Biomedical subjects

D Barceló

Publications and source records attributed to D Barceló.

At least 55 records · Page 3Linked to original sources

PubMed2001

Quantitative analysis of polycyclic aromatic hydrocarbons in sewage sludge from wastewater treatment plants.

Polycyclic aromatic hydrocarbons (PAHs) are an important group of organic contaminants present in sewage sludge. Due to their persistence and toxic potential, information about their presence in sewage sludge is needed in order to assess applicability on agricultural land. A method for the gas chromatographic-mass spectrometric (GC-MS) determination was developed and applied to the trace determination of PAHs present in sewage sludge samples from six wastewater treatment plants (WWTPs) differing in the type of treatment and the origin of wastewater. PAHs were extracted from freeze-dried samples by a dichloromethane-methanol (2:1) mixture in a sonication bath. The sludge extracts were cleaned-up by an alumina column. The method showed recovery values varying from 60 to 98%. Four surrogate standards ([2H8]naphthalene, [2H10]anthracene, [2H12]benzo[a]anthracene, and [2H12]benzo[ghi]perylene) were used for quantitation by GC-MS. A reference sludge sample was analysed in order to validate the method. The sum of the 16 US Environmental Protection Agency PAHs analysed in the sewage sludge samples varied from 1.13 to 5.52 mg/kg. No significant difference between the different WWTPs was found.

Calibration↗

PubMed2001

Choosing between atmospheric pressure chemical ionization and electrospray ionization interfaces for the HPLC/MS analysis of pesticides.

An evaluation of over 75 pesticides by high-performance liquid chromatography/mass spectrometry (HPLC/MS) clearly shows that different classes of pesticides are more sensitive using either atmospheric pressure chemical ionization (APCI) or electrospray ionization (ESI). For example, neutral and basic pesticides (phenylureas, triazines) are more sensitive using APCI (especially positive ion). While cationic and anionic herbicides (bipyridylium ions, sulfonic acids) are more sensitive using ESI (especially negative ion). These data are expressed graphically in a figure called an ionization-continuum diagram, which shows that protonation in the gas phase (proton affinity) and polarity in solution, expressed as proton addition or subtraction (pKa), is useful in selecting APCI or ESI. Furthermore, sodium adduct formation commonly occurs using positive ion ESI but not using positive ion APCI, which reflects the different mechanisms of ionization and strengthens the usefulness of the ionization-continuum diagram. The data also show that the concept of "wrong-way around" ESI (the sensitivity of acidic pesticides in an acidic mobile phase) is a useful modification of simple PKa theory for mobile-phase selection. Finally, this finding is used to enhance the chromatographic separation of oxanilic and sulfonic acid herbicides while maintaining good sensitivity in LC/MS using ESI negative.

Atmospheric Pressure↗

PubMed2001

Identification of a new degradation product of the antifouling agent irgarol 1051 in natural samples.

A main degradation product of Irgarol [2-(methylthio)-4-(tert-butylamino)-6-(cyclopropylamino)-s-triazine], one of the most widely used compounds in antifouling paints, was detected at trace levels in seawater and sediment samples collected from several marinas on the Mediterranean coast. This degradation product was identified as 2-methylthio-4-tert-butylamino-s-triazine. The unequivocal identification of this compound in seawater samples was carried out by solid-phase extraction (SPE) coupled on-line with liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS). SPE was carried out by passing 150 ml of seawater sample through a cartridge containing a polymeric phase (PLRP-s), with recoveries ranging from 92 to 108% (n=5). Using LC-MS detection in positive ion mode, useful structural information was obtained by increasing the fragmentor voltage, thus permitting the unequivocal identification of this compound in natural samples. Method detection limits were in the range of 0.002 to 0.005 microg/l. Overall, the combination of on-line SPE and LC-APCI-MS represents an important advance in environmental analysis of herbicide degradation products in seawater, since it demonstrates that trace amounts of new polar metabolites may be determined rapidly. This paper reports the LC-MS identification of the main degradation product of Irgarol in seawater and sediment samples.

