Science of the Total Environment 487 (2014) 696–702

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Science of the Total Environment

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Use of illicit stimulant drugs in Finland: A wastewater study in tenmajor cities

Aino Kankaanpää a, Kari Ariniemi a, Mari Heinonen b, Kimmo Kuoppasalmi a, Teemu Gunnar a,⁎a National Institute for Health and Welfare (THL), Department of Alcohol, Drugs and Addiction, Mannerheimintie 166, FI-00300 Helsinki, Finlandb Helsinki Region Environmental Services HSY, Hernepellontie 24, FI-00560 Helsinki, Finland

H I G H L I G H T S

• First large scale national study of illicit drug use in Finland based on wastewater analysis• Illicit stimulant drug use is more common in the large cities in Southern Finland.• Amphetamine use is much more common than cocaine use.• First estimations of consumed vs. seized drugs based on wastewater analysis.• Local hotspot of a new psychoactive substance (MDPV) was observed.

⁎ Corresponding author at: PL 30, 00271 Helsinki, FinlaE-mail address: teemu.gunnar@thl.fi (T. Gunnar).

0048-9697/$ – see front matter © 2013 Elsevier B.V. All rihttp://dx.doi.org/10.1016/j.scitotenv.2013.11.095

a b s t r a c t

a r t i c l e i n f o

Article history:Received 1 August 2013Received in revised form 15 November 2013Accepted 17 November 2013Available online 9 December 2013

Keywords:Illicit drugsWastewaterDrug consumptionLiquid chromatography–tandemmassspectrometryMDPVFinland

Estimations of drug use at the national level are generally based on various sources of information, such asdrug seizures, socio-scientific studies, toxicological data and hospital records. Nevertheless, all of these ap-proaches have limitations that cannot be overcome, even if conclusions are drawn from combined data re-trieved from different sources. Drug epidemiology throughwastewater analysis has the potential to provideunique perspectives, internationally comparable data, and up-to-date information on the use of both tradi-tional illicit drugs and new psychoactive substances (NPSs). In Finland, no large-scale studies on regionalillicit drug consumption, based on a wastewater approach, have been reported. In this study, 24-h influentcomposite samples were collected during two 1-week study periods from ten different wastewater treat-ment plants in May and November–December 2012. The cities included in the study represent the geo-graphical areas throughout Finland and cover 40% of the Finnish population. The samples were analyzedwith an in-house validated, ultra high-performance liquid–chromatography mass spectrometric (UHPLC–MS/MS) method for various common illicit drugs and some NPS type stimulant drugs. The results werealso compared with available statistics, information on drug seizures and laboratory-confirmed toxicolog-ical data, as well as other studies available based onwastewater analysis. The data show that illicit stimulantdrug use is more common in the larger cities of Southern Finland. Amphetamine was the most commonlyused drug in all 10 cities during both collection periods (excluding the collection period in May inLappeenranta). Cocaine consumption remains very low in Finland in comparison to other European coun-tries; it was concentrated in the biggest cities in Southern Finland. This study shows interesting temporaland spatial differences in drug use in Finland, as well as the possibilities of using wastewater analytics toreveal local hotspots of NPS consumption.

© 2013 Elsevier B.V. All rights reserved.

1. Introduction

At the global level, the demand for illicit drugs has not been substan-tially reduced (United Nations Office on Drugs and Crime UNODC,2013). While it is evident that illicit drugs continue to jeopardize the

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health and welfare of people throughout the world, presenting anaccurate picture of drug use is a challenging task for authorities. Thephenomenon of drug abuse is such a complex one that no single mea-sure is able to provide a full picture of the current situation. Therefore,the overall strategy of a multi-indicator approach is clearly the methodof choice. For example, the annual assessment of the state of theEuropean drug problem is based on a joint interpretation of data onsupply and availability, prevalence as measured by epidemiologicalindicators such as drug use among the general population, treatment

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demand, drug-related infectious diseases and mortality (EuropeanMonitoring Centre for Drugs and Drug Addiction (EMCDDA), 2013).

