Concentration and risk of pharmaceuticals in freshwater systems are related to the population density and the livestock units in Iberian Rivers

Effects of antibiotics and metals on meiofauna assessed through taxon/functional and modeling tools: a case study of amoxicillin and copper

This research examines the impacts of amoxicillin and copper, separately and together, on the taxonomic and functional diversity of free-living marine nematodes. Sediment samples were gathered from the Jeddah shoreline in Saudi Arabia, and meiobenthic organisms were subjected to two concentrations of amoxicillin [550 and 1100 ng/L] and copper [130 mg/kg dry weight (dw) and 260 mg/kg dw] in microcosms for 30 days. The findings indicated a higher nematode tolerance than that of polychaetes, copepods, isopods, amphipods, and cumaceans. A notable decrease in both nematode species abundance and diversity was observed as contaminant levels rose, resulting in the reduction of sensitive bioindicators, specifically Paracanthonchus sadspitensis, Dorylaimopsis timmi, Cinctonema papillata, Eleutherolaimus obtusicaudatus, Terschellingia longicaudata, Theristus poloris, Halalaimus longicaudatus, Parodontophora breviseta, and Theristus pertenuis for copper, as well as C. papillata, T. longicaudata, H. longicaudatus, T. pertenuis, D. timmi, and Viscosia viscosia for amoxicillin. Conversely, tolerant/opportunistic species such as Metoncholaimus albidus for amoxicillin and Daptonema oxycerca for both copper and amoxicillin showed an increase in abundance. The pairing of amoxicillin and copper demonstrated a synergistic or additive toxic impact. Furthermore, pollution changed the functional characteristics of nematodes, leading to a rise in detritivore species with clavate tails, and a decline in microvore species with conical and filiform tails. A computational analysis also supported these findings by evaluating the toxicokinetics and molecular interactions of amoxicillin and copper.

Long-term exposure to sediment-associated antidepressants impacts life-history traits in an estuarine deposit-feeding worm

Hydrophobic pollutants, such as the antidepressant sertraline (SER), tend to sorb to particles in the water column and subsequently accumulate in the sediment. Long-term exposure to these pollutants may significantly affect sediment-dwelling organisms´ fitness and behavior. To address this knowledge gap, we investigated the impact of chronic exposure to a range of environmentally relevant and higher concentrations of sediment-associated SER on the deposit-feeding polychaete Capitella teleta. Since certain antidepressants can function as neurotoxic chemicals and endocrine disruptors on non-target species, we examined feeding rate and burrowing behavior in adult worms after 23 days of exposure (Experiment 1), and key life-history traits in juvenile worms during 35 days of exposure (Experiment 2) to sediment-associated SER (0.33 - 100 µg/g dw sediment). SER did not affect survival but reduced maturation and time to first reproduction: 37%, 50%, and 29% of the worms exposed respectively to SER 0.33, 3.3 and 33 µg/g reached maturation on day 21, whereas worms in the other treatments did not mature (0%; control) or reached a lower maturation degree (6%; 100 µg/g). Although not statistically significant, growth, feeding, and burrowing manifested non-monotonic trends: at environmentally relevant SER concentrations adults increased feeding and extended time to fully burrow into the sediment, and juveniles increased growth, whereas high concentrations had an inhibitory or no effect. Reproductive endpoints appeared most sensitive to chronic SER exposure. Even at low environmental concentrations, antidepressants can cause sublethal effects in non-target species, potentially affecting population dynamics and ecosystem functioning. Further research is key to fully understanding the ecological impact of hydrophobic chemicals in natural environments.

Assessment of emerging and persistent contaminants in an anthropogenic-impacted watershed: Application using targeted, non-targeted, and in vitro bioassay techniques

Emerging and persistent contaminants (EPC) pose a significant challenge to water quality monitoring efforts. Effect-based monitoring (EBM) techniques provide an efficient and systematic approach in water quality monitoring, but they tend to be resource intensive. In this study, we investigated the EPC distribution for various land uses using target analysis (TA) and non-target screening (NTS) and in vitro bioassays, both individually and integrated, in the upper Ping River Catchment, northern Thailand. Our findings of NTS showed that urban areas were the most contaminated of all land use types, although agriculture sites had high unexpected pollution levels. We evaluated the reliability of NTS data by comparing it to TA and observed varying inconsistencies likely due to matrix interferences and isobaric compound interferences. Integrating NTS with in vitro bioassays for a thorough analysis posed challenges, primary due to a scarcity of concentration data for key compounds, and potentially additive or non-additive effects of mixture samples that could not be accounted for. While EBM approaches place emphasis on toxic sites, this study demonstrated the importance of considering non-bioactive sites that contain toxic compounds with antagonistic effects that may go undetected by traditional monitoring approaches. The present work emphasizes the importance of improving NTS workflows and ensuring high-quality EBM analyses in future water quality monitoring programs.

Challenges and effective tracking down strategies of antibiotic contamination in aquatic ecosystem

A growing environmental concern revolves around the widespread use of medicines, particularly antibiotics, which adversely impact water quality and various life forms. The unregulated production and utilization of antibiotics not only affect non-targeted organisms but also exert significant evolutionary pressures, leading to the rapid development of antimicrobial resistance (AMR) in bacterial communities. To address this issue, global studies have been conducted to assess the prevalence and quantities of antibiotics in various environmental components including freshwater, ocean, local sewage, and fish. These studies aim to establish effective analytical methods for identifying and measuring antibiotic residues in environmental matrices that might enable authorities to establish norms for the containment and disposal of antibiotics. This article offers a comprehensive overview of methods used to extract antibiotics from environmental matrices exploring purification techniques such as liquid-liquid extraction, solid-phase extraction, green extraction techniques, and concentration methods like lyophilization and rotary evaporation. It further highlights qualitative and quantitative analysis methods, high-performance liquid chromatography, ultra-high-performance liquid chromatography, and liquid chromatography-tandem along with analytical methods such as UV-Vis and tandem mass spectrometry for detecting and measuring antibiotics. Urgency is underscored for proactive strategies to curb antibiotic contamination, safeguarding the integrity of aquatic ecosystems and public health on a global scale.

Computational modeling (in silico) methods combined with ecotoxicological experiments (in vivo) to predict the environmental risks of an antihistamine drug (loratadine)

This study employed computational modeling (in silico) methods, combined with ecotoxicological experiments (in vivo) to predict the persistence/biodegradability, bioaccumulation, mobility, and ecological risks of an antihistamine drug (Loratadine: LOR) in the aquatic compartment. To achieve these goals, four endpoints of the LOR were obtained from different open-source computational tools, namely: (i) "STP total removal"; (ii) Predicted ready biodegradability; (iii) Octanol-water partition coefficient (KOW); and (iv) Soil organic adsorption coefficient (KOC). Moreover, acute and chronic, ecotoxicological assays using non-target freshwater organisms of different trophic levels (namely, algae Pseudokirchneriella subcapitata; microcrustaceans Daphnia similis and Ceriodaphnia dubia; and fish Danio rerio), were used to predict the ecological risks of LOR. The main results showed that LOR: (i) is considered persistent (after a weight-of-evidence assessment) and highly resistant to biodegradation; (ii) is hydrophobic (LOG KOW = 5.20), immobile (LOG KOC = 5.63), and thus, it can potentially bioaccumulate and/or can cause numerous deleterious effects in aquatic species; and (iii) after ecotoxicological evaluation is considered "toxic" and/or "highly toxic" to the three trophic levels tested. Moreover, both the ecotoxicological assays and risk assessment (RQ), showed that LOR is more harmful for the crustaceans (RQcrustaceans = moderate to high risks) than for algae and fish. Ultimately, this study reinforces the ecological concern due to the indiscriminate disposal of this antihistamine drug in worldwide aquatic ecosystems.

Antibiotic residue contamination in the aquatic environment, sources and associated potential health risks

Antibiotic residues are widely recognized as major pollutants in the aquatic environment on a global scale. As a significant class of pharmaceutically active compounds (PhACs), antibiotics are extensively consumed worldwide. The primary sources of these residues include hospitals, municipal sewage, household disposal, and manures from animal husbandry. These residues are frequently detected in surface and drinking waters, sewage effluents, soils, sediments, and various plant species in countries such as China, Japan, South Korea, Europe, the USA, Canada, and India. Antibiotics are used medicinally in both humans and animals, with a substantial portion excreted into the environment as metabolites in feces and urine. With the advancement of sensitive and quantitative analytical techniques, antibiotics are consistently reported in environmental matrices at concentrations ranging from nanograms per liter (ng/L) to milligrams per liter (mg/L). Agricultural soils, in particular, serve as a significant reservoir for antibiotic residues due to their strong particle adsorption capacities. Plants grown in soils irrigated with PhAC-contaminated water can uptake and accumulate these pharmaceuticals in various tissues, such as roots, leaves, and fruits, raising serious concerns regarding their consumption by humans and animals. There is an increasing need for research to understand the potential human health risks associated with the accumulation of antibiotics in the food chain. The present reviews aims to shed light on the rising environmental pharmaceutical contamination concerns, their sources in the environment, and the potential health risks as well as remediation effort. To discuss the main knowledge gaps and the future research that should be prioritized to achieve the risk assessment. We examined and summarized the available data and information on the antibiotic resistance associated with antibiotic residues in the environment. As studies have indicated that vegetables can absorb, transport, and accumulate antibiotics in edible parts when irrigated with wastewater that is either inadequately treated or untreated. These residues and their metabolites can enter the food chain, with their persistence, bioaccumulation, and toxicity contributing to drug resistance and adverse health effects in living organisms.

