The behavior of pharmaceutically active compounds and contrast agents during wastewater treatment - Combining sampling strategies and analytical techniques: A critical review

Increasing consumption of pharmaceuticals and the respective consequences for the aquatic environment have been the focus of many studies over the last thirty years. Various aspects in this field were investigated, considering diverse pharmaceutical groups and employing a wide range of research methodologies. Various questions from the perspectives of different research areas were devised and answered, resulting in a large mix of individual findings and conclusions. Collectively, the results of the studies offer a comprehensive overview. The large variety of methods and strategies, however, demands close attention when comparing and combining information from heterogeneous projects. This review critically examines the application of diverse sampling techniques as well as analytical methods in investigations concerning the behavior of pharmaceutically active compounds (PhACs) and contrast agents (CAs) in wastewater treatment plants (WWTPs). The combination of sampling and analysis is discussed with regard to its suitability for specific scientific problems. Different research focuses need different methods and answer different questions. An overview of studies dealing with the fate and degradation of PhACs and CAs in WWTPs is presented, discussing their strategic approaches and findings. This review includes surveys of anticancer drugs, antibiotics, analgesics and anti-inflammatory drugs, antidiabetics, beta blockers, hormonal contraceptives, lipid lowering agents, antidepressants as well as contrast agents for X-ray and magnetic resonance imaging.

Occurrence of micropollutants in rural domestic wastewater in Zhejiang Province, China and corresponding wastewater-based epidemiology analysis

By 2021, rural regions in China were occupied by over 500 million residents, generating an annual volume of 19.5 billion m3 of rural domestic wastewater (RDW). This study aimed to investigate the occurrence and removal of micropollutants (MPs) in RDW treatment facilities and to perform a corresponding wastewater-based epidemiology analysis (WBE). Our findings indicated the significantly high levels of influent MPs, particularly pharmaceuticals, such as ofloxacin and diclofenac being most prevalent (ranging from several to tens of μg/L) across different facilities. After various treatments, regular water indexes in the effluent, like NH3 -N and COD, have basically satisfied the local discharge standard. However, the concentration of certain dominant MPs in effluent remained notably high, ranging from hundreds of ng/L to several μg/L. The risk quotients of MPs like diclofenac, ciprofloxacin, ofloxacin, sulfamethoxazole, diuron, and isoproturon were all above 1 in the effluent, signifying significant hazards to aquatic organisms. The quantitative meta-analysis revealed higher average standardized removal efficiency for membrane bioreactor (MBR) treatment (-11 %) compared to anaerobic/anoxic/aerobic (A2O) treatment (11 %), indicating the higher efficiency of MBR treatment in outperforming the A2O as a secondary treatment. Additionally, employing biofilter as a tertiary treatment proved to be more effective as compared to flocculation-air flotation and artificial wetlands. Moreover, the results of WBE analysis showed that diclofenac and ofloxacin emerged as the most commonly used pharmaceuticals (of seven), with consumption levels recorded at 1222 and 517 mg/(d·103 capita), with daily defined doses per day per 103 capita of 12.2/1000 and 1.29/1000, respectively. This study addresses the existing knowledge gaps regarding the occurrence and removal of MPs in RDW and offers valuable insights into pharmaceutical consumption patterns in rural regions, thereby improving our understanding of public health.

Wastewater surveillance of pharmaceuticals during the COVID-19 pandemic in Mexico City and the Mezquital Valley: A comprehensive environmental risk assessment

This study tracked five pharmaceutically active compounds (PhACs) in Mexico City's sewage, namely, famotidine, indomethacin, dexamethasone, azithromycin, and ivermectin, which were used to treat COVID-19. The monitoring campaign was carried out over 30 months (May 2020 to November 2022), covering the five COVID-19 waves in Mexico. In the Central Emitter, the main sewage outflow, famotidine displayed levels of 132.57 ± 28.16 ng L-1 (range from < LOQ to 189.1 ng L-1), followed by indomethacin (average 672.46 ± 116.4 ng L-1, range from 516.7 to 945.2 ng L-1), dexamethasone (average 610.4 ± 225.7 ng L-1, range from 233.4 to 1044.5 ng L-1), azithromycin (average 4436.2 ± 903.6 ng L-1, range from 2873.7 to 5819.6 ng L-1), and ivermectin (average 3413.3 ± 1244.6 ng L-1, range from 1219.8 to 4622.4 ng L-1). The concentrations of dexamethasone, azithromycin and ivermectin were higher in sewage from a temporary COVID-19 care unit, by a factor of 3.48, 3.52 and 2.55, respectively, compared with those found in municipal wastewater. In the effluent of the Atotonilco Wastewater Treatment Plant (AWWTP), which treats near 60 % of the Mexico City's sewage, famotidine was absent, while concentrations of indomethacin, dexamethasone, azithromycin and ivermectin were 78.2 %, 76.7 %, 74.4 %, and 88.1 % lower than those in the influent, respectively. The occurrence of PhACs in treated and untreated wastewater resulted in medium to high environmental risk since Mexico City's wastewater is reused for irrigation in the Mezquital Valley. There, PhACs were found in irrigation canals at lower levels than those observed in Mexico City throughout the monitoring. On the other hand, famotidine, indomethacin, and dexamethasone were not found in surface water resulting from the infiltration of wastewater through soil in Mezquital Valley, while azithromycin and ivermectin sporadically appeared in surface water samples collected through 2021. Using an optimized risk assessment based on a semi-probabilistic approach, the PhACs were prioritized as ivermectin > azithromycin > dexamethasone > famotidine > indomethacin.

