INTRODUCTION<\/h2>\n
85\u00a0% of\u00a0the\u00a0population in\u00a0the\u00a0Czech Republic is connected to almost 3,000\u00a0wastewater treatment plants (WWTPs; Fig.\u00a01<\/em>). These figures rank the\u00a0country among the\u00a0most advanced countries in\u00a0the\u00a0EU in\u00a0terms of\u00a0water management, as even many original EU member states do not reach these figures\u00a0[1]. Municipal wastewater contains a\u00a0number of\u00a0substances that, when analysed, provide very significant information about the\u00a0state of\u00a0the\u00a0population. This is being exploited by the\u00a0recently rapidly developing multidisciplinary scientific discipline of\u00a0Wastewater-Based Epidemiology (WBE). The\u00a0hypothesis that wastewater could be treated as a\u00a0very diluted urine sample led to the\u00a0emergence of\u00a0this field [2, 3]. This approach was first applied in\u00a0the\u00a0Po River basin\u00a0to detect cocaine consumption\u00a0[4]. The\u00a0WWTP does not remove all contaminants contained in\u00a0municipal wastewater; with the\u00a0treated wastewater, residues of\u00a0illegal substances \u2013 drugs \u2013 enter surface waters as well.<\/p>\n For this article, we selected several profiles on smaller streams that flow into the\u00a0Vltava in\u00a0Prague and below Prague and which are affected by WWTP outlets into these streams. A\u00a0sampling point above Prague Central Wastewater Treatment Plant (CWWTP) was chosen as the\u00a0control profile; the\u00a0sampling was carried out from Trojsk\u00e1 l\u00e1vka (Fig.\u00a02<\/em>). Another sampling point was below both outlets from Prague CWWTP in\u00a0Podbaba (Fig.\u00a03<\/em>).<\/p>\n Treated wastewater from Doln\u00ed Chabry WWTP is discharged into Drahansk\u00fd brook, a\u00a0right-hand tributary of\u00a0the\u00a0Vltava. The\u00a0sampling point was approximately 1 km from its mouth into the\u00a0Vltava. Drahansk\u00fd brook (Fig.\u00a04<\/em>) is 3.3\u00a0km long, and its catchment area is 6.7\u00a0km2<\/sup>. The\u00a0average flow rate is 7.7\u00a0m3<\/sup>\/s. The\u00a0long-term average flow rate Qa at the\u00a0outlet of\u00a0Doln\u00ed Chabry WWTP (at\u00a0river km\u00a03) is 83\u00a0l\/s. Q355 (the\u00a0average daily flow rate reached or exceeded during 355\u00a0days of\u00a0the\u00a0year) is 12.0\u00a0l\/s. The\u00a0average amount of\u00a0treated wastewater discharged into the\u00a0recipient is 10.6\u00a0l\/s. In\u00a0the\u00a0immediate vicinity of\u00a0Chabry there are several protected areas, such as Drahansk\u00e9 \u00fadol\u00ed, in\u00a0the\u00a0lower part also called Drahansk\u00e1 rokle. The\u00a0data are taken from the\u00a0Sewerage Rules of\u00a0the\u00a0WWTP-Doln\u00ed\u00a0Chabry<\/em> [5].<\/p>\n The\u00a0left-hand tributary of\u00a0the\u00a0Vltava, the\u00a0Podmor\u00e1\u0148sk\u00fd brook (Fig.\u00a05<\/em>), is affected by treated wastewater from Velk\u00e9 P\u0159\u00edlepy WWTP discharged into the\u00a0recipient at river km 2.8; the\u00a0sampling profile was before the\u00a0stream\u2019s\u00a0influx into the\u00a0Vltava. The\u00a0length of\u00a0the\u00a0stream is 4.1 km, and the\u00a0average flow rate is 24\u00a0l\/s. The\u00a0catchment area is 9.6\u00a0km2<\/sup>. The\u00a0average amount of\u00a0wastewater discharged is 11.8\u00a0l\/s. The\u00a0data are taken from the\u00a0Sewerage Rules of\u00a0the\u00a0Velk\u00e9 P\u0159\u00edlepy WWTP<\/em> [6].