Disposable electrochemical sensor: Highly sensitive determination of nitrofurazone antibiotic in environmental samples and pharmaceutical formulations

The study presents the successful development of a new electrochemical sensor with low cost and disposability for application in nitrofurazone detection in environmental and pharmaceutical samples. The sensors were fabricated using materials obtained from local storage and conductive carbon ink. The modification of the screen-printed electrodes with the hybrid nanomaterial based on silver nanoparticles, carbon quantum dots, and carbon nanotubes showed synergistic contributions in the nitrofurazone electrooxidation, as observed in the wide linear range (0.008 at 15.051 μM), with a sensitivity of 0.650 μA/μM. The limit of detection obtained was 4.6 nM. Differential pulse voltammetry, cyclic voltammetry, X-ray photoelectron spectroscopy, X-ray diffraction analysis, and high-resolution transmission electron microscopy were used to evaluate the electrochemical and structural characteristics. Studies of possible interferences were considered with nitrofurazone in the presence of the ions and organic molecules. The results were satisfactory, with a variation of 93.3% ± 4.39% at 100% ± 2.40%. The low volume used in the analyses (50 μL), disposability, high sensibility, selectivity, and low limit of detection are advantages that make the proposed sensor an electrochemical tool of high viability for the NFZ detection in environmental matrices and pharmaceutical formulations.

Contrasting toxicity response to a mixture of azithromycin and ivermectin between a freshwater and a euryhaline rotifer

Organisms are usually exposed to mixtures of emerging pollutants in aquatic environments. Due to their widespread use and environmental relevance, the individual and combined effects of the drugs azithromycin (AZT) and ivermectin (IVM) on the freshwater rotifer Lecane papuana and the euryhaline rotifer Proales similis were investigated. Rotifers showed greater sensitivity to IVM compared to AZT. The LC50 values of IVM and AZT for L. papuana and P. similis were 0.163 and 0.172 mg/L, and 13.52 and 20.00 mg/L, respectively. Population growth rates, assessed in chronic toxicity assays, responded negatively to increasing concentrations of both toxicants, either individually or in combination. Our results revealed two distinct combined toxicity responses: a strong synergistic effect in the freshwater rotifer and a marked antagonistic impact of the AZT-IVM mixtures in the euryhaline rotifer.

Assessment, distribution, and ecological risk of contaminants of emerging concern in a surface water-sediment-fish system impacted by wastewater

The presence of contaminants of emerging concern in aquatic ecosystems represents an ever-increasing environmental problem. Aquatic biota is exposed to these contaminants, which can be absorbed and distributed to their organs. This study focused on the assessment, distribution, and ecological risk of 32 CECs in a Spanish river impacted by effluents from a wastewater treatment plant, analyzing the organs and plasma of common carp. Environmental concentrations in water and sediment were examined at sites upstream and downstream of the wastewater treatment plant. The two downstream sites showed 15 times higher total concentrations (12.4 μg L-1 and 30.1 μg L-1) than the two upstream sites (2.08 μg L-1 and 1.66 μg L-1). Half of the CECs were detected in fish organs, with amantadine having the highest concentrations in the kidney (158 ng g-1 w.w.) and liver (93 ng g-1 w.w.), followed by terbutryn, diazepam, and bisphenol F in the brain (50.2, 3.82 and 1.18 ng g-1 w.w.). The experimental bioaccumulation factors per organ were compared with the bioconcentration factors predicted by a physiologically based pharmacokinetic model, obtaining differences of one to two logarithmic units for most compounds. Risk quotients indicated a low risk for 38 % of the contaminants. However, caffeine and terbutryn showed an elevated risk for fish. The mixed risk quotient revealed a medium risk for most of the samples in the three environmental compartments: surface water, sediment, and fish.

Preparation of iota-carrageenan@bentonite@4-phenyl-3-thiosemicarbazide ternary hydrogel for adsorption of Losartan potassium and sulfamethoxazole

A rising quantity of drugs has been discharged into the aquatic environment, posing a substantial hazard to public health. In the current work, a novel hydrogel (i.Carr@Bent@PTC), comprised of iota-carrageenan, bentonite, and 4-phenyl-3-thiosemicarbazide, was successfully prepared. The introduction of 4-phenyl-3-thiosemicarbazide and bentonite in iota-carrageenan significantly increased the mechanical strength of iota-carrageenan hydrogel and improved its degree of swelling, which can be attributed to the hydrophilic properties of PTC and Bent. The recorded contact angle was 70.8°, 59.1°, 53.9°, and 34.6° for pristine i.Carr, i.Carr@Bent, and i.Carr@Bent@PTC, respectively. The low contact angle measurement of the Bent and PTC loaded-i.Carr hydrogel was attributed to the hydrophilic Bent and PTC. The ternary i.Carr@Bent@PTC hydrogel demonstrated broad pH adaptability and excellent adsorption capacities for sulfamethoxazole (SMX) and losartan potassium (LP), i.e., 467.61 mg. g-1 and 274.43 mg. g-1 at 298.15 K, respectively. The pseudo-first-order (PSO) model provided a better fit for the adsorption kinetics. The adsorption of SMX and LP can be better explained by employing the Sips and Langmuir isotherm models. As revealed by XPS and FTIR investigations, π-π stacking, complexation, electrostatic interaction, and hydrogen bonding were primarily involved in the adsorption mechanisms.

River ecological status is shaped by agricultural land use intensity across Europe

Agriculture impacts the ecological status of freshwaters through multiple pressures such as diffuse pollution, water abstraction, and hydromorphological alteration, strongly impairing riverine biodiversity. The agricultural effects, however, likely differ between agricultural types and practices. In Europe, agricultural types show distinct spatial patterns related to intensity, biophysical conditions, and socioeconomic history, which have been operationalised by various landscape typologies. Our study aimed at analysing whether incorporating agricultural intensity enhances the correlation between agricultural land use and the ecological status. For this, we aggregated the continent's agricultural activities into 20 Areas of Farming-induced Freshwater Pressures (AFFP), specifying individual pressure profiles regarding nutrient enrichment, pesticides, water abstraction, and agricultural land use in the riparian zone to establish an agricultural intensity index and related this intensity index to the river ecological status. Using the agricultural intensity index, nearly doubled the correlative strength between agriculture and the ecological status of rivers as compared to the share of agriculture in the sub-catchment (based on the analysis of more than 50,000 sub-catchment units). Strongest agricultural pressures were found for high intensity cropland in the Mediterranean and Temperate regions, while extensive grassland, fallow farmland and livestock farming in the Northern and Highland regions, as well as low intensity mosaic farming, featured lowest pressures. The results provide advice for pan-European management of freshwater ecosystems and highlight the urgent need for more sustainable agriculture. Consequently, they can also be used as a basis for European Union-wide and global policies to halt biodiversity decline, such as the post-2027 renewal of the Common Agricultural Policy.

Pesticide screening of surface water and soil along the Mekong River in Cambodia

Widespread use of pesticides globally has led to serious concerns about environmental contamination, particularly with regard to aquatic and soil ecosystems. This work involved investigating concentrations of 64 pesticides in surface-water and soil samples collected in four provinces along the Mekong River in Cambodia during the dry and rainy seasons (276 samples in total), and conducting semi-structured interviews with local farmers about pesticide use. Furthermore, an ecological risk assessment of the detected pesticides was performed. In total, 56 pesticides were detected in surface water and 43 in soil, with individual pesticides reaching maximum concentrations of 1300 ng/L in the surface-water samples (tebufenozide) and 1100 ng/g dry weight in the soil samples (bromophos-ethyl). The semi-structured interviews made it quite evident that the instructions that farmers are provided regarding the use of pesticides are rudimentary, and that overuse is common. The perceived effect of pesticides was seen as an end-point, and there was a limited process of optimally matching pesticides to pests and crops. Several pesticides were used regularly on the same crop, and the period between application and harvest varied. Risk analysis showed that bromophos-ethyl, dichlorvos, and iprobenfos presented a very high risk to aquatic organisms in both the dry and rainy seasons, with risk quotient values of 850 for both seasons, and of 67 in the dry season and 78 in the rainy season for bromophos-ethyl, and 49 in the dry season and 16 in the rainy season for dichlorvos. Overall, this work highlights the occurrence of pesticide residues in surface water and soil along the Mekong River in Cambodia, and emphasizes the urgent need for monitoring and improving pesticide practices and regulations in the region.

Understanding pharmaceutical exposure and the potential for effects in marine biota: A survey of bonefish (Albula vulpes) across the Caribbean Basin

Most research on pharmaceutical presence in the environment to date has focused on smaller scale assessments of freshwater and riverine systems, relying mainly on assays of water samples, while studies in marine ecosystems and of exposed biota are sparse. This study investigated the pharmaceutical burden in bonefish (Albula vulpes), an important recreational and artisanal fishery, to quantify pharmaceutical exposure throughout the Caribbean Basin. We sampled 74 bonefish from five regions, and analyzed them for 102 pharmaceuticals. We assessed the influence of sampling region on the number of pharmaceuticals, pharmaceutical assemblage, and risk of pharmacological effects. To evaluate the risk of pharmacological effects at the scale of the individual, we proposed a metric based on the human therapeutic plasma concentration (HTPC), comparing measured concentrations to a threshold of 1/3 the HTPC for each pharmaceutical. Every bonefish had at least one pharmaceutical, with an average of 4.9 and a maximum of 16 pharmaceuticals in one individual. At least one pharmaceutical was detected in exceedance of the 1/3 HTPC threshold in 39% of bonefish, with an average of 0.6 and a maximum of 11 pharmaceuticals exceeding in a Key West individual. The number of pharmaceuticals (49 detected in total) differed across regions, but the risk of pharmacological effects did not (23 pharmaceuticals exceeded the 1/3 HTPC threshold). The most common pharmaceuticals were venlafaxine (43 bonefish), atenolol (36), naloxone (27), codeine (27), and trimethoprim (24). Findings suggest that pharmaceutical detections and concentration may be independent, emphasizing the need to monitor risk to biota regardless of exposure diversity, and to focus on risk quantified at the individual level. This study supports the widespread presence of pharmaceuticals in marine systems and shows the utility of applying the HTPC to assess the potential for pharmacological effects, and thus quantify impact of exposure at large spatial scales.

