GC-MS analysis and ecotoxicological risk assessment of triclosan, carbamazepine and parabens in Indian rivers

Ecotoxicological risk assessment of triclosan, an emerging pollutant in a riverine and estuarine ecosystems: A comparative study

Triclosan (TCS), an antibacterial biocide, pervades water and sediment matrices globally, posing a threat to aquatic life. In densely populated cities like Mumbai, rivers and coastal bodies demand baseline TCS data for ecotoxicological assessment due to the excessive use of personal care products comprising TCS. This pioneering study compares spatiotemporal TCS variations and risks in freshwater and marine ecosystems employing multivariate analysis of physicochemical parameters. Over five months (January to May 2022), Mithi River exhibited higher TCS concentrations (water: 1.68 μg/L, sediment: 3.19 μg/kg) than Versova Creek (water: 0.49 μg/L, sediment: 0.69 μg/kg). Principal component analysis revealed positive correlations between TCS and physicochemical parameters. High-risk quotients (>1) underscore TCS threats in both water bodies. This study furnishes crucial baseline data, emphasizing the need for effective treatment plans for TCS in effluent waters released into the adjacent aquatic systems.

Critical review on the environmental behaviors and toxicity of triclosan and its removal technologies

As a highly effective broad-spectrum antibacterial agent, triclosan (TCS) is widely used in personal care and medical disinfection products, resulting in its widespread occurrence in aquatic and terrestrial environments, and even in the human body. Notably, the use of TCS surged during the COVID-19 outbreak, leading to increasing environmental TCS pollution pressure. From the perspective of environmental health, it is essential to systematically understand the environmental occurrence and behavior of TCS, its toxicological effects on biota and humans, and technologies to remove TCS from the environment. This review comprehensively summarizes the current knowledge regarding the sources and behavior of TCS in surface water, groundwater, and soil systems, focusing on its toxicological effects on aquatic and terrestrial organisms. Effluent from wastewater treatment plants is the primary source of TCS in aquatic systems, whereas sewage application and/or wastewater irrigation are the major sources of TCS in soil. Human exposure pathways to TCS and associated adverse outcomes were also analyzed. Skin and oral mucosal absorption, and dietary intake are important TCS exposure pathways. Reducing or completely degrading TCS in the environment is important for alleviating environmental pollution and protecting public health. Therefore, this paper reviews the removal mechanisms, including adsorption, biotic and abiotic redox reactions, and the influencing factors. In addition, the advantages and disadvantages of the different techniques are compared, and development prospects are proposed. These findings provide a basis for the management and risk assessment of TCS and are beneficial for the application of treatment technology in TCS removal.

Tricks and tracks of prevalence, occurrences, treatment technologies, and challenges of mixtures of emerging contaminants in the environment: With special emphasis on microplastic

This paper aims to emphasize the occurrence of various emerging contaminant (EC) mixtures in natural ecosystems and highlights the primary concern arising from the unregulated release into soil and water, along with their impacts on human health. Emerging contaminant mixtures, including pharmaceuticals, personal care products, dioxins, polychlorinated biphenyls, pesticides, antibiotics, biocides, surfactants, phthalates, enteric viruses, and microplastics (MPs), are considered toxic contaminants with grave implications. MPs play a crucial role in transporting pollutants to aquatic and terrestrial ecosystems as they interact with the various components of the soil and water environments. This review summarizes that major emerging contaminants (ECs), like trimethoprim, diclofenac, sulfamethoxazole, and 17α-Ethinylestradiol, pose serious threats to public health and contribute to antimicrobial resistance. In addressing human health concerns and remediation techniques, this review critically evaluates conventional methods for removing ECs from complex matrices. The diverse physiochemical properties of surrounding environments facilitate the partitioning of ECs into sediments and other organic phases, resulting in carcinogenic, teratogenic, and estrogenic effects through active catalytic interactions and mechanisms mediated by aryl hydrocarbon receptors. The proactive toxicity of ECs mixture complexation and, in part, the yet-to-be-identified environmental mixtures of ECs represent a blind spot in current literature, necessitating conceptual frameworks for assessing the toxicity and risks with individual components and mixtures. Lastly, this review concludes with an in-depth exploration of future scopes, knowledge gaps, and challenges, emphasizing the need for a concerted effort in managing ECs and other organic pollutants.

Neurotoxic effects of carbamazepine on the mosquitofish Gambusia affinis

In recent years, the presence of pharmaceuticals in the aquatic environment has gained a significant attention. Carbamazepine, a commonly prescribed antiepileptic drug, has been consistently found in aquatic environments at concentrations ranging from nanograms to micrograms, raising concerns about its potential negative impacts on aquatic organisms. The study examined the acute and chronic neurotoxic effects of environmentally relevant and sublethal concentrations of carbamazepine in the mosquitofish Gambusia affinis. After a 96-hour exposure period, the median lethal concentration (LC50) of carbamazepine for G. affinis was determined as 24 mg L - 1. For the current study, sublethal concentrations i.e., one-tenth (2.4 mg L - 1) and one-fifth (4.8 mg L - 1) of the LC50 value were chosen for assessing the neurotoxic effects along with the environmentally relevant concentration (13 ng L - 1). The research findings indicated that carbamazepine had a disruptive impact on the typical growth and behavior of the fish. During the acute exposure phase, physical deformities were observed in the fish, resulting in neonatal and postneonatal fatalities. Furthermore, the neurotoxic effects of carbamazepine were clearly demonstrated through alterations in various neurological parameters, including acetylcholinesterase, dopamine, gamma-aminobutyric acid, serotonin, monoamine oxidase, 5-hydroxyindole acetic acid, adrenaline, and nor-adrenaline. These findings raise concerns about the survival of fish populations in their natural environment.

Multilevel assessment of carbamazepine effects: An integrative approach using zebrafish early-life stages

Carbamazepine (CBZ) is the most commonly used drug in epilepsy treatment, and its metabolites are commonly detected among persistent pharmaceuticals in the aquatic environment. This study aimed to investigate CBZ effects on early-life-stage zebrafish (Danio rerio) (from 2 to 168 hpf) by employing of an integrative approach linking endpoints from molecular to individual level: (i) development; (ii) locomotor activity; (iii) biochemical markers (lactate dehydrogenase, glutathione-S-transferase, acetylcholinesterase and catalase) and (iv) transcriptome analysis using microarray. A 168 h - LC50 of 73.4 mg L-1 and a 72 h - EC50 of 66.8 mg L-1 for hatching were calculated while developmental effects (oedemas and tail deformities) were observed at CBZ concentrations above 37.3 mg L-1. At the biochemical level, AChE activity proved to be the most sensitive parameter, as evidenced by its decrease across all concentrations tested (∼25% maximum reduction, LOEC (lowest observed effect concentration) < 0.6 μg L-1). Locomotor behaviour seemed to be depressed by CBZ although this effect was only evident at the highest concentration tested (50 mg L-1). Molecular analysis revealed a dose-dependent effect of CBZ on gene expression. Although only 25 genes were deregulated in organisms exposed to CBZ when compared to controls, both 0.6 and 2812 μg L-1 treatments impaired gene expression related to development (e.g. crygmxl1, org, klf2a, otos, stx16 and tob2) and the nervous system (e.g. Rtn3, Gdf10, Rtn3), while activated genes were associated with behavioural response (e.g. prlbr and taar). Altogether, our results indicate that environmentally relevant CBZ concentrations might affect biochemical and genetic traits of fish. Thus, the environmental risk of CBZ cannot be neglected, especially in a realistic scenario of constant input of domestic effluents into aquatic systems.

