Mining the Chemical Information on Urban Wastewater: Monitoring Human Exposure to Phosphorus Flame Retardants and Plasticizers.

At the individual level, exposure to contaminants is generally assessed through the analysis of specific biomarkers in biological matrices. However, these studies are costly and logistically demanding, limiting their applicability to monitor population-wide exposure over time and space. By focusing on a selection of exposure biomarkers to phosphorus flame retardants and plasticizers (PFRs), this study aims to explore the possibility of using wastewater as a complementary source of information about exposure. Wastewater samples were collected from five cities in Europe and analyzed using a previously established method. Substantial differences in biomarker levels were observed between the investigated catchments, suggesting differences in exposure. Time trends in biomarkers observed between 2013 and 2016 were found to agree with results from human biomonitoring studies and reports about production volumes. Using Monte Carlo simulations, average urinary concentrations were estimated. These were generally higher compared to results from human biomonitoring studies. Various explanations for these differences were formulated (i.e., other excretion routes, external sources and different sampling approaches). Obtained results show that wastewater analysis provides unique information about geographical and temporal differences in exposure, which would be difficult to gather using other monitoring tools.

Population normalization with ammonium in wastewater-based epidemiology: application to illicit drug monitoring.

Fluctuations in ammonium (NH4+), measured as NH4-N loads using an ion-selective electrode installed at the inlet of a sewage treatment plant, showed a distinctive pattern which was associated to weekly (i.e., commuters) and seasonal (i.e., holidays) fluctuations of the population. Moreover, population size estimates based on NH4-N loads were lower compared to census data. Diurnal profiles of benzoylecgonine (BE) and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH) were shown to be strongly correlated to NH4-N. Characteristic patterns, which reflect the prolonged nocturnal activity of people during the weekend, could be observed for BE, cocaine, and a major metabolite of MDMA (i.e., 4-hydroxy-3-methoxymethamphetamine). Additional 24 h composite samples were collected between February and September 2013. Per-capita loads (i.e., grams per day per 1000 inhabitants) were computed using census data and NH4-N measurements. Normalization with NH4-N did not modify the overall pattern, suggesting that the magnitude of fluctuations in the size of the population is negligible compared to those of illicit drug loads. Results show that fluctuations in the size of the population over longer periods of time or during major events can be monitored using NH4-N loads: either using raw NH4-N loads or population size estimates based on NH4-N loads, if information about site-specific NH4-N population equivalents is available.

The Use of Passive Samplers to Reveal Industrial and Agricultural Pollution Trends in Swiss Rivers.

This study shows the efficiency of passive sampling to reveal industrial and agricultural pollution trends. Two practical applications for nonpolar and polar contaminants are presented. Low-density polyethylene (LDPE) samplers were deployed for one year in the Venoge River (VD) to monitor indicator PCBs (iPCBs, IUPAC nos. 28, 52, 101, 138, 153 and 180). The results showed that the impact of PCB emissions into the river is higher in summer than in other seasons due to the low flow rate of the river during this period. Polar organic chemical integrative samplers (POCIS) were deployed for 4 months in the Sion-Riddes canal (VS) to investigate herbicides (terbuthylazine, diuron and linuron). Desisopropylatrazine-d5 (DIA-d5) was tested as a performance reference compound (PRC) to estimate aqueous concentration. The results showed an increase of water contamination due to the studied agricultural area. The maximal contamination was observed in April and corresponds to the period of herbicide application on the crops.

Exploring the added value of portable devices such as near infrared spectrometer in the field of illicit drugs analyses.