<\/p>\n The\u00a0next left-hand tributary, the\u00a0\u00dan\u011btick\u00fd brook (Figs. 6<\/em> and 7<\/em>), receives treated wastewater from Horom\u011b\u0159ice and Tuchom\u011b\u0159ice WWTPs; in\u00a0this case, too, the\u00a0sampling profile was before the\u00a0stream influx into the\u00a0Vltava. The\u00a0\u00dan\u011btick\u00fd brook originates in\u00a0Kn\u011b\u017eeves, flows through Tuchom\u011b\u0159ice. Statenice. \u010cern\u00fd V\u016fl, and \u00dan\u011btice, and then flows into Prague, where it forms its border. This part is home to \u00dadol\u00ed \u00dan\u011btick\u00e9ho potoka (\u00dan\u011btick\u00fd Brook Valley) natural monument and Tich\u00e9 \u00fadol\u00ed and Roztock\u00fd h\u00e1j nature reserves. In\u00a0Roztoky. \u00dan\u011btick\u00fd brook flows into the\u00a0Vltava. The\u00a0stream is 4.1 km long; the\u00a0catchment area is 19 km\u00b2. The\u00a0average flow rate is 100\u00a0l\/s.<\/p>\n The\u00a0sampling points are marked in\u00a0Fig.\u00a08<\/em> and described in\u00a0Tab.\u00a01<\/em>; the\u00a0characteristics of\u00a0individual WWTPs on the\u00a0monitored streams are given in\u00a0Tab.\u00a02<\/em>. The\u00a0data are taken from the\u00a0publication by Zv\u011b\u0159inov\u00e1 Mlejnkov\u00e1 et al., focused on microbial contamination of\u00a0the\u00a0Vltava below Prague [7].<\/p>\n Illicit substances and their metabolites are not routinely monitored in\u00a0wastewater or surface waters and are not subject to relevant legislation. In\u00a0surface waters, these substances can have an impact on the\u00a0environment, as shown, for example, by studies on fish behaviour [8\u201311].<\/p>\n <\/p>\n <\/p>\n The method for determining trace substances in water used for the analyses in this project was developed according to the procedure published by Postigo et al. [12]. This method has been used in the hydrochemical laboratory of TGM WRI for more than ten years, and new substances are gradually being included among the determined compounds depending on the current situation on the drug scene. Fully automated on-line SPE and LC-MS\/MS methods of determination in ESI+ or ESI- mode are accredited for surface and wastewater. The laboratory annually participates in the international comparison of tests, which takes place within the framework of the global drug situation monitoring under the auspices of the SCORE-network (https:\/\/score-network.eu\/).<\/p>\n The\u00a0concentrations of\u00a0a\u00a0selected group of\u00a0substances listed in\u00a0Tab.\u00a03<\/em> were monitored in\u00a0the\u00a0samples.<\/p>\n <\/p>\n Sampling was carried out by employees from the\u00a0TGM WRI Department of\u00a0Hydrobiology. In\u00a0the\u00a0same profiles, they monitored the\u00a0effect of\u00a0wastewater\u00a0on microbial contamination of\u00a0the\u00a0Vltava\u00a0[7]. For hydrochemical analyses, samples taken during 2022 and 2023 at approximately two-month intervals were used.<\/p>\n Samples were collected in\u00a0polypropylene containers. After transport to the\u00a0laboratory, these samples were further processed according to the\u00a0relevant standard operating procedures. After collection, the\u00a0samples were kept cool and dark at a\u00a0temperature of\u00a0up to 8\u00a0\u00b0C. If samples could not be analysed within\u00a072 hours of\u00a0collection, they were frozen and stored at -20 \u00b1 4\u00a0\u00b0C. Before analysis, samples were centrifuged (4,500 rpm, 15\u00a0minutes) and solid particles were removed from the\u00a0sample by filtration through disposable regenerated cellulose membrane filters with a\u00a0porosity of\u00a00.45\u00a0\u00b5m.