Marcus Östman

Spatial differences and temporal changes in illicit drug use in Europe quantified by wastewater analysis

Aims To perform wastewater analyses to assess spatial differences and temporal changes of illicit drug use in a large European population. Design Analyses of raw wastewater over a 1-week period in 2012 and 2013. Setting and Participants Catchment areas of wastewater treatment plants (WWTPs) across Europe, as follows: 2012: 25 WWTPs in 11 countries (23 cities, total population 11.50 million); 2013: 47 WWTPs in 21 countries (42 cities, total population 24.74 million). Measurements Excretion products of five illicit drugs (cocaine, amphetamine, ecstasy, methamphetamine, cannabis) were quantified in wastewater samples using methods based on liquid chromatography coupled to mass spectrometry. Findings Spatial differences were assessed and confirmed to vary greatly across European metropolitan areas. In general, results were in agreement with traditional surveillance data, where available. While temporal changes were substantial in individual cities and years (P ranging from insignificant to <10−3), overall means were relatively stable. The overall mean of methamphetamine was an exception (apparent decline in 2012), as it was influenced mainly by four cities. Conclusions Wastewater analysis performed across Europe provides complementary evidence on illicit drug consumption and generally concurs with traditional surveillance data. Wastewater analysis can measure total illicit drug use more quickly and regularly than is the current norm for national surveys, and creates estimates where such data does not exist.

Occurrence and behaviour of 105 active pharmaceutical ingredients in sewage waters of a municipal sewer collection system

The concentrations and behaviour of 105 different active pharmaceutical ingredients (APIs) in the aqueous phase of sewage water within a municipal sewer collection system have been investigated. Sewage water samples were gathered from seven pump stations (one of which was located within a university hospital) and from sewage water treatment influent and effluent. The targeted APIs were quantified using a multi-residue method based on online solid phase extraction liquid chromatography tandem mass spectrometry. The method was thoroughly validated and complies with EU regulations on sample handling, limits of quantification, quality control and selectivity. 51 APIs, including antibiotics, antidepressants, hypertension drugs, analgesics, NSAIDs and psycholeptics, were found frequently within the sewer collection system. API concentrations and mass flows were evaluated in terms of their frequency of detection, daily variation, median/minimum/maximum/average concentrations, demographic dissimilarities, removal efficiencies, and mass flow profiles relative to municipal sales data. Our results suggest that some APIs are removed from, or introduced to, the aqueous phase of sewage waters within the studied municipal collection system.

Tissue-specific bioconcentration of antidepressants in fish exposed to effluent from a municipal sewage treatment plant

Tissue-specific bioconcentration of selected antidepressants was studied in rainbow trout (Oncorhynchus mykiss) exposed to undiluted effluent from a Swedish municipal sewage treatment plant for 13 days. Citalopram, sertraline and venlafaxine were found in the brains and livers of most fish, but not in blood plasma or muscle. Venlafaxine was the only drug found in plasma (3/20 fish). Fluoxetine was not detected in any fish tissue, in accordance with a low concentration in the effluent and a comparably high limit of quantification in tissues. Concentrations of citalopram, sertraline and venlafaxine in fish brain were up to 1/12, 1/8 and 1/26, respectively, of the lowest concentrations found in the brains of mammals treated with therapeutic doses. Thus, given co-exposure to several antidepressants and an assumed similar potency in fish, the margin of safety for target-related effects in fish residing in effluent-dominated streams is relatively low. Furthermore, the non-detectable levels of these drugs in blood plasma suggest that analyses of concentrations in target tissues (brain) would be more informative in field studies and other studies with environmentally realistic exposure concentrations.

A snapshot of illicit drug use in Sweden acquired through sewage water analysis

Analytical measurements of sewage water have been used many times to estimate the consumption of specific drugs in an area. This study measured a large number of illicit drugs and metabolites (>30) at a large number of sewage treatment plants (STPs) distributed across Sweden. Twenty-four illicit and prescription drugs, classified as narcotic substances in Sweden, and seven selected metabolites were included in the study. A 24 hour composite sample of incoming sewage water was collected from 33 different municipalities at various geographic locations across Sweden. Species were analyzed using an on-line solid-phase extraction-liquid chromatography electrospray tandem mass spectrometry method. The method proved to be rapid with minimum need for sample work up and was able to detect 13 compounds above their respective limits of quantification. The results for all compounds were presented as per capita loads. Multivariate data analysis was used to relate drug consumption to geographical location and/or population of cities. The results showed that geographical differences in drug consumption were apparent across the country. For the narcotic pharmaceuticals, the geographical differences suggested by the multivariate model were supported by prescription statistics.