Facing the problem of backlogs in the forensic laboratories, the field of illicit drugs analyses has recently seen the development of different types of portable devices. Their main purpose is to be used directly by the police in order to reduce the number of specimens that are sent to the laboratories. Several portable devices have shown promising results. To avoid misuses, the added value of these devices should be explored, in order to establish "good practices" and keep the communication channels open between the police and the laboratories. Adapting sampling procedures around the use of portable devices allows for real-time qualitative and quantitative data. Forensic scientists can therefore rapidly assess whether every specimen in a seizure contain illicit drugs and if the seizure is composed of specimens showing different composition. Based on these information, forensic scientists can proceed to an intelligence-led sampling and prioritise specimens that would require further analyses. Additionally, the availability of more analysis data can strengthen the confidence in the reporting of the sampling process and the analyses results. Various scenarios have been tested in an operational context at the Geneva Cantonal Police Force using an ultraportable NIR device. The focus was oriented on sampling issues and the intelligence produced. Results indicate a great potential to detect the different classes within a seizure and therefore to ensure a representative sampling for further analyses.

What is the future of illicit drug profiling in Switzerland? Condemned to disappear or forgotten treasure.

Illicit drug profiling bears a long history. Developments in the field from mid-90s have led to several international profiling programs. Several countries have put their efforts to develop and implement the routine use of illicit drug profiling in the investigation and prosecution of illicit drug-related crimes. For more than 20 years, the School of Criminal Sciences (ESC) at the University of Lausanne has, through its illicit drug expertise laboratory, played a main role in promoting the use of illicit drug profiling. In Switzerland, there is no national illicit drug profiling practice and the ESC laboratory is the only one offering such service. However, only a limited number of Swiss jurisdictions send regularly all or part of their seized specimens for analysis to the ESC laboratory. Profiling results are furnished to investigators and prosecutors regardless if they have been requested or not and are stored in a database with limited contextual information with no further data treatment. In 2020, the interruption of a project intended to develop and implement an intercantonal database gathering traditional police data, forensic data (e.g., DNA, fingerprints, etc.), and physical and chemical links, to produce intelligence and support investigation, led to the fundamental question: Is illicit drug profiling in Switzerland condemned to disappear or is it a forgotten treasure, a neglected approach that deserves to be revalued? This paper reports the Swiss situation regarding illicit drug profiling practices and discusses some factors that are thought to impact its use in day-to-day work.

Retrospective suspect and non-target screening combined with similarity measures to prioritize MDMA and amphetamine synthesis markers in wastewater.

3,4-Methylenedioxymethamphetamine (MDMA) and amphetamine are commonly used psychoactive stimulants. Illegal manufacture of these substances, mainly located in the Netherlands and Belgium, generates large amounts of chemical waste which is disposed in the environment or released in sewer systems. Retrospective analysis of high-resolution mass spectrometry (HRMS) data was implemented to detect synthesis markers of MDMA and amphetamine production in wastewater samples. Specifically, suspect and non-target screening, combined with a prioritization approach based on similarity measures between detected features and mass loads of MDMA and amphetamine was implemented. Two hundred and thirty-five 24 h-composite wastewater samples collected from a treatment plant in the Netherlands between 2016 and 2018 were analyzed by liquid chromatography coupled to high-resolution mass spectrometry. Samples were initially separated into two groups (i.e., baseline consumption versus dumping) based on daily loads of MDMA and amphetamine. Significance testing and fold-changes were used to find differences between features in the two groups. Then, associations between peak areas of all features and MDMA or amphetamine loads were investigated across the whole time series using various measures (Euclidian distance, Pearson's correlation coefficient, Spearman's rank correlation coefficient, distance correlation and maximum information coefficient). This unsupervised and unbiased approach was used for prioritization of features and allowed the selection of 28 presumed markers of production of MDMA and amphetamine. These markers could potentially be used to detect dumps in sewer systems, help in determining the synthesis route and track down the waste in the environment.

Illicit drug profiling practices in Finland: An exploratory study about end users' perceptions.