<\/p>\n Based on the\u00a0chemical properties of\u00a0the\u00a0substances, the\u00a0following procedures were used for analysis:<\/p>\n Analytical procedures are described in\u00a0detail in\u00a0Posp\u00edchalov\u00e1 et al. [13].<\/p>\n When we analyse untreated wastewater, the\u00a0findings of\u00a0the\u00a0drugs listed in\u00a0Tab.\u00a02<\/em> are positive in\u00a0all samples. In\u00a0the\u00a0case of\u00a0surface water analysis, the\u00a0situation is different. Ecstasy, benzoylecgonine, cotinine, and trans<\/em>-3-hydroxycotinine were found in\u00a0all samples analysed in\u00a0this pilot study. Methadone and its metabolite EDDP were determined only in\u00a0some sampling profiles. Amphetamine was found sporadically, mostly at the\u00a0limit of\u00a0detection. This is also consistent with our findings within\u00a0the\u00a0DRAGON project (No. VG20122015101), in\u00a0which we had the\u00a0opportunity to compare the\u00a0concentration of\u00a0selected drugs in\u00a0the\u00a0influent and effluent of\u00a0some WWTPs\u00a0[14]. Amphetamine was removed most successfully (85\u2013100\u00a0%), methamphetamine, ecstasy and benzoylecgonine only 40\u201350\u00a0% (Tab.\u00a04<\/em>, Fig.\u00a09<\/em>). Other compounds were not monitored in\u00a0the\u00a0DRAGON project.<\/p>\n <\/p>\n In\u00a0the\u00a0Vltava \u2013 Trojsk\u00e1 l\u00e1vka control profile, all monitored substances occurred in\u00a0very low concentrations, mostly close to the\u00a0limit of\u00a0detection. Concentrations of\u00a0nor-THC, a\u00a0metabolite of\u00a0marijuana, ranged from the\u00a0limit of\u00a0detection of\u00a00.2\u00a0ng\/l to 2.8\u00a0ng\/l, with 45\u00a0% of\u00a0findings below the\u00a0limit of\u00a0detection. From the\u00a0group of\u00a0amphetamines, methamphetamine was determined in\u00a0all samples; the\u00a0concentrations ranged from 0.3\u00a0ng\/l to 2.9\u00a0ng\/l. The\u00a0limit of\u00a0detection for MAMP is 0.1\u00a0ng\/l. AMP was below the\u00a0limit of\u00a0detection (0.3\u00a0ng\/l) in\u00a0all samples. From the\u00a0perspective of\u00a0the\u00a0Czech drug scene, amphetamine is primarily a\u00a0metabolite of\u00a0MAMP, not a\u00a0drug used on its own. At the\u00a0same time, it is successfully removed in\u00a0wastewater treatment plants (Tab.\u00a03<\/em>). The\u00a0party drug ecstasy (MDMA) was detected at concentrations between the\u00a0detection limit of\u00a00.1\u00a0ng\/l and 8.3\u00a0ng\/l, with 50\u00a0% of\u00a0the\u00a0findings below 1.0\u00a0ng\/l. The\u00a0samples were taken on weekdays and MDMA is a\u00a0typical weekend drug. The\u00a0concentrations of\u00a0this drug may have influenced by this. Cocaine and its main\u00a0metabolite benzoylecgonine were detected in\u00a0all analysed samples (Fig.\u00a010<\/em>), the\u00a0determined amounts ranged between 0.8\u20132.03\u00a0ng\/l (BE) and 0.22\u20130.59\u00a0ng\/l (CO). Apart from the\u00a0findings on 5 June 2023 and 24 October 2023, the\u00a0ratio of\u00a0concentrations of\u00a0these compounds corresponds, as only 1\u20139\u00a0% of\u00a0cocaine is excreted unchanged, while 35\u201353\u00a0% leaves the\u00a0body as benzoylecgonine. The\u00a0reasons for the\u00a0unusual findings on the\u00a0above-mentioned days cannot be explained. On\u00a05\u00a0June 2023, the\u00a0concentration of\u00a0cocaine was 4.48\u00a0ng\/l and benzoylecgonine was 4.69\u00a0ng\/l, while on 24 October 2023 it was 1.82\u00a0ng\/l and 1.71\u00a0ng\/l, respectively. Methadone used for substitution treatment and its metabolite EDDP were also found in\u00a0the\u00a0control profile; methadone in\u00a0only three samples at values close to the\u00a0limit of\u00a0detection (0.2\u00a0ng\/l), its metabolite in\u00a0all samples. Its concentration in\u00a0water was very stable, between 0.4\u00a0and 0.6\u00a0ng\/l. The\u00a0concentration of\u00a0the\u00a0licit drug nicotine and its metabolites is always higher than that of\u00a0illicit drugs, with both metabolites occurring in\u00a0surface waters in\u00a0particular.