Triclosan, an antimicrobial drug, induced reproductive impairment in the freshwater fish, Anabas testudineus (Bloch, 1792)

Triclosan (TCS), an antimicrobial drug, is known to occupy different compartments in aquatic ecosystems. The present study focused to evaluate the reproductive toxicity of triclosan, at environmentally relevant (0.009 and 9 μg L-1) and sublethal (176.7 μg L-1) concentrations for 90 days in the pre-spawning phase of the fish, Anabas testudineus. The reproductive biomarkers, namely, gonadal steroidogenic enzymes, expression of aromatic genes, levels of serum gonadotropins, sex hormones, and histology of gonads were analyzed. The weight of the animal, brain weights along with gonadosomatic index decreased while mucus deposition increased significantly at all concentrations of triclosan as the primary defensive mechanism to prevent the entry of toxicants. Triclosan disrupted gonadal steroidogenesis as evidenced by a reduction in the activities of gonadal steroidogenic enzymes. The expressions of cyp19a1a and cyp19a1b genes were up-regulated in the brain of both sexes and testis, while down-regulated in the ovary indicating estrogenic effects of the compound. The endocrine-disrupting effects of triclosan were confirmed. The current results suggest that chronic exposure to triclosan altered reproductive endpoints thereby impairing normal reproductive functions in fish.

Pollution levels and ecological risks of PPCPs in water and sediment samples of Danjiangkou Reservoir

The concentrations and distribution patterns of three typical pharmaceuticals and personal care products (PPCPs) in water and sediment samples obtained from Danjiangkou Reservoir during two seasonal sampling periods were studied to determine their impact on water quality. The temporal and spatial variations in concentrations measured were analyzed and related to ecological risks with data obtained during the mean-flow period (in June) and the dry period (in November). We found a high detection rate of ketoprofen (KTP) in water samples from Danjiangkou Reservoir; the concentrations ranged from not detected (ND) to 46.80 ng/L with the highest values measured in the Hanku tributary samples followed by the samples collected in the main body of Danjiangkou Reservoir. The KTP concentrations in the Danku tributary samples were the lowest measured in this study. In addition, the concentrations of KTP in the Shending River, Sihe River, Jianghe River, Guanshan River, and Jianhe River water samples were relatively high in the mean-flow period. The water sample detection rates and concentrations of triclosan (TCS) and triclocarban (TCC) were low in both the mean-flow period and the dry period. All three kinds of PPCPs were detected in the sediment samples with the concentrations of KTP, TCS, and TCC ranging from 0.76 to 7.89 μg/kg, 0.01 to 0.59 μg/kg, and 0.01 to 11.36 μg/kg, respectively. Overall, the concentrations of the three measured PPCPs in the water and sediment samples were all relatively low compared to results reported in the recent literature. The dry period concentrations of PPCPs in the water samples were lower than the concentrations measured in the mean-flow period. However, dry period concentrations were higher in the sediment samples compared to those in the mean-flow period samples. Our interpretation of the spatial and temporal patterns of PPCPs in Danjiangkou Reservoir suggests that these compounds were likely mainly derived from wastewater discharge in the upper reaches of the reservoir. The risk quotient (RQ) method was used for an ecological risk assessment of the detected PPCPs in this study. We found that TCS in water and sediment posed medium ecological risks to algae at different times of the year. In view of the extreme importance of water safety in Danjiangkou Reservoir, the ecological risks of PPCPs require additional attention.

Distribution of parabens and 4-HB in human blood

Human blood has been commonly and routinely analyzed to determine internal human exposure to parabens. However, data on the occurrence of parabens and their common metabolite, p-hydroxybenzoic acid (4-HB), in different human blood matrixes is still limited. In this study, 139 pairs of serum and whole blood samples were collected from Chinese adults, and then analyzed them for 5 parabens and 4-HB. Methylparaben (MeP) and propylparaben (PrP) were consistently the predominant parabens in human serum (mean 2.3 and 2.1 ng/mL, respectively) and whole blood (1.9 and 1.3 ng/mL, respectively). Mean concentrations of 4-HB in human serum and whole blood were 7.7 and 12 ng/mL, respectively. Concentrations of parabens, except benzylparaben (BzP), and 4-HB in human serum were significantly (p < 0.01) correlated with that in whole blood. Distribution pattern of parabens and 4-HB in human blood was evaluated, for the first time, based on their partitioning between human serum and whole blood (Kp). Mean Kp values of parabens, except BzP, increased with the alkyl chain length from 0.83 to 1.6. BzP (mean 1.4) had a comparable mean Kp value to PrP (mean 1.4). Among target analytes, 4-HB had the lowest mean Kp value (0.75). These data are important to select appropriate blood matrixes for conducting human exposure assessment and epidemiological studies on parabens.

Advanced oxidation and biological integrated processes for pharmaceutical wastewater treatment: A review

The stress of pharmaceutical and personal care products (PPCPs) discharging to water bodies and the environment due to increased industrialization has reduced the availability of clean water. This poses a potential health hazard to animals and human life because water contamination is a great issue to the climate, plants, humans, and aquatic habitats. Pharmaceutical compounds are quantified in concentrations ranging from ng/Lto μg/L in aquatic environments worldwide. According to (Alsubih et al., 2022), the concentrations of carbamazepine, sulfamethoxazole, Lutvastatin, ciprofloxacin, and lorazepam were 616-906 ng/L, 16,532-21635 ng/L, 694-2068 ng/L, 734-1178 ng/L, and 2742-3775 ng/L respectively. Protecting and preserving our environment must be well-driven by all sectors to sustain development. Various methods have been utilized to eliminate the emerging pollutants, such as adsorption and biological and advanced oxidation processes. These methods have their benefits and drawbacks in the removal of pharmaceuticals. Successful wastewater treatment can save the water bodies; integrating green initiatives into the main purposes of actor firms, combined with continually periodic awareness of the current and potential implications of environmental/water pollution, will play a major role in water conservation. This article reviews key publications on the adsorption, biological, and advanced oxidation processes used to remove pharmaceutical products from the aquatic environment. It also sheds light on the pharmaceutical adsorption capability of adsorption, biological and advanced oxidation methods, and their efficacy in pharmaceutical concentration removal. A research gap has been identified for researchers to explore in order to eliminate the problem associated with pharmaceutical wastes. Therefore, future study should focus on combining advanced oxidation and adsorption processes for an excellent way to eliminate pharmaceutical products, even at low concentrations. Biological processes should focus on ideal circumstances and microbial processes that enable the simultaneous removal of pharmaceutical compounds and the effects of diverse environments on removal efficiency.

