Occurrence of fibrates and their metabolites in source and drinking water in Shanghai and Zhejiang, China.

Fibrates, which are widely used lipidaemic-modulating drugs, are emerging environmental pollutants. However, fibrate concentrations in the environment have not been thoroughly surveyed. Here, we determined concentrations of the most commonly used fibrates and their metabolites in source water and drinking water samples from ten drinking water treatment plants in Shanghai and Zhejiang, China, using solid-phase extraction and liquid chromatography-tandem mass spectrometry. All the target compounds were detected in at least some of the source water samples, at concentrations ranging from 0.04 ng/L (fenofibrate) to 1.53 ng/L (gemfibrozil). All the compounds except fenofibrate were also detected in at least some of the drinking water samples, at recoveries ranging from 35.5% to 91.7%, suggesting that these compounds are poorly removed by typical drinking water treatment processes. In a peroxisome proliferator-activated receptor α agonistic activity assay, the target compounds showed no significant activity at nanogram per litre concentrations; therefore, our results suggest that the fibrate concentrations in drinking water in Shanghai and Zhejiang, China do not significantly affect human health. However, because of the increasing westernization of the Chinese diet, fibrate use may increase, and thus monitoring fibrate concentrations in aquatic environments and drinking water in China will become increasingly important.

Mechanisms of removal of three widespread pharmaceuticals by two clay materials.

Pharmaceutical residues presence in the environment is among nowadays top emergent environmental issues. For removal of such pollutants, adsorption is a generally efficient process that can be complementary to conventional treatment. Research of cheap, widely available adsorbents may make this process economically attractive. The aim of the present work was to evaluate the capacity of two clay materials (exfoliated vermiculite, LECA) to adsorb gemfibrozil, mefenamic acid and naproxen in lab-scale batch assays. Results show that both adsorbents are able to remove the pharmaceuticals from aqueous medium. Although vermiculite exhibited higher adsorption capacities per unit mass of adsorbent, LECA yielded higher absolute removals of the pharmaceuticals due to the larger mass of adsorbent. Quantum chemistry calculations predicted that the forms of binding of the three molecules to the vermiculite surface are essentially identical, but the adsorption isotherm of naproxen differs substantially from the other two's. The linear forms of the latter impose limits at lower concentrations to the removal efficiencies of these pharmaceuticals by vermiculite, thereby electing LECA as more efficient. Notwithstanding, vermiculite's high specific adsorption capacity and also its much faster adsorption kinetics suggest that there may be some benefits in combining both materials as a composite adsorbent solution.

ß-Cyclodextrin anchoring onto pericarpium granati-derived magnetic mesoporous carbon for selective capture of lopid in human serum and pharmaceutical wastewater samples.

Functionalized magnetic carbonaceous nanomaterials, which are important materials with many practical and research applications in biomedical, pharmaceutical and biological fields, have recently attracted much attention. In this study, a magnetic mesoporous carbon coated with ß-cyclodextrin (MMC@ß-CD) was synthesized for the first time from natural pericarpium granati (PG). The as-obtained MMC@ß-CD has high surface areas (203 m(2)g(-1)), large pore volumes (0.16 cm(3)g(-1)), relatively broad mesoporous sizes (6.8 nm) and a high saturation magnetization of 26.2 emu g(-1), which is sufficient for magnetic separation by an external magnetic field. The MMC@ß-CD was used as an innovative adsorbent for magnetic solid-phase extraction of lopid via host-guest interaction prior to spectrofluorometric analysis. The proposed method was successfully applied to analyze lopid in human serum and pharmaceutical wastewater samples with recoveries in the range of 85.0-103.5% for the spiked samples. Overall, this work not only provides an inexpensive and eco-friendly method to fabricate MMC@ß-CD (or MMC) from PG, but also develops a highly selective approach for capture of lopid in biological samples and environmental substances.

Parallel artificial liquid membrane extraction of acidic drugs from human plasma.