Critical review of technologies for the on-site treatment of hospital wastewater: From conventional to combined advanced processes

This review aims to assess different technologies for the on-site treatment of hospital wastewater (HWW) to remove pharmaceutical compounds (PhCs) as sustances of emerging concern at a bench, pilot, and full scales from 2014 to 2020. Moreover, a rough characterisation of hospital effluents is presented. The main detected PhCs are antibiotics and psychiatric drugs, with concentrations up to 1.1 mg/L. On the one hand, regarding the presented technologies, membrane bioreactors (MBRs) are a good alternative for treating HWW with PhCs removal values higher than 80% in removing analgesics, anti-inflammatories, cardiovascular drugs, and some antibiotics. Moreover, this system has been scaled up to the pilot plant scale. However, some target compounds are still present in the treated effluent, such as psychiatric and contrast media drugs and recalcitrant antibiotics (erythromycin and sulfamethoxazole). On the other hand, ozonation effectively removes antibiotics found in the HWW (>93%), and some studies are carried out at the pilot plant scale. Even though, some families, such as the X-ray contrast media, are recalcitrant to ozone. Other advanced oxidation processes (AOPs), such as Fenton-like or UV treatments, seem very effective for removing pharmaceuticals, Antibiotic Resistance Bacteria (ARBs) and Antibiotic Resistance Genes (ARGs). However, they are not implanted at pilot plant or full scale as they usually consider extra reactants such as ozone, iron, or UV-light, making the scale-up of the processes a challenging task to treat high-loading wastewater. Thus, several examples of biological wastewater treatment methods combined with AOPs have been proposed as the better strategy to treat HWW with high removal of PhCs (generally over 98%) and ARGs/ARBs (below the detection limit) and lower spending on reactants. However, it still requires further development and optimisation of the integrated processes.

Cosmetic wastewater treatment technologies: a review

Over the past three decades, environmental concerns about the water pollution have been raised on societal and industrial levels. The presence of pollutants stemming from cosmetic products has been documented in wastewater streams outflowing from industrial as well as wastewater treatment plants. To this end, a series of consistent measures should be taken to prevent emerging contaminants of water resources. This need has driven the development of technologies, in an attempt to mitigate their impact on the environment. This work offers a thorough review of existing knowledge on cosmetic wastewater treatment approaches, including, coagulation, dissolved air flotation, adsorption, activated sludge, biodegradation, constructed wetlands, and advanced oxidation processes. Various studies have already documented the appearance of cosmetics in samples retrieved from wastewater treatment plants (WWTPs), which have definitely promoted our comprehension of the path of cosmetics within the treatment cycle; however, there are still multiple blanks to our knowledge. All treatments have, without exception, their own limitations, not only cost-wise, but also in terms of being feasible, effective, practical, reliable, and environmentally friendly.

UV/Chlorination of sulfamethazine (SMZ) and other prescription drugs: kinetics, transformation products and insights into the combined toxicological assessment

The UV/chlorination of three prescription drugs, sulfamethazine (SMZ), gemfibrozil (GEM) and antipyrine (ANT) were studied by the investigation of kinetics, transformation products and combined toxicological assessment. The degradation followed pseudo-first-order kinetics, with half-lives significantly affected by chlorine dosage, without being greatly influenced by pH value and bromide concentration. Based on the Frontier Orbital Theory, the structures of products by hydroxylation or chlorine substitution were proposed and the transformation pathways were introduced, with two, two and one never-before-reported products identified for SMZ, GEM and ANT, respectively. Compared to the results of the experiments with artificial water sample, the degradation kinetics of the three prescription drugs was observed with a prolonged half-lives in both Yangtze River and Taihu Lake water, suggesting that aromatic containing transformation products (TPs) may also exist in UV/chlorine treated natural waters. The results of combined toxicity on E. coli showed that the antagonism effect predominated in most binary and ternary combinations. However, the synergistic toxicity of combinations at low concentrations of prescription drugs subjected to UV/chlorine should be cautioned, which was more close to the natural concentration of prescription drugs in waters.