<\/p>\n The\u00a0Vltava \u2013 Podbaba sampling profile, situated below both outputss of\u00a0treated wastewater from the\u00a0Prague WWTP into the\u00a0recipient, shows significantly higher findings of\u00a0individual monitored substances. Concentrations of\u00a0the\u00a0marijuana metabolite nor-THC are in\u00a0the\u00a0range of\u00a00.7\u20134.4\u00a0ng\/l, i.e. approximately 2\u00d7 higher. Again, amphetamine was not present in\u00a0detectable amounts, with concentrations slightly above the\u00a0limit of\u00a0detection in\u00a0only two cases. Methamphetamine was detected in\u00a0all samples, at concentrations ranging from 7.9 to 36.0\u00a0ng\/l, i.e. at concentrations up to 10 times higher than in\u00a0the\u00a0control profile. Methamphetamine is removed significantly less than amphetamine in\u00a0the\u00a0treatment process (Tab.\u00a03<\/em>). Another of\u00a0the\u00a0monitored amphetamines, ecstasy, was also found in\u00a0significantly higher concentrations in\u00a0the\u00a0Vltava \u2013 Podbaba profile; from 10.5\u00a0ng\/l to 65.4\u00a0ng\/l, i.e. up to 8 times higher concentrations. MDMA is removed approximately as successfully as pervitin\u00a0(MAMP), i.e.\u00a040\u201350\u00a0%. Cocaine and benzoylecgonine concentrations were also higher in\u00a0this profile than in\u00a0the\u00a0control profile, with the\u00a0exception of\u00a0the\u00a0sample from 5 June 2023, which ranged between 0.4\u00a0ng\/l and 2.2\u00a0ng\/l\u00a0(CO) and 1.1 to 3.4\u00a0ng\/l (BE). The\u00a0concentration of\u00a0cocaine on 5 June 2023 was 21.6\u00a0ng\/l and benzoylecgonine 19.0\u00a0ng\/l, again\u00a0in\u00a0an unusual ratio, approximately 4 times higher than in\u00a0the\u00a0control profile. A\u00a0higher concentration of\u00a0cocaine metabolite (BE) was also detected on 23\u00a0August 2023, at 19.3\u00a0ng\/l, but the\u00a0concentration of\u00a0cocaine in\u00a0this case was low (0.4\u00a0ng\/l). Methadone and EDDP were determined in\u00a0all samples; methadone between 1.4\u20135.4\u00a0ng\/l and EDDP between 2.8\u20138.9\u00a0ng\/l, again\u00a0in\u00a0concentrations several times higher. The\u00a0concentration of\u00a0these two substances is always relatively stable, which results mainly from the\u00a0regular use of\u00a0methadone as an opioid for substitution treatment. Nicotine metabolites were determined in\u00a0all samples; cotinine at concentrations of\u00a013\u201374\u00a0ng\/l, and trans-3-hydroxycotinine at concentrations of\u00a018\u201346\u00a0ng\/l. In\u00a0this profile, relatively high nicotine findings were also found in\u00a0more than half of\u00a0the\u00a0samples. The\u00a0highest concentration was determined in\u00a0the\u00a0sample taken on 25\u00a0March\u00a02022, at 1,040\u00a0ng\/l, which also corresponds to the\u00a0highest values for COT and T3H-COT.<\/p>\n Fig. 11<\/em> compares the concentrations of cocaine metabolites in the Vltava \u2013 Trojsk\u00e1 l\u00e1vka control profile and in the profile below the wastewater outlet from Prague CWWTP.<\/p>\n <\/p>\n <\/p>\n WWTPs discharging treated wastewater (WW) into monitored streams are in\u00a0the\u00a0same category according to population equivalent (PE); see Tab.