Iria González-Mariño

Spatial differences and temporal changes in illicit drug use in Europe quantified by wastewater analysis

Aims To perform wastewater analyses to assess spatial differences and temporal changes of illicit drug use in a large European population. Design Analyses of raw wastewater over a 1-week period in 2012 and 2013. Setting and Participants Catchment areas of wastewater treatment plants (WWTPs) across Europe, as follows: 2012: 25 WWTPs in 11 countries (23 cities, total population 11.50 million); 2013: 47 WWTPs in 21 countries (42 cities, total population 24.74 million). Measurements Excretion products of five illicit drugs (cocaine, amphetamine, ecstasy, methamphetamine, cannabis) were quantified in wastewater samples using methods based on liquid chromatography coupled to mass spectrometry. Findings Spatial differences were assessed and confirmed to vary greatly across European metropolitan areas. In general, results were in agreement with traditional surveillance data, where available. While temporal changes were substantial in individual cities and years (P ranging from insignificant to <10−3), overall means were relatively stable. The overall mean of methamphetamine was an exception (apparent decline in 2012), as it was influenced mainly by four cities. Conclusions Wastewater analysis performed across Europe provides complementary evidence on illicit drug consumption and generally concurs with traditional surveillance data. Wastewater analysis can measure total illicit drug use more quickly and regularly than is the current norm for national surveys, and creates estimates where such data does not exist.

Simultaneous determination of parabens, triclosan and triclocarban in water by liquid chromatography/electrospray ionisation tandem mass spectrometry.

A method for the determination of several household biocides in water by liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) is presented. It permits the simultaneous determination of triclosan (TCS), triclocarban (TCC) and seven parabens, including the distinction between branched and linear isomers of propyl (i-PrP and n-PrP) and butyl parabens (i-BuP and n-BuP). Prior to LC/MS/MS, analytes are preconcentrated by solid-phase extraction (SPE) on Oasis HLB (60 mg) cartridges at natural sample pH and subsequently eluted with 4 mL of methanol. This simple SPE procedure provides extraction recoveries above 85% except for raw wastewater, where it falls to 65% for TCC. The performance of the method was tested with two triple-quadrupole LC/MS instruments from a low/mid and mid/high market range: a Varian 1200L and an API-4000. The latter system provided between 3 and 80 times lower limits of quantification (LOQs) than the first one, in the 0.08-0.44 ng/L range for surface water. Moreover, a comparison of matrix effects on both instruments showed a very different behaviour, particularly in the case of parabens. For these compounds signal suppression was observed in the 1200L instrument and signal enhancement with the 4000 instrument. As a result, different calibration approaches were chosen for them and this pointed to the need of matrix effect re-evaluation in method transfer between different LC/MS systems. The application of the method to real samples showed the ubiquity of methyl paraben (MeP) and n-PrP (at the 1-6 microg/L in raw wastewater) and the coexistence of i-BuP and n-BuP at similar levels (ca. 100-200 ng/L in raw wastewater).

Evaluation of the occurrence and biodegradation of parabens and halogenated by-products in wastewater by accurate-mass liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-QTOF-MS).

An assessment of the sewage occurrence and biodegradability of seven parabens and three halogenated derivatives of methyl paraben (MeP) is presented. Several wastewater samples were collected at three different wastewater treatment plants (WWTPs) during April and May 2010, concentrated by solid-phase extraction (SPE) and analysed by liquid chromatography-electrospray-quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS). The performance of the QTOF system proved to be comparable to triple-quadrupole instruments in terms of quantitative capabilities, with good linearity (R(2) > 0.99 in the 5-500 ng mL(-1) range), repeatability (RSD < 5.6%) and LODs (0.3-4.0 ng L(-1) after SPE). MeP and n-propyl paraben (n-PrP) were the most frequently detected and the most abundant analytes in raw wastewater (0.3-10 μg L(-1)), in accordance with the data displayed in the bibliography and reflecting their wider use in cosmetic formulations. Samples were also evaluated in search for potential halogenated by-products of parabens, formed as a result of their reaction with residual chlorine contained in tap water. Monochloro- and dichloro-methyl paraben (ClMeP and Cl(2)MeP) were found and quantified in raw wastewater at levels between 0.01 and 0.1 μg L(-1). Halogenated derivatives of n-PrP could not be quantified due to the lack of standards; nevertheless, the monochlorinated species (ClPrP) was identified in several samples from its accurate precursor and product ions mass/charge ratios (m/z). Removal efficiencies of parabens and MeP chlorinated by-products in WWTPs exceeded 90%, with the lowest percentages corresponding to the latter species. This trend was confirmed by an activated sludge biodegradation batch test, where non-halogenated parabens had half-lives lower than 4 days, whereas halogenated derivatives of MeP turned out to be more persistent, with up to 10 days of half-life in the case of dihalogenated derivatives. A further stability test performed with raw wastewater also showed that parabens degrade rapidly in real sewage, with half-lives lower than 10 h for n-butyl-paraben, while dihalogenated species again turned out to be more stable, with half-lives longer than a week.