Triclosan disturbs nitrogen removal in constructed wetlands: Responses of microbial structure and functions

This study investigated the influence of wetland types (vertical and tidal flow constructed wetlands [CWs] [VFCW and TFCW, respectively]) and concentrations of triclosan (TCS) on the removal of pollutants (TCS and nitrogen) and microbial characteristics. The efficiency of TCS removal was significantly higher with 5 μg/L TCS (Phase B) than with 30 μg/L (Phase C) in the two CWs. The efficiencies of removal of NH4+-N and NO3--N were significantly inhibited in Phase C. Compared with the VFCW, the TFCW removed more NH4+-N at the same concentration of TCS, whereas less NO3--N was removed, and it even accumulated. Saccharimondales, an important functional genus with the highest abundance and more node connections with other genera, had a sharp decrease in relative abundance as the increasing concentrations of TCS of the two CWs conformed with its relative abundance and significantly negatively correlated with the concentration of TCS. Differentiated Roseobacter_Clade_CHAB-I-5_Lineage and Sphaerotilus were enriched in the VFCW and TFCW, respectively. The abundance of enzymes that catalyzed nitritation was significantly inhibited by TCS, whereas nitrate reductase (EC 1.7.99.4) catalyzed both denitrification and dissimilatory nitrate reduction to ammonium (DNRA), and nitrite reductase (NADH) (EC 1.7.1.15) that catalyzed DNRA comprised a larger proportion in the two CWs. Simultaneously, the abundances of two enzymes were higher in the TFCW than in the VFCW. The network analysis indicated that the main genera were promoted more by TCS in the VFCW, while inhibited in the TFCW. Moreover, the concentrations of nitrogen (NH4+-N, NO3--N, and TN) significantly positively correlated with TCS-resistant bacteria, and negatively correlated with most nitrogen-transforming bacteria with species that varied between the VFCW and TFCW. The results of this study provide a reference for the molecular biological mechanism of the simultaneous removal of nitrogen and TCS in the CWs.

Acute and chronic effects of triclosan on the behavior, physiology, and multigenerational characteristics of the water flea Moina macrocopa

Triclosan, a chlorinated biphenyl ether is widely used in industrial products and cosmetics due to its antibiotic activity. Although relatively levels of triclosan have been detected in aquatic ecosystems, limited information is available regarding the acute and chronic impacts of triclosan on aquatic invertebrates, especially planktonic crustaceans. In this study, we analyzed the acute (24 h) and chronic (14 days exposure across three generations) effects of different concentrations of triclosan [1/10 of the no observed effect concentration (NOEC), the NOEC, and 1/10 of the LC50] calculated from the 24 h acute toxicity value, on the water flea Moina macrocopa. In the acute exposure experiment, the 1/10 LC50 value of triclosan significantly reduced survival, feeding rate, thoracic limb activity, heart activity, and acetylcholinesterase activity. In response to the 1/10 LC50 value, intracellular reactive oxygen species increased along with elevated levels of malondialdehyde and glutathione. Enzymatic activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase were significantly increased by the 1/10 LC50 value, suggesting active protection of the antioxidant defense system against oxidative stress. Chronic exposure to the 1/10 NOEC and NOEC values revealed multigenerational adverse impacts of triclosan. The second generation was found to be the most sensitive to triclosan, as the NOEC value significantly reduced the survival rate, body length, and the number of neonates per brood, along with a delayed hatching period. Taken together, these results indicate that even sublethal levels of triclosan can have detrimental effects on the water flea population's maintenance through intergenerational toxicity.

Parabens, Triclosan and Bisphenol A in Surface Waters and Sediments of Baiyang Lake, China: Occurrence, Distribution, and Potential Risk Assessment

The extensive use of the parabens triclosan (TCS) and bisphenol A (BPA) has potential adverse effects on human health and aquatic organisms. However, their monitoring information in freshwater lakes is still limited. This study simultaneously summarized the concentrations, spatial distribution characteristics, and correlations of four types of parabens, TCS, and BPA in the surface water and sediment of Baiyang Lake. Finally, the potential risks of target pollutants were evaluated from two aspects: human health risks and ecological risks. The average contaminations of target compounds in surface water and sediment-BPA, TCS, and ∑4 parabens-was 33.1, 26.1, 0.7 ng/L and 24.5, 32.5, 2.5 ng/g, respectively. The total concentration of target compounds at the inlet of the upstream Fu River and Baigouyin River is significantly higher than that near Hunan and the outlet. In addition, Spearman's correlation analysis showed a significant positive correlation between compounds. The health hazards of target compounds in surface water were all within safe limits. However, the risk quotient results indicate that in some locations in surface water, TCS poses a high risk to algae and a moderate risk to invertebrates and fish, and appropriate attention should be paid to these areas.

Parabens as environmental contaminants of aquatic systems affecting water quality and microbial dynamics

Among different pollutants of emerging concern, parabens have gained rising interest due to their widespread detection in water sources worldwide. This occurs because parabens are used in personal care products, pharmaceuticals, and food, in which residues are generated and released into aquatic environments. The regulation of the use of parabens varies across different geographic regions, resulting in diverse concentrations observed globally. Concentrations of parabens exceeding 100 μg/L have been found in wastewater treatment plants and surface waters while drinking water (DW) sources typically exhibit concentrations below 6 μg/L. Despite their low levels, the presence of parabens in DW is a potential exposure route for humans, raising concerns for both human health and environmental microbiota. Although a few studies have reported alterations in the functions and characteristics of microbial communities following exposure to emerging contaminants, the impact of the exposure to parabens by microbial communities, particularly biofilm colonizers, remains largely understudied. This review gathers the most recent information on the occurrence of parabens in water sources, as well as their effects on human health and aquatic organisms. The interactions of parabens with microbial communities are reviewed for the first time, filling the knowledge gaps on the effects of paraben exposure on microbial ecosystems and their impact on disinfection tolerance and antimicrobial resistance, with potential implications for public health.

Comparative risk assessment studies estimating the hazard posed by long-term consumption of PPCPs in river water

This study assesses the risk due to Emerging Contaminants (ECs), present in Indian rivers - Ganga (650 million inhabitants), Yamuna (57 million inhabitants), and Musi (7,500,000 inhabitants), 13 ECs in total, have been used for risk assessment studies. Their concentrations (e.g., Fluconazole: 236950 μg/l, Ciprofloxacin: 31000 μg/l, Caffeine: 21.57 μg/l, etc.) were higher than the threshold concentrations for safe consumption (e.g. Fluconazole allowable level is 3.8 μg/l, and Ciprofloxacin allowable level is 0.51 μg/l). Three different pathways of emerging contaminants (ECs) transfer (oral water ingestion, oral fish ingestion, and dermal water contact) have been considered and the study is carried out in 2 ways: (i) deterministic and (ii) probabilistic approaches (using Monte Carlo iterative methods with 10000 simulations) with the aid of a software - Risk (version 7.5). The risk value, quantified by Hazard Quotient (HQ) is higher than the allowable limit of 1 for several compounds in the three rivers like Fluconazole (HQ = 18276.713), Ciprofloxacin (HQ = 278.675), Voriconazole (HQ = 14.578), Cetirizine (HQ = 1006.917), Moxifloxacin (HQ = 8.076), Caffeine (HQ = 55.150), and Ibuprofen (HQ = 9.503). Results show that Fluconazole and Caffeine pose the maximum risk in the rivers via the "oral pathway" that allows maximum transfer of the ECs present in the river (93% and 82% contribution to total risk). The risk values vary from nearly 25 times to 19000 times the United States Environmental Protection Agency (USEPA) threshold limit of 1 (e.g., Caffeine Infant Risk = 25.990 and Fluconazole Adult Risk = 18276.713). The most susceptible age group, from this study, is "Adults" (19-70 years old), who stand the chance of experiencing the adverse health hazards associated with prolonged over-exposure to the ECs present in the river waters. Musi has the maximum concentration of pollutants and requires immediate remediation measures. Further, both methods indicate that nearly 60-70% of the population in all the three study areas are at risk of developing health hazards associated with over-exposure to ECs regularly, making the areas inhabitable.