Minimal selective concentrations of tetracycline in complex aquatic bacterial biofilms

Selection pressure generated by antibiotics released into the environment could enrich for antibiotic resistance genes and antibiotic resistant bacteria, thereby increasing the risk for transmission to humans and animals. Tetracyclines comprise an antibiotic class of great importance to both human and animal health. Accordingly, residues of tetracycline are commonly detected in aquatic environments. To assess if tetracycline pollution in aquatic environments promotes development of resistance, we determined minimal selective concentrations (MSCs) in biofilms of complex aquatic bacterial communities using both phenotypic and genotypic assays. Tetracycline significantly increased the relative abundance of resistant bacteria at 10 μg/L, while specific tet genes (tetA and tetG) increased significantly at the lowest concentration tested (1 μg/L). Taxonomic composition of the biofilm communities was altered with increasing tetracycline concentrations. Metagenomic analysis revealed a concurrent increase of several tet genes and a range of other genes providing resistance to different classes of antibiotics (e.g. cmlA, floR, sul1, and mphA), indicating potential for co-selection. Consequently, MSCs for the tet genes of ≤ 1 μg/L suggests that current exposure levels in e.g. sewage treatment plants could be sufficient to promote resistance. The methodology used here to assess MSCs could be applied in risk assessment of other antibiotics as well.

Does antifouling paint select for antibiotic resistance

There is concern that heavy metals and biocides contribute to the development of antibiotic resistance via co-selection. Most antifouling paints contain high amounts of such substances, which risks turning painted ship hulls into highly mobile refuges and breeding grounds for antibiotic-resistant bacteria. The objectives of this study were to start investigate if heavy-metal based antifouling paints can pose a risk for co-selection of antibiotic-resistant bacteria and, if so, identify the underlying genetic basis. Plastic panels with one side painted with copper and zinc-containing antifouling paint were submerged in a Swedish marina and biofilms from both sides of the panels were harvested after 2.5-4weeks. DNA was isolated from the biofilms and subjected to metagenomic sequencing. Biofilm bacteria were cultured on marine agar supplemented with tetracycline, gentamicin, copper sulfate or zinc sulfate. Biofilm communities from painted surfaces displayed lower taxonomic diversity and enrichment of Gammaproteobacteria. Bacteria from these communities showed increased resistance to both heavy metals and tetracycline but not to gentamicin. Significantly higher abundance of metal and biocide resistance genes was observed, whereas mobile antibiotic resistance genes were not enriched in these communities. In contrast, we found an enrichment of chromosomal RND efflux system genes, including such with documented ability to confer decreased susceptibility to both antibiotics and biocides/heavy metals. This was paralleled by increased abundances of integron-associated integrase and ISCR transposase genes. The results show that the heavy metal-based antifouling paint exerts a strong selection pressure on marine bacterial communities and can co-select for certain antibiotic-resistant bacteria, likely by favoring species and strains carrying genes that provide cross-resistance. Although this does not indicate an immediate risk for promotion of mobile antibiotic resistance, the clear increase of genes involved in mobilizing DNA provides a foundation for increased opportunities for gene transfer in such communities, which might also involve yet unknown resistance mechanisms.

Detailed mass flows and removal efficiencies for biocides and antibiotics in Swedish sewage treatment plants

Antimicrobial compounds, such as biocides and antibiotics, are widely used in society with significant quantities of these chemicals ending up in sewage treatment plants (STPs). In this study, mass flows and removal efficiency in different treatment steps at three Swedish STPs were evaluated for eleven different biocides and antibiotics. Mass flows were calculated at eight different locations (incoming wastewater, water after the first sedimentation step, treated effluent, primary sludge, surplus sludge, digested sludge, dewatered digested sludge and reject water). Samples were collected for a total of nine days over three weeks. The STPs were able to remove 53->99% of the antimicrobial compounds and 0-64% were biodegraded on average in the three STPs. Quaternary ammonium compounds were removed from the wastewater >99%, partly through biodegradation, but 38-96% remained in the digested sludge. Chlorhexidine was not biodegraded but was efficiently removed from the wastewater to the sludge. The biological treatment step was the most important step for the degradation of the studied compounds, but also removed several compounds through the surplus sludge. Compounds that were inefficiently removed included benzotriazoles, trimethoprim and fluconazole. The study provides mass flows and removal efficiencies for several compounds that have been seldom studied.

Effect of full-scale ozonation and pilot-scale granular activated carbon on the removal of biocides, antimycotics and antibiotics in a sewage treatment plant

Several micropollutants show low removal efficiencies in conventional sewage treatment plants, and therefore enter the aquatic environment. To reduce the levels of micropollutants in sewage effluent, and thereby the effects on biota, a number of extra treatment steps are currently being evaluated. Two such techniques are ozonation and adsorption onto activated carbon. In this study, we investigated the efficiency of Swedens first full-scale ozonation treatment plant at removing a number of antibiotics, antimycotics and biocides. The effect of adding granular activated carbon (GAC) on a pilot scale and pilot-scale ozonation were also evaluated. The conventional treatment (13,000 PE) with the add-on of full-scale ozonation (0.55 g O3/g Total organic carbon (TOC)) was able to remove most of the studied compounds (>90%), except for benzotriazoles and fluconazole (<50%). Adsorption on GAC on a pilot scale showed a higher removal efficiency than ozonation (>80% for all studied compounds). Three types of GAC were evaluated and shown to have different removal efficiencies. In particular, the GAC with the smallest particle sizes exhibited the highest removal efficiency. The results demonstrate that it is important to select an appropriate type of carbon to achieve the removal goal for specific target compounds.