Determination of drugs of abuse in water by solid-phase extraction, derivatisation and gas chromatography–ion trap-tandem mass spectrometry

An alternative method for the sensitive determination of several drugs of abuse and some of their metabolites in surface and sewage water samples is proposed. Analytes are concentrated using a solid-phase extraction (SPE) sorbent, converted into the corresponding trimethylsilyl derivatives and selectively determined by gas chromatography (GC) with tandem mass spectrometry (MS/MS) detection. Parameters affecting the performance of extraction, derivatisation and determination steps are systematically investigated. Moreover, the stability of target analytes in sewage water samples is discussed. Under final working conditions, water samples were adjusted at pH 8.5 and concentrated using a 200mg OASIS HLB SPE cartridge. Analytes were sequentially eluted with ethyl acetate followed by acetone and silylated using N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA). The reaction was completed in 60 min at 80 degrees C and the mixture injected directly in the GC-MS/MS system without further purification. In most cases, analytes presented a poor stability in sewage water samples; however, once they are submitted to the SPE process, cartridges can be stored at -20 degrees C for at least 3 months without significant degradation and/or inter-conversion reactions of illicit drugs. The proposed method provided recoveries over 74% and LODs between 0.8 and 15 ng/L for river and treated wastewater samples. In the case of raw wastewater slightly worse recoveries, between 63 and 137%, and similar LODs were attained. Analysis of a limited number of waste and surface water samples confirmed the presence of several illicit drugs in the aquatic environment, with the highest levels and frequency corresponding to benzoylecgonine, the main metabolite of cocaine.

Screening and selective quantification of illicit drugs in wastewater by mixed-mode solid-phase extraction and quadrupole-time-of-flight liquid chromatography-mass spectrometry.

For the first time, a mixed-mode solid-phase extraction with fractionation of basic analytes from neutral and acidic species during cartridge elution and liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS) was combined for the quantitative determination of 24 illicit drugs and metabolites in urban sewage samples. The effects of several sample preparation and instrumental parameters in the sensitivity and selectivity of the quantitative method are thoroughly discussed. Under final working conditions, recoveries above 63% and 82% were attained for all species in raw and treated sewage, respectively; whereas, the limits of quantification of the method, defined for a signal-to-noise of 10 (S/N = 10), ranged from 2 to 50 ng L(-1). Sequential elution of mixed-mode cartridges allowed a significant reduction of matrix effects observed during electrospray ionization of basic drugs versus those measured for hydrophilic balance reversed-phase sorbents and the same mixed-mode polymer without fractionated elution. Analysis of raw wastewater samples confirmed the ubiquity of cocaine (COC), benzoylecgonine (BE), and 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THCCOOH) in this matrix. The capability of the above methodology to identify new illicit drugs and/or metabolites in sewage samples is also discussed. With this aim, a two step strategy is proposed. First, high-resolution MS chromatograms, acquired throughout each chromatographic run, are automatically searched against an in-house built database, a reduced list of candidate drugs is generated, and the corresponding extracted ion chromatograms are obtained. In a further LC run, the tandem mass spectrometry (MS/MS) spectra of unknown peaks are acquired using different collision energies and compared with those existing in public libraries, or interpreted, to assign the unknown peak to one of the previously selected candidates.

Comparison of molecularly imprinted, mixed-mode and hydrophilic balance sorbents performance in the solid-phase extraction of amphetamine drugs from wastewater samples for liquid chromatography–tandem mass spectrometry determination

Recent studies have shown that amphetamines and other drugs of abuse residues occur in wastewater. Consequently, several methods have been developed for their determination by solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). However, a major drawback of these methods is the lack of selectivity during SPE that results in reduced sensitivity, due to matrix effects, and in some cases in low precision and poor accuracy. In order to tackle this problem, three different SPE alternatives have been evaluated in this work for the determination of five amphetamines: common hydrophilic balance (Oasis HLB), mixed-mode (Oasis MCX) and molecularly imprinted polymers (MIPs) sorbents. Among them, Oasis HLB showed the worst performance, as three amphetamines (MDA, MDMA and MDEA) could not be determined because of interfering signals in the LC-MS/MS chromatogram, and amphetamine recoveries could not be corrected by the use of the deuterated analogue internal standard. Oasis MCX permitted the determination of all target analytes, but with still strong signal suppression: ca. 70% signal drop with wastewater samples, which could in this case be corrected by the internal standards providing acceptable trueness (overall recoveries: 101-137%), precision (RSD: 2.0-12%) and limits of detection (LOD: 1.5-4.4 ng/L). Alternatively, MIPs rendered cleaner extracts with less matrix effects (ca. 30% signal drop), and thus lower LODs (0.5-2.7 ng/L) and even better trueness (91-114% overall recovery) and precision (1.5-4.4%RSD). The final application of the method with MIP cartridges showed the presence of MDA and MDMA in the seven analysed wastewaters at the 4-20 ng/L level.