Selection of priority emerging contaminants in surface waters of India, Pakistan, Bangladesh, and Sri Lanka

The challenge of emerging contaminants (ECs) in global surface water bodies and particularly in low- and middle-income countries such as India, Pakistan, Bangladesh, and Sri Lanka, is evident from the literature. The complexity arises from the high costs involved in EC analysis and the extensive list of ECs, which complicates the selection of essential compounds for scientific and regulatory investigations. Consequently, monitoring programs often include ECs that may have minimal significance within a region and do not pose known or suspected ecological or human health risks. This study aims to address this issue by employing a multi-risk assessment approach to identify priority ECs in the surface waters of the aforementioned countries. Through an analysis of occurrence levels and frequency data gathered from published literature, an optimized risk quotient (RQ) was derived. The findings reveal a priority list of 38 compounds that exhibit potential environmental risks and merit consideration in future water quality monitoring programs. Furthermore, the majority of antibiotics in India (12 out of 17) and Pakistan (7 out of 17) exhibit a risk quotient for antimicrobial resistance selection (RQAMR) greater than 1, highlighting the need for devising effective strategies to mitigate the escalation of antibiotic resistance in the environment.

Contamination in mangrove ecosystems: A synthesis of literature reviews across multiple contaminant categories

Mangrove forests are exposed to diverse ocean-sourced and land-based contaminants, yet mangrove contamination research lags. We synthesize existing data and identify major gaps in research on five classes of mangrove contaminants: trace metals, persistent organic pollutants, polycyclic aromatic hydrocarbons, microplastics, and pharmaceuticals and personal care products. Research is concentrated in Asia, neglected in Africa and the Americas; higher concentrations are correlated with waste water treatment plants, industry, and urbanized landscapes. Trace metals and polycyclic aromatic hydrocarbons, frequently at concentrations below regulatory thresholds, may bioconcentrate in fauna, whereas persistent organic pollutants were at levels potentially harmful to biota through short- or long-term exposure. Microplastics were at variable levels, yet lack regulatory and ecotoxicological thresholds. Pharmaceuticals and personal care products received minimal research despite biological activity at small concentrations. Given potential synergistic effects, multi-contaminant research, increased monitoring of multiple contaminant classes, and increased public outreach and involvement are needed.

Effects of weathering on the properties and fate of secondary microplastics from a polystyrene single-use cup

In this work, we probed the changes to some physicochemical properties of polystyrene microplastics generated from a disposable cup as a result of UV-weathering, using a range of spectroscopy, microscopy, and profilometry techniques. Thereafter, we aimed to understand how these physicochemical changes affect the microplastic transport potential and contaminant sorption ability in model freshwaters. Exposure to UV led to measured changes in microplastic hydrophobicity (20-23 % decrease), density (3% increase), carbonyl index (up to 746 % increase), and microscale roughness (24-86 % increase). The settling velocity of the microplastics increased by 53 % after weathering which suggests that UV aging can increase microplastic deposition to sediments. This impact of aging was greater than the effect of the water temperature. Weathered microplastics exhibited reduced sorption capacity (up to 52 % decrease) to a model hydrophobic contaminant (triclosan) compared to unaged ones. The adsorption of triclosan to both microplastics was slightly reversible with notable desorption hysteresis. These combined effects of weathering could potentially increase the transport potential while decreasing the contaminant transport abilities of microplastics. This work provides new insights on the sorption capacity and mobility of a secondary microplastic, advances our knowledge about their risks in aquatic environments, and the need to use environmentally relevant microplastics.

An overview on the prevalence and potential impact of antimicrobials and antimicrobial resistance in the aquatic environment of India

India at present is one of the leading countries in antimicrobial drug production and use, leading to increasing antimicrobial resistance (AMR) and public health problems. Attention has mainly been focused on the human and food animals' contribution to AMR neglecting the potential contribution of the perceptibly degraded aquatic environment in India. The paper reviews the available published literature in India on the prevalence of antimicrobial residues and their dissemination pathways in wastewater of pharmaceutical industries, sewage treatment plants, hospitals, riverine, community pond water, and groundwater. The prevalence of antimicrobial residue concentration, pathogenic and non-pathogenic bacteria antimicrobial resistant bacteria (ARB), their drug resistance levels, and their specific antimicrobial resistant genes (ARGs) occurring in various water matrices of India have been comprehensively depicted from existing literature. The concentration of some widely used antimicrobials recorded from the sewage treatment plants and hospital wastewater and rivers in India has been compared with other countries. The ecotoxicological risk posed by these antimicrobials in the various water matrices in India indicated high hazard quotient (HQ) values for pharmaceutical effluents, hospital effluents, and river water. The degraded aquatic environment exhibited the selection of a wide array of co-existent resistant genes for antibiotics and metals. The review revealed improper use of antibiotics and inadequate wastewater treatment as major drivers of AMR contaminating water bodies in India and suggestion for containing the challenges posed by AMR in India has been proposed.

Occurrence, distribution, and risk assessment of parabens in the surface water of Terengganu River, Malaysia

The concentration, distribution, and risk assessment of parabens were determined in the surface water of the Terengganu River, Malaysia. Target chemicals were extracted via solid-phase extraction, followed by high-performance liquid chromatography analysis. Method optimization produced a high percentage recovery for methylparaben (MeP, 84.69 %), ethylparaben (EtP, 76.60 %), and propylparaben (PrP, 76.33 %). Results showed that higher concentrations were observed for MeP (3.60 μg/L) as compared with EtP (1.21 μg/L) and PrP (1.00 μg/L). Parabens are ubiquitously present in all sampling stations, with >99 % of detection. Salinity and conductivity were the major factors influencing the level of parabens in the surface water. Overall, we found no potential risk of parabens in the Terengganu River ecosystem due to low calculated risk assessment values (risk quotient < 1). In conclusion, parabens are present in the river, but their levels are too low to pose risks to aquatic organisms.