\u00a02<\/em>. The\u00a0characteristics of\u00a0individual streams are presented in\u00a0the\u00a0previous chapter. The\u00a0average flow rate of\u00a0Drahansk\u00fd brook is the\u00a0lowest of\u00a0the\u00a0monitored streams, but the\u00a0number of\u00a0people connected to Doln\u00ed Chabry WWTP is the\u00a0highest of\u00a0the\u00a0monitored WWTPs (with the\u00a0exception of\u00a0Prague WWTP) and the\u00a0annual volume of\u00a0treated water discharged is also large. Therefore, the\u00a0stream experiences the\u00a0least dilution of\u00a0this treated WW.<\/p>\n Positive THC metabolite findings were found in 75 % of the samples taken, with the concentrations ranging between the values at the detection limit, i.e. 0.2 ng\/l and 4.2 ng\/l. Illicit substances from the amphetamine group MDMA and MAMP were found in all analysed samples; again, amphetamine did not occur in values above the limit of detection. Ecstasy (MDMA) concentrations ranged from 0.3 to 17.4 ng\/l, with 92 % of samples containing up to 9.4 ng\/l. Pervitin was present in the tested samples at concentrations of 12.5 to 90.7 ng\/l.; these values are higher than in the Vltava \u2013 Podbaba profile. Cocaine and benzoylecgonine were present in detectable amounts in all analysed samples, and their ratio was consistent. Cocaine concentrations ranged from 0.85 to 5.89 ng\/l, while benzoylecgonine values ranged from 2.4 ng\/l to 51.7 ng\/l. These values are also higher than in the Vltava \u2013 Podbaba profile. Substitution treatment contributes to the Drahansk\u00fd brook contamination in the case of methadone, with concentrations of 1.5\u201315.6 ng\/l, and its metabolite EDDP, with 5.0\u201326.2 ng\/l. The situation is the same as for the previous analytes; the values are higher than in the Vltava profile below Prague CWWTP. Nicotine metabolites were also present in all tested samples, with concentrations ranging between\u00a015 and 53\u00a0ng\/l for cotinine and 21\u2013107\u00a0ng\/l for trans-3-hydroxycotinine. Nicotine was detectable in\u00a042\u00a0% of\u00a0samples, with concentrations of\u00a0120 to 525\u00a0ng\/l. In\u00a0this case, the\u00a0values were lower than in\u00a0the\u00a0recipient below Prague CWWTP.<\/p>\n The\u00a0average flow of\u00a0Podmor\u00e1\u0148sk\u00fd brook is 24\u00a0l\/s; the\u00a0average amount of\u00a0discharged wastewater is 11.8\u00a0l\/s; the\u00a0number of\u00a0people connected to the\u00a0treatment plant in\u00a0Velk\u00e9 P\u0159\u00edlepy is almost half lower than in\u00a0the\u00a0Drahansk\u00fd brook. Therefore, the\u00a0treated water in\u00a0Podmor\u00e1\u0148sk\u00fd brook is more diluted than in\u00a0Drahansk\u00fd brook. The\u00a0metabolite nor-THC, which represents marijuana, was found in\u00a0surface water samples at concentrations of\u00a00.4\u20133.5 ng\/l in\u00a0all tested samples. The\u00a0concentrations are similar to those in\u00a0samples of\u00a0Vltava water below Prague CWWTP. Ecstasy was also found in\u00a0all samples, at values between 2.2 and 34.2 ng\/l. Methamphetamine at concentrations of\u00a018.5\u2013168 ng\/l was also detected in\u00a0all samples, and its metabolite amphetamine was present in\u00a0detectable amounts in\u00a0two-thirds of\u00a0the\u00a0tested samples, at concentrations between 0.3 and 2.5 ng\/l. Cocaine and benzoylecgonine were also present in\u00a0100\u00a0% of\u00a0samples, with cocaine concentrations ranging from 0.06 to 11.1 ng\/l, and the\u00a0respective metabolite in\u00a0concentrations