Pharmaceuticals, hazard and ecotoxicity in surface and wastewater in a tropical dairy production area in Latin America

Pharmaceuticals comprise a complex group of emerging pollutants. Despite the significant number of pharmaceuticals used in veterinary medicine, the input of these compounds into the environment due to livestock activities has been scarcely described. This work assays for the first time in Central America the occurrence of pharmaceuticals in farm wastewater in an area devoted to dairy production, and in the surrounding surface waters. Among 69 monitored pharmaceuticals, a total of eight compounds were detected in wastewater samples collected from seven dairy farms after three sampling campaigns. Six pharmaceuticals were considered either of high (albendazole, lovastatin and caffeine) or intermediate estimated hazard (ciprofloxacin, acetaminophen and ketoprofen) based on the HQ approach, while 26% of the samples were considered of high estimated hazard according to the cumulative ∑HQ approach. Similarly, when ecotoxicological tests were applied, all the samples showed some level of toxicity towards Daphnia magna, and most samples towards Vibrio fischeri and Lactuca sativa. Fourteen pharmaceuticals were detected in surface water samples collected in the surroundings of the dairy production farms, including rural and urban areas. Seven out of these compounds showed high estimated risk (risperidone, diphenhydramine, trimethoprim, fluoxetine, ofloxacin, caffeine and ibuprofen), while three (gemfibrozil, ciprofloxacin and cephalexin) exhibited intermediate estimated risk. In a similar worrisome way, 27% of these samples were estimated to pose high environmental risk according to the pharmaceutical content. Despite being nontoxic for D. magna or V. fischeri, frequent inhibition (>20%) of GI in L. sativa was determined in 34% of surface water samples; such findings raise concern on the apparent inceptive environmental pollution and risk within the area. According to the pharmaceutical content patterns in both kinds of studied matrices, no clear evidence of significant contamination in surface water due to livestock activities could be retrieved, suggesting a main role of urban influence.

Non-target analysis for water characterization: wastewater treatment impact and selection of relevant features

Non-target analyses were conducted to characterize and compare the molecular profiles (UHPLC-HRMS fingerprint) of water samples from a wastewater treatment plant (WWTP). Inlet and outlet samples were collected from three campaigns spaced 6 months apart in order to highlight common trends. A significant impact of the treatment on the sample fingerprints was shown, with a 65-70% abatement of the number of features detected in the effluent, and more polar, smaller and less intense molecules found overall compared to those in WWTP influent waters. Multivariate analysis (PCA) associated with variations of the features between inlets and outlets showed that features appearing or increasing were correlated with effluents while those disappearing or decreasing were correlated with influents. Finally, effluent features considered as relevant to a potentially adverse effect on aqueous media (i.e. those which appeared or increased or slightly varied from the influent) were highlighted. Three hundred seventy-five features common with the 3 campaigns were thus selected and further characterized. For most of them, elementary composition was found to be C, H, N, O (42%) and C, H, N, O, P (18%). Considering the MS2 spectra and several reference MS2 databases, annotations were proposed for 35 of these relevant features. They include synthetic products, pharmaceuticals and metabolites.

Effects of azithromycin exposure during pregnancy at different stages, doses and courses on testicular development in fetal mice

Azithromycin is a commonly used antibiotic during pregnancy, but some studies have suggested its potential developmental toxicity. Currently, the effects and mechanisms of prenatal azithromycin exposure (PAzE) on fetal testicular development are still unclear. The effects of prenatal exposure to the same drug on fetal testicular development could vary depending on different stages, doses, and courses. Hence, in this study, based on clinical medication characteristics, Kunming mice was administered intragastrically with azithromycin at different stages (mid-/late-pregnancy), doses (50, 100, 200 mg/kg·d), and courses (single-/multi-course). Fetal blood and testicular samples were collected on GD18 for relevant assessments. The results indicated that PAzE led to changes in fetal testicular morphology, reduced cell proliferation, increased apoptosis, and decreased expression of markers related to Leydig cells (Star), Sertoli cells (Wt1), and spermatogonia (Plzf). Further investigation revealed that the effects of PAzE on fetal testicular development were characterized by mid-pregnancy, high dose (clinical dose), and single course having more pronounced effects. Additionally, the TGFβ/Smad and Nrf2 signaling pathways may be involved in the changes in fetal testicular development induced by PAzE. In summary, this study confirmed that PAzE influences fetal testicular morphological development and multicellular function. It provided theoretical and experimental evidence for guiding the rational use of azithromycin during pregnancy and further exploring the mechanisms underlying its developmental toxicity on fetal testicles.

Fate of pharmaceuticals in the Ebro River Delta region: The combined evaluation of water, sediment, plastic litter, and biomonitoring

The increasing consumption of pharmaceuticals, alongside their limited removal in wastewater treatment plants (WWTPs), have led to their ubiquitous occurrence in receiving aquatic environments. This study addresses the occurrence of 68 pharmaceuticals (PhACs) in the Ebro River Delta region (NE Spain), as well as their distribution in different environmental compartments, including surface water, sediments, biota (river biofilm and fish tissues), and field-collected plastic litter. In addition, their concentrations in serving WWTPs, as possible sources of environmental contamination, were also determined. Our study confirmed the widespread occurrence of PhACs in riverine and, to a more limited extent, coastal environments. Most frequently detected PhACs belonged to analgesics/anti-inflammatories (e.g., ibuprofen) and psychiatric drugs (e.g., venlafaxine) therapeutic groups, followed by antihypertensives (e.g., valsartan) and antibiotics (e.g., azithromycin). Seasonal differences in cumulative levels of PhACs were reported for water and sediments (winter>summer). Despite spatial gradients were not clear along the river, a non-negligible contribution of upstream Ebro sites (reference area) was highlighted, which was unexpected based on the low anthropogenic pressure. Sediments represented a minor attenuation pathway for the selected PhACs, whereas they were more heavily accumulated in biota: fish liver (up to 166 ng/g dw), river biofilms (up to 108 ng/g dw), fish plasma (up to 63 ng/mL), and fish muscle (up to 31 ng/g dw). These findings highlight the importance of biomonitoring in the characterization of polluted areas and prioritization of hazardous substances (e.g., psychiatric drugs) in aquatic systems, and a particular interest of fish plasma as non-destructive biomonitoring matrix. PhACs were also detected on plastic litter, demonstrating their role as environmental sinks for certain PhACs (e.g., analgesics/anti-inflammatories, psychiatric drugs). Overall, the widespread detection of PhACs in a variety of biotic and abiotic matrices from the lower Ebro River and Delta warns about their possible environmental implications.

Occurrence of antibiotics and antibiotic-resistant bacteria in the Lebanese polluted Litani River

Antibiotic contamination in polluted rivers is well recognized as an environmental and public health challenge. In this study, the occurrence, distribution, and ecological risk assessment of three commonly used antibiotics (amoxicillin, ciprofloxacin, and azithromycin) were assessed in the Litani River, the most important and highly polluted river in Lebanon. Physicochemical and microbiological water quality parameters including the antibiotic-resistant ones were in parallel determined in the same sites. Water samples from five sites stretching across the river upper basin were analyzed for the antibiotics under study using high-performance liquid chromatography, with both fluorometric and UV detectors post-extraction using a solid-phase method with a hydrophilic-lipophilic balance cartridges. The disc diffusion method and standardized water quality methods were used for antibiotic-resistant bacteria and water quality assessment, respectively. Amoxicillin and ciprofloxacin were found at concentrations of 250 ng/L and 107.2 ng/L, while azithromycin was not detected in any of the sites under study. Varying levels of antibiotic resistance were detected with the isolated Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) while the total coliforms showed resistance to multiple antibiotics. COD, TP, PO43-, TN, NO3-, NH4 + , E. coli, total coliform, P. aeruginosa, and Cd levels surpassed permissible levels. Correlation analysis with water quality parameters (COD, total phosphate, phosphate, total nitrogen, and cadmium) showed a significant positive correlation with ciprofloxacin (r > 0.5, p value < 0.05). Also, the resistant P. aeruginosa showed a significant positive correlation with cadmium (r > 0.5, p value < 0.05) while the resistant E. coli was positively correlated with total nitrogen, nitrate, and lead levels (r > 0.5, p value < 0.05). The ecological risk assessment revealed that all the tested antibiotics pose low risks (ecological risk quotient RQ < 0.1) except ciprofloxacin, which could pose a medium risk (0.1 < RQ < 1). Future research concerning the long-term assessment of antibiotics' residues and the identification of resistance genes in the river is recommended.