Atmospheric Pressure↗

PubMed2001

Evaluation of a multidimensional solid-phase extraction platform for highly selective on-line cleanup and high-throughput LC-MS analysis of triazines in river water samples using molecularly imprinted polymers.

A novel highly selective sample cleanup procedure based on the use of molecularly imprinted polymers (MIPs) as solid-phase extraction materials has been evaluated with respect to its applicability and routine use in environmental analysis. The method comprises the combination of a restricted access material (RAM) and a MIP allowing a selective sample preparation to be achieved in the online mode. This combination is called the size-selective sample separation and solvent switch (six-SPE). The RAM column combines size exclusion and adsorption chromatography, reducing the concentration of matrix molecules by a cutoff of 15 kDa. The MIP column selectively retains the triazine analytes whereas the residual matrix is not retained and separated completely. Thus, the automated RAM-MIP is capable of excluding all matrix and nontarget compounds. The cleaned and enriched extract is subsequently eluted to an HPLC column and analyzed by LC-MS. A complete on-line analysis cycle including multidimensional solid-phase extraction, separation, and detection takes less than 15 min. Terbuthylazine, atrazine, propazine, simazine, ametryn, prometryn, irgarol, and also the metabolites deethylatrazine and deisopropylatrazine can be determined without any matrix interferences, e.g., by humic acids. The whole setup is fully automated and may be continuously operated. Nonspecific interactions with the polymer are below 1% in all cases. The accuracy of the LC-MIP-LC-MS system was controlled using a certified reference material (Aquacheck). The applicability of the method to the cleanup of real samples was demonstrated by injection of contaminated river water samples. The stability of different polymers was tested by consecutive injections, and it was shown that the performance of the materials did not vary even after more than 300 enrichment and desorption cycles.

Journal Article↗

PubMed2001

Determination of steroid sex hormones and related synthetic compounds considered as endocrine disrupters in water by fully automated on-line solid-phase extraction-liquid chromatography-diode array detection.

In this study, a procedure for the simultaneous determination in water of six estrogens (estradiol, estriol, estrone, ethynyl estradiol, mestranol, and diethylstilbestrol) and three progestogens (progesterone, norethindrone, and levonorgestrel), selected based on their abundance in the human body, their estrogenic potency, and the extent of their use in contraceptive pills, was developed. The procedure, based on the on-line solid-phase extraction (SPE) of the water sample and subsequent analysis by liquid chromatography/diode array detection (LC/DAD), allows for the monitoring of up to 16 samples in a completely automated, unattended way. The SPE experimental conditions were optimized and the polymeric cartridge PLRP-S selected out of four different cartridges evaluated. The chromatographic separation was carried out on a LiChrospher 100 RP-18 and detection was performed at 200, 225, and 240 nm. The applicability of the method to the analysis of various environmental water samples, including drinking water, groundwater, surface water and sewage treatment plant effluents, was evaluated. Method detection limits were in the range 10-20 ng/l. The method precision and accuracy were satisfactory with recovery percentages ranging from 96 to 111% and relative standard deviations lower than 3%. The technique is also considerably cheap, fast, and easy, and, therefore, very adequate for routing monitoring. To the authors' knowledge it constitutes the first work describing a fully automated, on-line methodology for the continuous monitoring of these compounds in water.

Chromatography, Liquid↗

PubMed2001

Analysis of ethoxylated nonionic surfactants and their metabolites by liquid chromatography/atmospheric pressure ionization mass spectrometry.

