Pharmaceutical and narcotics monitoring in Brno wastewater system and estimation of seasonal effect on the abuse of illicit drugs by a wastewater-based epidemiology approach

The presence of pharmaceuticals (PHA) and narcotics (NAR) in wastewater (WW) has attracting growing interest due to concern for aquatic environment and the possibility to exploit their presence to estimate drug consumption by population. This work aims to (i) quantify PHA and NAR in the WW of the Brno metropolitan area, (ii) determine the effectiveness of the current conventional wastewater treatment plant (WWTP), and (iii) estimate the illicit drug (ID) consumption. 23 PHA and 9 NAR were frequently detected in the untreated WW and studied for their removal. One year monitoring was carried out to highlight a possible seasonal pattern with PHA and NAR load in WW, WWTP effectiveness, and illicit consumption. Results highlighted that the most abundant PHA and NAR were caffeine (73.9 ± 6.9 μg L−1) and methamphetamine (2.3 ± 0.1 μg L−1) while oxazepam (0.13 ± 0.05 μg L−1) and EDDP (0.02 ± 0.01 μg L−1) were the lowest ones, respectively. Only paracetamol, caffeine, atenolol, ciprofloxacin, amphetamine, cocaine, morphine, and benzoylecgonine exhibited a high biodegradability being removed almost completely (> 90 %). A predominant illicit use of methamphetamine was estimated (17 ± 0.6 doses 1000.inh−1 d−1) that might suggest a higher number of consumers than previous official estimation. A lower abuse of cocaine (2.7 ± 0.5 doses 1000.inh−1 d−1), amphetamine (2.2 ± 0.3 doses 1000.inh−1 d−1), methadone (1.1 ± 0.2 doses 1000.inh−1 d−1), heroin (0.9 ± 0.2 doses 1000.inh−1 d−1), and MDMA (0.7 ± 0.1 doses 1000.inh−1 d−1) was found. A seasonality pattern was highlighted for some PHA and NAR influent load and removal, and, about ID consumption, only for heroin and methadone. These results will be useful for water utilities, to enhance the knowledge about the presence and removal of PHA and NAR, and local and national authorities to evaluate and counteract the problem of ID abuse.