A promising new approach for mapping drug consumption is drugepidemiology through sewage analysis, which is based on the ideathat untreated municipal wastewater can be considered as a highlydiluted urine sample from the population residing in the catchmentarea (Daughton, 2001). While technological developments inchromatography–mass spectrometric techniques have made it possibleto identify the urinary and faecal excretion of illicit drugs and theirmainmetabolites in wastewater at very low concentrations, numerous stud-ies depicting the drug situation in European and US cities (see van Nuijset al., 2011a), as well as in Australia (Irvine et al., 2011), have been pub-lished in the last few years. Recently, two cities in Finland, Helsinki andTurku, were included in a study of illicit drug use in nineteen Europeancities. In that study (Thomas et al., 2012), sewage samples were ana-lyzed for biomarkers of cocaine, amphetamine, methamphetamine,3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) and canna-bis (the last of these biomarkers was not analyzed in the Finnishsamples).

The aim of this study was to investigate stimulant drug use in tenmajor cities, covering 40% of the Finnish population and representinggeographical areas throughout Finland, based on drug epidemiologythrough sewage analysis. In addition to traditional stimulant drugs,the synthetic cathinones 3,4-methylenedioxypyrovalerone (MDPV)and methylone were included in the study to evaluate whether thisapproach is applicable for monitoring new psychoactive substances(NPSs) as well. The choice of including MDPV and methylone as repre-sentative of new substances in this study was based on our preliminarywastewater study (Kankaanpää et al., 2011) in the Helsinki area, recentlegislative status changes1 pertaining to those drugs in Finland and dataon the local drug situation (Ojanperä et al., 2011; Kriikku et al., 2011).Two separate one-week sampling campaigns were carried out, one inlate May and the other in November–December 2012. All of theindividual 24-hour sampleswere analyzed for amphetamine-type stim-ulant drugs (ATSs), MDPV, methylone and cocaine (as its metabolitebenzoylecgonine, BE), as well as the methadone metabolite EDDP. Theoverall consumption levels for the drugs in the different cities and thedifferent collection periods were calculated as the mean of all samples,while the results from the daily samples were used to evaluate varia-tions in drug consumption during the different days of the week. Theestimations of drug consumption based on wastewater analysiswere compared with available records on drug seizures as well aslaboratory-confirmed toxicological data.

2. Material and methods

2.1. Chemicals, reagents and materials

Amphetamine sulfate, cocaine hydrochloride andMDMAhydrochlo-ridewere purchased from Sigma-Aldrich (St. Louis, MO, USA). Metham-phetamine hydrochloride and methylenedioxyamphetamine (MDA)hydrochloride were donated by the UN Narcotics Laboratory (Vienna,Austria). The cocaine metabolite BE and the methadone metaboliteEDDP, as well as the deuterated drug analogs amphetamine-d6,cocaine-d3, MDMA-d5, methamphetamine-d14 and benzoylecgonine-d3, were purchased from Cerilliant (Round Rock, TX, USA) at concentra-tions of 1 mg/ml, or 100 μg/ml in methanol or acetonitrile. Methylonehydrochloride was obtained from LGC GmbH (Luckenwalde,Germany), while MDPV andMDPV-d8 were obtained from Toronto Re-searchChemicals (Toronto, Canada). All of the reagents usedwere of thehighest quality. Water was purified to a UHQ grade using a MilliporeDirect-Q system (EMD Millipore Corporation, Billerica, MA, USA)

1 MDPVwas thefirst compound to be put under theNarcotics Act by a national decisionin Finland in June 2010 (Amendment 595/2010 to the Narcotics Act 373/2008), whilemethylone was put under the Narcotics Act in March 2012 (Amendment 117/2012).

equipped with an LC-Pak™ (Millipore), C 18, reverse-phase silica car-tridge to minimize interference from organic impurities in the mobilephase. The Oasis MCX Vac RC (60 mg) SPE cartridges were fromWaters(Milford, MA, USA).

2.2. Sample collection and storage conditions

Samples of untreated wastewater were collected from the inletsat ten wastewater treatment plants (WWTPs) located in the citiesof Espoo, Helsinki, Jyväskylä, Kuopio, Lahti, Lappeenranta, Oulu,Rovaniemi, Tampere and Turku (Fig. 1). All of the WWTPs serve morethan 50,000 inhabitants, with Helsinki Viikinmäki wastewater treat-ment plant being the largest WWTP in the Nordic Countries (Table 1).