Illicit drug profiling (i.e. chemical and/or physical profiling) to compare and relate illicit drugs samples has been actively used in routine case work at the National Bureau of Investigation (NBI) in Finland. This preliminary and exploratory work reviews NBI's illicit drug profiling practices. Particular emphasis is put on communication of forensic results and how the NBI has promoted the use of forensic data in an intelligence perspective by establishing a case coordination service. Moreover, our study evaluates the comprehension, integration and usefulness of illicit drug profiling from end users' point of view by means of an online survey and face-to-face interviews. Findings are compared with theoretical aspects as described in literature. Results show that in the Finnish context illicit drug profiling is used and useful in the investigation and in court. From end users' perspective, real practical relevance relies in its use as intelligence during the investigation. However, to be truly useful, illicit drug profiling results must be communicated promptly during the investigation, with sufficient clarity and interpreted correctly by end users. Factors influencing the integration of illicit drug profiling in the forensic process are addressed.

New perspective for the in-field analysis of cannabis samples using handheld near-infrared spectroscopy: A case study focusing on the determination of Δ9-tetrahydrocannabinol.

The aim of the present study was to explore the feasibility of applying near-infrared (NIR) spectroscopy for the quantitative analysis of Δ9-tetrahydrocannabinol (THC) in cannabis products using handheld devices. A preliminary study was conducted on different physical forms (entire, ground and sieved) of cannabis inflorescences in order to evaluate the impact of sample homogeneity on THC content predictions. Since entire cannabis inflorescences represent the most common types of samples found in both the pharmaceutical and illicit markets, they have been considered priority analytical targets. Two handheld NIR spectrophotometers (a low-cost device and a mid-cost device) were used to perform the analyses and their predictive performance was compared. Six partial least square (PLS) models based on reference data obtained by UHPLC-UV were built. The importance of the technical features of the spectrophotometer for quantitative applications was highlighted. The mid-cost system outperformed the low-cost system in terms of predictive performance, especially when analyzing entire cannabis inflorescences. In contrast, for the more homogeneous forms, the results were comparable. The mid-cost system was selected as the best-suited spectrophotometer for this application. The number of cannabis inflorescence samples was augmented with new real samples, and a chemometric model based on machine learning ensemble algorithms was developed to predict the concentration of THC in those samples. Good predictive performance was obtained with a root mean squared error of prediction of 1.75 % (w/w). The Bland-Altman method was then used to compare the NIR predictions to the quantitative results obtained by UHPLC-UV and to evaluate the degree of accordance between the two analytical techniques. Each result fell within the established limits of agreement, demonstrating the feasibility of this chemometric model for analytical purposes. Finally, resin samples were investigated by both NIR devices. Two PLS models were built by using a sample set of 45 samples. When the analytical performances were compared, the mid-cost spectrophotometer significantly outperformed the low-cost device for prediction accuracy and reproducibility.

Providing illicit drugs results in five seconds using ultra-portable NIR technology: An opportunity for forensic laboratories to cope with the trend toward the decentralization of forensic capabilities.

The analysis of illicit drugs faces many challenges, mainly regarding the production of timely and reliable results and the production of added value from the generated data. It is essential to rethink the way this analysis is operationalised, in order to cope with the trend toward the decentralization of forensic applications. This paper describes the deployment of an ultra-portable near-infrared detector connected to a mobile application. This allows analysis and display of results to end users within 5s. The development of prediction models and their validation, as well as strategies for deployment within law enforcement organizations and forensic laboratories are discussed.

Testing wastewater from a music festival in Switzerland to assess illicit drug use.