The widespread use and questionable environmental acceptability of nonionic surfactants make the alkylphenol ethoxylates (APEOs) and their neutral and acidic degradation products a focus of interest in environmental analytical chemistry. The characterization and especially quantification of polyethoxylate mixtures in environmental matrices is a challenge, because of the complexity of the mixtures. A review on trace analysis of APEOs using atmospheric pressure ionization mass spectrometry, including sample preparation and liquid chromatographic separation, is presented. In this Special Feature, the performances of two ionization methods, atmospheric pressure chemical ionization and electrospray ionization, is discussed in terms of selectivity and sensitivity toward oligomeric mixtures of APEOs. Capabilities and limitations associated with the liquid chromatographic/mass spectrometric detection of APEOs, their main degradation products and their halogenated metabolites, and also specific issues related to the sample preparation, formation of fragments, adducts and cluster ions, quantification of oligomeric mixtures and signal suppression effects in complex matrices, are discussed. Conclusions and future perspectives are outlined.

Chromatography, High Pressure Liquid↗

PubMed2001

Identification of photocatalytic degradation products of non-ionic polyethoxylated surfactants in wastewaters by solid-phase extraction followed by liquid chromatography-mass spectrometric detection.

The photodegradation of non-ionic surfactants (nonylphenol- and alcohol-polyethoxylates, NPEOx and CnEOx) was investigated in different waters with and without a photoinducter (Fe(III)). Deionized water and industrial effluent spiked at 0.5 mg/L with C10EO6 and NPEO9 were irradiated using a xenon arc lamp. Aliquots of the test solutions were taken at different time intervals and were preconcentrated using solid phase extraction (SPE) with C18 cartridges. Liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) was used to identify the chemical species generated from phototransformation of non-ionic surfactants. The intermediates detected included nonylphenol diethoxylate (NPEO2) and nonylphenol ethoxy acetic acid (NPE2C). Much smaller amounts of degradation products of NPEO9 having only the alkyl chain carboxylated were also formed in the photocatalysis experiment. The identified C10EO6 photoproducts included fatty alcohols and acids. Polyethylene glycols (PEGs) were also formed as the consequence of the central scission of C10EO6 and the deethoxylation of NPEO9. The photodegradation in wastewater samples was more efficient than in deionized water being the half-life (t(1/2)) of C10EO6, 48 h and 29 h in deionized water and wastewater, respectively, and for NPEO9, 17 h and 14 h in deionized water and wastewater, respectively. When induced photodegradation was undertaken, the t(1/2) for NPEO9 was 21 min and 29 min in deionized water and wastewater, respectively. Disappearance of parent compounds was observed after 120 h from the beginning of the photodegradation experiment, or after 210 min of irradiation for the photocatalysis.

Journal Article↗

PubMed2001

Determination of antifouling pesticides and their degradation products in marine sediments by means of ultrasonic extraction and HPLC-APCI-MS.

A method has been developed for the simultaneous determination of antifouling pesticides and some of their degradation products, e.g. dichlofluanid, diuron, demethyldiuron, 1-(3,4-dichlorophenyl)urea, sea-nine, Irgarol 1051 and one of its metabolites (2-methylthio-4-tert-butylamino-s-triazine) in marine sediments. The determination of these compounds in sediment samples was performed by means of methanolic ultrasonic extraction then clean-up on an Isolute ENV+ solid phase extraction (SPE) cartridge. The resulting extract was then analyzed by reversed-phase high-performance liquid chromatography coupled with atmospheric-pressure chemical-ionization mass spectrometry in negative and positive ion modes (HPLC-APCI-MS). Recovery ranged from 54-109% for the antifouling agents and their degradation products. The determination limits for the different compounds varied between 0.2 and 1.6 microg kg(-1) dry sediment. The analytical procedure was successfully applied to the determination of these pesticides and their degradation products in marine sediment samples from different marinas of the Catalan coast. The compounds detected were: diuron, dichlofluanid, demethyldiuron, sea-nine, and Irgarol 1051. The highest concentrations were those of diuron and Irgarol 1051--136 and 88 microg kg(-1), respectively.