The new sample preparation concept "Parallel artificial liquid membrane extraction (PALME)" was evaluated for extraction of the acidic drugs ketoprofen, fenoprofen, diclofenac, flurbiprofen, ibuprofen, and gemfibrozil from human plasma samples. Plasma samples (250 µL) were loaded into individual wells in a 96-well donor plate and diluted with HCl to protonate the acidic drugs. The acidic drugs were extracted as protonated species from the individual plasma samples, through corresponding artificial liquid membranes each comprising 2 µL of dihexyl ether, and into corresponding acceptor solutions each comprising 50 µL of 25 mM ammonia solution (pH 10). The liquid membranes and the acceptor solutions were located in a 96-well filter plate, which was sandwiched with the 96-well donor plate during extraction. Parallel extraction of several samples was performed for 15 to 60 min, followed by high-performance liquid chromatography-ultraviolet detection of the individual acceptor solutions. Important PALME parameters including the chemical composition of the liquid membrane, extraction time, and sample pH were optimized, and the extraction performance was evaluated. Except for flurbiprofen, exhaustive extraction was accomplished from plasma. Linearity was obtained for all six drugs in the range 0.025-10 µg/mL, with r (2) values ranging between 0.998 and 1.000. Precision data were in the range 3-22% RSD, and accuracy data were within 72-130% with spiked plasma samples. Based on the current experiences, PALME showed substantial potential for future high-throughput bioanalysis of non-polar acidic drugs.

Removal of trace organic chemical contaminants by a membrane bioreactor.

Emerging wastewater treatment processes such as membrane bioreactors (MBRs) have attracted a significant amount of interest internationally due to their ability to produce high quality effluent suitable for water recycling. It is therefore important that their efficiency in removing hazardous trace organic contaminants be assessed. Accordingly, this study investigated the removal of trace organic chemical contaminants through a full-scale, package MBR in New South Wales, Australia. This study was unique in the context of MBR research because it characterised the removal of 48 trace organic chemical contaminants, which included steroidal hormones, xenoestrogens, pesticides, caffeine, pharmaceuticals and personal care products (PPCPs). Results showed that the removal of most trace organic chemical contaminants through the MBR was high (above 90%). However, amitriptyline, carbamazepine, diazepam, diclofenac, fluoxetine, gemfibrozil, omeprazole, sulphamethoxazole and trimethoprim were only partially removed through the MBR with the removal efficiencies of 24-68%. These are potential indicators for assessing MBR performance as these chemicals are usually sensitive to changes in the treatment systems. The trace organic chemical contaminants detected in the MBR permeate were 1 to 6 orders of magnitude lower than guideline values reported in the Australian Guidelines for Water Recycling. The outcomes of this study enhanced our understanding of the levels and removal of trace organic contaminants by MBRs.

Validation and use of in vivo solid phase micro-extraction (SPME) for the detection of emerging contaminants in fish.

A variety of emerging chemicals of concern are released continuously to surface water through the municipal wastewater effluent discharges. The ability to rapidly determine bioaccumulation of these contaminants in exposed fish without sacrificing the animal (i.e. in vivo) would be of significant advantage to facilitate research, assessment and monitoring of their risk to the environment. In this study, an in vivo solid phase micro-extraction (SPME) approach was developed and applied to the measurement of a variety of emerging contaminants (carbamazepine, naproxen, diclofenac, gemfibrozil, bisphenol A, fluoxetine, ibuprofen and atrazine) in fish. Our results indicated in vivo SPME was a potential alternative extraction technique for quantitative determination of contaminants in lab exposures and as well after exposure to two municipal wastewater effluents (MWWE), with a major advantage over conventional techniques due to its ability to non-lethally sample tissues of living organisms.

Removal of selected pharmaceuticals by chlorination, coagulation-sedimentation and powdered activated carbon treatment.

Removal property of nine pharmaceuticals (clofibric acid, diclofenac, fenoprofen, gemfibrozil, ibuprofen, indomethacin, ketoprofen, naproxen and propyphenazone) by chlorination, coagulation-sedimentation and powdered activated carbon treatment was examined by laboratory-scale experiments under the conditions close to actual drinking water treatment processes. Indomethacin and propyphenazone were completely degraded by chlorination within 30 minutes, but others remained around 30% (naproxen and diclofenac) or more than 80% of the initial concentration after 24 hours. A couple of unidentified peaks in a chromatogram of the chlorinated samples suggested the formation of unknown chlorination by-products. Competitive adsorption was observed when the mixed solution of the target pharmaceuticals was subjected to batch adsorption test with powdered activated carbon. Clofibric acid and ibuprofen, which were relatively less hydrophobic among the nine compounds, persisted around 60% of the initial concentration after 3 hours of contact time. Removal performance in actual drinking water treatment would become lower due to existence of other competitive substances in raw water (e.g. natural organic matter). Coagulation-sedimentation using polyaluminium chloride hardly removed most of the pharmaceuticals even under its optimal dose for turbidity removal. It is suggested that the most part of pharmaceuticals in raw water might persist in the course of conventional drinking water treatments.