of\u00a00.54 to 17.0 ng\/l. Methadone was detectable in\u00a0only three samples, EDDP in\u00a0all but one sample, ranging from the\u00a0limit of\u00a0detection to 1.0 ng\/l. The\u00a0findings of\u00a0these substances representing substitution treatment are related to the\u00a0numbers of\u00a0people using this treatment in\u00a0the\u00a0monitored area. Substances representing the\u00a0legal drug nicotine were present in\u00a0all samples in\u00a0the\u00a0case of\u00a0both metabolites, nicotine was determined in\u00a0two thirds of\u00a0the\u00a0samples. Their concentrations ranged from 122 to 685\u00a0ng\/l\u00a0(NIC), 21 to 74 ng\/l (COT) and 31 to 206 ng\/l (T3H-COT). The\u00a0Podmor\u00e1\u0148sk\u00fd brook therefore burdens the\u00a0Vltava less than the\u00a0Drahansk\u00fd brook.<\/p>\n The\u00a0\u00dan\u011btick\u00fd brook has the\u00a0largest water content of\u00a0all the\u00a0monitored tributaries of\u00a0the\u00a0Vltava; the\u00a0average flow rate is 100\u00a0l\/s. At 19 km\u00b2, the\u00a0catchment area is also the\u00a0largest, and the\u00a0length of\u00a0the\u00a0stream is similar or the\u00a0same as that of\u00a0the\u00a0other tributaries \u2013 4.1 km. The\u00a0\u00dan\u011btick\u00fd stream is fed by the\u00a0outlets of\u00a0two WWTP, Horom\u011b\u0159ice and Tuchom\u011b\u0159ice, which serve a\u00a0total of\u00a05,266 connected residents. The\u00a0annual volume of\u00a0discharged water is 423,000\u00a0m3\/year. At the\u00a0end of\u00a0this chapter, Figs. 12<\/em> and 13<\/em> compare the\u00a0concentrations of\u00a0the\u00a0most commonly used drugs in\u00a0the\u00a0Czech Republic, marijuana and methamphetamine, in\u00a0the\u00a0monitored streams.<\/p>\n <\/p>\n <\/p>\n <\/p>\n The\u00a0study is small in\u00a0scope, however, it does confirm that even treated wastewater contains drug residues and their metabolites and is thus a\u00a0source of\u00a0both licit and illicit drugs entering into surface waters. Their quantity is influenced by the\u00a0character and quality of\u00a0the\u00a0specific WWTP, the\u00a0concentration of\u00a0monitored substances in\u00a0untreated urban wastewater and, last but not least, the\u00a0ratio of\u00a0the\u00a0amount of\u00a0discharged water to the\u00a0size of\u00a0the\u00a0recipient. It also depends on the\u00a0sociodemographic and socioeconomic characteristics of\u00a0the\u00a0monitored locations, which have an impact on the\u00a0type of\u00a0drugs used. Studies focusing, for example, on the\u00a0influence of\u00a0these substances on the\u00a0behaviour of\u00a0aquatic animals, have shown that these compounds have an undesirable effect on the\u00a0environment as well.<\/p>\n We expect that this will change in\u00a0the\u00a0future thanks to the\u00a0fundamental revision of\u00a0Council Directive 91\/271\/EEC of\u00a021 May 1991, on urban wastewater treatment, which introduces new principles for the\u00a0treatment of\u00a0urban wastewater, including quaternary treatment, which should remove micropollutants present in\u00a0urban wastewater. These micropollutants undoubtedly include both illegal and legal drugs.<\/p>\n The\u00a0article was written with the\u00a0support of\u00a0Institutional Funds for the\u00a0Development of\u00a0the\u00a0Research Organization TGM WRI under internal grant No. 3600.52.24\/2022 and project No. SS02030008 \u201cCentre for Environmental Research: Waste and Circular Economy and Environmental Safety\u201d (CEVOOH) and other institutional funds.