This article describes the application of a recently proposed framework for deploying wastewater-based epidemiology (WBE) to monitor illicit drug use within festivals (Benaglia et al., 2019). The festival under study was a week-long music festival in Switzerland (Swiss Festival) which attracted around 50,000 people daily. Wastewater sampling was performed during its 2014 and 2015 editions. As the Swiss Festival's wastewater is conveyed to the sewage treatment plant (STP) of the nearby city, to assess illicit drug use when there is no festival (i.e. the background consumption) wastewater sampling was also carried out during an off-festival week in 2015. During the 2014 and 2015 editions of the Swiss Festival, WBE highlighted that the most consumed illicit drugs were cannabis, MDMA, cocaine and amphetamine. Excluding cannabis, the means per capita loads of all illicit drugs were not statistically different between both editions of the Swiss Festival. The results were then compared to those of an Australian festival which had also been subject of a quantitatively assessed illicit drug use study (Lai et al., 2013). This comparison confirmed that MDMA is highly prevalent, as well as amphetamine, although to a lesser extent. Consumption of cocaine (in Switzerland) and methamphetamine (in Australia) is also high, but their use seems to be related to their availability (i.e. to the country where the festival takes place). Furthermore, it was observed that MDMA and amphetamine are more consumed during the festival compared to normal times, when there is no festival. This might suggest that their availability is increased and therefore, that a market for these substances potentially exists during the festival. This last hypothesis was assessed by consulting drug seizures made by the police during the 2015 Swiss Festival. Despite very limited data, police records suggested that most of the drugs were purchased at the festival, which supports the previous hypothesis. Results validate, on the one hand, WBE as a useful indicator to monitor illicit drug use within festivals and on the other hand, the suggested framework for deploying WBE in such environment. In addition, this study suggests the need for prevention and harm reduction measures targeted on MDMA and amphetamine during the Swiss Festival, such as drug checking laboratories.

Substances injected at the Sydney supervised injecting facility: A chemical analysis of used injecting equipment and comparison with self-reported drug type.

Providing information about substances injected can reduce the negative impact of illicit drug consumption and support people who inject drugs to make informed decisions. In Australia, information about drugs injected relies largely on periodic self-report surveys. For the first time, the analysis of the residual content of used injecting equipment was conducted in a supervised injecting facility (SIF) located in Sydney, Australia. The aim was to gain a better understanding of the substances injected by clients through: (1) chemical analyses of the content of used syringes; (2) comparison of these results with clients' self-reported drug use; and (3) assessing the usefulness of analysing other injecting equipment to detect substances used. During one week in February 2019, syringes and other injecting equipment were collected at the Sydney SIF. Their residual content was analysed by gas-chromatography/mass-spectrometry. Heroin was the most commonly detected substance (present in 51% of syringes), followed by methamphetamine (22%) and oxycodone (10%). In addition to the main psychoactive substance, cutting agents reported in the literature were also detected in used syringes. The main psychoactive substance identified by laboratory analysis reliably corresponded with users' self-reported drug type. Analytical confirmation of substances injected allows for the provision of better targeted harm reduction messaging based on timely and objective data. The approach used is amenable to clients and feasible in the Australian SIF context. Upscaling and wider implementation could be done through Needle and Syringe Programs, and would support the early detection of harmful substances entering drug markets and better inform harm reduction strategies.

Spatio-temporal assessment of illicit drug use at large scale: evidence from 7 years of international wastewater monitoring.

BACKGROUND AND AIMS: Wastewater-based epidemiology is an additional indicator of drug use that is gaining reliability to complement the current established panel of indicators. The aims of this study were to: (i) assess spatial and temporal trends of population-normalized mass loads of benzoylecgonine, amphetamine, methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA) in raw wastewater over 7 years (2011-17); (ii) address overall drug use by estimating the average number of combined doses consumed per day in each city; and (iii) compare these with existing prevalence and seizure data. DESIGN: Analysis of daily raw wastewater composite samples collected over 1 week per year from 2011 to 2017. SETTING AND PARTICIPANTS: Catchment areas of 143 wastewater treatment plants in 120 cities in 37 countries. MEASUREMENTS: Parent substances (amphetamine, methamphetamine and MDMA) and the metabolites of cocaine (benzoylecgonine) and of Δ9 -tetrahydrocannabinol (11-nor-9-carboxy-Δ9 -tetrahydrocannabinol) were measured in wastewater using liquid chromatography-tandem mass spectrometry. Daily mass loads (mg/day) were normalized to catchment population (mg/1000 people/day) and converted to the number of combined doses consumed per day. Spatial differences were assessed world-wide, and temporal trends were discerned at European level by comparing 2011-13 drug loads versus 2014-17 loads. FINDINGS: Benzoylecgonine was the stimulant metabolite detected at higher loads in southern and western Europe, and amphetamine, MDMA and methamphetamine in East and North-Central Europe. In other continents, methamphetamine showed the highest levels in the United States and Australia and benzoylecgonine in South America. During the reporting period, benzoylecgonine loads increased in general across Europe, amphetamine and methamphetamine levels fluctuated and MDMA underwent an intermittent upsurge. CONCLUSIONS: The analysis of wastewater to quantify drug loads provides near real-time drug use estimates that globally correspond to prevalence and seizure data.