Exposure to low levels of antidiabetic glibenclamide had no evident adverse effects on intestinal microbial composition and metabolic profiles in amphibian larvae

Unmetabolized human pharmaceuticals may enter aquatic environments, and potentially exert adverse effects on the survival of non-target organisms. Here, Pelophylax nigromaculatus tadpoles were exposed to different concentrations of antidiabetic glibenclamide (GLB) for 30 days to evaluate its potential ecotoxicological effect in amphibians using intestinal microbiomic and metabolomic profiles. The mortality rate of GLB-exposed groups appeared to be lower than that of the control group. Despite not being statistically significant, there was a tendency for a decrease in intestinal microbial diversity after exposure. The relative abundance of bacteria phylum Firmicutes was shown to decrease, but those of other phyla did not in GLB-exposed tadpoles. Some potentially pathogenic bacteria (e.g., Clostridium, Bilophila, Hafnia) decrease unexpectedly, while some beneficial bacteria (e.g., Akkermansia, Faecalibacterium) increased in GLB-exposed tadpoles. Accordingly, GLB-induced changes in intestinal microbial compositions did not seem harmful to animal health. Moreover, minor changes in a few intestinal metabolites were observed after GLB exposure. Overall, our results suggested that exposure to low levels of GLB did not necessarily exert an adverse impact on amphibian larvae.

Effect of common low-molecular-weight organic acid on the photodegradation of sertraline by ferrihydrite

Sertraline is one of the most commonly used antidepressant pharmaceuticals with ubiquitous distribution in the aqueous environment. However, the environmental behavior of sertraline in the co-presence of low-molecular-weight organic acid (LMWOA) and iron oxide mineral is still poorly understood. In this study, the photodegradation of sertraline was systematically investigated in a common photosensitizing system (ferrihydrite (Fh)-LMWOA). Six LMWOAs, including citrate acid (CA), tartrate acid (TA), malate acid (MA), lactate acid (LA), succinate acid (SA) and malonic acid (MOA) were chosen as the representatives. Our results implied that the different Fe3+ dissolution rates would lead to rather different sertraline degradation patterns following the order of Fh-CA > Fh-TA > Fh-MA > Fh-LA > Fh-SA > Fh-MOA. The reaction was initiated by the interaction between LMWOA and Fh via ligand-promoted-dissolution mechanism. Furthermore, the Fe3+ dissolution rates also showed a strong correlation with the metal-organic complexation constants, indicating that the photodegradation process is strongly related to the complexation ability of LMWOA with Fe3+. •OH, O2•- and CO2•- were detected, indicating that they contributed to the photodegradation of sertraline. •OH was demonstrated to be the dominant Reactive oxygen species (ROS) for the degradation of sertraline, and the detailed transformation pathways were proposed based on the product analysis and theoretical calculation. According to the ecological structure activity relationship estimation, the photodegradation products of sertraline possessed lower toxicity compared to the parent compound. These findings contribute to a more comprehensive understanding of the environmental fate of sertraline and evaluate its potential ecotoxicity in natural systems.

A novel approach for the assessment of invertebrate behavior and its use in behavioral ecotoxicology

Sublethal effects are becoming more relevant in ecotoxicological test methods due to their higher sensitivity compared to lethal endpoints and their preventive nature. Such a promising sublethal endpoint is the movement behavior of invertebrates which is associated with the direct maintenance of various ecosystem processes, hence being of special interest for ecotoxicology. Disturbed movement behavior is often related to neurotoxicity and can affect drift, mate-finding, predator avoidance, and therefore population dynamics. We show the practical implementation of the ToxmateLab, a new device that allows monitoring the movement behavior of up to 48 organisms simultaneously, for behavioral ecotoxicology. We quantified behavioral reactions of Gammarus pulex (Amphipoda, Crustacea) after exposure to two pesticides (dichlorvos and methiocarb) and two pharmaceuticals (diazepam and ibuprofen) at sublethal, environmentally relevant concentrations. We simulated a short-term pulse contamination event that lasted 90 min. Within this short test period, we successfully identified behavioral patterns that were most pronounced upon exposure to the two pesticides: Methiocarb initially triggered hyperactivity, after which baseline behavior was restored. On the other hand, dichlorvos induced hypoactivity starting at a moderate concentration of 5 μg/L - a pattern we also found at the highest concentration of ibuprofen (10 μg/L). An additional acetylcholine esterase inhibition assay revealed no significant impact of the enzyme activity that would explain the altered movement behavior. This suggests that in environmentally realistic scenarios chemicals can induce stress - apart from mode-of-action - that affects non-target organisms' behavior. Overall, our study proves the practical applicability of empirical behavioral ecotoxicological approaches and thus represents a next step towards routine practical use.

Bioaccumulation and fate of pharmaceuticals in a Mediterranean coastal lagoon: Temporal variation and impact of a flash flood event

Coastal ecosystems are particularly vulnerable to terrestrial inputs from human-impacted areas. The prevalence of wastewater treatment plants, unable to remove contaminants such as pharmaceuticals (PhACs), leads to their continuous input into the marine environment. In this paper, the seasonal occurrence of PhACs in a semi-confined coastal lagoon (the Mar Menor, south-eastern Spain) was studied during 2018 and 2019 by evaluating their presence in seawater and sediments, and their bioaccumulation in aquatic organisms. Temporal variation in the contamination levels was evaluated by comparison to a previous study carried out between 2010 and 2011 before the cessation of permanent discharges of treated wastewater into the lagoon. The impact of a flash flood event (September 2019) on PhACs pollution was also assessed. A total of seven compounds (out of 69 PhACs analysed) were found in seawater during 2018-2019, with a limited detection frequency (<33%) and concentrations (up to 11 ng/L of clarithromycin). Only carbamazepine was found in sediments (ND-1.2 ng/g dw), suggesting an improved environmental quality in comparison to 2010-2011 (when 24 and 13 compounds were detected in seawater and sediments, respectively). However, the biomonitoring of fish and molluscs showed a still remarkable accumulation of analgesic/anti-inflammatory drugs, lipid regulators, psychiatric drugs and β-blocking agents, albeit not higher than in 2010. The flash flood event from 2019 increased the prevalence of PhACs in the lagoon, compared to the 2018-2019 sampling campaigns, especially in the upper water layer. After the flash flood the antibiotics clarithromycin and sulfapyridine yielded the highest concentrations ever reported in the lagoon (297 and 145 ng/L, respectively), alongside azithromycin in 2011 (155 ng/L). Flash flood events associated with sewer overflows and soil mobilisation, which are expected to increase under climate change scenarios, should be considered when assessing the risks posed by pharmaceuticals to vulnerable aquatic ecosystems in the coastal areas.

Accumulation and metabolization of the antidepressant venlafaxine and its main metabolite o-desmethylvenlafaxine in non-target marine organisms Holothuria tubulosa, Anemonia sulcata and Actinia equina

The assessment of exposure to the antidepressant venlafaxine and its major metabolite o-desmethylvenlafaxine in Holothuria tubulosa, Anemonia sulcata and Actinia equina is proposed. A 28-day exposure experiment (10 μg/L day) followed by a 52-day depuration period was conducted. The accumulation shows a first-order kinetic process reaching an average concentration of 49,125/54342 ng/g dw in H. tubulosa and 64,810/93007 ng/g dw in A. sulcata. Venlafaxine is considered cumulative (BCF > 2000 L/kg dw) in H. tubulosa, A. sulcata and A. equina respectively; and o-desmethylvenlafaxine in A. sulcata. Organism-specific BCF generally followed the order A. sulcata > A. equina > H. tubulosa. The study revealed differences between tissues in metabolizing abilities in H. tubulosa this effect increases significantly with time in the digestive tract while it was negligible in the body wall. The results provide a description of venlafaxine and o-desmethylvenlafaxine accumulation in common and non-target organisms in the marine environment.

Insight into pharmaceutical and personal care products removal using constructed wetlands: A comprehensive review

Pharmaceutical and personal care products (PPCPs) were regarded as emerging environmental pollutants due to their ubiquitous appearance and high environmental risks. The wastewater treatment plants (WWTPs) became the hub of PPCPs receiving major sources of PPCPs used by humans. Increasing concern has been focused on promoting cost-effective ways to eliminate PPCPs within WWTPs for blocking their route into the environment through effluent discharging. Among all advanced technologies, constructed wetlands (CWs) with a combination of plants, substrates, and microbes attracted attention due to their cost-effectiveness and easier maintenance during long-term operation. This study offers baseline data for risk control and future treatment by discussing the extent and dispersion of PPCPs in surface waters over the past ten years and identifying the mechanisms of PPCPs removal in CWs based on the up-to-present research, with a special focus on the contribution of sediments, vegetation, and the interactions of microorganisms. The significant role of wetland plants in the removal of PPCPs was detailed discussed in identifying the contribution of direct uptake, adsorption, phytovolatilization, and biodegradation. Meanwhile, the correlation between the physical-chemical characteristics of PPCPs, the configuration operation of wetlands, as well as the environmental conditions with PPCP removal were also further estimated. Finally, the critical issues and knowledge gaps before the real application were addressed followed by promoted future works, which are expected to provide a comprehensive foundation for study on PPCPs elimination utilizing CWs and drive to achieve large-scale applications to treat PPCPs-contaminated surface waters.