Fully automated determination of parabens, triclosan and methyl triclosan in wastewater by microextraction by packed sorbents and gas chromatography–mass spectrometry

A fully automated method for the determination of triclosan (TCS), its derivative methyl triclosan (MeTCS) and six parabens (esters of 4-hydroxybenzoic acid) including branched and linear isomers of propyl (i-PrP and n-PrP) and butyl paraben (i-BuP and n-BuP) in sewage water samples is presented. The procedure includes analytes enrichment by microextraction by packed sorbent (MEPS) coupled at-line to large volume injection-gas chromatography-mass spectrometry (LVI-GC-MS). Under optimised conditions, compounds were extracted from 2 mL samples, adjusted at pH 3, using a C18 MEPS-sorbent. Adsorbed analytes were eluted directly into the Programmable Temperature Vaporizer (PTV) injector of the chromatograph with 2×25 μL of ethyl acetate. They were quantified using standard solutions in ultrapure water submitted to the same sample enrichment process as real sewage water samples. After signal normalisation using isotopic labelled species as internal surrogates, no differences were noticed among the extraction efficiency for sewage and ultrapure water; moreover, the proposed method reported lineal calibration curves from 0.1 to 10 ng mL(-1), relative standard deviations (%RSD) between 2 and 7.1% and limits of detection (LODs) varying from 0.001 to 0.015 ng mL(-1) in ultrapure water and from 0.02 to 0.59 ng mL(-1) in the most complex sample (raw wastewater).

Alcohol and cocaine co-consumption in two European cities assessed by wastewater analysis

The quantitative determination of urinary biomarkers in raw wastewater has emerged in recent years as a promising tool for estimating the consumption of illicit drugs, tobacco and alcohol in a population and for comparing local and temporal trends. In this study, a three-year monitoring campaign (2012-2014) was conducted to compare alcohol and cocaine use in two European cities (Santiago de Compostela, Spain, and Milan, Italy) by wastewater analysis. Ethyl sulphate and benzoylecgonine were used, respectively, as biomarkers of ethanol and cocaine consumption and cocaethylene as an indicator of co-consumption of both substances. Biomarkers were measured using liquid chromatography-tandem mass spectrometry and concentrations were converted to rates of consumption using specific correction factors. Results were statistically compared in terms of geographic and temporal tendencies. Alcohol intake was significantly higher in Santiago than in Milan (13.6L versus 5.1L ethanol/1000 people day, averages). Cocaine use was higher in Milan than in Santiago de Compostela (800 versus 632 mg/1000 people day, averages). A significant higher consumption of both alcohol and cocaine was observed during the weekends (~23-75% more than on weekdays) in both cities. In terms of years, slight changes were observed, but no clear trends as representative of the whole year could be identified because of the limited number of days sampled. Co-consumption was evaluated using the cocaethylene/benzoylecgonine ratio, which was higher during the weekend in both cities (58% in Santiago and 47% in Milan over the non-weekend day means), indicating a greater co-consumption when cocaine is used as a recreational drug. Wastewater-based epidemiology gave estimates of alcohol and cocaine use in agreement with previous wastewater studies and with recent European surveillance and prevalence data, and weekly profiles of use and preferential patterns of consumption could be plot.

Measuring biomarkers in wastewater as a new source of epidemiological information: Current state and future perspectives

The information obtained from the chemical analysis of specific human excretion products (biomarkers) in urban wastewater can be used to estimate the exposure or consumption of the population under investigation to a defined substance. A proper biomarker can provide relevant information about lifestyle habits, health and wellbeing, but its selection is not an easy task as it should fulfil several specific requirements in order to be successfully employed. This paper aims to summarize the current knowledge related to the most relevant biomarkers used so far. In addition, some potential wastewater biomarkers that could be used for future applications were evaluated. For this purpose, representative chemical classes have been chosen and grouped in four main categories: (i) those that provide estimates of lifestyle factors and substance use, (ii) those used to estimate the exposure to toxicants present in the environment and food, (iii) those that have the potential to provide information about public health and illness and (iv) those used to estimate the population size. To facilitate the evaluation of the eligibility of a compound as a biomarker, information, when available, on stability in urine and wastewater and pharmacokinetic data (i.e. metabolism and urinary excretion profile) has been reviewed. Finally, several needs and recommendations for future research are proposed.

Investigation of the transformation of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol during water chlorination by liquid chromatography–quadrupole-time-of-flight-mass spectrometry

The stability of the main metabolite of cannabis, (±)-11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THCCOOH), during water chlorination has been investigated. THCCOOH was degraded in few seconds following a pseudo-first order kinetics. Sample pH turned out to be a significant factor, decreasing THCCOOH half-life with an increase in its values. Seven by-products could be positively identified from accurate mass measurements: three compounds resulted from electrophilic substitutions of hydrogen per chlorine (or bromine) in the aromatic ring, whereas the formation of the remaining four involved additional reactions in the C-C double bond (hydration and halogenation). The software predicted toxicity of these products towards Daphnia magna indicates that they are expected to have toxicity values similar or higher than its precursor compound. Experiments conducted with diluted urine showed that THCCOOH was stable in this matrix, probably due to a rapid and complete reaction between chlorine and other organic constituents already present in the samples. In real surface waters, the extent of the reaction was also affected by the organic matter content, and so THCCOOH was rapidly degraded in samples scarcely affected by human activities, being more stable in waters with a higher level of pollution.