Temporal and spatial variation in pharmaceutical concentrations in an urban river system

Optimization of screening-level risk assessment and priority selection of emerging pollutants - The case of pharmaceuticals in European surface waters

Pharmaceuticals in surface waters have raised significant concern in recent years for their potential environmental effects. This study identified that at present a total of 477 substances (including 66 metabolites and transformation products) have been analyzed in European surface waters. Around 60% (284) of these compounds belonging to 16 different therapeutic groups were positively detected in one or more of 33 European countries. To conveniently and effectively prioritize potential high-risk compounds, an optimized method that considers the frequency of concentrations above predicted no effects levels was developed on the basis of the traditional method, and it was then used to identify and screen candidate priority pollutants in European surface waters. The results proved the feasibility and advantages of the optimized method. Pharmaceuticals detected in European surface waters were classified into 5 categories (high, moderate, endurable, negligible and safe) depending on their potential environmental effects and the distribution of pharmaceuticals. Circa 9% (45 out of 477) analyzed compounds showed a potential environmental risk to aquatic ecosystems. Among these 45 compounds, 12 compounds were indicated to have high environmental risk in aquatic environments, while 17 and 7 compounds showed moderate and small-scale environmental risks, respectively.

Tracking changes in the occurrence and source of pharmaceuticals within the River Thames, UK; from source to sea

There is a growing interest in the occurrence and sources of pharmaceutical substances in the environment. This paper reports the first detailed transect of pharmaceutical occurrence along the River Thames, UK, from source to sea, undertaken during a period of high flow in 2016. In 37 samples a total of 41 pharmaceuticals and 2 lifestyle compounds (cocaine and sucralose) were detected. Total concentration of pharmaceuticals ranged from 0.0012 μg/l to 10.24 μg/l with a median of 2.6 μg/l. Sucralose concentrations varied from <0.01 to 5.9 μg/l with a median concentration of 1.93 μg/l and was detected in every sample except the groundwater-dominated sources of the Thames. Antimicrobials, including those on the surface water watch list (erythromycin, clarithromycin and azithromycin) were detected in every site downstream of the Thames source. Diclofenac, recently on the surface water watch list, was detected in 97% of Thames samples and above the proposed EQS of 0.1 μg/l in 12 samples. Distinct increases in concentration and number of pharmaceuticals were found downstream of the Oxford, Mogdon and Hogsmill wastewater treatment works (WWTW) but were more subdued downstream of the Crossness and Beckton WWTW due to the tidal nature of the Thames and combined sewer outflows. Sucralose was found to be an excellent tracer of wastewaters (treated and untreated) and can be used as a proxy for many pharmaceuticals. Paracetamol and ibuprofen were tracers of untreated wastewater inputs to the Thames due to their high biodegradation within WWTWs.

Host-parasite interaction as a toxicity test endpoint using asymmetrical exposures

Interspecific relationships frequently determine the effect a pollutant can have on an organism, and this is especially true in closely interacting species such as hosts and parasites. The high spatial and temporal variability of contaminant concentrations combined with the movement of aquatic biota can further influence the consequences that are associated with contamination. We used a full factorial design for the exposed and unexposed partners of the relationship between the parasitic larvae (glochidia) of the European freshwater mussel (Anodonta anatina) and its host fish (Squalius cephalus) to identify the sources of variation in the sublethal endpoints of species interaction (the intensity of parasite attachment, the spatial position of glochidia on the host body, and encapsulation success). We used the water-borne human pharmaceutical compounds methamphetamine (a central nervous system stimulant) and tramadol (an opioid) at environmentally relevant concentrations (˜ 6.7 and 3.8 nmol L^-1 of methamphetamine and tramadol, respectively) as a proxy for contaminant exposure because these compounds are emerging aquatic stressors that are known for high spatial and temporal variability in their detected concentration levels. The relationship between the bivalve and the fish species was influenced by the preceding contact with both methamphetamine and tramadol, but this effect was highly asymmetric. Our experimental design enabled us to identify the specific changes in the relationship outcome that are elicited by the exposure of individual partners, such as the significant increase in glochidia infection success rate from 59.6 ± 3.9% to 78.7 ± 2.8% (means ± s.e.) that was associated with host exposure to methamphetamine. Additionally, the significant interaction effect of the exposure was demonstrated by the lowered proportion of glochidia attached to gills after the coexposure of both partners to tramadol. The impact of pharmaceuticals on wild aquatic host-parasite relationships provides an example of the risks that are associated with the unintentional discharge of biologically active compounds into freshwater habitats. Given the increasing evidence showing the ecological impact of waste pharmaceuticals, the use of multitrophic interaction endpoints after joint and unilateral exposures provides an important step towards the realistic risk assessment of these compounds.

