Effects of sewer biofilm on the degradation of drugs in sewage: A microcosm study

Amphetamine-like substances and synthetic cathinones in Portuguese wastewater influents: Enantiomeric profiling and role of suspended particulate matter

Wastewater based epidemiology (WBE) has been used worldwide to estimate drug consumption routinely. Even though WBE provides valuable data to support legal and health interventions associated to drug use, monitoring studies in Portuguese wastewaters are scarce. Hence, this work aimed to estimate the consumption of some conventional abuse and illicit drugs such as amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxymethamphetamine (MDMA), and the synthetic cathinones buphedrone (BPD), butylone (BTL), 3,4-dimethylmethcathinone (3,4-DMMC) and 3-methylmethcathinone (3-MMC), considering not only the liquid phase, but also the suspended particulate matter (SPM). Moreover, the enantiomeric profiling of the samples was studied, exploring for the first time the possible enantioselective sorption of these drugs onto SPM. For that, 24 h composite raw wastewaters were collected from a conventional wastewater treatment plant (WWTP) in Portugal. After extraction, the liquid phase and SPM extracts were derivatized with an enantiomerically pure reagent and then, analysed using a gas chromatography-mass spectrometry (GC-MS) analytical method. The results showed a low and non-enantioselective adsorption to SPM at environmental relevant levels. Only (S)-AMP was detected in two SPM samples, whereas AMP, MAMP, MDMA, BPD, and 3,4-DMMC were detected in the liquid phase. AMP was the most frequently found drug with an estimated load up to 166.0 mg day-1 1000 people-1 and mostly found with enrichment of (S)-AMP. Nevertheless, (R)-AMP was also determined, which may be related to the consumption of either the illicit racemic AMP or the medicine (R)-deprenyl. The use of MDMA, MAMP and synthetic cathinones (BPD and 3,4-DMMC) was also suggested in Portugal. Nevertheless, the levels and the consumption estimate of the target chemicals were lower than in other European countries or worldwide. These findings provide the first step to the implementation of WBE monitoring campaigns to assess the status of drug consumption in Portuguese communities, contributing to the understanding of drug use patterns and trends worldwide and helping enforce preventive measures.

Remediation of pharmacophoric laboratory waste by using biodegradable carbon nanoparticles of bacterial biofilm origin

Research laboratories generate a broad range of hazardous pharmacophoric chemical contaminants, from drugs to dyes used during various experimental procedures. In the recent past, biological methods have demonstrated great potential in the remediation of such contaminants. However, the presence of pharmacophoric chemicals containing antibiotics, xenobiotics, and heavy metals suppresses the growth and survivability of used microbial agents, thus decreasing the overall efficiency of biological remediation processes. Bacterial biofilm is a natural arrangement to counter some of these inhibitions but its use in a systemic manner, portable devices, and pollutant remediation plants post serious challenges. This could be countered by synthesizing a biodegradable carbon nanoparticle from bacterial biofilm. In this study, extracellular polymeric substance-based carbon nanoparticles (Bio-EPS-CNPs) were synthesized from bacterial biofilm derived from Bacillus subtilis NCIB 3610, as a model bacterial system. The produced Bio-EPS-CNPs were investigated for physiochemical properties by dynamic light scattering, optical, Fourier-transformed infrared, and Raman spectroscopy techniques, whereas X-ray diffraction study, scanning electron microscopy, and transmission electron microscopy were used to investigate structural and morphological features. The Bio-EPS-CNPs exhibited negative surface charge with spherical morphology having a uniform size of sub-100 nm. The maximum remediation of some laboratory-produced pharmacophoric chemicals was achieved through a five-round scavenging process and confirmed by UV/Vis spectroscopic analysis with respect to the used pharmacophore. This bioinspired remediation of used pharmacophoric chemicals was achieved through the mechanism of surface adsorption via hydrogen bonding and electrostatic interactions, as revealed by different characterizations. Further experiments were performed to investigate the effects of pH, temperature, stirring, and the protocol of scavenging to establish Bio-EPS-CNP as a possible alternative to be used in research laboratories for efficient removal of pharmacophoric chemicals by incorporating it in a portable, filter-based device.