Analysis of the effect of triclosan on gonadal differentiation of zebrafish based on metabolome

Although the previous research confirmed that triclosan (TCS) affects the female proportion at the early stage of zebrafish (Danio rerio) and has an estrogen effect, the mechanism by which TCS affects the sex differentiation of zebrafish is not entirely clear. In this study, zebrafish embryos were exposed to different concentrations of TCS (0, 2, 10, and 50 μg/L) for 50 consecutive days. The expression of sex differentiation related genes and metabolites were then determined in larvae using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Liquid Chromatography-Mass Spectrometer (LC-MS), respectively. TCS upregulated the expression of the sox9a, dmrt1a and amh genes, down-regulating the expression of wnt4a, cyp19a1b, cyp19a1a, and vtg2 gene. The overlapped classification of Significant Differential Metabolites (SDMs) between the control group and three TCS treated groups related to gonadal differentiation was Steroids and steroid derivatives, including 24 down-regulated SDMs. The enriched pathways related to gonadal differentiation were Steroid hormone biosynthesis, Retinol metabolism, Metabolism of xenobiotics by cytochrome P450, and Cortisol synthesis and secretion. Moreover, SDMs were significantly enriched in Steroid hormone biosynthesis in the 2 μg/L TCS group, which included Dihydrotestosterone, Cortisol, 11beta-hydroxyandrost-4-ene-3, 17-dione, 21-Hydroxypregnenolone, Androsterone, Androsterone glucuronide, Estriol, Estradiol, 19-Hydroxytestosterone, Cholesterol, Testosterone, and Cortisone acetate. Results showed that TCS affects the female proportion mainly through Steroid hormone biosynthesis, in which aromatase plays a key role in zebrafish. Retinol metabolism, metabolism of xenobiotics by cytochrome P450, and cortisol synthesis and secretion may also participate in TCS-mediated sex differentiation. These findings reveal the molecular mechanisms of TCS-induced sex differentiation, and provide theoretical guidance for the maintenance of water ecological balance.

Triclosan and related compounds in the environment: Recent updates on sources, fates, distribution, analytical extraction, analysis, and removal techniques

Triclosan (TCS) has been widely used in daily life because of its broad-spectrum antibacterial activities. The residue of TCS and related compounds in the environment is one of the critical environmental safety problems, and the pandemic of COVID-19 aggravates the accumulation of TCS and related compounds in the environment. Therefore, detecting TCS and related compound residues in the environment is of great significance to human health and environmental safety. The distribution of TCS and related compounds are slightly different worldwide, and the removal methods also have advantages and disadvantages. This paper summarized the research progress on the source, distribution, degradation, analytical extraction, detection, and removal techniques of TCS and related compounds in different environmental samples. The commonly used analytical extraction methods for TCS and related compounds include solid-phase extraction, liquid-liquid extraction, solid-phase microextraction, liquid-phase microextraction, and so on. The determination methods include liquid chromatography coupled with different detectors, gas chromatography and related methods, sensors, electrochemical method, capillary electrophoresis. The removal techniques in various environmental samples mainly include biodegradation, advanced oxidation, and adsorption methods. Besides, both the pros and cons of different techniques have been compared and summarized, and the development and prospect of each technique have been given.

Pharmaceuticals and personal care products (PPCPs) in surface water and fish from three Asian countries: Species-specific bioaccumulation and potential ecological risks

In Asian developing countries, undeveloped and ineffective sewer systems are causing surface water pollution by a lot of contaminants, especially pharmaceuticals and personal care products (PPCPs). Therefore, the risks for freshwater fauna need to be assessed. The present study aimed at: i) elucidating the contamination status; ii) evaluating the bioaccumulation; and iii) assessing the potential risks of PPCP residues in surface water and freshwater fish from three Asian countries. We measured 43 PPCPs in the plasma of several fish species as well as ambient water samples collected from India (Chennai and Bengaluru), Indonesia (Jakarta and Tangerang), and Vietnam (Hanoi and Hoa Binh). In addition, the validity of the existing fish blood-water partitioning model based solely on the lipophilicity of chemicals is assessed for ionizable and readily metabolizable PPCPs. When comparing bioaccumulation factors calculated from the PPCP concentrations measured in the fish and water (BAF_measured) with bioconcentration factors predicted from their pH-dependent octanol-water partition coefficient (BCF_predicted), close values (within an order of magnitude) were observed for 58-91 % of the detected compounds. Nevertheless, up to 110 times higher plasma BAF_measured than the BCF_predicted were found for the antihistamine chlorpheniramine in tilapia but not in other fish species. The plasma BAF_measured values of the compound were significantly different in the three fish species (tilapia > carp > catfish), possibly due to species-specific differences in toxicokinetics (e.g., plasma protein binding and hepatic metabolism). Results of potential risk evaluation based on the PPCP concentrations measured in the fish plasma suggested that chlorpheniramine, triclosan, haloperidol, triclocarban, diclofenac, and diphenhydramine can pose potential adverse effects on wild fish. Results of potential risk evaluation based on the PPCP concentrations measured in the surface water indicated high ecological risks of carbamazepine, sulfamethoxazole, erythromycin, and triclosan on Asian freshwater ecosystems.

Acute toxicity, oxidative stress, and apoptosis due to short-term triclosan exposure and multi- and transgenerational effects on in vivo endpoints, antioxidant defense, and DNA damage response in the freshwater water flea Daphnia magna

In this study, we measured the acute toxicity of triclosan (TCS) in neonate and adult Daphnia magna water fleas. The median lethal concentrations were 184.689 and 349.511 μg/L, respectively. Oxidative stress induced by TCS was analyzed based on changes in reactive oxygen species (ROS) content and antioxidant enzymatic activities in D. magna. Based on these endpoints, TCS concentrations of 50 and 100 μg/L induced oxidative stress. However, several apoptosis-mediated proteins showed TCS-induced oxidative-stress damage in response to 25 μg/L, indicating that apoptotic proteins were the most sensitive mediators. We also evaluated the multi- and transgenerational effects of TCS on D. magna over three generations in terms of various in vivo endpoints, DNA damage responses, and biochemical reactions. The transgenerational group exposed to TCS exhibited greater negative impacts on antioxidant responses, DNA fragmentation status, and biological endpoints compared with the multigenerational exposure group, leading to decreased reproductive rates and higher ROS content. The transcriptional expression levels of glutathione S-transferase genes in the transgenerational exposure group were upregulated compared to those in the multigenerational group but were fully recovered in F2 offspring. Our findings provide an in-depth understanding of the adaptive effects of multigenerational exposure to TCS.

Comprehensive insight into triclosan-from widespread occurrence to health outcomes

Humans are exposed to the variety of emerging environmental pollutant in everyday life. The special concern is paid to endocrine disrupting chemicals especially to triclosan which could interfere with normal hormonal functions. Triclosan could be found in numerous commercial products such as mouthwashes, toothpastes and disinfectants due to its antibacterial and antifungal effects. Considering the excessive use and disposal, wastewaters are recognized as the main source of triclosan in the aquatic environment. As a result of the incomplete removal, triclosan residues reach surface water and even groundwater. Triclosan has potential to accumulate in sediment and aquatic organisms. Therefore, the detectable concentrations of triclosan in various environmental and biological matrices emerged concerns about the potential toxicity. Triclosan impairs thyroid homeostasis and could be associated with neurodevelopment impairment, metabolic disorders, cardiotoxicity and the increased cancer risk. The growing resistance of the vast groups of bacteria, the evidenced toxicity on different aquatic organisms, its adverse health effects observed in vitro, in vivo as well as the available epidemiological studies suggest that further efforts to monitor triclosan toxicity at environmental levels are necessary. The safety precaution measures and full commitment to proper legislation in compliance with the environmental protection are needed in order to obtain triclosan good ecological status. This paper is an overview of the possible negative triclosan effects on human health. Sources of exposure to triclosan, methods and levels of detection in aquatic environment are also discussed.