Aniline Compounds↗

PubMed2001

Characterization of wastewater toxicity by means of a whole-cell bacterial biosensor, using Pseudomonas putida, in conjunction with chemical analysis.

A new amperometric biosensor based on inhibition of Pseudomonas putida has been developed to assess the acute toxicity of wastewater. This system uses the biological component immobilized on disposable screen-printed electrodes. The responses for a selected group of polar organic standard substances were studied using Pseudomonas putida as biological component. The results have been compared with responses obtained using the same system and Escherichia coli as biological component and with the bioluminescence inhibition of Vibrio fisheri using ToxAlert 100. Different properties, e.g. the standard deviation (SD) of the data, the goodness of fit (R2) and the standard deviation (Syx) of the vertical distances of the points from the inhibition curve, the 50% effective concentration (EC50) and the toxicity units (TII50) of the standard substance, were calculated and compared. This biosensor was used to assess the acute toxicity of real wastewater samples collected at different wastewater treatment plants (WWTP). Finally, a sequential solid-phase extraction (SSPE) procedure followed by liquid chromatography-mass spectrometry (LC-MS) was used to determine the polar organic toxic substances present in the wastewater samples.

Biosensing Techniques↗

PubMed2001

Review of analytical methods for the determination of estrogens and progestogens in waste waters.

Steroid sex hormones and related synthetic compounds, e.g. those used in contraceptive pills, have been shown to be present in the aquatic environment, mainly as a result of inefficient removal in waste-water-treatment plants (WWTP). The concentrations of the compounds, although very low (low ng L(-1)), are sufficient to induce estrogenic responses and alter the normal reproduction and development of wildlife organisms. The compounds have been determined, by a variety of analytical procedures, in the influents and effluents of WWTP, within research programs conducted in different countries to evaluate the efficiency of the waste-water-treatment processes currently in use. Determination of natural and synthetic estrogens and progestogens in waste water is, however, a difficult analytical task, because the very low detection limits required and the complexity of the waste-water matrix necessitate the execution of a considerable number of steps. Thus, in general, complicated, time-consuming extraction and purification processes, usually based on the application of solid-liquid extraction, are performed before final determination by immunoassay, high-performance liquid chromatography, or, most often, gas chromatography coupled with mass spectrometry. This paper reviews the analytical methods so far described for the analysis of these important environmental pollutants in waste water and discusses the key procedural steps, from sampling to analysis, and the techniques most commonly used in the determination.

Estrogens↗

PubMed2001

LC-MS determination of linear alkylbenzene sulfonates and their carboxylic degradation products in influent and effluent water samples and sludges from sewage-treatment plants.

Linear alkylbenzene sulfonates (LAS) have been determined in samples of the influent and the effluent, and in the sludge, from sewage-treatment plants (STP). LAS and sulfophenyl carboxylate compounds (SPC) were isolated by solid-phase extraction (SPE) with the polymeric phase Isolute ENV, then determined by liquid chromatography-electrospray mass spectrometry (LC-ESI-MS). The method enabled unequivocal identification of C10-C13 LAS by monitoring the ion at m/z 183 and the base peak corresponding to the [M-H]- ion. Average recoveries varied from 77-93% and the linear range of the method varied from 0.2 to 10 microg L(-1), with a limit of detection ranging from 10 ng L(-1) to 1.5 microg L(-1) when 200 mL waste water were preconcentrated. For sewage sludge, recoveries varied from 58 to 90% and the linear range was between 0.2 and 100 microg L(-1), with a detection limit ranging from 0.4 to 120 microg kg(-1) when 2.5 g sewage sludge was extracted. Unequivocal identification and determination of some metabolites of the LAS, the sulfophenyl carboxylate compounds (SPC), was achieved by monitoring [M-H]- ions.

Alkanesulfonic Acids↗

PubMed2001

Occurrence of polycyclic aromatic hydrocarbons in sewage sludge and their contribution to its toxicity in the toxalert 100 bioassay.