Using the equipment available at eachWWTP, five to seven consec-utive 24-h wastewater influent composite samples were collected ineither a volume- or time-proportional mode. Details on the samplecollections from eachWWTP as well as such parameters as the popula-tion residing in a particular catchment area and the influentwastewaterflow rates are listed in Table 1, compiled in close cooperation with theWWTP operators. From the sampling device, sampleswere immediatelytransferred to glass bottles and acidified (pH 2 with hydrochloric acid)to prevent the degradation of compounds prior to analyses (Gheorgheet al., 2008; Baker and Kasprzyk-Hordern, 2011). The samples werestored in a refrigerator until dispatched in coolers to the NationalInstitute for Health and Welfare (THL), Helsinki, where they werestored in a deep-freeze state (at−18 °C) until analyzed. The first sam-pling campaign was carried out between 19 and 28 May 2012 (week21), and the second between 25 November and 1 December 2012(week 48).

Copyright: Maanmittauslaitos 2005ESTONIA

Fig. 1. Location and size of population served by the ten wastewater treatment plantsincluded in the study.

Table 1Overview of the general parameters and the sampling parameters of the10 different wastewater treatment plants (WWTPs) included in the study.

WWTP(location)

Populationa Sampling mode Flow range,min–max(week 21;1000 m3)

Flow range,min–max(week 48;1000 m3)

Sampling andinterval range(min), weeks 21and 48

Wastewater fromindustrial sources(volume %)a

Helsinki 800,000 Volume 266.1–320.9 241.9–289.0 22–28b/25–30 8Espoo 310,000 Volume 87.3–100.0 91.5–100.0 8.6–9.9/7.2–7.9 8Turku 275,000 Volume 64.4–74.8 76.9–88.7 12–14/15–18 7Tampere 200,000 Volume 58.6–66.3 69.4–75.8 22–25/9.5–10 15Jyväskylä 150,000 Volume 40.2–48.4 39.0–42.0 21–25/24–26 15–20Oulu 147,350 Time 51.9–60.0 45.4–49.7 39/30 8Lahti 100,000 Volume 22.1–23.1 18.6–23.7 28–29/27–34 14Kuopio 80,000 Volume 23.8–29.0 20.6–23.5 79–96/98–112 7Lappeenranta 60,000 Time 16.3–18.5 16.6–19.8 15/10–20c 10Rovaniemi 58,000 Time 18.7–32.9 20.3–25.7 60/60 5

a Based upon the expert knowledge of the local WWTP.b One sample took 57 min.

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2.3. Sample pre-treatment

The Oasis MCX cartridges were first conditioned with 5 ml of MeOHand 5 ml of purified water. Then, 40-ml aliquots of the acidified waste-water were mixed with a phosphate buffer (adjusted with H3PO4 topH 2.5) containing the deuterated internal standards and centrifuged;then, the supernatants were loaded into the cartridges. Next, thecartridges were washed with 3 ml of purified water, 2 ml of 0.01 MHCl (pH 2) and 3 ml of toluene, consecutively. After drying thecartridges with a stream of nitrogen, the compounds of interest wereeluted with 5 ml of a MeOH–NH3 (100:3) solution. To prevent the lossof basic analytes vulnerable to evaporation while concentrating theeluate at 75 °C, 140 μl of formic acid was added to acidify the solutionand ionize the compounds. Finally, 50 μl of 0.2 M HCl was added tothe approximately 100-μl residue prior to injection (and without filtra-tion) for UHPLC-MS/MS analysis.

2.4. Instrumentation and analytical conditions

All the instrumental analyses were performed with an Agilent Tech-nologies (Santa Clara, CA, USA) Series 1290 Infinity LC system consistingof a degasser, a binary pump, a column thermostat and an autosamplerequippedwith anAgilent Technologies 6460 Triple Quad LC/MS tandemmass-spectrometer. The ion sourcewas electrospray ionization (ESI) JetStream that was operated in the positive ionization mode. Separationwas performed on an Acquity CSH™ C18 column (2.1 mm × 75 mm,1.7 μm; Waters, UK) and an Acquity CSH™ C18 VanGuard™ guardcolumn (2.1 mm × 5 mm, 1.7 μm; waters), both of which weremaintained at 40 °C. The mobile phase consisted of 5 mM of aqueousammonium formate/0.05% formic acid with a pH of 3.4 (eluent A) andacetonitrile (eluent B). Until the beginning of the analysis, the HPLCsystem was equilibrated with a mixture of the two eluents (7% eluentB). The flow rate was 0.5 ml/min. The gradient was programmed asfollows: at 0 to 1.0 min, 7% B; at 3.0 min, 18.3% B; at 6.96 min, 32.1%B; at 8.0 min, 80% B; and at 10.0 min, 95%B. The following ESI inlet con-ditions were applied: drying gas, nitrogen (8 l/min, 305 °C); nebulizergas, nitrogen (30 psi); sheath gas, nitrogen (12 l/min, 350 °C; capillaryvoltage), 3000 V. The mass spectrometer was operated in the dynamicmultiple reaction monitoring mode (dMRM). For further MS/MSparameters, please see Table S1.