Neurotoxic mechanisms of triclosan: The antimicrobial agent emerging as a toxicant

Several scientific studies have suggested a link between increased exposure to pollutants and a rise in the number of neurodegenerative disorders of unknown origin. Notably, triclosan (an antimicrobial agent) is used in concentrations ranging from 0.3% to 1% in various consumer products. Recent studies have also highlighted triclosan as an emerging toxic pollutant due to its increasing global use. However, a definitive link is missing to associate the rising use of triclosan and the growing number of neurodegenerative disorders or neurotoxicity. In this article, we present systematic scientific evidence which are otherwise scattered to suggest that triclosan can indeed induce neurotoxic effects, especially in vertebrate organisms including humans. Mechanistically, triclosan affected important developmental and differentiation genes, structural genes, genes for signaling receptors and genes for neurotransmitter controlling enzymes. Triclosan-induced oxidative stress impacting cellular proteins and homeostasis which triggers apoptosis. Though the scientific evidence collated in this article unequivocally indicates that triclosan can cause neurotoxicity, further epidemiological studies may be needed to confirm the effects on humans.

Ecotoxicological effects and bioaccumulation in Eichhornia crassipes induced by long-term exposure to triclosan

In this study, the ecotoxicological effects and bioaccumulation of triclosan (TCS) in Eichhornia crassipes (E. crassipes) were investigated with 28 d exposure experiments. The results showed that chlorophyll content was increased after 7 d exposure to 0.05-0.1 mg L^-1 TCS, while it was inhibited significantly by 0.5 mg L^-1 TCS after 21 d exposure. The concentrations of soluble protein in the leaves increased during the initial stage (7 d and 14 d), whereas they decreased during 21 d and 28 d. The concentrations of soluble protein in the roots gradually reduced during the exposure time. The antioxidant enzyme activities in roots decreased continually with the exposure time. However, the antioxidant enzyme (SOD and CAT) activities in leaves decreased after exposure longer than 14 d. Moreover, differentially expressed genes (DEGs) were observed in the root of E. crassipes after a 28 d exposure to 0.5 mg L^-1 TCS, with 11023 DEGs down-regulated and 3947 DEGs up-regulated. 5 SOD down-regulated genes and 3 CAT down-regulated genes were identified from transport and catabolism in cellular processes. After 28 d exposure, the TCS content in roots and leaves stressed by 0.5 mg L^-1 TCS were up to 13.04 μg g^-1 and 1.97 μg g^-1, respectively. SOD in leaves was negatively correlated with TCS content in leaves, CAT in roots was negatively correlated with TCS content in roots. These results provide experimental data to assess the ecological risk of TCS with long exposure in aquatic systems.

Screening of antimicrobials, fragrances, UV stabilizers, plasticizers and preservatives in sewage treatment plants (STPs) and their risk assessment in India

Community/industrial wastewater is the prime source of anthropogenic chemicals, its treatment is often a daunting task and unaffordable for many countries. Emerging Contaminants (ECs) have been drained into wastewater after continuous use/misuse and Conventional treatments in STPs do not remove them completely. ECs including antimicrobial agents, synthetic musks, Benzotriazole UV stabilizers (BUVSs), plasticizers, and preservatives are frequently reported in environment, and cause health effects to non-target organisms. Monitoring of ECs is important to understand their status in aquatic environment. Hence, it was aimed to monitor ECs (n = 21) from 11 STPs in Tamil Nadu, India. The detection frequency of most of these analytes was >90%. Antimicrobials ranged from 247 to 22,714 ng/L and 11-14,369 ng/L in influents and effluents, respectively. The synthetic musks were in the order of Tonalide > Galaxolide > Musk Ketone. BUVSs ranged from 4 to 1632 ng/L (influents) and < LOD to 29,853 ng/L (effluents). Concentration of phthalates in influents and effluents were < LOD - 11,311 ng/L and < LOD - 17,618 ng/L, respectively. Parabens were found in the order of Prophyl > Methyl > Ethyl > Butyl in influents and Methyl > Prophyl > Butyl > Ethyl in effluents. Mass loads of ECs through STPs were found as antimicrobials > plasticizers > fragrances > BUVSs > Preservatives. This study reveals increasing usage of ECs and inadequate treatment processes at STPs in India. Also helps to adopt suitable treatment processes to remove ECs from wastewater and to reuse the wastewater.

Pharmaceuticals in water as emerging pollutants for river health: A critical review under Indian conditions

The wastewaters from pharmaceutical manufacturing units, hospitals, and domestic sewage contaminated with excretal matters of medicine users are the prime sources of pharmaceutical pollutants (PPs) in natural water bodies. In the present study, PPs have been considered one of the emerging pollutants (EPs) and a cause of concern in river health assessment. Beyond the reported increase in antibiotic-resistant bacteria (ABRB), PPs have been found adversely affecting the biotic diversity in such water environments. Considering Algae, Macroinvertebrates, and Fishes as three distinct trophic level indicators, the present study puts forward a framework for showing River Health Condition (RHC) based on the calculation of a River Health Index (RHI). The RHI is calculated using six Indicator Group Scores (IGS) which individually reflect river health in a defined category of water quality characteristics. While Dissolved Oxygen Related Parameters (DORP), Nutrients (NT), and PPs are taken as causative agents affecting RHCs, scores of Algal-Bacterial (AB) symbiosis, Macroinvertebrates (MI), and Fishes (F) are considered as an effect of such environmental conditions. Current wastewater treatment technologies are also not very effective in the removal of PPs. The objective of the present study is to review the harmful effects of PPs on the aquatic environment, particularly on the chemical and biotic indicators of river health. Based on predicted no-effect concentrations (PNEC) for algae, macroinvertebrates, and fishes in the aquatic environment and measured environmental concentration (MEC) in the river, the estimated risk quotient (RQ) for norfloxacin in the Isakavagu-Nakkavagu stream of river Godavari, Hyderabad is found 293 for algae, 39 for MI, and 335 for fish. Among PPs, in Indian rivers, the presence of caffeine is the most frequent, with algae at the highest level of risk (RQ_max= 24.5). Broadly six PPs, including azithromycin, caffeine, diclofenac, naproxen, norfloxacin, and sulfamethoxazole are found above PNEC values in Indian rivers. The application of IGS and RHI in understanding and presenting the river health condition (RHC) through colored hexagons has been demonstrated for the river Ganga near Varanasi (India) as an example. Identification of critical indicator groups, based on IGS provides a scientific basis for planned intervention for river health restoration to achieve an acceptable category.