Electrokinetic migration of acidic drugs across a supported liquid membrane.

Electrokinetic cross membrane extraction of acidic drugs was demonstrated for the first time. The acidic drugs were extracted from an alkaline aqueous donor solution (300 microl), through a thin supported liquid membrane of 1-heptanol sustained in the pores of the wall of a porous hollow fiber, and into an aqueous alkaline acceptor solution (30 microl) present inside the lumen of the hollow fiber by the application of a d.c. electrical potential. The negative electrode was placed in the donor solution, and the positive electrode was placed in the acceptor solution. Optimal extractions were accomplished with 1-heptanol as the supported liquid membrane, with 50 V as the driving force, and with pH 12.0 in both the donor and acceptor solutions, respectively (NaOH). Equilibrium extraction conditions were obtained after 5 min of operation with the whole assembly agitated at 1200 rpm. Eleven different acidic drugs were extracted with recovery values between 8 and 100%, and initial data supported that electrokinetic cross membrane extraction provided repeatable data and linear response between original donor concentration and final acceptor concentration of the acidic model compounds.

Enantiomeric separation of gemfibrozil chiral analogues by capillary electrophoresis with heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin as chiral selector.

The enantiomeric separation of gemfibrozil chiral analogues was performed by capillary zone electrophoresis (CZE). Resolution of the enantiomers was achieved using heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TM-beta-CD) as chiral selector dissolved into a buffer solution. In order to optimize the separation conditions, type, pH and concentration of running buffer and chiral selector concentration were varied. For each pH value, the optimum chiral selector concentration that produced the resolution of the isomers was found. The migration order of labile diastereoisomers formed was valued at the optimum experimental conditions by adding a pure optical isomer to the racemic mixture. Data from 1H NMR studies confirmed host-guest interaction between TM-beta-CD and 5-(2,5-dimethylphenoxy)-2-ethylpentanoic acid sodium salt. The hypothesized stoichiometry host:guest was 1:1. An apparent equilibrium constant (Ka) was estimated monitoring the chemical shift variation as a function of TM-beta-CD concentration. Salt effect on complexation equilibrium constant was also investigated.

Removal of selected non-steroidal anti-inflammatory drugs (NSAIDs), gemfibrozil, carbamazepine, beta-blockers, trimethoprim and triclosan in conventional wastewater treatment plants in five EU countries and their discharge to the aquatic environment.

The removal of commonly used pharmaceuticals (ibuprofen, naproxen, diclofenac, gemfibrozil, carbamazepine, atenolol, metoprolol and trimethoprim) and a biocide (triclosan) in operating wastewater treatment plants in five EU countries has been studied. Under normal operating conditions the acidic drugs and triclosan were partially removed with removal rates varying from ca. 20 to >95%. The highest removal rate was found for ibuprofen and triclosan (>90%) followed by naproxen (80%), gemfibrozil (55%) and diclofenac (39%). Ibuprofen undergoes an oxidative transformation to corresponding hydroxy- and carboxy-metabolites, which contributes to its high removal rate. Disturbances in the activated sludge process resulted in lower removal rates for all acidic drugs, mostly for diclofenac (<10% removed) but also for ibuprofen (<60% removed). The treatment of wastewaters by activated sludge usually did not result in any practical removal (<10%) of neutral carbamazepine or basic atenolol, metoprolol and trimethoprim. The removal rates of the investigated drugs and triclosan are discussed in terms of mechanisms responsible for their removal. Discharges of carbamazepine, diclofenac, gemfibrozil, naproxen, triclosan and trimethoprim from WWTPs to the aquatic environment, expressed as the average concentration in the effluent and the daily discharged quantity per person served by WWTPs were assessed.