Evaluation of ibuprofen and diclofenac in the main rivers of Colombia and striped catfish Pseudoplatystoma magdaleniatum

This is one of the first studies carried out over three climatic seasons on the determination of ibuprofen and diclofenac, in the main rivers of Colombia and striped catfish Pseudoplatystoma magdaleniatum. Determination of water concentrations was carried out using SPE extraction, while for the analysis of the muscular tissue, the extraction was carried out by QuEChERS. For both matrices, quantification was done by UHPLC-MS/MS. No levels of ibuprofen or diclofenac concentrations were found in the muscle tissue of Pseudoplatystoma magdaleniatum, in any season or sampling site, during the 2 years of sampling. In some sampling sites, concentrations of up to 75 µg/L of diclofenac were detected, corresponding to the sampling carried out in the dry season, being the highest reported so far in surface waters, possibly generated by large concentrations of population or agricultural activities. On the other hand, for ibuprofen, no concentrations above the limit of quantification (0.50 µg/L) were found in the waters of the Cauca and Magdalena rivers, for any season and sampling site.

Enhanced Removal and Toxicity Declineof Diclofenac by Combining UVA Treatmentand Adsorption of Photoproductsto Polyvinylidene Difluoride

The occurrence of micropollutants in the environment is an emerging issue. Diclofenac, a non-steroidal anti-inflammatory drug, is one of the most frequently detected pharmaceuticals in the environment worldwide. Diclofenac is transformed by UVA light into different products with higher toxicity. The absorbance of the transformation products overlaps with the absorbance of diclofenac itself and inhibits the ongoing photoreaction. By adding polyvinylidene difluoride (PVDF), the products adsorb to the surface of PVDF. Therefore, phototransformation of diclofenac and total organic carbon (TOC) removal is enhanced and the toxicity decreased. At 15 min and 18 h of UVA treatment, removal of diclofenac and TOC increases from 56% to 65% and 18% to 54%, respectively, when PVDF is present. The toxicity of a UVA treated (18 h) diclofenac solution doubles (from 5 to 10, expressed in toxicity units, TU), while no toxicity was detectable when PVDF is present during UVA treatment (TU = 0). PVDF does not need to be irradiated itself but must be present during photoreaction. The adsorbent can be reused by washing with water or ethanol. Diclofenac (25 mg L^-1) UVA light irradiation was monitored with high performance liquid chromatography (HPLC), UV-Vis spectroscopy and by analysing the decrease of TOC. The toxicity towards Vibrio fischeri was examined according to DIN EN ISO 11348-1: 2009-05. Density functional theory (DFT) was used to simulate the phototransformation products known in literature as well as further products identified via gas chromatography-mass spectrometry (GC-MS). The absorption spectra, reaction enthalpies (ΔH) and Gibbs free energy of reactions (ΔG) were calculated. The combination of UVA irradiation of diclofenac with adsorption of photoproducts to PVDF is unique and opens up new possibilities to enhance removal of pollutants from water.

Fate of sterols, polycyclic aromatic hydrocarbons, pharmaceuticals, ammonia and solids in single-stage anaerobic and sequential anaerobic/aerobic/anoxic sludge digestion

Emerging contaminants (ECs), such as pharmaceuticals, sterols and polycyclic aromatic hydrocarbons (PAHs) are frequently detected in the environment. ECs are refractory, toxic, tend to bioaccumulate and have a potential to disrupt the endocrine system of living organisms. These compounds are only partially eliminated in wastewater treatment plants (WWTPs). Due to their hydrophobic nature, they tend to accumulate in sludge. However, the fate of the majority of ECs in sludge treatment processes is not fully understood. In this study, the effect of a sequential anaerobic/aerobic/anoxic (AN/AERO/ANOX) digestion and a conventional single-stage AN digestion (as control) was investigated on mixed primary and secondary sludge. Digesters were operated at an overall solid retention time (SRT) of 18 days. The steady-state results have shown that sequential AN/AERO/ANOX digestion configurations improved the removal of three classes of ECs (e.g., sterols, PAHs and pharmaceuticals) by either reducing their accumulation or enhancing their removal. Moreover, sequential AN/AERO/ANOX digestion also achieved 45% less ammonia generation, 20% faster digestate dewaterability and 4% enhanced volatile solids removal compared to single-stage AN digestion.

Effect of O3 Dose on the O3/UV Treatment Process for the Removal of Pharmaceuticals and Personal Care Products in Secondary Effluent

A municipal wastewater treatment plant (WWTP) is a melting pot of numerous pharmaceuticals and personal care products (PPCPs) together with many other substances. The removal of PPCPs using advanced oxidation processes within a WWTP is one way to reduce the amount of PPCPs that potentially enter an aquatic environment. The aim of this study was to examine the effectiveness of the ozone (O3)/UV treatment process, especially, the effects of O3 dose and reaction time, on the removal of PPCPs in the secondary effluent of a WWTP. Experiments were conducted using a pilot-scale treatment process that consisted of two flow-through reactors connected in series. Each reactor was equipped with three 65 W lamps (UV65W). The experimental variables were ozone dosage (1, 2, 3, 4, and 6 mg L−1) and hydraulic retention time (HRT; 5 and 10 min). On the basis of the PPCP concentrations after O3/UV65W treatment and their limit of detection (LOD), 38 PPCPs detected in the secondary effluent were classified into 5 groups ranging from the category of “sensitive” to O3/UV65W or “unstable” in the O3/UV65W process to the category of “insensitive” to O3/UV65W or “very stable” in the O3/UV65W process.