Aquatic and human health risk assessment of Humanogenic Emerging Contaminants (HECs), Phthalate Esters from the Indian Rivers

Phthalate esters (PEs) one of the widely used plasticizers, and are known for their environmental contamination and endocrine disruption. Hence, it is important to study their distribution in a riverine environment. This study was aimed to determine the Spatio-temporal trends of 16 PEs in surface water, sediment and fish from rivers in southern India, and to assess their environmental health risks. Phthalates were quantified in all matrices with the mean concentrations (∑₁₆PEs) in water, sediment and fish as 35.6 μg/L, 1.25 μg/kg and 17.0 μg/kg, respectively. The Kaveri River is highly loaded with PEs compared to the Thamiraparani and Vellar Rivers. PEs such as DBP, DEHP, DCHP and DiBP were most frequently detected in all matrices, and at elevated concentrations in the dry season. The risk quotient (RQ < 1) suggests that the health risk of PEs from river water and fish to humans is negligible. However, DBP and DEHP from the Kaveri River pose some risk to aquatic organisms (HQ > 1). DEHP from the Vellar River may pose risks to algae and crustaceans. Non-priority phthalate (DiBP) may pose risks to Kaveri and Vellar River fish. The bioaccumulation factor of DCHP and DEHP was found to be very high in Sardinella longiceps and in Centropristis striata, and also exceeded the threshold limit of 5000 suggesting that PEs in the riverine environment may pose some health concerns. This is the first study to assess the spatio-temporal distribution, riverine flux and potential ecological effects of 16 PEs from the southern Indian Rivers.

Biological responses of alga Euglena gracilis to triclosan and galaxolide and the regulation of humic acid

Although the toxicity of triclosan (TCS) and galaxolide (HHCB) in freshwater has been reported, little study is shed light on their molecular toxicity mechanism and the regulation of humic acid (HA). In this work, freshwater algae E. gracilis was selected to explore these processes, and the molecular toxicity mechanism was analyzed by metabolomics. TCS was more toxic to E. gracilis than HHCB at 1 d exposure with the EC₅₀ value of 0.76 mg L^-1, but HHCB showed a higher toxicity as the exposure time prolonged. HA could alleviate the toxicity of TCS and HHCB, mainly due to the inhibition of TCS uptake and oxidative stress, respectively. The perturbations on a number of antioxidant defense-related metabolites in response to TCS or HHCB also indicated oxidative stress was a main toxicity mechanism. However, the exposure to HHCB resulted in more pronounced perturbations in the purine metabolism than TCS, implying that HHCB may pose a genetic toxicity on algae. It may explain the higher toxicity of HHCB to algae as the exposure time increased. These findings provide a comprehensive understanding on the ecological risks of TCS or HHCB in natural waters.

Molecular mechanism of ethylparaben on zebrafish embryo cardiotoxicity based on transcriptome analyses

Ethylparaben (EP), one of the parabens, a ubiquitous food and cosmetic preservatives, has caused widespread concern due to its health risks. Recently, studies have found that parabens exposure during pregnancy is negatively correlated with fetal and early childhood development. However, studies about EP on embryo development are few. In this study, the cardiotoxicity effects of EP concentrations ranging from 0 to 20 mg/L on zebrafish embryo development were explored. Results showed that EP exposure induce abnormal cardiac function and morphology, mainly manifested as pericardial effusion and abnormal heart rate in early-stage development of zebrafish embryos. Through transcriptome sequencing followed by Gene Ontology enrichment analysis, and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, we further confirmed that EP exposure ultimately leads to cardiac morphologic abnormalities via the following three mechanisms: 1. Disruption of the retinoic acid signaling pathway related to original cardiac catheter development; 2. Inhibition of gene expression related to myocardial contraction; 3. Orientation development disturbance of heart tube. Moreover, O-Dianisidine staining, whole-mount in situ hybridization at 30 and 48 hours post fertilization (hpf) and hematoxylin-eosin staining results all confirmed the decreased heart's return blood volume, misoriented heart tubes toward either the right or the middle side, and heart loop defects. For the first time, we explored the mechanism by which EP exposure causes abnormal heart development in zebrafish embryos, laying the foundation for further revealing of the EP toxicity on embryonic development.

Prioritizing Pharmaceutical Contaminants in Great Lakes Tributaries Using Risk-Based Screening Techniques

In a study of 44 diverse sampling sites across 16 Great Lakes tributaries, 110 pharmaceuticals were detected of 257 monitored. The present study evaluated the ecological relevance of detected chemicals and identified heavily impacted areas to help inform resource managers and guide future investigations. Ten pharmaceuticals (caffeine, nicotine, albuterol, sulfamethoxazole, venlafaxine, acetaminophen, carbamazepine, gemfibrozil, metoprolol, and thiabendazole) were distinguished as having the greatest potential for biological effects based on comparison to screening-level benchmarks derived using information from two biological effects databases, the ECOTOX Knowledgebase and the ToxCast database. Available evidence did not suggest substantial concern for 75% of the monitored pharmaceuticals, including 147 undetected pharmaceuticals and 49 pharmaceuticals with screening-level alternative benchmarks. However, because of a lack of biological effects information, screening values were not available for 51 detected pharmaceuticals. Samples containing the greatest pharmaceutical concentrations and having the highest detection frequencies were from Lake Erie, southern Lake Michigan, and Lake Huron tributaries. Samples collected during low-flow periods had higher pharmaceutical concentrations than those collected during increased-flow periods. The wastewater-treatment plant effluent content in streams correlated positively with pharmaceutical concentrations. However, deviation from this correlation demonstrated that secondary factors, such as multiple pharmaceutical sources, were likely present at some sites. Further research could investigate high-priority pharmaceuticals as well as those for which alternative benchmarks could not be developed. Environ Toxicol Chem 2022;41:2221-2239. Published 2022. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Road runoff as a significant nonpoint source of parabens and their metabolites in urban rivers

Parabens are widely added to food, cosmetics, and medicines as preservatives and are typical contaminants of pharmaceuticals and personal care products (PPCPs). However, their fate and transport in urban watersheds remain largely unexplored. This study investigated the role of road runoff as a critical nonpoint source of parabens and their metabolites in urban rivers based on 73 multimedia (road runoff and dust in different urban land uses, wastewater, stormwater discharge and river water) samples collected from a highly urbanized drainage area. Seven parabens and five metabolites were detected in the road runoff, with mean concentrations of ∑parabens and ∑metabolites equal to 47.5 ng/L and 4710 ng/L, respectively. The concentrations in road runoff were comparable to those in treated wastewater and river water and showed a land use pattern of residential > industrial > commercial. A first flush effect of the contaminants was observed in a heavy rainfall event with an antecedent dry period. In general, the population-based and area-based emission intensities of ∑parabens and ∑metabolites in road runoff were one order of magnitude higher than those in wastewater effluent during the rainfall events. This study provides quantitative evidence that road runoff can be a major pollution source of parabens and their metabolites in rapidly growing cities during the wet season and calls for the integrated management of nonpoint sources to prevent urban river contamination by typical PPCPs.

Assessment, characterization, and quantification of microplastics from river sediments

Microplastic (MP), as a pollutant, is currently posing a biological hazard to the aquatic environment. The study aims to isolate, quantify, and characterize the MP pollutants in sediment samples from 14 study sites at Kaveri River, Killa Chinthamani, Tiruchirappalli, South India. With Sediment-MP Isolation (SMI) unit, density separation was done with a hydrogen peroxide solution. Four forms of MPs namely, fragments, films, foams, and fibers with orange, white, green, and saffron red were observed. The plenitude and distribution of four forms of MPs and natural substrates were geometrically independent, with large amounts of microfragments within the research region accounting for 79.72% variation by Principal Component Analysis. FT-IR analyses of MPs showed the presence of polyamide, polyethylene, polyethylene glycol, polyethylene terephthalate, polypropylene, and polystyrene. Additionally, the scanning electron microscopic analysis revealed that the MPs have differential surface morphology with rough surfaces, porous structures, fissures, and severe damage. Most MPs comprised Si, Mg, Cu, and Al, according to energy dispersive X-ray analyses. The combined SMI, instrumental analyses and evaluation (heat map) of MPs in river sediments help assess contamination levels and types of MPs. The findings might provide an insight into the status of MPs in Kavery River sediments that could help in formulating regulations for MPs reduction and contamination in rivers eventually to protect the environment.