Unravelling joint cytotoxicity of ibuprofen and oxytetracycline on Chlamydomonas reinhardtii using a programmed cell death-related biomarkers panel

Pharmaceutical active compounds (PhACs) are emerging contaminants that pose a growing concern due to their ubiquitous presence and harmful impact on aquatic ecosystems. Among PhACs, the anti-inflammatory ibuprofen (IBU) and the antibiotic oxytetracycline (OTC) are two of the most used compounds whose presence has been reported in different aquatic environments worldwide. However, there is still scarce information about the cellular and molecular alterations provoked by IBU and OTC on aquatic photosynthetic microorganisms as microalgae, even more if we refer to their potential combined toxicity. To test the cyto- and genotoxicity provoked by IBU, OTC and their binary combination on Chlamydomonas reinhardtii, a flow cytometric panel was performed after 24 h of single and co-exposure to both contaminants. Assayed parameters were cell vitality, metabolic activity, intracellular ROS levels, and other programmed cell death (PCD)-related biomarkers as cytoplasmic and mitochondrial membrane potentials and caspase-like and endonuclease activities. In addition, a nuclear DNA fragmentation analysis by comet assay was carried out. For most of the parameters analysed (vitality, metabolic activity, cytoplasmic and mitochondrial membrane potentials, and DNA fragmentation) the most severe damages were observed in the cultures exposed to the binary mixture (IBU+OTC), showing a joint cyto- and genotoxicity effect. Both PhACs and their mixture caused a remarkable decrease in cell proliferation and metabolic activity and markedly increased intracellular ROS levels, parallel to a noticeable depolarization of cytoplasmic and mitochondrial membranes. Moreover, a strong increase in both caspase and endonuclease activities as well as a PCD-related loss of nuclear DNA integrity was observed in all treatments. Results analysis showed that the PhACs caused cell death on this non-target organism, involving mitochondrial membrane depolarization, enhanced ROS production and activation of PCD process. Thus, PCD should be an applicable toxicological target for unraveling the harmful effects of co-exposure to PhACs in aquatic organisms as microalgae.

Elucidating the Effects of the Lipids Regulators Fibrates and Statins on the Health Status of Finfish Species: A Review

The most documented fibrates are gemfibrozil, clofibrate and bezafibrate, while for statins, the majority of the published literature focuses on atorvastatin and simvastatin. The present work reviews previously published research concerning the effects of these hypocholesterolaemic pharmaceuticals on fish, with a particular focus on commercially important species, commonly produced by the European aquaculture industry, specifically in recirculated aquaculture systems (RAS). Overall, results suggest that both acute and chronic exposures to lipid-lowering compounds may have adverse effects on fish, disrupting their capacity to excrete exogenous substances, as well as both lipid metabolism and homeostasis, causing severe ontogenetic and endocrinological abnormalities, leading to hampered reproductive success (e.g., gametogenesis, fecundity), and skeletal or muscular malformations, having serious repercussions on fish health and welfare. Nonetheless, the available literature focusing on the effects of statins or fibrates on commonly farmed fish is still limited, and further research is required to understand the implications of this matter on aquaculture production, global food security and, ultimately, human health.

Neuroactive pharmaceuticals in estuaries: Occurrence and tissue-specific bioaccumulation in multiple fish species

Contamination of surface waters by pharmaceuticals is an emerging problem globally. This is because the increased access and use of pharmaceuticals by a growing world population lead to environmental contamination, threatening non-target species in their natural environment. Of particular concern are neuroactive pharmaceuticals, which are known to bioaccumulate in fish and impact a variety of individual processes such as fish reproduction or behaviour, which can have ecological impacts and compromise fish populations. In this work, we investigate the occurrence and bioaccumulation of 33 neuroactive pharmaceuticals in brain, muscle and liver tissues of multiple fish species collected in four different estuaries (Douro, Tejo, Sado and Mira). In total, 28 neuroactive pharmaceuticals were detected in water and 13 in fish tissues, with individual pharmaceuticals reaching maximum concentrations of 1590 ng/L and 207 ng/g ww, respectively. The neuroactive pharmaceuticals with the highest levels and highest frequency of detection in the water samples were psychostimulants, antidepressants, opioids and anxiolytics, whereas in fish tissues, antiepileptics, psychostimulants, anxiolytics and antidepressants showed highest concentrations. Bioaccumulation was ubiquitous, occurring in all seven estuarine and marine fish species. Notably, neuroactive compounds were detected in every water and fish brain samples, and in 95% of fish liver and muscle tissues. Despite variations in pharmaceutical occurrence among estuaries, bioaccumulation patterns were consistent among estuarine systems, with generally higher bioaccumulation in fish brain followed by liver and muscle. Moreover, no link between bioaccumulation and compounds' lipophilicity, species habitat use patterns or trophic levels was observed. Overall, this work highlights the occurrence of a highly diverse suite of neuroactive pharmaceuticals and their pervasiveness in waters and fish from estuarine systems with contrasting hydromorphology and urban development and emphasizes the urgent need for toxicity assessment of these compounds in natural ecosystems, linked to internalized body concentration in non-target species.

An overall assessment of the effects of antidepressant paroxetine on aquatic organisms and human cells

Paroxetine (PRX) is one of the most used antidepressants and an emerging contaminant with potential harmful effects to the environment and human health. The present study investigates in detail the toxic potential of PRX using a battery of bioassays on fresh- and marine species, marine bacteria, and human lymphocytes. All the tested organisms and human lymphocytes were exposed at concentrations ranging from μg L^-1 to mg L^-1. It was found that PRX can cause toxic effects to aquatic organisms at environmental relevant concentrations (μg L^-1 level). A significant effect of PRX was observed in all tested algal species especially at the first 24 h. However, differences in responses and sensitivities among the tested algal species were observed. The most sensitive organism was found to be Dunaliella tertiolecta with IC₅₀ = 0.092 mg L^-1 (72 h). In the case of Aliivibrio fischeri, EC₅₀ values were determined to be 16.65, 14.31 and 14.41 mg L^-1 for 5, 15 and 30 min of exposure, respectively. PRX also induced cytotoxic and genotoxic effects in human lymphocytes. A dose-dependent increase in micronucleus frequencies was occurred at all tested concentrations with a statistically significant increase in micronucleus frequencies at the medium to high PRX tested concentrations. The findings of the present study expand the available toxicity profile of PRX on aquatic organisms and the knowledge about the potential risk of PRX to induce genotoxic effects in cultured human lymphocytes.

Time- and dose-dependent biological effects of a sub-chronic exposure to realistic doses of salicylic acid in the gills of mussel Mytilus galloprovincialis

Among nonsteroidal anti-inflammatory drugs (NSAIDs) commonly found in seawater and wastewater, salicylic acid (SA) represents one of the most persistent and hazardous compounds for aquatic organisms. This study was therefore designed to elucidate the biological effects of SA in mussel Mytilus galloprovincialis. During a sub-chronic exposure (12 days), mussels were exposed to five realistic concentrations of SA (C1: 0.05 μg/L; C2: 0.5 μg/L; C3: 5 μg/L; C4: 50 μg/L; C5: 100 μg/L) and gills, selected as the target organ, were collected at different time points (T3: 3 days; T5: 5 days; T12: 12 days). Exposure to SA induced no histological alterations in mussel gills, despite a relevant hemocyte infiltration was observed throughout the exposure as a defensive response to SA. Temporal modulation of glutathione S-transferase (GST), catalase (CAT), and superoxide dismutase (SOD) activities suggested the occurrence of antioxidant and detoxifying responses against SA exposure, while lipid peroxidation (LPO), except for a partial increase at T3, was prevented. Inhibition of the cholinergic system was also reported by reduced acetylcholinesterase (AChE) activity, mainly at T12. Overall, findings from this study contribute to enlarge the current knowledge on the cytotoxicity of SA, on non-target aquatic organisms, and might for the enhancement of new ecopharmacovigilance programs and optimization of the efficacy of wastewater treatment plants for mitigation of pharmaceutical pollution in coastal areas.

Antibiotics in the Basque coast (N Spain): Occurrence in waste and receiving waters, and risk assessment (2017-2020)

The study of the presence of antibiotics in the aquatic environment is a preliminary step to analyse their possible harmful effects on aquatic ecosystems. In order to monitor their occurrence in the aquatic environment, the European Commission established in 2015, 2018, and 2020 three Watch Lists of substances for Union-wide monitoring (Decisions (EU) 2015/495, 2018/840, and 2020/1161), where some antibiotics within the classes of macrolides, fluoroquinolones and penicillins were included. In the Basque coast, northern Spain, three macrolide antibiotics (erythromycin, clarithromycin, azithromycin) and ciprofloxacin were monitored quarterly from 2017 to 2020 (covering a period before and after the COVID19 outbreak), in water samples collected from two Waste Water Treatment Plants (WWTPs), and three control points associated with receiving waters (transitional and coastal water bodies). This work was undertaken for the Basque Water Agency (URA). The three macrolide antibiotics in water showed a frequency of quantification >65 % in the Basque coast, with higher concentrations in the WWTP emission stations than in receiving waters. Their frequency of quantification decreased from 2017 to 2020, as did the consumption of antibiotics in Spanish primary care since 2015. Ciprofloxacin showed higher frequencies of quantification in receiving waters than in wastewaters, but the highest concentrations were observed in the WWTP emission stations. Although consumption of fluoroquinolones (among which is ciprofloxacin) in primary care in the Basque Country has decreased in recent years, this trend was not observed in the waters sampled in the present study. On the other hand, concentrations of clarithromycin, azithromycin, and ciprofloxacin in receiving waters exceeded their respective Predicted No-Effect Concentrations, so they could pose an environmental risk. These substances are widely used in human and animal medicine, so, although only ciprofloxacin is included in the third Watch List, it would be advisable to continue monitoring macrolides in the Basque coast as well.