Quantification of THC in Cannabis plants by fast-HPLC-DAD: A promising method for routine analyses.

Nowadays, Gas Chromatography Mass Spectrometry (GC-MS) is mainly used in forensic sciences but suffers from limitations when the analysed compounds are thermally instable as it is the case for THC-A (Tetrahydrocannabinolic Acid) which is converted into Δ9-THC (Δ9-Tetrahydrocannabinol) that subsequently partially degrades. We propose herein a Fast High Pressure Liquid Chromatography (Fast-HPLC-DAD) method which allows the efficient separation of CBN (Cannabinol), CBD (Cannabidiol), THC-A and Δ9-THC, the major cannabinoids compounds found in cannabis plants in less than 5 min. Our method allows also the proper quantification of Δ9-THC in plant extracts using an external calibration method with a very good accuracy as pointed out by a recovery of 100.53 ±â€¯3.12%. It is also an interesting low cost alternative to Ultra High Pressure Liquid Chromatography (UPLC) for routine analyses in forensic sciences.

When does the cutting of cocaine and heroin occur? The first large-scale study based on the chemical analysis of cocaine and heroin seizures in Switzerland.

BACKGROUND: Illicit drug profiling can provide knowledge about illicit drug markets, informing on the level of distribution and its evolution in space and time. Illicit drug profiling is usually limited to impurities originally present in the illicit drug (e.g. alkaloids, co-extracted compounds or by-products). However, the benefit of a comprehensive analysis of cutting agents in drug seizures for law enforcement agencies, intelligence and health policy has not been thoroughly investigated in the literature and is the focus of this research. AIM: This research aims at assessing when and how cutting (i.e. adulteration and dilution) occurs in the supply chain by analysing cocaine and heroin seizures made between 2006 and 2015 in Switzerland. METHODS: Cocaine and heroin seizures made along the supply chain by law enforcement agencies in the Western region of Switzerland were investigated for adulteration and dilution. A total number of 7841 cocaine and 3476 heroin specimens coming from 1341 and 721 seizures, respectively, were analysed. RESULTS: The results show that, for both illicit drugs, adulteration and/or dilution occur before arrival into Switzerland as well as in Switzerland. While cocaine is adulterated and diluted, heroin is only adulterated. Interestingly, the same mixture of adulterants (i.e. caffeine-paracetamol) is used to cut heroin at each step in the supply chain. CONCLUSION: Gaining knowledge about adulteration and dilution at different stages in the supply chain enhances our understanding of drug markets. It also highlights differences along the supply chain and in the distribution of both drugs in Switzerland.

Forensic intelligence on illicit markets: The example of watch counterfeiting.

Counterfeit luxury fashion goods have rarely been the subject of scientific studies. Very little is known about the mechanisms of this illicit market despite the apparent prevalence and their adverse consequences. Counterfeit watches remain one of the preferred targets in the luxury goods segment. The study of marks or traces in a forensic intelligence perspective can contribute to an improved understanding of the phenomenon. The aim of our research was to highlight different types of links that can be drawn between specimens of counterfeit watches, to carry out a thorough study of the information conveyed by the revealed links, to study their complementarity and to get an understanding of the intelligence that can be produced from these pieces of information. Thirty-five counterfeit watches of a commonly counterfeit watch brand including seven popular models were studied in this research. Chemical and physical links were found that corroborated existing knowledge and also revealed new connections between different seizures or specimens. The comparison of chemical and physical features combined with spatiotemporal information on the seized watches enabled us to produce intelligence disclosing possible aspects of the structure and the organisation of production and distribution channels. We were able to reveal or confirm links between watches that were previously unknown or uncertain and demonstrated the interconnection of all watches on a chemical and/or physical level, suggesting an overhead organised network with substructures. Despite the limited set of specimens that was considered, this study illustrates that forensic intelligence on this illicit market can be used to support consistent decision-making from all the key-players involved in the anti-counterfeiting process.

