by O(3) occurs in seconds (t(1/2)≤ 100 s; 1 mg L(-1) O(3)) while half-lives for oxidations by HOCl differ by at least two orders of magnitude. Ozone appears to be efficient in oxidizing pharmaceuticals in aquatic environments. The limited work on Fe(VI) shows that it can also potentially transform pharmaceuticals in treatment processes.

Occurrence, fate and antibiotic resistance of fluoroquinolone antibacterials in hospital wastewaters in Hanoi, Vietnam

Occurrence and behavior of fluoroquinolone antibacterial agents (FQs) were investigated in hospital wastewaters in Hanoi, Vietnam. Hospital wastewater in Hanoi is usually not treated and this untreated wastewater is directly discharged into one of the wastewater channels of the city and eventually reaches the ambient aquatic environment. The concentrations of the FQs, ciprofloxacin (CIP) and norfloxacin (NOR) in six hospital wastewaters ranged from 1.1 to 44 and from 0.9 to 17 micrgl(-1), respectively. Total FQ loads to the city sewage system varied from 0.3 to 14 g d(-1). Additionally, the mass flows of CIP and NOR were investigated in the aqueous compartment in a small wastewater treatment facility of one hospital. The results showed that the FQ removal from the wastewater stream was between 80 and 85%, probably due to sorption on sewage sludge. Simultaneously, the numbers of Escherichia coli (E. coli) were measured and their resistance against CIP and NOR was evaluated by determining the minimum inhibitory concentration. Biological treatment lead to a 100-fold reduction in the number of E. coli but still more than a thousand E. coli colonies per 100ml of wastewater effluent reached the receiving water. The highest resistance was found in E. coli strains of raw wastewater and the lowest in isolates of treated wastewater effluent. Thus, wastewater treatment is an efficient barrier to decrease the residual FQ levels and the number of resistant bacteria entering ambient waters. Due to the lack of municipal wastewater treatment plants, the onsite treatment of hospital wastewater before discharging into municipal sewers should be considered as a viable option and consequently implemented.

Destruction of estrogens using Fe-TAML/peroxide catalysis

Endocrine disrupting chemicals (EDCs) impair living organisms by interfering with hormonal processes controlling cellular development Reduction of EDCs in water by an environmentally benign method is an important green chemistry goal. One EDC, 17alpha-ethinylestradiol (EE2), the active ingredient in the birth control pill, is excreted by humans to produce a major source of artificial environmental estrogenicity, which is incompletely removed by currenttechnologies used by municipal wastewater treatment plants (MWTPs). Natural estrogens found in animal waste from concentrated animal feeding operations (CAFOs) can also increase estrogenic activity of surface waters. An iron-tetraamidomacrocyclic ligand (Fe-TAML) activator in trace concentrations activates hydrogen peroxide and was shown to rapidly degrade these natural and synthetic reproductive hormones found in agricultural and municipal effluent streams. On the basis of liquid chromatography tandem mass spectrometry, apparent half-lives for 17 alpha- and 17 beta-estradiol, estriol, estrone, and EE2 in the presence of Fe-TAML and hydrogen peroxide were approximately 5 min and included a concomitant loss of estrogenic activity as established by E-Screen assay.

Optimization of peroxidase-catalyzed oxidative coupling process for phenol removal from wastewater using response surface methodology

Hydroxylated aromatic compounds (HACs) are considered to be primary pollutants in a wide variety of industrial wastewaters. Horseradish peroxidase (HRP) is suitable for the removal of these toxic substances. However, development of a mathematical model and optimization of the HRP-based treatment considering the economical issues by novel methods is a necessity. In the present study, optimization of phenol removal from wastewater by horseradish peroxidase (HRP) was carried out using response surface methodology (RSM) and central composite design (CCD). As the initial experimental design, 2(4-1) half-fraction factorial design (H-FFD) is accomplished in triplicate at two levels to select the most significant factors and interactions in the phenol removal procedure. Temperature (degrees C), pH, concentration of enzyme (unit mL(-1)), and H202 (mM) were determined as the most effective independent variables. Finally, a fourfactor-five coded level CCD, 30 runs, was performed in order to fit a second-order polynomial function to the results and calculate the economically optimum conditions of the reaction. The goodness of the model was checked by different criteria including the coefficient of determination (R2 = 0.93), the corresponding analysis of variance ((Pmodel > F) < 0.0001) and parity plot (r = 0.96). These analyses indicated that the fitted model is appropriate for this enzymatic system. With the assumption that the minimum enzyme concentration was 0.26 unit mL(-1), the analysis of the response surface contour and surface plots defined the optimum conditions as follows: pH = 7.12, hydrogen peroxide concentration 1.72 mM, and 10 degrees C. This work improves phenol removal operation economically by applying minimum enzyme concentration and highest removal in comparison with previous studies.