Ozone facilitated degradation of caffeine using Ce-TiO2 catalyst

The ozone initiated oxidation of 1,3,7-trimethylxanthine (caffeine), commonly found in wastewaters as model compound is reported using cerium (Ce)/titanium dioxide (TiO₂) as catalyst. The effect of pH and loading of ceria on titania were investigated. Effect of reaction conditions on degradation of caffeine based on their pseudo first-order rate constants were compared. The combination of catalyst Ce-TiO₂ and ozone aeration significantly enhanced the degradation of caffeine compared to uncatalysed ozonation. The oxidation of caffeine ensued via the free radical mechanism, through enhanced ozone decomposition into OH radicals. Ce/TiO₂(0.5 wt%) showed good activity in degradation of caffeine at pH 6, in both natural stream and river water samples showing about 60% total organic carbon removal in 2 h ozonation period. Using liquid chromatography-mass spectroscopy, degradation products were analysed. A reaction intermediate and one final product were positively identified. Nano-catalysts with different loadings of Ce on TiO₂ synthesized by sol-gel route were characterized by scanning electron microscope, transmission electron microscopy, BET and powder X-ray diffraction spectrum techniques. The results showed that the material retained a highly ordered mesoporous structure and possessed large surface area.

Derivation of aquatic predicted no-effect concentration (PNEC) for ibuprofen and sulfamethoxazole based on various toxicity endpoints and the associated risks

For pharmaceuticals, the ecological risk assessment based on traditional endpoints of toxicity could not be properly protective in the long run since the mode of action could vary because they are intended for different therapeutic uses. In this study, the predicted no-effect concentrations (PNECs) of two selected pharmaceuticals, ibuprofen (IBU) and sulfamethoxazole (SMX), were derived based on either traditional endpoints of survival and growth data or some nonlethal endpoints such as reproduction, biochemical and molecular data. The PNECs of IBU based on biochemical-cellular and reproduction data were 0.018 and 0.026 μg L^-1 that were significantly lower than those derived from other endpoints, while the lowest PNEC for SMX derived from growth data with the concentration of 0.89 μg L^-1. Ecological risk assessment was performed for IBU and SMX to the aquatic environment by applying hazard quotient and probabilistic distribution based quotient (DBQs) methods. The results showed that the probability of DBQs of IBU exceeding 0.1 was 11.2%, while for SMX the probability was 0.9% that could be neglected.

Photodegradation kinetics, transformation, and toxicity prediction of ketoprofen, carprofen, and diclofenac acid in aqueous solutions

Photodegradation of 3 commonly used nonsteroidal anti-inflammatory drugs, ketoprofen, carprofen, and diclofenac acid, was conducted under ultraviolet (UV) irradiation. The kinetic results showed that the 3 pharmaceuticals obeyed the first-order reaction with decreasing rate constants of 1.54 × 10^-4 , 5.91 × 10^-5 , and 7.78 × 10^-6  s^-1 for carprofen, ketoprofen, and diclofenac acid, respectively. Moreover, the main transformation products were identified by ion-pair liquid-liquid extraction combined with injection port derivatization-gas chromatography-mass spectrometry and high-performance liquid chromatography-quadrupole-time of flight mass spectrometric analysis. There were 8, 3, and 6 transformation products identified for ketoprofen, carprofen, and diclofenac acid, respectively. Decarboxylation, dechlorination, oxidation, demethylation, esterification, and cyclization were proposed to be associated with the transformation of the 3 pharmaceuticals. Toxicity prediction of the transformation products was conducted on the EPI Suite software based on ECOSAR model, and the results indicate that some of the transformation products were more toxic than the parent compounds. The present study provides the foundation to understand the transformation behavior of the studied pharmaceuticals under UV irradiation. Environ Toxicol Chem 2017;36:3232-3239. © 2017 SETAC.

Deriving acute and chronic predicted no effect concentrations of pharmaceuticals and personal care products based on species sensitivity distributions

Pharmaceuticals and personal care products (PPCPs), as emerging contaminants, have been detected in various environmental matrices and caused adverse effects on human health and the ecosystem. But water quality criterias (WQCs) of PPCPs for protecting aquatic environment are lacking, which hinders the environmental management of these emerging contaminants. In the present study, in order to support their WQC derivation, acute and chronic hazardous concentrations for 5% of species (HC₅s) of some frequently detected PPCPs in China were calculated based on acute and chronic species sensitivity distributions (SSDs), respectively, using both parametric (log-normal and log-logistic) and nonparametric bootstrap approaches. The groups of aquatic species used in SSDs included planktons, zooplanktons, invertebrates and vertebrates. Acute and chronic predicted no effect concentrations (PNECs) were derived from the HC₅s. The acute PNECs of the selected PPCPs were in a range from 1.1 to 4993μg/L. While the chronic PNECs were one or two orders of magnitude lower than the acute PNECs, with a range from 0.02 to 298μg/L. Among these PPCPs, the compound with the highest acute effect on the aquatic environment was clarithromycin while erythromycin was the one with the highest chronic toxicity effect. Among the studied PPCPs, erythromycin caused a relatively higher aquatic ecological risk in China. This study helps derive WQCs of PPCPs in the aquatic environment, which is essential for environmental managment of these emerging contaminants.