2.5. Identification and quantification

Two MRM transitions (one for each IS) and the relative ion abun-dance of qualifier ion with respect to the target ion and retention timeof the analyte updated during each analysis were used to identify thetarget analytes. The protonated molecular ion was used as the

precursor, and the most abundant transition product ion was typicallyused as a target ion with a second transition as a qualifier. For quantifi-cation, the peak area ratios of the analytes relative to the carefully cho-sen IS were compared using the linear calibration model. Deuteratedinternal standards were used to compensate for signal suppression orenhancement, as well as SPE recoveries. If deuterated standards werenot available, an internal standard as similar as possible in structure,physicochemical properties and analytical response was chosen.

2.6. Validation of the methodology

The analytical methodology was validated prior to the samplingcollection periods. A detailed description of the validation experimentsis found in the supplementary material.

2.7. Back-calculations

Measured concentrations (in ng/L) of illicit drugs or their metabo-lites in wastewater were used to calculate the daily consumption ofdrugs in a given community. First, the measured concentrations weremultiplied by the measured flow rate of the wastewater stream(L/day) to transform the drug concentrations into mass loads. Then, acorrection factor for urinary drug excretion was applied to back-calculate from mass loads (in mg/day) into the amount of an illicitdrug that was being consumed (in mg/day). The correction factors forthe drug excretion being applied were 3.0 for cocaine (measured asBE), 3.3 for amphetamine, 5.0 for MDMA, 2.3 for methamphetamineand 4.8 for methadone (measured as EDDP), as proposed by van Nuijset al. (2011b). Finally, daily consumption rates were further dividedby the population being served by the respective WWTP to expressthe results as mg/day per 1000 inhabitants; this was done to make iteasier to compare different locations and with other available studies.It should be noted, however, that no correction factor was used forMDPVdue to unavailability of studies in the existing scientific literature.

3. Results and discussion

3.1. Analytical method validation

According to the validation guidelines widely accepted (Shah et al.,2000), the performance of the method fulfilled quantitative determina-tion criteria for the stimulant drugs. The methadone metabolite EDDP,which was included as an example of a drug with stable use patterns,could only be measured semi-quantitatively. Accuracy (expressed asbias), within-day (repeatability) and intermediate precision, as well asrecovery and the matrix effect validation results, are presented inTable S2. Recoveries for the stimulant drugs ranged from 93.9%

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(MDMA) to 100.3% (cocaine), thereby demonstrating the efficiency ofthe SPE procedure when using mixed mode cartridges as well as theacid/base properties and cationic interactions of the compounds forefficient extraction and sample purification. Despite the high evapora-tion temperature and rapid evaporation rates, good sensitivities wereobtained for volatile amphetamines using a pH where basic analytes(amines) were in ionic forms.

In post-column infusion experiments done to evaluate the matrixeffects of real wastewater samples, the effects of ion suppression weremainly observed in the regions of 0–1 min and 8–10 min. Nevertheless,no major matrix effects were observed in regions eluted by the studiedstimulants; possibleminormatrix effects should, therefore, be efficientlycompensated by the deuterated standard analogs as internal standards.

3.2. Stimulant drug consumption

The mean loads of amphetamine, methamphetamine, MDMA andcocaine (measured as BE) in the wastewater of each city are presentedin Fig. 2. The average nationwide consumption rate (mg/day per 1000inhabitants) was 190 for amphetamine, 26 for methamphetamine, 73for MDMA and 12 for cocaine (based on two 1-week collection periodscovering 40% of the Finnish population).