Stereoisomeric profiling of chiral pharmaceutically active compounds in wastewaters and the receiving environment - A catchment-scale and a laboratory study

Chiral pharmaceutically active compounds (cPACs) are not currently governed by environmental regulation yet are expected to be in the future. As cPACs can exert stereospecific toxicity in the aquatic environment, it is essential to better understand their stereoselective behaviour here. Therefore, this study aims to provide a new perspective towards comprehensive evaluation of cPACs at a river catchment level, including their stereochemistry as a chemical phenomenon driving fate of chiral molecules in the environment. A large spatial and temporal monitoring program was performed in Southwest England. It included 5 sewage treatment works and the receiving waters of the largest river catchment in Southwest England. Simultaneously, lab-scale microcosm studies in simulated activated sludge bioreactors and river water microcosm were performed to evaluate stereoselective degradation of cPACs. A multi-residue enantioselective method allowed the analysis of a total of 18 pairs of enantiomers and 3 single enantiomers in wastewater and river water samples. Our monitoring program revealed: (1) spatial and temporal variations of cPACs in influent wastewaters resulting from different patterns of usage as well as an (2) enantiomeric enrichment of cPACs, likely due to human metabolism, despite their commercialization as racemic mixtures. A similar chiral signature was observed in effluent and receiving waters. Stereoselective degradation was observed in trickling filters (TF) for naproxen, ketoprofen, cetirizine and 10,11-dihydroxy-10-hydroxycarbamazepine, in sequencing batch reactors (SBR) for ifosfamide and in activated sludge (AS) for cetirizine. The extent of enantiomer-specific fate was wastewater treatment dependent in the case of naproxen (TF showed higher stereoselectivity than AS and SBR) and cetirizine (TF and AS showed higher stereoselectivity than SBR) due to differing microbial population. Furthermore, stereoselective degradation of naproxen was highly variable among STWs using similar treatments (TF) and operating in the same region. Microbial stereoselective degradation was also confirmed by both activated and river water simulated microcosm for chloramphenicol, ketoprofen, indoprofen, naproxen and 10,11-dihydroxy-10-hydroxycarbamazepine. Results from our large scale river catchment monitoring study and lab simulated microcosm show wide-ranging implications of enantiomerism of cPACs on environmental risk assessment (ERA). As two enantiomers of the same compound show different biological effects (e.g. toxicity), their non-racemic presence in the environment might lead to inaccurate ERA. This is because current ERA approaches do not require analysis at enantiomeric level.

Occurrence of Micropollutants in Wastewater and Evaluation of Their Removal Efficiency in Treatment Trains: The Influence of the Adopted Sampling Mode

The monitoring of micropollutants in water compartments, in particular pharmaceuticals and personal care products, has become an issue of increasing concern over the last decade. Their occurrence in surface and groundwater, raw wastewater and treated effluents, along with the removal efficiency achieved by different technologies, have been the subjects of many studies published recently. The concentrations of these contaminants may vary widely over a given time period (day, week, month, or year). In this context, this paper investigates the average concentration and removal efficiency obtained by adopting four different sampling modes: grab sampling, 24-h time proportional, flow proportional and volume proportional composite sampling. This analysis is carried out by considering three ideal micropollutants presenting different concentration curves versus time (day). It compares the percentage deviations between the ideal concentration (and removal efficiencies) and the differently measured concentrations (removal efficiencies) and provides hints as to the best sampling mode to adopt when planning a monitoring campaign depending on the substances under study. It concludes that the flow proportional composite sampling mode is, in general, the approach which leads to the most reliable measurement of concentrations and removal efficiencies even though, in specific cases, the other modes can also be correctly adopted.