<\/em><\/p>\n The\u00a0 Czech version of\u00a0 this article was peer-reviewed, the\u00a0 English version was\u00a0translated from the\u00a0Czech original by Environmental Translation Ltd.<\/p>\n","protected":false},"excerpt":{"rendered":" The majority of the population (85 %) in the Czech Republic is connected to the public sewerage network of almost 3,000 wastewater treatment plants (WWTPs). Municipal wastewater contains a number of substances providing information on the state of the population. This information is evaluated by Wastewater-Based Epidemiology (WBE). A WWTP does not remove all contaminants that are discharged into the recipient. In this study, the loading of a recipient with selected licit and illicit drugs was monitored. <\/p>\n","protected":false},"author":8,"featured_media":34599,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[87,92],"tags":[667,668,3352,3734,3190,666,1107,316,3189,3735],"coauthors":[599,1855,1857],"class_list":["post-34665","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hydrochemistry-radioecology-microbiology","category-main","tag-amphetamine","tag-cocaine","tag-cotinine","tag-illicit-substances","tag-mdma","tag-methamphetamine","tag-nicotine","tag-surface-water","tag-thc","tag-trans-3-hydroxycotinine"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/34665","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/comments?post=34665"}],"version-history":[{"count":5,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/34665\/revisions"}],"predecessor-version":[{"id":34741,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/34665\/revisions\/34741"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media\/34599"}],"wp:attachment":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media?parent=34665"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/categories?post=34665"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/tags?post=34665"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/coauthors?post=34665"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/www.vtei.cz\/wp-content\/uploads\/2025\/02\/Ocenaskova-obr-1.jpg\")
<\/a>\nFig. 1. Wastewater treatment plants in the Czech Republic (source: TGM WRI)<\/h6>\n
Monitored streams and characteristics of\u00a0the\u00a0relevant\u00a0WWTPS<\/h3>\n
<\/a>\nFig. 2. Vltava control profile \u2013 Trojsk\u00e1 l\u00e1vka (source: Mapy.cz)<\/h6>\n
<\/a>\nFig. 3. Output from the Prague CWWTP to the Vltava river (source: \u0160J\u016f \/ Wikimedia Commons. This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license)<\/h6>\n
<\/a>\nFig. 4. Drahansk\u00fd brook (source: \u0160J\u016f \/ Wikimedia Commons. This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license)<\/h6>\n
<\/a>\nFig. 5. Podmor\u00e1\u0148sk\u00fd brook (photo: Horakvlado \/ Wikimedia Commons. This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license)<\/h6>\n
<\/a>\nFig. 6. \u00dan\u011btick\u00fd brook in Tuchom\u011b\u0159ice (source: Aktron \/ Wikimedia Commons. This file is licensed under the\u00a0Creative Commons\u00a0Attribution-Share Alike 3.0 Unported\u00a0license)<\/h6>\n
<\/a>\nFig. 7. \u00dan\u011btick\u00fd brook Valley Nature Reserve (source: Meruzalka \/ Wikimedia Commons. This\u00a0file is under Creative Commons license)<\/h6>\n
METHODOLOGY<\/h2>\n
<\/a>\nFig. 8. Map with marked sampling profiles; the profiles used for this study are marked with a\u00a0red dot (source: H. Zv\u011b\u0159inov\u00e1 Mlejnkov\u00e1\u00a0[7])<\/h6>\n
Tab. 1. Sampling place description (source: H. Zv\u011b\u0159inov\u00e1 Mlejnkov\u00e1 [7])<\/h5>\n