Degradation of indomethacin in river water under stress and non-stress laboratory conditions: degradation products, long-term evolution and adsorption to sediment

The pharmaceutical compound indomethacin is not totally removed in wastewater treatment plants, whose effluents flow into aquatic environments; concentrations in the 0.1-100ng/L range are commonly found in surface waters, and its fate is unknown. Here, biological, photochemical and thermal degradation assays were conducted under stress and non-stress conditions to estimate its degradation rate in river water and establish its degradation products over time. The results revealed that direct sunlight irradiation promoted the complete degradation of indomethacin (2μg/L) in less than 6hr, but indomethacin was detected over a period of 4months when water was kept under the natural day-night cycle and the exposure to sunlight was partially limited, as occurs inside a body of water. The biological degradation in water was negligible, while the hydrolysis at pH7.8 was slow. Residues were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction, and six degradation products were found; their structures were proposed based on the molecular formulae and fragmentation observed in high-resolution tandem mass spectra. 4-Chlorobenzoic and 2-acetamido-5-methoxybenzoic acids were the long-term transformation products, persisting for at least 30weeks in water kept under non-stress conditions. Furthermore, the degradation in the presence of sediment was also monitored over time, with some differences being noted. The adsorption coefficients of indomethacin and degradation products on river sediment were calculated; long-term degradation products did not have significant adsorption to sediment.

Organic Contaminants in Chinese Sewage Sludge: A Meta-Analysis of the Literature of the Past 30 Years

The production of sewage sludge is increasing in China but with unsafe disposal practices, causing potential risk to human health and the environment. Using literature from the past 30 years (N = 159), we conducted a meta-analysis of organic contaminants (OCs) in Chinese sludge. Most data were available from developed and populated regions, and no data were found for Tibet. Since 1987, 35 classes of chemicals consisting of 749 individual compounds and 1 mixture have been analyzed, in which antibiotics and polycyclic aromatic hydrocarbons (PAHs) were the most targeted analytes. For 13 classes of principal OCs (defined as chemicals detected in over five studies) in sludge, the median (expressed in nanograms per gram dry weight) was the highest for phthalate esters (27 900), followed by alkylphenol polyethoxylates (12 000), synthetic musks (5800), antibiotics (4240), PAHs (3490), ultraviolet stabilizers (670), bisphenol analogs (160), organochlorine pesticides (110), polybrominated diphenyl ethers (100), pharmaceuticals (84), hormones (69), perfluorinated compounds (21), and polychlorinated biphenyls (15). Concentrations of PAHs in sludges collected between 1998 and 2012 showed a decreasing trend. Study findings suggest the need for a Chinese national sewage sludge survey to identify and regulate toxic OCs, ideally employing both targeted as well as nontargeted screening approaches.

Acesulfame-K and pharmaceuticals as co-tracers of municipal wastewater in a receiving river

Wastewater treatment plant (WWTP) effluents are important sources of emerging contaminants at environmentally-relevant concentrations. In this study, water samples were collected from a river downstream of two WWTPs to identify practical tracers for tracking wastewater. The results of the study indicate elevated concentrations of Cl(-), nutrients (NH3-N and NO2(-)), the artificial sweetener acesulfame-K (ACE-K), and the pharmaceuticals carbamazepine (CBZ), caffeine (CAF), sulfamethoxazole (SMX), ibuprofen (IBU), gemfibrozil (GEM), and naproxen (NAP) in the river close to the WWTPs that decreased with distance downstream. A correlation analysis using the Spearman Rank method showed that ACE-K, CBZ, GEM, NAP, and Cl(-) were strongly correlated with each other over a 31 km stretch of the river in the study area. The strong correlations of these target compounds indicate that the artificial sweetener ACE-K and the pharmaceuticals CBZ, GEM, and NAP can potentially be used as co-tracers to track wastewater.