The results demonstrate that ATSs, especially amphetamine itself,dominate the Finnish drug scene in every part of the country, whilecocaine use is far less common and limited to larger cities in SouthernFinland. This is consistent with data available from other nationalsources. In cases having to do with driving under the influence ofdrugs (DUID), amphetamine has long been the predominant drug ofabuse in Finland (Lillsunde and Gunnar, 2007; National Bureau ofInvestigation, 2012, 2013). For example, in 2011 amphetamine wasobserved in 2180 DUID cases, methamphetamine in 326 cases, MDMAin 152 cases and cocaine (measured as BE) in 30 cases, while in 2012the corresponding figures were 1699 for amphetamine, 513 for meth-amphetamine, 132 for MDMA and 49 for cocaine (measured as BE). Indrug seizures by the police and Customs authorities, roughly 100 kg ofamphetamine has been confiscated yearly in the last few years, whilefor cocaine and methamphetamine only a few kilograms and a fewtens of kilograms have typically been confiscated, respectively

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(National Bureau of Investigation and the Finnish Customs, 2013). How-ever, annual variation in these figures may be considerable.

Although there have not been dramatic changes in the generalpicture of Finnish ATS consumption lately, Fig. 2 shows that smalleralterations in the ratios of different compounds in wastewater havebeen discovered in the course of time. Between the collection periodsof week 21 and week 48, methamphetamine consumption decreasedin 9 of the 10 cities (38 vs. 14 mg/day/1000p), while that of MDMAincreased in 9 of the 10 cities (52 vs. 94). Furthermore, the only citythat showed dissimilar temporal patterns of ATS consumption was thecity of Rovaniemi, where the melting of heavy loads of winter snowcaused significant sewer overflow that affects the reliability of theresults from the first sampling campaign (week 21). The consumptionof amphetamine was more stable, but increased from 164 to 218 mg/day/1000p. Thefluctuation in the ratios of individual drugs is a phenom-enon typical for ATSs: they are often substituted for each other, depend-ing on availability, price, and the “quality” of the drugs on the market(see EMCDDA, 2013). This fluctuation can be seen, apart from in officialstatistics on drug seizures (National Bureau of Investigation and theFinnish Customs, 2013), also in toxicological data from any drug testinglaboratory, including ours.

Although our estimations on amphetamine and methamphetamineconsumption are in accordance with data from other national sources,they clearly conflict with those presented in a study by Thomas et al.(2012), in which no amphetamine and exceptionally high metham-phetamine loads were detected in the wastewater samples from bothTurku and Helsinki. One obvious reason for a missing compound inany analytical method is a lower limit of quantification (LLOQ) that isinsufficiently high. Indeed, given the fact that the LLOQ used for theHelsinki and Turku samples in the study by Thomas et al. (2012) wasas high as 25 μg/L, this is a plausible explanation for amphetamineremaining undetected. However, LLOQs do not explain the differencesbetween the methamphetamine loads discovered in our (14–71 mg/day/1000 inhabitants) and the ones in their study (300–400 mg/day/1000 inhabitants). Based on our results, methamphetamine useremained at much lower level than amphetamine use in 2012 inFinland.

In contrast to methamphetamine, the consumption of MDMA wassomewhat higher in our study than in the study by Thomas et al.(2012). The mean MDMA consumptions in Helsinki and Turku were90–140 and 10–25 mg/day/1000 inhabitants, respectively, in ourstudy, while Thomas et al. (2012) reported corresponding values ofroughly 20 and 5 mg/day/1000 inhabitants. These values, however,are not necessarily discordant because the availability of MDMA mayfluctuate substantially in the course of time, and it has increased from2011 to 2012 based on the number of ecstasy tablets confiscated byFinnish Customs authorities and the police (National Bureau ofInvestigation and the Finnish Customs, 2013).

Low-level cocaine consumption was detected in Helsinki and Turkuin both the study by Thomas et al. (2012) and in our study. The rate ofcocaine consumption during our two sampling campaigns was roughly13–15 mg/day/1000 inhabitants in Helsinki, and approximately1–3 mg/day/1000 inhabitants in Turku, while the corresponding valuesreported by Thomas et al. (2012) were 18 and 6, respectively. Whencomparing our data from Finnish cities to that of other European coun-tries, it is clear that cocaine consumption remains, even in the largercities of Southern Finland, quite low in comparison to other Europeancountries and the results reported in other studies (van Nuijset al., 2011b; Thomas et al., 2012). For example, values as high as1800 mg/day cocaine per 1000 inhabitants were found in large citiesin Belgium during weekends (van Nuijs et al., 2009), whereas valuesas high as 2400 mg/day per 1000 inhabitants were found in Franceduring weekends (Nefau et al., 2013). The maximum value measuredin our study was 25 mg/day cocaine per 1000 inhabitants during theboth collection periods (weeks 21 and 48) from Sunday to Mondaymorning in Helsinki. In the Northern part of Finland, in Rovaniemi and

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Oulu, there was practically no cocaine use observed. Interestingly,MDMA use was much more evenly distributed throughout the wholeFinland and the cities studied.