Elemental analysis for profiling counterfeit watches.

Counterfeit watches are products of illicit activity and contain traces of their production and distribution. Traces provide pertinent information through one of their fundamental characteristics: the ability to reveal links between specimens or cases. The aim of this study was to develop an analytical strategy to obtain the elemental composition of watchcases, by analysing a selection of 35 counterfeit watches. We propose a methodology based on multivariate statistical analysis of chemical results that discriminates between watches from common and different origins, and, ultimately, classifies them into chemical groups. All watchcases were analysed using inductively coupled plasma mass spectrometry (ICP-MS), providing representative descriptive data on the composition of watchcases. Several multivariate approaches were assessed, considering different scenarios, each using a different set of variables. It appeared that the model that performed best in terms of classification criteria could be misleading, especially in an exploratory context that focuses on the production of intelligence. At the end of the day, hierarchical cluster analysis (HCA) allowed us to classify the specimens into 14 chemical classes. Information gained through chemical analysis revealed several links between the specimens. This initial study was performed on a very limited number of watches. Although still in the developmental stage, our approach exhibits promising capabilities and encourages chemical profiling of counterfeit watches on larger scale.

The use of wastewater analysis in forensic intelligence: drug consumption comparison between Sydney and different European cities.

Wastewater analysis offers objective and complementary information to illicit drug agencies by monitoring patterns of illicit drug consumption. In this study, wastewater samples from three different wastewater treatment plants in Sydney, Australia were collected in March 2016. Ten targeted drugs were analysed and temporal and geographical analyses were performed to obtain a better understanding of the type and amount of illicit drugs consumed in Sydney in comparison with similar studies conducted around Australia and in Europe. Among the targeted drugs, methamphetamine was consumed the most, followed by cocaine and 3,4-methylenedioxymethamphetamine (MDMA). Weekly patterns were observed where a peak during the weekend was present. The geographical analysis showed differences between the regions targeted. This observation may be related to socio-demographic aspects. The comparison of our study to other data sources from Australia showed a high consumption of methamphetamine in Sydney and Western Australia. The comparison between Sydney and different European cities revealed a difference in consumption, which is in line with traditional market indicators. The information obtained through wastewater analysis provides complementary information regarding illicit drug consumption, the size, and the evolution of the illicit drug market. This, ultimately, will assist authorities in making informed decisions.

Monitoring new psychoactive substances: Exploring the contribution of an online discussion forum.

BACKGROUND: The rapid emergence of new psychoactive substances (NPS) is a challenge for public health authorities and law enforcement. The phenomenon is strengthened since the increase of the Internet usage. Not only used to trade NPS, the Web is an important source of information for both potential drug consumers and experienced users. Discussion forums are among these sources of information. They are meeting points for different groups of users and include a wide range of trip reports, questions and consumption tips. Since the discussions are archived over a long period, they can be used to monitor the interest of consumers for particular substances over time. This research aims at understanding the contribution of data extracted from a major online discussion forum within a systematic monitoring process. METHOD: Data were collected from a discussion forum (i.e. Drugs-forum). Within the sections of the forum, the titles, content of discussion, number of replies, and the date of the first discussion were crawled and stored in a dedicated database. The intensity of the discussions related to 42 substances considered as NPS was measured through an indicator allowing to assess the popularity of substances. Furthermore, the appearance of 15 substances on the forum was compared to the date of formal notification to the EU early warning system. RESULTS: An evolution of the different classes of substances, as well as an evolution of specific substances within a class were highlighted. Some substances were discussed for a long period of time (e.g. Kratom, 25i-NBOMe, MDPV) while others were discussed very briefly (e.g. 5-MeO-DPT, NM-2AI). Out of the fifteen substances subjected to a risk assessment from the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), nine of them appeared on the forum before or at the same time as their first date of notification to the EU early warning system. CONCLUSION: In line with previous research on doping products, this article shows the potential of the monitoring of online forums in the context of psychoactive substances. Besides, the system designed to collect the data is flexible and can be systematically updated to fuel a monitoring process. It informs not only on the presence/absence of a substance in discussions between consumers, but also on its evolution over time. Such results could benefit academic research and organizations studying the NPS phenomenon. Precisely, it could complement existing early warning systems and benefit law enforcement agencies and policy makers.