Occurrence and ecological potential of pharmaceuticals and personal care products in groundwater and reservoirs in the vicinity of municipal landfills in China

Pharmaceutical and personal care products (PPCPs), including antibiotics, azole anti-fungals, non-steroid anti-inflammatory drugs, lipid regulators, parabens, antiseptics, and bisphenol A, were investigated in groundwater and reservoirs in the vicinity of two municipal landfills in the metropolis of Guangzhou, South China. Dehydroerythromycin, sulfamethoxazole, fluconazole, salicylic acid, methylparaben, triclosan, and bisphenol A were the mostly frequently detected PPCPs in the groundwater at low ng L(-1) levels. In the reservoirs, the PPCPs were widely detected at higher frequencies and concentrations, especially sulfamethoxazole, propiconazole, and ibuprofen, with maximal concentrations above 1 μg L(-1). The PPCPs in the groundwater did not show significant seasonal differences or spatial trends. However, in the reservoirs, higher PPCP concentrations were observed in spring than in other seasons. The anti-bacterials in the groundwater posed medium risks to algae. In the reservoirs, the sulfonamides and macrolides posed low to high risks, while ibuprofen, salicylic acid, and clofibric acid presented low to medium risks to aquatic organisms. Overall, the results showed that the PPCP contaminants and subsequent ecological risks in the groundwater and surface water in the vicinity of the landfills may be of serious concern. More research is needed to better correlate the landfill leachates and PPCP contamination in the nearby aquatic environments.

Systematic screening of common wastewater-marking pharmaceuticals in urban aquatic environments: implications for environmental risk control

In this report, we refer to pharmaceuticals that are widespread in the urban aquatic environment and that mainly originate from wastewater treatment plants or non-point source sewage as "wastewater-marking pharmaceuticals" (WWMPs). To some extent, they reflect the condition or trend of water contamination and also contribute to aquatic environmental risk assessment. The method reported here for screening typical WWMPs was proposed based on academic concerns about them and their concentrations present in the urban aquatic environment, as well as their properties of accumulation, persistence, eco-toxicity and related environmental risks caused by them. The screening system consisted of an initial screening system and a further screening system. In the former, pharmaceuticals were categorised into different evaluation levels, and in the latter, each pharmaceutical was given a normalised final evaluation score, which was the sum of every score for its properties of accumulation, persistence, eco-toxicity and environmental risk in the aquatic environment. The system was applied to 126 pharmaceuticals frequently detected in the aquatic environment. In the initial screening procedure, five pharmaceuticals were classified into the "high" category, 16 pharmaceuticals into the "medium" category, 15 pharmaceuticals into the "low" category and 90 pharmaceuticals into the "very low" category. Subsequently, further screening were conducted on 36 pharmaceuticals considered as being of "high", "medium" and "low" categories in the former system. We identified 7 pharmaceuticals with final evaluation scores of 1-10, 10 pharmaceuticals with scores of 11-15, 15 pharmaceuticals with scores from 16 to 20 and 4 pharmaceuticals with scores above 21. The results showed that this screening system could contribute to the effective selection of target WWMPs, which would be important for spatial-temporal dynamics, transference and pollution control of pharmaceuticals in the urban aquatic environment. However, there remains a number of pharmaceutical parameters with measured data gaps, such as organic carbon adsorption coefficients and bioconcentration factors, which, if filled, would improve the accuracy of the screening system.

Chiral profiling of azole antifungals in municipal wastewater and recipient rivers of the Pearl River Delta, China

Enantiomeric compositions and fractions (EFs) of three chiral imidazole (econazole, ketoconazole, and miconazole) and one chiral triazole (tebuconazole) antifungals were investigated in wastewater, river water, and bed sediment of the Pearl River Delta, South China. The imidazole pharmaceuticals in the untreated wastewater were racemic to weakly nonracemic (EFs of 0.450-0.530) and showed weak enantioselectivity during treatment in the sewage treatment plant. The EFs of the dissolved azole antifungals were usually different from those of the sorbed azoles in the suspended particulate matter, suggesting different behaviors for the enantiomers of the chiral azole antifungals in the dissolved and particulate phases of the wastewater. The azole antifungals were widely present in the rivers. The bed sediment was a sink for the imidazole antifungals. The imidazoles were prevalently racemic, whereas tebuconazole was widely nonracemic in the rivers. Seasonal effects were observed on distribution and chirality of the azole antifungals. Concentrations of the azole antifungals in the river water were relatively higher in winter than in spring and summer while the EF of miconazole in the river water was higher in summer. The mechanism of enantiomeric behavior of the chiral azole antifungals in the environment warrants further research.

Pharmaceuticals and personal care products in the aquatic environment in China: a review

Pharmaceuticals and personal care products (PPCPs) have been detected as contaminants of emerging concern ubiquitously in the aquatic environment in China and worldwide. A clear picture of PPCP contamination in the Chinese aquatic environment is needed to gain insight for both research and regulatory needs (e.g. monitoring, control and management). The occurrence data of 112 PPCPs in waters and sediments in China has been reviewed. In most cases, the detected concentration of these PPCPs in waters and sediments were at ng/L and ng/g levels, which were lower than or comparable to those reported worldwide. A screening level risk assessment (SLERA) identified six priority PPCPs in surface waters, namely erythromycin, roxithromycin, diclofenac, ibuprofen, salicylic acid and sulfamethoxazole. The results of SLERA also revealed that the hot spots for PPCP pollution were those river waters affected by the megacities with high density of population, such as Beijing, Tianjin, Guangzhou and Shanghai. Limitations of current researches and implications for future research in China were discussed. Some regulatory issues were also addressed.