Occurrences, transport drivers, and risk assessments of antibiotics in typical oasis surface and groundwater

Intensive use of antibiotics affects biogeochemical cycles and stimulates the evolution of antibiotic resistance, thus threatening global health and social development. The spatiotemporal distributions of antibiotics in single aqueous matrices have been widely documented; however, their occurrence in surface-groundwater systems has received less attention, especially in arid regions that usually have fragile ecosystems. Therefore, we investigated the occurrence of thirty-one antibiotics in the surface water and adjacent groundwater in the Xinjiang Uygur Autonomous Region, China. The results showed that the total concentrations of detected antibiotics varied from 17.37 to 84.09 ng L^-1 and from 16.38 to 277.41 ng L^-1 in surface and groundwater, respectively. The median concentration of antibiotics showed the pattern of norfloxacin (4.86 ng L^-1) > ciprofloxacin (3.93 ng L^-1) > pefloxacin (3.39 ng L^-1) in surface water; whereas in groundwater, this was in the order of pefloxacin (6.30 ng L^-1) > norfloxacin (4.33 ng L^-1) > ciprofloxacin (2.68 ng L^-1). Heatmap analysis indicated that vertical infiltration had limited effects on antibiotic exchange in surface-ground water systems because of the high potential evaporation and low water storage. Redundancy analysis suggested that the oxidation-reduction potential (p < 0.01) and dissolved oxygen (p < 0.05) jointly affected the distribution of antibiotics in surface water. Ecological risk assessment showed that antibiotics in 98.9% of surface water and 99.1% of groundwater did not pose significant risks to aquatic species. The findings of this study will help develop effective mitigation strategies for antibiotics in aquatic environments.

First report on the occurrence of pharmaceuticals and cocaine in the coastal waters of Santa Catarina, Brazil, and its related ecological risk assessment

The worldwide occurrence of pharmaceuticals and personal care products (PPCPs) in aquatic ecosystems is reason for public concern. These emerging micropollutants include a large and diverse group of organic compounds, with continuous input, high environmental persistence and potential threat to biota and human health. The aim of this study was to evaluate, for the first time, the occurrence of twenty-seven PPCPs of various therapeutic classes (including cocaine and its primary metabolite, benzoylecgonine), in the coastal waters of Santa Catarina, southern Brazil. Water samples were taken in November 2020, during the low tide periods, at eight sampling points located along the coast of Santa Catarina, covering its entire geographical extension. Sampling was carried out in triplicate and at different depths of the water column. Nine compounds were detected through liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS): caffeine (12.58-119.80 ng/L), diclofenac (1.34-7.92 ng/L), atenolol (1.13-2.50 ng/L), losartan (0.43-3.20 ng/L), acetaminophen (0.21-10.04 ng/L), orphenadrine (0.07-0.09 ng/L), cocaine (0.02-0.17 ng/L), benzoylecgonine (0.01-1.1 ng/L) and carbamazepine (0.02-0.27 ng/L). The highest occurrence of these compounds was detected in the northern and central coastal region of Santa Catarina, namely in Penha and Palhoça cities. Moreover, the risk assessment showed that almost compounds (atenolol, benzoylecgonine, carbamazepine, cocaine and orphenadrine) presented no ecological risk in the recorded concentrations. However, a few compounds suggest low (caffeine and diclofenac) to moderate (acetaminophen and losartan) risk taking into consideration the acute and chronic effects for the three trophic levels (algae, crustacean and fish) tested. These compounds are usually found in areas with high population density, aggravated by tourism, because of the sanitary sewage and solid waste. Although in low concentrations, the occurrence of these chemical compounds can imply deleterious effects on the environmental health of Santa Catarina coastal zone, and therefore deserve more attention by the public authorities and environmental agencies.

Occurrence, distribution and risk of pharmaceutical and personal care products in the Haihe River sediments, China

In the aquatic environment, pharmaceuticals and personal care products (PPCPs) detected in sediments are rising health concerns to human and aquatic ecosystem. The migration of PPCPs in the sediments poses a potential risk to surface water and groundwater environment. Insight on the spatial distribution and vertical profile of PPCPs in sediments at the regional scale is valuable for comprehensive prevention of PPCP risk. The Haihe River is one of the major water systems for the rapid development of urbanization, industrialization and agriculture in Northern China. The study aimed to characterize the occurrence, distribution and ecological risks of PPCPs in the sediments of the Haihe River, especially to investigate the vertical distribution of PPCPs using core sediments. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to analyze 24 selected PPCPs in sediment samples. In total, 11 PPCPs were detected, and the detected concentrations (0-1.26 ng g^-1) were, lower than in other water bodies in literature (0-24.4 ng g^-1). The sediments of the Haihe River located in the Tianjin downtown were most-severely polluted, with the highest cumulative concentration of PPCPs of 9.45 ng g^-1, indicating the relatively high contribution of human consumption of PPCPs for the megacity. Spearman correlation analysis shows that both of the TOC contents and particle size distribution can influence the migration and deposition of PPCPs. The risk assessment results showed that the current level of PPCPs has no severe adverse effects on aquatic organisms in the Haihe River. However, special attention should be paid to the environmental risks caused by the migration of PPCPs with high loading and mobility (such as sulfamethoxazole).

Antibiotics along an alpine river and in the receiving lake with a catchment dominated by grazing husbandry

The livestock breeding industries face overuse of antibiotics, which has been intensively studied in recent years. However, the occurrence and fate of antibiotics as well as their potential threats to the aquatic environments in alpine and arid regions remain unclear. This study investigated the relationship of the occurrence and concentrations of antibiotics between the Kaidu River and Bosten Lake in a typical alpine basin in China. Hot spots with antibiotic pollution source were explored. The antibiotic concentrations in river water and suspended sediment (SPS) were 2.20-99.4 ng/L and 1.03-176 ng/g. The dominant antibiotics were tetracyclines, sulphacetamide, and ofloxacin in river water and sulfonamides, clarithromycin, roxithromycin, and ofloxacin in SPS. The apparent differences in pollution sources and landscapes in different reaches led to the obvious spatial patterns of antibiotics in the Kaidu River. Higher partition coefficient of antibiotic between SPS and water phases for sulfonamides than tetracyclines was because that tetracyclines strongly responded to clay contents while sulfonamides significantly responded to organic carbon contents in SPS. There were significant differences in detected antibiotic categories between the river and the lake. Fluoroquinolones (especially ciprofloxacin and enrofloxacin) were detected in the lake while sulphacetamide was only detected in the river. Therefore, the surrounding husbandry and aquaculture around the Bosten Lake was an important antibiotic pollution source in addition to inputs from the Kaidu River. This research suggested that alpine lakes could be an important sink of antibiotics in alpine dry regions, and thus impose greater threats to the aquatic ecosystem.

Pharmaceutical compounds used in the COVID-19 pandemic: A review of their presence in water and treatment techniques for their elimination

During the COVID-19 pandemic, high consumption of antivirals, antibiotics, antiparasitics, antiprotozoals, and glucocorticoids used in the treatment of this virus has been reported. Conventional treatment systems fail to efficiently remove these contaminants from water, becoming an emerging concern from the environmental field. Therefore, the objective of the present work is to address the current state of the literature on the presence and removal processes of these drugs from water bodies. It was found that the concentration of most of the drugs used in the treatment of COVID-19 increased during the pandemic in water bodies. Before the pandemic, Azithromycin concentrations in surface waters were reported to be in the order of 4.3 ng L-1, and during the pandemic, they increased up to 935 ng L-1. Laboratory scale studies conclude that adsorption and advanced oxidation processes (AOPs) can be effective in the removal of these drugs. Up to more than 80% removal of Azithromycin, Chloroquine, Ivermectin, and Dexamethasone in aqueous solutions have been reported using these processes. Pilot-scale tests achieved 100% removal of Azithromycin from hospital wastewater by adsorption with powdered activated carbon. At full scale, treatment plants supplemented with ozonation and artificial wetlands removed all Favipiravir and Azithromycin, respectively. It should be noted that hybrid technologies can improve removal rates, process kinetics, and treatment cost. Consequently, the development of new materials that can act synergistically in technically and economically sustainable treatments is required.

Abundance, fate, and effects of pharmaceuticals and personal care products in aquatic environments

Pharmaceuticals and personal care products (PPCPs) are found in wastewater, and thus, the environment. In this study, current knowledge about the occurrence and fate of PPCPs in aquatic systems-including wastewater treatment plants (WWTPs) and natural waters around the world-is critically reviewed to inform the state of the science and highlight existing knowledge gaps. Excretion by humans is the primary route of PPCPs entry into municipal wastewater systems, but significant contributions also occur through emissions from hospitals, PPCPs manufacturers, and agriculture. Abundance of PPCPs in raw wastewater is influenced by several factors, including the population density and demography served by WWTPs, presence of hospitals and drugs manufacturers in the sewershed, disease burden of the population served, local regulations, and climatic conditions. Based on the data obtained from WWTPs, analgesics, antibiotics, and stimulants (e.g., caffeine) are the most abundant PPCPs in raw wastewater. In conventional WWTPs, most removal of PPCPs occurs during secondary treatment, and overall removal exceeds 90% for treatable PPCPs. Regardless, the total PPCP mass discharged with effluent by an average WWTP into receiving waters (7.35-20,160 g/day) is still considerable, because potential adverse effects of some PPCPs (such as ibuprofen) on aquatic organisms occur within measured concentrations found in surface waters.