Development of predicted environmental concentrations to prioritize the occurrence of pharmaceuticals in rivers from Catalonia

The main objective of the present study is to prioritize those pharmaceuticals that have higher chances to be detected in water due to incomplete removal in Wastewater Treatment Plants (WWTPs). To do so, the total consumption of pharmaceuticals in Catalonia (NE Spain) were compiled to calculate the predicted environmental concentrations (PECs) in wastewater effluents and in river water. PECs were estimated using publicly available consumption data in the period of 2013-2016 for a suite of 165 compounds. The selected compounds were based on generic pharmaceuticals with emphasis on drugs consumed by people aged 65 or over as they represent the age group with the highest consumption of pharmaceuticals. The mean total consumption of pharmaceuticals in the period studied was of 623 ± 3 t per year. Paracetamol, metformin and ibuprofen were the most administered drugs although the highest PEC values corresponded to metformin, amoxicillin and metamizole. Finally, predicted environmental levels together with acute and chronic toxicological data allowed estimating the risks of these compounds. Amoxicillin is expected to pose adverse effects for cyanobacteria, whereas metformin and ibuprofen pose a small potential for adverse effects to invertebrates and fish, respectively.

Surface water pollution by pharmaceuticals and an alternative of removal by low-cost adsorbents: A review

Micropollutants, also called emerging contaminants, consist of an extensive group of synthetic and natural substances, including pharmaceuticals, personal care products, steroid hormones, and agrochemicals. Currently, the monitoring of residual pharmaceuticals in the environment has been highlighted due to the fact that many of these substances are found in wastewater treatment plants effluents and surface waters, in concentrations ranging from ng L^-1 to μg L^-1. Most of these compounds are discharged into the environment continuously through domestic sewage treatment systems. In the present work, it is presented an overview of water pollution by these pollutants, as well as a review of the recent literature about the use of low-cost adsorbents for the removal of the main pharmaceuticals found in surface water, focusing on municipal and agroindustrial wastes as precursors. It was possible to observe several examples of high adsorption capacities of these compounds with such materials, however other aspects must be considered in order to evaluate the real applicability in water and wastewater treatment, such as competition, recyclability and production cost.

Vertical distribution and assemblages of microbial communities and their potential effects on sulfur metabolism in a black-odor urban river

Black-odor phenomenon in highly urbanized river is increasingly recognized as a global ecological risk. Biotransformation associated with sulfur cycle is a major contributor to the blank-odor phenomenon. The vertical geochemical gradient in black-odor rivers is likely to alter microbial community assemblages and functions in the sulfur cycle. However, the interactions between geochemical gradients and microbial communities, as well as the changes in the process of sulfur biotransformation under different environmental conditions remain largely unknown. The vertical community assembly patterns and the impacts of microbial communities and genes on the biotransformation in the sulfur cycle were revealed in our study for the first time in a typical urban black-odor river, Jinchuan River, in China. Vertical beta-diversity patterns of microbial communities mainly resulted from species replacement that was largely driven by spatial turnover (β_SIM = 0.43) but also influenced by nestedness (β_NES = 0.08). MiSeq sequencing and GeoChip 5.0 microarray chip approaches were applied and identify 41 bacterial genera, 8 archaeal genera, and 26 genes involved in the sulfur cycle in Jinchuan River. The vertical beta-diversity patterns of microbial profile mainly resulted from species replacement. Those sulfur-related bacterial and archaeal genera, accounting for 23.15% and 42.65% of the total bacteria and archaea respectively in analysed samples, were mainly responsible for sulfur reduction. According to redundancy analysis, oxidation-reduction potential (r = -0.8662, P < 0.05), S^2- concentration (r = -0.6288, P < 0.05), and total nitrogen concentration (r = -0.6782, P < 0.05) were identified as factors that significantly affect sulfur-related microbial communities. The highest reaction potential was detected in the dissimilated sulfate reduction action and experienced an increase with depth increasing in the river system. The results indicated that the sulfur biotransformation in a deeper layer in river sediment could make more contribution to the black-odor phenomenon in urban rivers.