Stereoisomeric profiling of pharmaceuticals ibuprofen and iopromide in wastewater and river water, China

Stereoisomeric compositions can provide insights into sources, fate, and ecological risks of contaminants in the environment. In this study, stereoisomeric profiles of ibuprofen and iopromide were investigated in wastewater and receiving surface water of the Pearl River Delta, south China. The enantiomeric fraction (EF) of ibuprofen was 0.108-0.188 and 0.480, whereas the isomer ratio (IR) of iopromide was 1.426-1.673 and 1.737-1.898 in the influent and final effluent, respectively, suggesting stereoselective degradation occurred for both pharmaceuticals during wastewater treatment. Ibuprofen showed enantioselective degradation in the anaerobic, anoxic, and aerobic conditions, whereas iopromide displayed isomer-selective degradation only under the aerobic condition. In the river waters, the EF of ibuprofen was 0.130-0.327 and the IR of iopromide was 1.500-2.531. The results suggested that pharmaceuticals in the mainstream Pearl River were mainly from discharge of treated wastewater, whereas in the tributary rivers and urban canals, direct discharge of untreated wastewater represented a significant contribution. The IR of iopromide can be an applicable and efficient tracer for wastewater discharge in the environment.

Pharmaceuticals and personal care products (PPCPs): a review on environmental contamination in China

Pharmaceuticals and personal care products (PPCPs) which contain diverse organic groups, such as antibiotics, hormones, antimicrobial agents, synthetic musks, etc., have raised significant concerns in recently years for their persistent input and potential threat to ecological environment and human health. China is a large country with high production and consumption of PPCPs for its economic development and population growth in recent years. This may result in PPCP contamination in different environmental media of China. This review summarizes the current contamination status of different environment media, including sewage, surface water, sludge, sediments, soil, and wild animals, in China by PPCPs. The human body burden and adverse effects derived from PPCPs are also evaluated. Based on this review, it has been concluded that more contamination information of aquatic environment and wildlife as well as human body burden of PPCPs in different areas of China is urgent. Studies about their environmental behavior and control technologies need to be conducted, and acute and chronic toxicities of different PPCP groups should be investigated for assessing their potential ecological and health risks.

Using high-throughput sequencing to assess the impacts of treated and untreated wastewater discharge on prokaryotic communities in an urban river

In many megacities wastewater is an important source of surface water, particularly during drought periods. While changes in surface water chemistry associated with effluent inflow have generally been well-studied, few data have been collected on the effects to prokaryotic communities. The objective of this study was to explore the impacts of treated and untreated wastewater discharges on prokaryotic community in an urban river. High-throughput sequencing was conducted for analyzing the prokaryotic community composition and function in river water, treated wastewater and untreated wastewater. Results revealed that the prokaryotic community compositions in the upstream river reach were dominated by treated wastewater discharge. In the middle- and downstream river reaches, untreated effluent volumes are higher, thus affecting the structure of the prokaryotic community, promoting a rise in Cyanobacteria and Thaumarchaeota. Function annotation revealed a number of genes associated with xenobiotic metabolism and human diseases were observed in river and wastewater samples, suggesting wastewater discharge to river may pose a risk to human health. Quantitative real-time PCR results revealed that the treated and untreated wastewater discharges also affected the abundance of ammonia oxidation bacteria (AOB) and ammonia oxidation archaea (AOA) in river.

Removal of diclofenac by conventional drinking water treatment processes and granular activated carbon filtration

This study was carried out to evaluate the efficiency of conventional drinking water treatment processes with and without pre-oxidation with chlorine and chlorine dioxide and the use of granular activated carbon (GAC) filtration for the removal of diclofenac (DCF). Water treatment was performed using the Jar test with filters on a lab scale, employing nonchlorinated artesian well water prepared with aquatic humic substances to yield 20HU true color, kaolin turbidity of 70 NTU and 1mgL(-1) DCF. For the quantification of DCF in water samples, solid phase extraction and HPLC-DAD methods were developed and validated. There was no removal of DCF in coagulation with aluminum sulfate (3.47mgAlL(-1) and pH=6.5), flocculation, sedimentation and sand filtration. In the treatment with pre-oxidation and disinfection, DCF was partially removed, but the concentration of dissolved organic carbon (DOC) was unchanged and byproducts of DCF were observed. Chlorine dioxide was more effective than chorine in oxidizing DCF. In conclusion, the identification of DCF and DOC in finished water indicated the incomplete elimination of DCF through conventional treatments. Nevertheless, conventional drinking water treatment followed by GAC filtration was effective in removing DCF (⩾99.7%). In the oxidation with chlorine, three byproducts were tentatively identified, corresponding to a hydroxylation, aromatic substitution of one hydrogen by chlorine and a decarboxylation/hydroxylation. Oxidation with chlorine dioxide resulted in only one byproduct (hydroxylation).