Monitoring of explosive residues in lake-bottom water using Polar Organic Chemical Integrative Sampler (POCIS) and chemcatcher: determination of transfer kinetics through Polyethersulfone (PES) membrane is crucial.

Between 1920 and 1967, approximatively 8200 tons of ammunition waste were dumped into some Swiss lakes. This study is part of the extensive historical and technical investigations performed since 1995 by Swiss authorities to provide a risk assessment. It aims to assess whether explosive monitoring by passive sampling is feasible in lake-bottom waters. Polar organic chemical integrative sampler (POCIS) and Chemcatcher were first calibrated in a channel system supplied with continuously refreshed lake water spiked with two nitroamines (HMX and RDX), one nitrate ester (PETN), and six nitroaromatics (including TNT). Exposure parameters were kept as close as possible to the ones expected at the bottom of two affected lakes. Sixteen POCIS and Chemcatcher were simultaneously deployed in the channel system and removed in duplicates at 8 different intervals over 21 days. Sorbents and polyethersulfone (PES) membranes were separately extracted and analyzed by UPLC-MS/MS. When possible, a three-compartment model was used to describe the uptake of compounds from water, over the PES membrane into the sorbent. Uptake of target compounds by sorbents was shown not to approach equilibrium during 21 days. However, nitroaromatics strongly accumulated in PES, thus delaying the transfer of these compounds to sorbents (lag-phase up to 9 days). Whereas sampling rate (RS) of nitroamines were in the range of 0.06-0.14 L day-1, RS of nitroaromatics were up to 10 times lower. As nitroaromatic accumulation in PES was integrative over 21 days, PES was used as receiving phase for these compounds. The samplers were then deployed at lake bottoms. To ensure that exposure conditions were similar between calibration and field experiments, low-density polyethylene strips spiked with performance reference compounds were co-deployed in both experiments and dissipation data were compared. Integrative concentrations of explosives measured in the lakes confirmed results obtained by previous studies based on grab sampling.

Drug residues in used syringes in Switzerland: A comparative study.

Harm reduction services, including needle-exchange programmes, have been implemented in Switzerland for over 20 years. Their main aim is to lessen the negative social and/or physical consequences associated with illicit drug consumption and, therefore, improve prevention messages. To this end, knowledge of illicit drug consumption practices is necessary. Periodic self-report surveys are the primary source of data for monitoring drug users' behaviour. Analysis of residual content of used syringes can bring further and objective knowledge about consumed products through analytically confirmed data. Used syringes were sampled in 2 syringe-exchange facilities in Lausanne. These structures are a bus where the users bring back their syringes (ABS) and an automatic injecting kit dispenser (AIKD). Once syringes were collected, a validated gas chromatography-mass spectrometry (GC-MS) method was implemented in order to detect drugs (licit or illicit) contained in the residual content of used syringes. Cocaine was the most common drug detected alone (39% in ABS and 31% in AIKD), followed by the simultaneous detection of heroin and cocaine (12% and 17%) and heroin and midazolam (12% and 17%). The differences between the illicit drugs distribution of used syringes collected in AIKD and ABS were not statistically significant. Analysis of residual content of used syringes as a monitoring tool is an original approach that has already led to a better understanding of the habits of drug-injection users. Over the long term, this approach is a powerful tool to track and detect new consumption practices in a quasi-real-time.