3.3. Weekly use patterns

Significant variations in use patterns depending on the day of theweek were observed for cocaine (measured as BE) and MDMA (Figs. 3and 4); the drugs were used most often for recreational purposes atthe weekends. The same phenomenon was to a lesser extent alsoobserved for amphetamine and methamphetamine. Nevertheless, formethadone (measured as EDDP) and MDPV no such day-to-day varia-tions were observed (Fig. 4). The former compound is widely used inopioid maintenance treatments and pain management treatments thatrequire constant administration of the drug, while the lack of a weeklypattern in the case of MDPV might be explained by the fact that thedrug has largely been used intravenously in Finland (Tammi et al.,2011; Ojanperä et al., 2011), and, as such, it is not among the firstchoices of drugs for recreational weekend users. Consequently, thesefindings may well point out that different user groups use differentstimulants: while for MDPV, amphetamine and methamphetaminethe users seem to be mainly problematic drug users engaging in moreor less steady drug use during the entire week, MDMA and cocaine aretaken at the weekend, thereby indicating a completely different usergroup with more occasional drug use for recreational purposes andalso, in general, better control of their substance abuse.

3.4. Local hotspots for new psychoactive substances

Of the two NPS-type drugs included in the study, methylone wasalmost absent, with only traces of the drug being occasionally detected.

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In contrast, the consumption of MDPV was as high as 19 mg/day/1000inhabitants without back-calculation during the first collection periodin May 2012 in the Lappeenranta region and 2.4 in Helsinki (Fig. 4),while the drug was almost completely absent in other cities. Takinginto account that MDPV is used in lower doses than amphetamine(EMCDDA, 2012), it indicates that MDPV use was at higher level thanamphetamine use at that time in Lappeenranta. The exceptionallyhigh amounts of MDPV in the Lappeenranta region of South-EasternFinland are also in accordance with the unusually high rate of MDPV-related crimes reported in the same area during the spring of 2012(Data given by the National Bureau of Investigation, Finland). Further-more, our laboratory records reveal a high degree of MDPV-positivebiological specimens from clinical sources located in the same region:of all the MDPV positive samples, 44% originated from South-EasternFinland in May, and 89% during the first half of the year of 2012(Laboratory records of the National Institute for Health and Welfare).According to these results for MDPV, the identification of NPSs in agiven community, as well as the estimation of their use and whether aspecific new drug will become popular or not, appears promising inlight of wastewater analysis.

3.5. Comparison of confiscated drugs and consumed drugs

It is an interesting prospect to use wastewater analysis to estimatethe ratio of illicit drugs seized by the authorities to the drugs actuallyconsumed by users. With its coverage of 40% of the Finnish population,this study affords a reasonable opportunity to perform such estimationsin combination with other relevant data. In Finland, police and Customsauthorities perform purity measurements in conjunction with drugseizures. Taking into account the reported drug seizures in Finland (in2012), the average purity of amphetamine (18%), methamphetamine

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(17%) and cocaine (30%) measured by the Finnish authorities (2012),the minor contribution of licit drug loads (2009, 2011) and the waste-water results (2012) extrapolated for the whole population, weestimate that 10–20 times more amphetamine (calculated 19.4), meth-amphetamine (22.6) and cocaine (10.9)2 was consumed than wasseized in 2012 in Finland.

However, this approach may actually slightly overestimate drugconsumption because rural areas and smaller cities where illicit druguse is generally less frequent than in more urbanized cities are under-represented in the study, whereas all of the major cities are included.This concentration on illicit drug use in the larger cities can clearly beseen in our results as well. In addition, a slight overestimation ofamphetamine consumption is caused by methamphetamine that ismetabolized to amphetamine in the human system (up to 43% of meth-amphetamine excreted unchanged, 4–7% as amphetamine in urine;Baselt, 2004). However, methamphetamine consumption was signifi-cantly less than that of amphetamine among this study population,resulting in less than 1% bias. Concerning the licit use of amphetamineand methamphetamine (including drugs that are metabolized toamphetamine or methamphetamine), Khan and Nicell (2012), haveestimated that their contributions to the sewer loads of these drugsare only expected to be of relevance in populations where minor levelsof illicit drugs are used. Therefore, in a country like Finland licit loads ofamphetamine are of negligible importance, while for methamphet-amine it accounts for approximately 5% of all mass loads based on thewastewater results presented in this study and thefigures for licitmeth-amphetamine loads (Khan and Nicell, 2012).