Acidic pharmaceuticals in domestic wastewater and receiving water from hyper-urbanization city of China (Shanghai): environmental release and ecological risk

The occurrence, behavior, and release of five acidic pharmaceuticals, including ibuprofen (IBP), naproxen (NPX), ketoprofen (KEP), diclofenac (DFC), and clofibric acid (CA), have been investigated along the different units in a tertiary-level domestic wastewater treatment plant (WWTP) in hyper-urbanization city of China (Shanghai). IBP was the most abundant chemicals among the measured in raw wastewater. The loads of the acidic pharmaceuticals in the WWTP influent ranged from 7.5 to 414 mg/day/1,000 inh, which were lower than those reported in the developed countries suggesting a less per capita consumption of pharmaceuticals in Shanghai. IBP obtained by highest removal (87 %); NPX and KEP were also significantly removed (69-76 %). However, DFC and CA were only moderately removed by 37-53 %, respectively. Biodegradation seemed to play a key role in the elimination of the studied pharmaceuticals except for DFC and CA. An annual release of acidic pharmaceuticals was estimated at 1,499 and 61.7 kg/year through wastewater and sludge, respectively, from Shanghai. Highest pharmaceuticals concentrations were detected in the effluent discharge point of the WWTP, indicating that WWTP effluent is the main source of the acidic pharmaceuticals to its receiving river. Preliminary results indicated that only DFC in river had a high risk to aquatic organisms. Nevertheless, the joint toxicity effects of these chemicals are needed to further investigate.

Paracetamol degradation intermediates and toxicity during photo-Fenton treatment using different iron species

The photo-Fenton degradation of paracetamol (PCT) was evaluated using FeSO(4) and the iron complex potassium ferrioxalate (FeOx) as iron source under simulated solar light. The efficiency of the degradation process was evaluated considering the decay of PCT and total organic carbon concentration and the generation of carboxylic acids, ammonium and nitrate, expressed as total nitrogen. The results showed that the degradation was favored in the presence of FeSO(4) in relation to FeOx. The higher concentration of hydroxylated intermediates generated in the presence of FeSO(4) in relation to FeOx probably enhanced the reduction of Fe(III) to Fe(II) improving the degradation efficiency. The degradation products were determined using liquid chromatography electrospray time-of-flight mass spectrometry. Although at different concentrations, the same intermediates were generated using either FeSO(4) or FeOx, which were mainly products of hydroxylation reactions and acetamide. The toxicity of the sample for Vibrio fischeri and Daphnia magna decreased from 100% to less than 40% during photo-Fenton treatment in the presence of both iron species, except for D. magna in the presence of FeOx due to the toxicity of oxalate to this organism. The considerable decrease of the sample toxicity during photo-Fenton treatment using FeSO(4) indicates a safe application of the process for the removal of this pharmaceutical.

Does non-steroidal anti-inflammatory (NSAID) ibuprofen induce antioxidant stress and endocrine disruption in mussel Mytilus galloprovincialis?

Ibuprofen (IBU) is one of the most sold over-the-counter non-steroidal anti-inflammatory drugs (NSAID) and widely detected in the aquatic ecosystems. Nevertheless, the information regarding IBU effects in biota is still sparse. The goal of this study was to assess IBU potential effect as oxidative stress and endocrine disruption inducer in mussel Mytilus galloprovincialis applying a battery of biomarkers. Over two weeks of exposure to IBU (250 ngL(-1)), superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), phase II glutathione S-transferase (GST) activities and lipid peroxidation (LPO) levels were determined in the digestive gland and alkali-labile phosphates (ALP) were carried out in sex-differentiated mussels' gonads. The results confirm a transitory induction of antioxidant activities responses concomitant to lipid peroxide formation outline and an increase of ALP levels over time, particularly in exposed males which may lead to mussels' reproductive fitness impairment highlighting a higher impact of IBU as an endocrine disruptor than as a short-term reactive oxygen species (ROS)-generator.

Differential presence of anthropogenic compounds dissolved in the marine waters of Puget Sound, WA and Barkley Sound, BC

Organic compounds were evaluated in March 2010 at 22 stations in Barkley Sound, Vancouver Island Canada and at 66 locations in Puget Sound. Of 37 compounds, 15 were xenobiotics, 8 were determined to have an anthropogenic imprint over natural sources, and 13 were presumed to be of natural or mixed origin. The three most frequently detected compounds were salicyclic acid, vanillin and thymol. The three most abundant compounds were diethylhexyl phthalate (DEHP), ethyl vanillin and benzaldehyde (∼600 n g L(-1) on average). Concentrations of xenobiotics were 10-100 times higher in Puget Sound relative to Barkley Sound. Three compound couplets are used to illustrate the influence of human activity on marine waters; vanillin and ethyl vanillin, salicylic acid and acetylsalicylic acid, and cinnamaldehyde and cinnamic acid. Ratios indicate that anthropogenic activities are the predominant source of these chemicals in Puget Sound.