The contribution of polycyclic aromatic hydrocarbons (PAH) present in sewage sludge samples to toxicity was investigated. Chemical analysis using gas chromatography mass spectrometry (GC-MS) and the ToxAlert 100 bioassay, based on the inhibition to Vibrio fischeri, were applied to sludge extracts after purification by column chromatography. The levels of the 16 US EPA PAH analyzed in the sewage sludge samples varied from 17 to 2,030 microg kg(-1). In all samples examined phenanthrene was the most prominent compound. The toxicity data obtained by ToxAlert 100 can be explained by the levels and composition of the different PAH in sewage sludge samples. The present approach can contribute to evaluate the toxicity of sewage sludge.

Environmental Monitoring↗

PubMed2001

Determination of linear alkylbenzene sulfonates and their polar carboxylic degradation products in sewage treatment plants by automated solid-phase extraction followed by capillary electrophoresis-mass spectrometry.

Linear alkylbenzene sulfonates (LAS) were determined by solid-phase extraction (SPE), followed by capillary electrophoresis and mass spectrometry detection (CE-MS). The linear range of the proposed method varied from 33 to 316 and from 215 to 2057 micrograms L-1, depending on the compound, with limits of detection ranging from 4.4 to 23 micrograms L-1 when 200 ml of wastewater were preconcentrated. The analysis and confirmation of the polar carboxylic metabolites of LAS, the sulfophenyl carboxylic acids (SPC) was also achieved, and their presence was detected in both, influent and effluents of the sewage treatment plant (STP). [M - H]- ions were used for CE-MS confirmation and quantification. CE-MS diagnostic ions were the same ones used in LC-electrospray (ESI)-MS and corresponded to m/z 297, 311, 325 and 339 for C10LAS, C11LAS, C12LAS and C13LAS, respectively. For SPC identification, diagnostic ions corresponded to m/z 215 to 369 (with 14 mass unit steps) for C2 to C13SPC, respectively. LAS were determined in wastewater samples of the influent and effluent of three sewage treatment plants (STP), two of them using biological treatment with secondary settlement and receiving mainly domestic wastewater whereas one of the plants was operated with physiochemical treatment and received mainly industrial wastewater. The concentration levels of total LAS varied from 1000 to 1900 micrograms L-1 in the influents of STP, whereas in the effluents the concentrations varied from 125 to 360 micrograms L-1.

Journal Article↗

PubMed2001

Identification of surfactant degradation products as toxic organic compounds present in sewage sludge.

A cost-effective strategy combining chemical analysis and bioassays for the identification of polar toxic compounds in sewage sludge is reported. ToxAlert 100 bioluminescence inhibition assay was used in combination with chemical analysis involving extraction, clean-up, chromatographic separation and mass spectrometry detection. This methodology was applied to real samples of sludge from three wastewater treatment plants (WWTP) located in Catalonia (Spain) during a 3 month period. In the first step, sewage sludge was lyophilized, treated by sonication with a mixture of methanol and chloroform and finally cleaned up using a sequential solid phase extraction (SSPE) with an octadecylsilica cartridge (C18) in series with a polymeric Lichrolut EN cartridge (Lic EN). In the second step, the toxicity of each fraction of the sludge sample was investigated using the ToxAlert 100. The unequivocal identification and quantification of polar organic cytotoxic substances present in the fractionated extracts were determined by liquid chromatography-mass spectrometry (LC-MS). Major toxic compounds identified were: non-ionic polyethoxylated surfactants (nonylphenol polyethoxylates, alcohol polyethoxylates), their intermediates (polyethylene glycol polyethoxylated, nonylphenol carboxylates and polyethoxylated alcohol carboxylates), linear alkylbenzenesulfonates and heavy metals. The toxic response (in terms of bioluminescence inhibition using ToxAlert 100), defined by the 50% effective concentration (EC50), and the toxicity units (TU) for every standard non-ionic surfactant were calculated. The results provided the identification of polar cytotoxic compounds as well as the evaluation of their contribution to the total toxicity observed in sewage sludge.