Comparison of Prioritisation Schemes for Human Pharmaceuticals in the Aquatic Environment

Only a small proportion of pharmaceuticals available for commercial use have been monitored in the aquatic environment, and even less is known about the effects on organisms. With thousands of pharmaceuticals in use, it is not feasible to monitor or assess the effects of all of these compounds. Prioritisation schemes allow the ranking of pharmaceuticals based on their potential as environmental contaminants, allowing resources to be appropriately used on those which are most likely to enter the environment and cause greatest harm. Many different types of prioritisation schemes exist in the literature and those utilising predicted environmental concentrations (PECs), the fish plasma model (FPM), critical environmental concentrations (CECs) and acute ecotoxicological data were assessed in the current study using the 50 most prescribed drugs in the UK. PECs were found to be overestimates of mean measured environmental concentrations but mainly underestimations of maximum concentrations. Acute ecological data identified different compounds of concern to the other effects assessments although the FPM and CECs methods were more conservative. These schemes highlighted antidepressants, lipid regulators, antibiotics, antihypertensive compounds and ibuprofen as priority compounds for further study and regulation.

Green pharmacy - a narrative review

Introduction

Active pharmaceutical ingredients are present in various sections of the environment, because of both the human and veterinary use of medicinal products. Ways of minimizing the risk of environmental contamination should be observed during all pharmaceutical activities (research, manufacturing, prescribing, dispensing and disposal of medicinal products).

Methods

For the present study we searched specific literature on this subject, using the main international databases (Thomson Reuters – Web of Science, SCOPUS and Science Direct).

Results

This narrative review focuses on the main aspects concerning environmental contamination with medicinal products. Consequently, the present study is structured on four different topics: environmental research on medicinal products, minimizing environmental contamination, waste disposal management and towards a greener community pharmacy.

Conclusion

Waste management activities are important for reducing the presence of active pharmaceutical ingredients in the environment. Pharmacists should inform patients on proper pharmaceutical waste disposal and organize collection programs for unused and expired medicines, in order to develop a greener pharmacy for the future.

Spatial and seasonal occurrence of micropollutants in four Portuguese rivers and a case study for fluorescence excitation-emission matrices

The European Union (EU) has recommended the monitoring of specific priority substances (PSs, Directive 2013/39) and some contaminants of emerging concern (CECs, Decision 2015/495) in surface waterbodies. The present study provides spatial distributions and temporal variations of a wide range of multi-class PSs and CECs in four stressed rivers in Portugal (Ave, Leça, Antuã, and Cértima). Thirteen micropollutants were found in all four rivers, including the priority pesticide isoproturon (up to 92 ng L^-1), various pharmaceuticals (up to 396 ng L^-1), and the UV-filter 2-ethyl-hexyl-4-methoxycinnamate (EHMC, up to 562 ng L^-1) identified in Decision 2015/495. The industrial priority compound perfluorooctanesulfonic acid (PFOS) was found in three rivers (Antuã, Cértima, and Leça) below the method quantification limit, together with four pharmaceuticals not included in these EU guidelines. The already banned priority pesticide atrazine was detected in Ave, Antuã, and Leça (up to 41 ng L^-1) and simazine in Cértima and Leça (up to 26 ng L^-1). Acetamiprid and imidacloprid (included in Decision 2015/495) were only detected during the dry season in the Ave. Leça river was selected as a waterbody case study for assessment of fluorescence excitation-emission matrices (EEMs). These results matched the spatial distribution trend of micropollutants along the river, with stronger fluorescence response and higher concentrations being found downstream of industrial areas and urban wastewater treatment plants (WWTPs). Moreover, the fluorescence signature of surface water collected downstream of an urban WWTP aligned very well with that obtained for the respective WWTP effluent. Thus, actions are needed to preserve a good environmental status of these stressed European waterbodies.