<\/a>\nTab. 2. Characteristics of WWTPs on monitored streams (source: H. Zv\u011b\u0159inov\u00e1 Mlejnkov\u00e1 [7])<\/h5>\n
<\/a>\nTab. 3. List of monitored substances<\/h5>\n
<\/a>\nCollection and pretreatment of\u00a0surface water samples<\/h3>\n
\n
RESULTS AND DISCUSSION<\/h2>\n
Tab.\u00a04. Examples of removal of illicit compounds at wastewater treatment plants [14]<\/h5>\n
<\/a>\n<\/a><\/h6>\nFig. 9. Removal of benzoylecgonine, the main metabolite of cocaine, at different treatment plants [14]<\/h6>\n
Vltava \u2013 Trojsk\u00e1 l\u00e1vka control profile<\/h3>\n
<\/a><\/h6>\nFig. 10. Concentrations of cocaine and benzoylecgonine in the Vltava control profile Vltava\u00a0\u2013\u00a0Trojsk\u00e1 l\u00e1vka<\/h6>\n
Vltava \u2013 Podbaba profile<\/h3>\n
<\/a>\n<\/a>\nFig. 11. Comparison of the concentration of the main metabolite of cocaine, benzoylecgonine, in the Vltava control profile above the Prague CWWTP Vltava \u2013 Trojsk\u00e1 l\u00e1vka and\u00a0in\u00a0the Vltava profile below the outlet of the treated wastewater from the Prague CWWTP into the Vltava river<\/h6>\n
Drahansk\u00fd brook profile<\/h3>\n
Podmor\u00e1\u0148sk\u00fd brook profile<\/h3>\n
\u00dan\u011btick\u00fd brook profile<\/h3>\n
\nDue to the high flow rate, the greatest dilution of treated WW occurs in the recipient, 64 % of the samples contained the THC metabolite, nor-THC, above the limit of detection; the concentrations were below 1.0 ng\/l, with the exception of the sample taken on 13 September 2022 with the concentration of 26.4 ng\/l. Ecstasy was determined in all samples, at concentrations between 0.9\u20135.1 ng\/l. In one analysed sample, from 18 September 2023, the MDMA concentration was higher \u2013 15.4 ng\/l. During this period, social events were taking place in the monitored location, which, given that ecstasy is a typical party drug, could have influenced the concentration found. Pervitin was in detectable amounts in all collected and analysed samples. Amphetamine was always below the limit of detection, while pervitin concentrations were in the range of 2.9 to 14.1 ng\/l. Cocaine (CO) and benzoylecgonine (BE) were detected in all samples of surface water collected; measured values for CO ranged between 0.27\u201317.5 ng\/l and 1.25\u201359.3 ng\/l for BE. The findings of this drug are relatively high, which may again be related to the sociodemographic and socioeconomic characteristics of the monitored locations; for example, in Horom\u011b\u0159ice, it can be assumed that the residents belong to an affluent population in which cocaine is popular. The opioid methadone, used for substitution treatment, and its metabolite EDDP were present in 100 % of the samples; their concentrations were relatively stable throughout the project, which is related to its method of application. For methadone, concentrations were between 0.6 and 1.3 ng\/l, for EDDP between 2.2 and 5.1 ng\/l. Nicotine was determined in 55 %\u00a0of\u00a0the\u00a0analysed samples, with values ranging between 138\u2013415 ng\/l. All samples were positive for both cotinine and trans-3-hydroxycotinine, at concentrations of\u00a013\u2013142\u00a0ng\/l and 15\u2013277\u00a0ng\/l, respectively.<\/p>\n<\/a>\n<\/a>\n<\/a>\n<\/h6>\n
<\/a>\n<\/h6>\n
<\/h6>\n
Fig. 12. Comparison of THC metabolite concentrations in monitored streams<\/h6>\n
<\/a>\n<\/a>\n<\/a>\n<\/h6>\n
<\/h6>\n
<\/a>\n<\/h6>\n
Fig. 13. Comparison of methamphetamine and amphetamine concentrations in monitored streams<\/h6>\n
CONCLUSION<\/h2>\n
Acknowledgements<\/h3>\n