Biodegradation, Environmental↗

PubMed2001

Main findings and conclusions of the implementation of Directive 76/464/CEE concerning the monitoring of organic pollutants in surface waters (Portugal, April 1999-May 2000).

The purpose of this paper is to relate the implementation of Directive 76/464/CEE concerning the survey of priority dangerous substances and indicate the main priority pollutants encountered throughout a systematic monitoring program carried out in Portugal during a period of 14 months (April 1999-May 2000). Contrary to what it seems, the implementation of such a Directive is not straightforward owing to the large number of compounds and samples to be analyzed at trace levels. During this period of time, 115 priority semivolatile organic compounds (SVOCs), 41 volatile organic compounds (VOCs), six organotin compounds, 14 heavy metals, phosphate, nitrates, nitrites and ammonia were determined in 644 surface water samples (corresponding to 14 months and 46 sites). In addition, priority SVOCs were also determined in sediment, mussels and fish (muscle and liver). This paper reports the procedure and analytical tools used and necessary to determine the levels of 115 priority toxic and persistent semivolatile organic compounds selected from the EC Council Directive list (76/464/EEC). An advanced analytical protocol was developed involving enrichment of water samples in Oasis solid-phase extraction cartridges (SPE) in the Lisbon laboratory with a Gilson ASPEC XL automated extraction system and by sending the enriched cartridges to Barcelona by aeroplane at 4 degrees C, where elution and analysis were performed. Final determination was performed with gas chromatography-electron ionization mass spectrometry (GC-EI-MS). Acidic herbicides were determined by liquid chromatography with diode array detection. Owing to the great amount of data generated throughout the monitoring study, statistical analysis of the more representative contaminants was performed, allowing the identification of the more relevant contamination sources, percentages of findings and the description of their temporal and spatial (geographical) distributions. Recommendations and compounds that should be included in future monitoring programs are given.

Environmental Monitoring↗

PubMed2001

Organic pollutants in surface waters from Portugal using chemometric interpretation.

Surface water samples from 45 sampling points across Portugal have been analyzed monthly by automated Solid Phase Extraction (SPE) and Gas Chromatography-Mass Spectrometry (GC/MS) in SIM and SCAN modes. Sampling was carried out during a period of six months (April-September, 1999), in order to determine the levels of contamination of 72 organic compounds mainly selected from the EC Council Directive list (CEC 76/464/EEC). Atrazine, simazine, deethylatrazine, alachlor, metolachlor, Irgarol, terbuthylazine, tributhylphosphate, 2,4,6-trichlorophenol, 2-chlorophenol, 3-chlorophenol, pentachlorophenol, dimethoate, lindane, linuron, propanil, o,p'-DDD, o,p'-DDT, o,p'-DDE and malathion were the main detected compounds. Although Irgarol, terbuthylazine, deethylatrazine and deisopropylatrazine are not listed in the EC Directive, these herbicides and transformation products are currently in use and they were also included in the monitoring program and detected at some sites. Fifty-nine percent of the samples were below 0.1 microg l(-1), the detection limit required the EEC Drinking Water Directive (DWD). Some compounds were detected at values higher than the DWD, e.g. atrazine (2.7 microg l(-1)) and alachlor (5.43 microg l(-1)) in April. Simazine was also present with a high value (2.3 microg l(-1)) in September. Tributhylphosphate (5.40 microg l(-1)) and 2,4,6-trichlorophenol (2.31 microg l(-1)) were also found at high concentrations near industrial sites. Chemometric interpretation of the more representative contaminants was performed by means of Principal Component Analysis, allowing the resolution of the more relevant contamination sources and the description of their temporal and spatial (geographical) distributions.