Multilayered solid phase extraction and ultra performance liquid chromatographic method for suspect screening of halogenated pharmaceuticals and photo-transformation products in freshwater - comparison between data-dependent and data-independent acquisition mass spectrometry

Since conventional biological wastewater treatments are not admittedly effective to convert pharmaceutical active compounds (PhACs) into nontoxic products, natural abiotic mechanisms such as solar photolysis arises as an important degradation process, especially for halogenated molecules. In the present work, photolysis simulation was carried out in-lab for precursors and their respective photo-transformation products (photo-TPs), which were analyzed through reversed-phase ultra-high performance liquid chromatography coupled to high resolution mass spectrometry (RP-UHPLCHRMS). An in-house library was created in order to provide reference information for target (precursors) and suspect screening (photo-TPs) analysis of freshwater samples from impacted aquatic environments. Strategies in the use of data-dependent acquisition (DDA) and data-independent acquisition (DIA), as well as the data processing software are discussed here for the identification of 6 PhACs and photo-TPs. Because no standards of photo-TPs were available, only the target compounds, i.e. sitagliptin (398 ± 2 ng L^-1), iohexol (209 ± 5 ng L^-1), lamotrigine (103 ± 10 ng L^-1), losartan (43 ± 10 ng L^-1), ofloxacin (28 ± 7 ng L^-1), and sertraline (25 ± 7 ng L^-1) could be quantified through multiple standard additions.

Removal of drug losartan in environmental aquatic matrices by heat-activated persulfate: Kinetics, transformation products and synergistic effects

In this study, the oxidative degradation of losartan (LOS), a widely administered medicine for high blood pressure by heat-activated persulfate was investigated. Increased temperature and persulfate concentration, as well as acidic conditions enhance the degradation efficiency of LOS, whose rate follows pseudo-first order kinetics. From the respective apparent rate constants in the range 40-60 °C, an apparent activation energy of 112.70 kJ/mol was computed. Radical scavenging tests demonstrated that both HO^• and [Formula: see text] contribute towards LOS degradation. LOS degradation was suppressed in real water matrices including bottled water (BW) and secondary wastewater effluent (WW), while other experiments indicated that the presence of bicarbonates and humic acid negatively affected its oxidation. Instead, the addition of chloride ions at 250 mg/L resulted in a positive effect on LOS removal. The combination of heat-activated PS with low-frequency ultrasound exhibited a synergistic effect, with the ratio S being 2.29 in BW and 1.52 in WW. Five transformation products of LOS were identified through HRMS suspect and non-target screening approaches, among which two are reported for the first time. Using the in-house risk assessment program, ToxTrAMs was revealed that most of the identified TPs present higher toxicity than LOS against Daphnia magna.

A Review of the Occurrence of Pharmaceutical Compounds as Emerging Contaminants in Treated Wastewater and Aquatic Environments

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In recent years, pharmaceutical compounds have emerged as potential contaminants in the aquatic matrices of the environment. High production, consumption, and limited removal through conventional treatment processes/wastewater treatment plants (WWTPs) are the major causes for the occurrence of pharmaceutical compounds in wastewater and aquatic environments worldwide. A number of studies report adverse health effects and risks to aquatic life and the ecosystem because of the presence of pharmaceutical compounds in the aquatic environment. This paper provides a state-of-the-art review of the occurrence of pharmaceutical compounds in treated wastewater from various WWTPs, surface water and groundwater bodies. Additionally, this review provides comprehensive information and pointers for research in wastewater treatment and waterbodies management.

Application of green nanoemulsion to treat contaminated water (bulk aqueous solution) with azithromycin

The present work aimed to remove azithromycin (AZM) from the contaminated aqueous system using a water/ethanol/transcutol/Capryol-90 green nanoemulsion. The drug is identified as a potential pharmaceutical contaminant detrimental for flora and fauna of aquatic lives as well as human health. Green nanoemulsions were tailored and characterized for thermodynamic stability, size, polydispersity index (PDI), zeta potential, viscosity, refractive index (RI), and morphological assessment using a transmission electron microscopy (TEM). Moreover, nanoemulsions were investigated for percent removal efficiency (%RE) and factors affecting percent removal efficiency (%RE). The results suggested that the developed green nanoemulsions (ANE1-ANE5) were transparent (˂ 200 nm) and stable. ANE5 exhibited the lowest value of globular size (49 nm), PDI (0.17), viscosity (~ 93 cP), and optimum zeta potential (-27.8 mV). The value of %RE depended upon the content of water and Capryol-90 of the nanoemulsion. Furthermore, the value of %RE was found to be increased with increased content of water, whereas this was decreased on increasing the Capryol-90 content in the nanoemulsions. Similarly, on decreasing the values of size and viscosity, the %RE values were observed to be increased. There was insignificant impact of the duration of exposure time on %RE. Thus, the maximum %RE value (96.8%) was obtained by ANE5 from the aqueous solution after 20 min of contact time with ANE5. Thus, this method could be a promising approach to remove AZM from the contaminated water and serve as an alternative to conventional methods.

Monitoring of pharmaceuticals in aquatic biota (Procambarus clarkii) of the Doñana National Park (Spain)

In this work the presence of different pharmaceuticals at Doñana National Park (Spain) and their main entry sources (input source or entry points) have been stated over the 2011-2016 years period. Twenty-three selected pharmaceuticals (corresponding to eight therapeutic families) were evaluated in crayfish and water samples from Doñana National Park (Spain) (six sampling points selected in order to cover different possible pollution sources into and surrounding the Park). The multiresidue determination was carried out using enzymatic-microwave assisted extraction prior to high performance liquid chromatography mass spectrometry detection. Sulphonamides (sulfadiazine, sulfamerazine, sulfamethazine, and sulfamethoxazole); trimethoprim, an antibiotic that is frequently co-administered with sulfamethoxazole; amphenicols (chloramphenicol, florfenicol and thiamphenicol); fluoroquinolones (ciprofloxacin, enrofloxacin, flumequine, danofloxacin, gatifloxacin, norfloxacin, marbofloxacin and grepafloxacin); penicillins (amoxicillin); tetracyclines (chlortetracycline and oxytetracycline); non-steroidal anti-inflammatory drugs (salicylic acid and ibuprofen); beta-blocker drugs (atenolol); and antiepileptics (carbamazepine) were analysed. Ciprofloxacin, ibuprofen, salicylic acid, flumequine, and carbamazepine were detected and/or quantified at some of the selected sampling points. A clear ecotoxicological risk to the ecosystem was demonstrated from the occurrence of ciprofloxacin in samples obtained after the punctual and massive presence of people inside the Park. Furthermore, flumequine and carbamazepine have been detected in Procambarus clarkii specimens in concentrations around 30 ng g^-1 and 14 ng g^-1, respectively, and their occurrence in the specimens could indicate the persistence of the discharge sources. The main source of pharmaceuticals into the Park might be the livestock farming activities, and the influence of urban wastewaters from surrounding villages does not seem to be very important.

Modern Carbon-Based Materials for Adsorptive Removal of Organic and Inorganic Pollutants from Water and Wastewater

Currently, a serious threat for living organisms and human life in particular, is water contamination with persistent organic and inorganic pollutants. To date, several techniques have been adopted to remove/treat organics and toxic contaminants. Adsorption is one of the most effective and economical methods for this purpose. Generally, porous materials are considered as appropriate adsorbents for water purification. Conventional adsorbents such as activated carbons have a limited possibility of surface modification (texture and functionality), and their adsorption capacity is difficult to control. Therefore, despite the significant progress achieved in the development of the systems for water remediation, there is still a need for novel adsorptive materials with tunable functional characteristics. This review addresses the new trends in the development of new adsorbent materials. Herein, modern carbon-based materials, such as graphene, oxidized carbon, carbon nanotubes, biomass-derived carbonaceous matrices-biochars as well as their composites with metal-organic frameworks (MOFs) and MOF-derived highly-ordered carbons are considered as advanced adsorbents for removal of hazardous organics from drinking water, process water, and leachate. The review is focused on the preparation and modification of these next-generation carbon-based adsorbents and analysis of their adsorption performance including possible adsorption mechanisms. Simultaneously, some weak points of modern carbon-based adsorbents are analyzed as well as the routes to conquer them. For instance, for removal of large quantities of pollutants, the combination of adsorption and other methods, like sedimentation may be recommended. A number of efficient strategies for further enhancing the adsorption performance of the carbon-based adsorbents, in particular, integrating approaches and further rational functionalization, including composing these adsorbents (of two or even three types) can be recommended. The cost reduction and efficient regeneration must also be in the focus of future research endeavors. The targeted optimization of the discussed carbon-based adsorbents associated with detailed studies of the adsorption process, especially, for multicomponent adsorbate solution, will pave a bright avenue for efficient water remediation.

Pharmaceutical Compounds in Aquatic Environments-Occurrence, Fate and Bioremediation Prospective

Various contaminants of emerging concern (CECs) have been detected in different ecosystems, posing a threat to living organisms and the environment. Pharmaceuticals are among the many CECs that enter the environment through different pathways, with wastewater treatment plants being the main input of these pollutants. Several technologies for the removal of these pollutants have been developed through the years, but there is still a lack of sustainable technologies suitable for being applied in natural environments. In this regard, solutions based on natural biological processes are attractive for the recovery of contaminated environments. Bioremediation is one of these natural-based solutions and takes advantage of the capacity of microorganisms to degrade different organic pollutants. Degradation of pollutants by native microorganisms is already known to be an important detoxification mechanism that is involved in natural attenuation processes that occur in the environment. Thus, bioremediation technologies based on the selection of natural degrading bacteria seem to be a promising clean-up technology suitable for application in natural environments. In this review, an overview of the occurrence and fate of pharmaceuticals is carried out, in which bioremediation tools are explored for the removal of these pollutants from impacted environments.