Stability and Degradation of Opioids in River Water

As the level of consumption of opioids continues to rise globally, there is increasing concern over the potential impacts of continuous opioid discharges into aquatic ecosystems. Opioids are psychoactive compounds that are not completely removed during wastewater treatment, and little is known about their stability and fate in the environment. In the present study, we evaluated the stability of four highly used opioids, buprenorphine, codeine, fentanyl, and tramadol, in river water via batch degradation experiments. The opioids were spiked at environmentally relevant concentrations into 150 mL of river microcosms designed to distinguish among hydrolysis, abiotic degradation, biodegradation, and sorption. All opioids exhibited relatively high stability in river water, with removal rates of only 15% (tramadol) to 26% (buprenorphine) after 6 days. Biodegradation was the most important attenuation pathway for all four opioids, with first-order biodegradation constants ranging from 0.011 d-1 (tramadol) to 0.018 d-1(buprenorphine). Overall, degradation rates were 1-4 orders of magnitude lower compared to the reported rates for wastewater systems. These results offer insights into the stability of opioids in freshwater systems and raise questions about the potential effects of their pseudopresence in surface waters on aquatic organisms.

In-sewer stability assessment of 140 pharmaceuticals, personal care products, pesticides and their metabolites: Implications for wastewater-based epidemiology biomarker screening

The monitoring of pharmaceuticals, personal care products (PCPs), pesticides, and their metabolites through wastewater-based epidemiology (WBE) provides timely information on pharmaceutical consumption patterns, chronic disease treatment rates, antibiotic usage, and exposure to harmful chemicals. However, before applying them for quantitative WBE back-estimation, it is necessary to understand their stability in the sewer system to screen suitable WBE biomarkers thereby reducing research uncertainty. This study investigated the in-sewer stability of 140 typical pharmaceuticals, PCPs, pesticides, and their metabolites across 15 subcategories, using a series of laboratory sewer sediment and biofilm reactors. For the first time, stability results for 89 of these compounds were reported. Among the 140 target compounds, 61 biomarkers demonstrated high stability in all sewer reactors, while 41 biomarkers were significantly removed merely by sediment processes. For biomarkers exhibiting notable attenuation, the influence of sediment processes was generally more pronounced than biofilm, due to its stronger microbial activities and more pronounced diffusion or adsorption processes. Adsorption emerged as the predominant factor causing biomarker removal compared to biodegradation and diffusion. Significantly different organic carbon-water partitioning coefficient (Koc) and distribution coefficient at pH = 7 (logD) values were observed between highly stable and unstable biomarkers, with most hydrophobic substances (Koc > 100 or logD > 2) displaying instability. In light of these findings, we introduced a primary biomarker screening process to efficiently exclude inappropriate candidates, achieving a commendable 77 % accuracy. Overall, this study represents the first comprehensive report on the in-sewer stability of 89 pharmaceuticals, PCPs, pesticides, and their metabolites, and provided crucial reference points for understanding the intricate sewer sediment processes.

Long-term wastewater-based surveillance and impacts of the COVID-19 pandemic on drug use trends in a U.S. Northeast rural town

Herein we discuss the findings of a two-year wastewater-based drug use surveillance from September 2018 to August 2020 and present objective evidence on the impacts of the COVID-19 pandemic on drug use in a rural community. 24-h composite wastewater samples were collected twice each month from a university town in Northeastern United States and were analyzed for ten priority opioids and stimulants: morphine, codeine, hydrocodone, methadone, fentanyl cocaine, methamphetamine, amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxy-N-ethylamphetamine (MDEA). All target drugs were detected at 100 % frequency in wastewater samples. On a mass basis, the average estimated per capita drug consumption were highest for cocaine, morphine, and amphetamine, and lowest for MDMA, MDEA, and hydrocodone. Furthermore, the estimated per capita consumption of fentanyl was higher than previous reports from rural and university settings in the U.S. Generally, drug consumption was higher during the spring semesters, with year-on-year semester increases also noted over the 2-y study period. Except for methadone and cocaine, the estimated average per capita consumption of drugs increased over the pandemic period, with the highest increase noted for MDMA (286 % increase compared to baseline, p = 0.016). Estimated average consumption of methadone and cocaine decreased slightly by 6 % and 7 %, respectively. These results demonstrate the utility and strength of wastewater-based approaches in capturing long-term and evolving trends in drug use within communities. Our study findings reflect the regionwide problem with opioid-related overdoses and increasing stimulant prescription rates. Our findings also provide objective data and insights for health policymakers on the effects of the pandemic period on community drug use in a rural U.S. town.