Environmental Monitoring↗

PubMed2001

Occurrence of antifouling biocides in the Spanish Mediterranean marine environment.

A compilation of the results of a monitoring program of the recently used antifouling pesticides diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea), Irgarol 1051 (2-methylthio-4-tertiary-butylamino-6-cyclopropylamino-s-teiazine), seanine 211 (4,5-dichloro-2-n-octyl-4-isothazolin-3-one), chlorothalonil (2,4,5,6-tetrachloro-isophthalonitrile), dichlofluanid (N'-dimethyl-N-phenylsulphanamide), TCMTB ((2-thiocyanomethylthio) benzothiazole), and three degradation products demethyldiuron (3-(3,4-dichlorophenyl)-1-methylurea),3,4-dichlorophenylurea and 2-methylthio-4-tert-butylamino-s-triazine (Irgarol degradation product) that was carried out between April 1996 and February 2000 in enclosed seawaters from Catalonia and Almería (Spanish Mediterranean coast) is reported. Nine points were sampled along the Catalan coast: Barcelona Olympic port, Masnou, Blanes, Sant Carles de la Ràpita, Tarragona, Cambrils and Salou marinas as well as the Cambrils and Tarragona fishing harbors and in marinas and ports from Almeria: Aguadulce port, Almería port, Almerimar fishing harbour and Almerimar marina. The analytical methodologies were based on Solid Phase Extraction followed by liquid chromatography (LC) or gas chromatography (GC) coupled to a mass spectrometry (MS) or -Diode Array Detector. The main pollutants found in the sampled points were diuron and Irgarol 1051 that were detected at concentrations up to 2.19 micrograms l-1 and 0.33 microgram l-1, respectively. On the other hand, seanine 211 was found at the highest concentration (up to 3.7 micrograms l-1) during the summer of 1999. Low concentrations of dichlofluanid and the above mentioned degradation products were detected for the first time in the Spanish coasts. Chlorothalonil, TCMTB were not found at concentrations higher than 1 and 20 ng l-1 respectively which were the limit of determination (LOD) of the method for these compounds. In general the contamination at the different marinas is higher at the end of spring and in summer where the boating activity is also higher. This paper shows for the first time that the contamination by the new antifouling pesticides in Spanish coastline, basically marinas and fishing harbours, is permanent along the whole calendar year. So, preventive actions by the harbour authorities will be needed in the near future in order to monitor and control the levels and effects of the new antifouling biocides in the marine environment.

Chromatography, High Pressure Liquid↗

PubMed2001

Monitoring of endocrine disruptors in surface waters by the yeast recombinant assay.

Endocrine disruptors exert physiological effects at very low concentrations. Surface waters present often a mixture of high concentrations of low-potency disruptors and low amounts of very powerful ones, making their chemical analysis complicated and expensive. We developed a recombinant yeast assay (RYA) for estrogenic compounds using 96-well microtiter plates. This assay is based on three yeast strains, transformed with self-propagating plasmids. One strain contains an expression plasmid for the human estrogen hormone receptor and an appropriate reporter; it detects estrogenic and antiestrogenic activities. The two other yeast strains, one expressing the human progesterone receptor and a second based on the yeast activator Gal4p, served to analyze the nature of antiestrogenic activities. We applied this technique to water samples from two tributaries on the Llobregat river (NE Spain) as well as from four sewage treatment plants discharging on them. Our results indicate that the efficiency of sewage treatment plants for eliminating estrogenic compounds varied notably, being in at least one case completely inefficient. We also observed a prevalence of an inhibitory activity all through the two rivers; this inhibition was hormone specific. These results were consistent to previously obtained chemical analyses of the same samples, although chemical and in vivo analyses showed rather different levels of sensitivity for some compounds. Our findings demonstrate the utility of the yeast recombinant assay for analyzing complex natural samples; at the same time, they stress the necessity of a panel of different yeast systems to adequately describe endocrine-disruptor activities.

Algorithms↗