Determination of pharmaceuticals and heavy metals in groundwater for human and animal consumption and crop irrigation in Galicia

Pharmaceuticals and heavy metals are contaminants present in groundwaters, which are the main source of drinking water in most parts of the world. In the northwest region of Spain, Galicia, groundwater harvesting is a common practice for drinking water supply, crop irrigation, cattle watering, as well as recreational use such as filling pools. In order to assess the quality of Galician groundwaters, the presence of 21 pharmaceuticals and 10 heavy metals was analysed by UPLC-MS/MS and ICP/MS methods, respectively, in a total of 118 groundwater samples from private wells. Seventeen of the 21 compounds studied were detected in 28% of the samples, with the highest presence of pharmaceuticals belonging to the antimicrobial group (52%), specifically the sulphonamides group in a range of concentration between 21 and 14.9 ng/L. In addition, 30% of the samples contained at least one heavy metal (Mn, As and Fe) above the legally permitted levels. Evaluation of the risk associated with the consumption of the analysed groundwater indicated no human risk for any of the detected pharmaceuticals but high cancer risk for children due to Cd, Cr and As concentrations was observe.

Ecological Risk Assessment of Amoxicillin, Enrofloxacin, and Neomycin: Are Their Current Levels in the Freshwater Environment Safe?

Veterinary pharmaceuticals may cause unexpected adverse effects on non-target aquatic species. While these pharmaceuticals were previously identified as priority compounds in ambient water, their ecological risks are relatively unknown. In this study, a series of chronic toxicity tests were conducted for these pharmaceuticals using algae, two cladocerans, and a fish. After a 21-d exposure to amoxicillin, enrofloxacin, and neomycin, no observed effect concentration (NOEC) for the reproduction of Daphnia magna was detected at 27.2, 3.3, and 0.15 mg/L, respectively. For the survival of juvenile Oryzias latipes following the 40-d exposure, NOEC was found at 21.8, 3.2, and 0.87 mg/L, respectively. Based on the results of the chronic toxicity tests and those reported in the literature, predicted no-effect concentrations (PNECs) were determined at 0.078, 4.9, and 3.0 µg/L for amoxicillin, enrofloxacin, and neomycin, respectively. Their hazard quotients (HQs) were less than 1 at their average levels of occurrence in ambient freshwater. However, HQs based on the maximum detected levels of amoxicillin and enrofloxacin were determined at 21.2 and 6.1, respectively, suggesting potential ecological risks. As the potential ecological risks of these veterinary pharmaceuticals at heavily contaminated sites cannot be ignored, hotspot delineation and its management are required.

Recent developments in physical, biological, chemical, and hybrid treatment techniques for removing emerging contaminants from wastewater

Emerging contaminants (ECs) in wastewater have recently attracted the attention of researchers as they pose significant risks to human health and wildlife. This paper presents the state-of-art technologies used to remove ECs from wastewater through a comprehensive review. It also highlights the challenges faced by existing EC removal technologies in wastewater treatment plants and provides future research directions. Many treatment technologies like biological, chemical, and physical approaches have been advanced for removing various ECs. However, currently, no individual technology can effectively remove ECs, whereas hybrid systems have often been found to be more efficient. A hybrid technique of ozonation accompanied by activated carbon was found significantly effective in removing some ECs, particularly pharmaceuticals and pesticides. Despite the lack of extensive research, nanotechnology may be a promising approach as nanomaterial incorporated technologies have shown potential in removing different contaminants from wastewater. Nevertheless, most existing technologies are highly energy and resource-intensive as well as costly to maintain and operate. Besides, most proposed advanced treatment technologies are yet to be evaluated for large-scale practicality. Complemented with techno-economic feasibility studies of the treatment techniques, comprehensive research and development are therefore necessary to achieve a full and effective removal of ECs by wastewater treatment plants.

Spatio-Temporal Distribution and Influencing Factors of Human and Veterinary Pharmaceuticals in the Tributary Surface Waters of the Han River Watershed, South Korea

Human and veterinary pharmaceuticals are being increasingly used for disease treatment; hence, their distribution and factors influencing them in the aquatic environment need to be investigated. This study observed the effect of human and animal populations, usage, purchasing criteria (prescription vs. non-prescription), and land use to identify the spatio-temporal distribution of eight pharmaceuticals at twenty-four sites of the tributaries of the Han River watershed. In rural areas, the mean concentration (detection frequency) of non-prescription pharmaceuticals (NPPs) was higher (lower) compared to that of prescription pharmaceuticals (PPs); in urban areas, a reverse trend was observed. Pharmaceutical concentrations in urban and rural areas were mainly affected by wastewater treatment plants (WWTPs) and non-point sources, respectively; concentrations were higher downstream (4.9 times) than upstream of the WWTPs. The concentration distribution (according to the target) was as follows: human–veterinary > human > veterinary. Correlation between total concentration and total usage of the pharmaceuticals was high, except for NPPs. Most livestock and land use (except cropland) were significantly positively correlated with pharmaceutical concentrations. Concentrations were mainly higher (1.5 times) during cold seasons than during warm seasons. The results of this study can assist policymakers in managing pharmaceutical pollutants while prioritizing emerging pollutants.

Can pharmaceutical drugs used to treat Covid-19 infection leads to human health risk? A hypothetical study to identify potential risk

This is the first study to assess human health risks due to the exposure of 'repurposed' pharmaceutical drugs used to treat Covid-19 infection. The study used a six-step approach to determine health risk estimates. For this, consumption of pharmaceuticals under normal circumstances and in Covid-19 infection was compiled to calculate the predicted environmental concentrations (PECs) in river water and in fishes. Risk estimates of pharmaceutical drugs were evaluated for adults as they are most affected by Covid-19 pandemic. Acceptable daily intakes (ADIs) are estimated using the no-observed-adverse-effect-level (NOAEL) or no observable effect level (NOEL) values in rats. The estimated ADI values are then used to calculate predicted no-effect concentrations (PNECs) for three different exposure routes (i) through the accidental ingestion of contaminated surface water during recreational activities only, (ii) through fish consumption only, and (iii) through combined accidental ingestion of contaminated surface water during recreational activities and fish consumption. Higher risk values (hazard quotient, HQ: 337.68, maximum; 11.83, minimum) were obtained for the combined ingestion of contaminated water during recreational activities and fish consumption exposure under the assumptions used in this study indicating possible effects to human health. Amongst the pharmaceutical drugs, ritonavir emerged as main drug, and is expected to pose adverse effects on r human health through fish consumption. Mixture toxicity analysis showed major risk effects of exposure of pharmaceutical drugs (interaction-based hazard index, HI_int: from 295.42 (for lopinavir + ritonavir) to 1.20 for chloroquine + rapamycin) demonstrating possible risks due to the co-existence of pharmaceutical in water. The presence of background contaminants in contaminated water does not show any influence on the observed risk estimates as indicated by low HQ_add values (<1). Regular monitoring of pharmaceutical drugs in aquatic environment needs to be carried out to reduce the adverse effects of pharmaceutical drugs on human health.

Pharmaceuticals in two watersheds in Eastern China and their ecological risks

Pharmaceuticals are of increasing environmental concern due to their potential threat to aquatic ecosystems. Intensive human activities are a major factor influencing the level of pharmaceutical pollution in aquatic ecosystems. In this study, we investigated the occurrence, ecological risks of 31 pharmaceuticals and the possible influence of human activities on pharmaceutical distribution in two watersheds in the Yangtze River Delta, Eastern China. The target compounds were grouped into six categories: three non-steroidal anti-inflammatory drugs, ten antibiotics, six cardiovascular drugs, five hormones, six psychotropic drugs, and one antiparasitic. All target pharmaceuticals were detected in the surface water samples, with dexamethasone (100% of samples), tetracycline (100% of samples), and cefradine (100% of samples) being the dominant compounds (maximum concentrations of 686, 128, and 2280 ng/L, respectively). The total pharmaceutical concentrations were significantly higher in the urban watershed (711-2790 ng/L, mean = 1150 ng/L) than in the peri-urban watershed (467-1525 ng/L, mean = 863 ng/L) (p < 0.05). Distinct variation in the total pharmaceutical concentration also occurred between the dry season (507-2790 ng/L, mean = 1100 ng/L) and the wet season (467-1525 ng/L, mean = 943 ng/L). Ecological risk assessment showed that in the two watersheds, benzylpenicillin potassium, tetracycline hydrochloride, chlormadinone, ampicillin, cefotaxime acid, atorvastatin, sertraline hydrochloride, and oxazepam posed a medium potential risk (0.1 < risk quotient < 1), while norethisterone posed a high potential risk (risk quotient > 1). Redundancy analysis revealed that the concentrations of pharmaceuticals in various categories were positively correlated with land-use type (urban and agricultural land-use percentages), population density, and distance from town in both watersheds. Urban and agricultural activities were likely the main factors influencing the concentrations and composition of pharmaceuticals in these aquatic environments. Positive correlations were also found between total pharmaceutical concentrations and population density in both watersheds, suggesting a significant contribution of human disturbance to pharmaceutical pollution. The results provide useful information for pharmaceutical pollution control, ecological risk assessment, and sustainable water management at the watershed scale.