3.6. Perspectives

In order to build a full image of the drug situation in a given commu-nity, joint interpretation of complementary data from various sources isneeded. Althoughmulti-indicator approaches have been used in reportssuch as the World Drug Report (UNODC) and European Drug Report(EMCDDA), these are more compilations of available data than rigorousanalyses of the data. A more thorough comparison of results from threecomplimentary techniques to estimate community cocaine consump-tion, including wastewater analysis, was presented in a recent reportby Reid et al. (2012). Still, an important future goal for researchersfrom different disciplines, such as social, medical, environmental andforensic sciences, is to step out of their scientific silos and together

2 One abnormally high cocaine seizure, which was nearly three times the size of all co-caine confiscated in 2012, was omitted from the calculations. The cocaine was foundamong a load of bananas with probably no intention being sold on the Finnishmarket (in-formation reported in public by the Police).

start combining and analyzing data obtained with advanced methodol-ogies and indicators – traditionally confined to a single discipline – for amore comprehensive approach.

4. Conclusions

This wastewater study conducted in 10 different cities representsgeographical areas throughout Finland and it covers 40% of the Finnishpopulation. The results clearly show that ATSs, especially amphetamineitself, dominate the Finnish drug scene in every part of the country,while cocaine use is far less common and limited to larger cities inSouthern Finland. Significant weekly use patterns were observed forcocaine and MDMA, with the patterns being the strongest for recrea-tional weekend use. The same phenomenon was also observed to asmaller extent for amphetamine and methamphetamine, while nosuch day-to-day variationwas observed formethadone andMDPV, sug-gesting more constant administration. Substantial MDPV consumptionobserved in the city of Lappeenranta during thefirst sampling campaignmatches well with toxicological laboratory findings as well as criminalrecords from the same region for the same period of time, thus demon-strating the potential of the wastewater methodology to identify localhotspots effectively and practically in real time. Furthermore, theseresults with MDPV suggest that wastewater analysis may also be effec-tively suited for detecting emergingNPSs in themarket.When using theresults of wastewater analysis to estimate the ratio of illicit drugs seizedby the authorities to the drugs actually consumed by users, we estimatethat 10–20 times more amphetamine, methamphetamine, and cocainewas consumed than was seized in 2012 in Finland.

Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.scitotenv.2013.11.095.

Acknowledgments

We are grateful to our collaborators at the various WWTPs, whomade this study possible by providing us with thewastewater samples:Kari Murtonen and Eija Lehtinen HSY, Helsinki Region EnvironmentalServices HSY, Viikinmäki WWTP (Helsinki) and Suomenoja WWTP(Espoo); Heikki Sandelin and Marja Pitkänen, Tampere Water,ViinikanlahtiWWTP (Tampere); AnniMeiseri, Lahti Aqua Ltd, KariniemiWWTP (Lahti); Riitta Moisio and Annikki Nyrkkö, Lappeenrannanenergia, Toikansuo WWTP (Lappeenranta); Jukka Mäkiö, Napapiirinvesi, Rovaniemi WWTP (Rovaniemi); Petri Tuominen and ArtoTolmunen, Jyväskylän seudun puhdistamo Ltd, Nenäinniemi WWTP(Jyväskylä); Mirva Levomäki, Turun seudun puhdistamo Ltd, andNina Leino, Lounais-Suomen vesi-ja ympäristötutkimus Ltd (NL)Kakolanmäki WWTP (Turku); Jarmo Lahtinen, Anu Väänänen and PasiMikkonen, Oulu Waterworks, Taskila WWTP (Oulu); Jarmo Hiltunen,Kuopion vesi, and Lehtoniemi WWTP (Kuopio). We would also like to

702 A. Kankaanpää et al. / Science of the Total Environment 487 (2014) 696–702

thank Tuija Hietaniemi, Matti Karjalainen and Ulla-Maija Laakkonen(National Bureau of Investigation) as well as Marianne Kyber (theFinnish Customs) for their valuable help.

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