A High-Resolution Spatial Model to Predict Exposure to Pharmaceuticals in European Surface Waters: ePiE

Environmental risk assessment of pharmaceuticals requires the determination of their environmental exposure concentrations. Existing exposure modeling approaches are often computationally demanding, require extensive data collection and processing efforts, have a limited spatial resolution, and have undergone limited evaluation against monitoring data. Here, we present ePiE (exposure to Pharmaceuticals in the Environment), a spatially explicit model calculating concentrations of active pharmaceutical ingredients (APIs) in surface waters across Europe at ∼1 km resolution. ePiE strikes a balance between generating data on exposure at high spatial resolution while having limited computational and data requirements. Comparison of model predictions with measured concentrations of a diverse set of 35 APIs in the river Ouse (UK) and Rhine basins (North West Europe), showed around 95% were within an order of magnitude. Improved predictions were obtained for the river Ouse basin (95% within a factor of 6; 55% within a factor of 2), where reliable consumption data were available and the monitoring study design was coherent with the model outputs. Application of ePiE in a prioritisation exercise for the Ouse basin identified metformin, gabapentin, and acetaminophen as priority when based on predicted exposure concentrations. After incorporation of toxic potency, this changed to desvenlafaxine, loratadine, and hydrocodone.

Quantification of Pharmaceutical Related Biological Activity in Effluents from Wastewater Treatment Plants in UK and Japan

While pharmaceuticals are now routinely detected in aquatic environments, we know little of the biological activity their presence might provoke. It is estimated that nearly 40% of all marketed pharmaceuticals are G protein-coupled receptors (GPCRs) acting pharmaceuticals. Here, we applied an in-vitro assay, called the TGFα shedding assay, to measure the biological activities of GPCRs-acting pharmaceuticals present in effluents from municipal wastewater treatment plants in the United Kingdom (UK) and Japan from 2014 to 2016. The results indicated that compounds were present in the wastewater with antagonistic activities against angiotensin (AT1), dopamine (D2), adrenergic (β1), acetylcholine (M1), and histamine (H1) receptors in both countries. The most consistent and powerful antagonistic activity was against the H1, D2, and AT1 receptors at up to microgram-antagonist-equivalent quantity/L. Chemical analysis of the same UK samples was also conducted in parallel. Comparing the results of the bioassay with the chemical analysis indicated (1) the existence of other D2 or M1 receptor antagonists besides sulpiride (D2 antagonist) or pirenzepine (M1 antagonist) in wastewater and (2) that there might be a mixture effect between agonist and antagonistic activities against β1 receptor. GPCR-acting pharmaceuticals should be paid more attention in the environmental monitoring and toxicity testing in future studies.

Application of prioritization approaches to optimize environmental monitoring and testing of pharmaceuticals

Pharmaceuticals are ubiquitous in the natural environment with concentrations expected to rise as human population increases. Environmental risk assessments are available for a small portion of pharmaceuticals in use, raising concerns over the potential risks posed by other drugs that have little or no data. With >1900 active pharmaceutical ingredients in use, it would be a major task to test all of the compounds with little or no data. Desk-based prioritization studies provide a potential solution by identifying those substances that are likely to pose the greatest risk to the environment and which, therefore, need to be considered a priority for further study. The aim of this review was to (1) provide an overview of different prioritization exercises performed for pharmaceuticals in the environment and the results obtained; and (2) propose a new holistic risk-based prioritization framework for drugs in the environment. The suggested models to underpin this framework are discussed in terms of validity and applicability. The availability of data required to run the models was assessed and data gaps identified. The implementation of this framework may harmonize pharmaceutical prioritization efforts and ensure that, in the future, experimental resources are focused on molecules, endpoints, and environmental compartments that are biologically relevant.