The impact of micropollutants on native algae and cyanobacteria communities in ecological filters during drinking water treatment

An attractive alternative for drinking water production is ecological filtration. Previous studies have reported high removal levels of pharmaceutical and personal care products (PPCPs) by this technology. Algae and cyanobacteria play an important role in the biological activity of ecological filters. The aim of this study was to characterize and identify the community of algae and cyanobacteria in relation to its composition, density and biovolume from 22 ecological filters that received spikings of 2 μg L^-1 PPCPs. For algae and cyanobacteria species, triplicate samples were collected before and 96 h after each spiking from the interface between the top sand layer of the ecological filters and the supernatant water. Results show that Chlorophyceae and Cyanobacteria were present in high numbers of taxa and abundance. The specie Lepocinclis cf. ovum (Euglenophyceae) had the highest percentage occurrence/abundance and frequency into the filters, indicating a possible tolerance by Lepocinclis cf. ovum to the concentration of selected PPCPs. Although the concentration of PPCPs did not affect the treated water quality, they did affect the algae and cyanobacteria community. No differences were detected between filters that received a single PPCP and filters that received a mixture of the six compounds. Also, changes in the composition of algae and cyanobacteria communities were observed before and 96 h after the spikings.

Biomolecular alterations in the early life stages of four food fish following acute exposure of Triclosan

We investigated the effect of acute concentrations of triclosan (TCS; 96 h exposure and 10d post exposure) on the free amino acid, primary (SDS-PAGE) and secondary (FT-IR) structure of proteins in the embryos/larvae of Cyprinus carpio, Ctenopharyngodon idella, Labeo rohita and Cirrhinus mrigala. A concentration dependent increase in free amino acids, upregulation of polypeptides (100 and 70 kDa in C. carpio, C. idella and L. rohita, 55, 45, 36 kda in C. idella and L. rohita and 22 kDa in all the fish) and a decline in percent area of all the selected peaks of the FT-IR spectra was observed after exposure and recovery period. The decline in percent area was greatest for L. rohita at peak 1080 - 1088 cm^-1 (-75.99%) after exposure and at peak 2854 - 2855 cm^-1 (-53.59%) after recovery. Curve fitting analysis revealed a decrease in α-helices and increase in β-sheets in all fish after exposure and recovery period. The results suggest that TCS elicits alterations in biomolecules of fish embryos.

Monsoon dilutes the concurrence but increases the correlation of viruses and Pharmaceuticals and Personal Care Products (PPCPs) in the urban waters of Guwahati, India: The context of pandemic viruses

Concurrence of pharmaceuticals and personal care products (PPCPs), pathogenic viruses, metals and microbial pollution along with their seasonal variations in the water environment are overarching in the context of existing pandemic, especially for tropical countries. The present study focuses on the seasonal influence on the vulnerability of urban water in Guwahati, the largest city in North-eastern India, through examining the concurrence of seven PPCPs, five viruses, faecal bacteria and nine metals in surface waters during monsoon (Summer-July 2017) and pre-monsoon (Winter-March 2018). Surface water sampling was carried out at different locations of the Brahmaputra River, its tributary Bharalu River (an unlined urban drain), and Dipor Bill Lake (Ramsar-recognized wetland). Both PPCPs and viruses were at high concentrations (e.g. up to 970 ng L^-1 caffeine, 2.5 × 10³ copies mL^-1 pepper mild mottle virus (PMMoV)) at the confluence points of urban drains and the river, while they were mostly undetectable at both upstream and downstream locations, implying strong self-purification ability of the river. All the analysed PPCPs and viruses were at much higher concentrations during pre-monsoon i.e., winter than during monsoon, implying heavy dilution and temperature effect during the monsoon. Overall, PPCPs and viruses were more correlated in monsoon but the risk quotient in the urban tributary was higher in pre-monsoon (e.g. 5061 in pre-monsoon and 1515 in monsoon for caffeine). PMMoV was found to be an excellent faecal pollution indicator due to its prevalence, detectability and specificity in all seasons. Overall, the seasonal fluctuations of the non-enveloped viruses monitored in this study is likely to be relevant for SARS-CoV-2. We contribute to address the literature scarcity pertaining to seasonal variations in the prevalence of viruses and their concurrences with contaminants of emerging concern.

Biosolids for safe land application: does wastewater treatment plant size matters when considering antibiotics, pollutants, microbiome, mobile genetic elements and associated resistance genes?

Soil fertilization with wastewater treatment plant (WWTP) biosolids is associated with the introduction of resistance genes (RGs), mobile genetic elements (MGEs) and potentially selective pollutants (antibiotics, heavy metals, disinfectants) into soil. Not much data are available on the parallel analysis of biosolid pollutant contents, RG/MGE abundances and microbial community composition. In the present study, DNA extracted from biosolids taken at 12 WWTPs (two large-scale, six middle-scale and four small-scale plants) was used to determine the abundance of RGs and MGEs via quantitative real-time PCR and the bacterial and archaeal community composition was assessed by 16S rRNA gene amplicon sequencing. Concentrations of heavy metals, antibiotics, the biocides triclosan, triclocarban and quaternary ammonium compounds (QACs) were measured. Strong and significant correlations were revealed between several target genes and concentrations of Cu, Zn, triclosan, several antibiotics and QACs. Interestingly, the size of the sewage treatment plant (inhabitant equivalents) was negatively correlated with antibiotic concentrations, RGs and MGEs abundances and had little influence on the load of metals and QACs or the microbial community composition. Biosolids from WWTPs with anaerobic treatment and hospitals in their catchment area were associated with a higher abundance of potential opportunistic pathogens and higher concentrations of QACs.

Wastewater irrigation in India: Current status, impacts and response options

Wastewater generated from urban agglomerations in India is estimated to be 26.4 km³ annually and 28% of it is treated. This has a potential to irrigate about 2.1 million-ha agricultural land, contribute 4 million Mg of plant nutrients, generate 2.8 million person-days of employment and reduce green house gas (GHG) emission by 73.7 million Mg CO₂-e. Farmers in peri-urban areas depend largely on raw and partially treated wastewater for livelihood via raising high value crops such as vegetable, fodders and fruits. Both controlled and uncontrolled disposal of waste waters leads to progressive and irreversible contamination of soils, surface and ground waters with pathogens, heavy metals and organic micro-contaminants and consequently their bio-transfer through the chain: sewage-soil-vegetation-animal-humans. This has led to the development of a considerable assortment of regulatory measures and guidelines aimed at reducing or eliminating wastewater related health risks. Because conventional treatment technologies are cost prohibitive, alternate methods based on biological and land treatment systems are being advocated. Since soils are the most logical sinks for wastewater, efforts are to optimise rates and methods of water application, quantify the sink capacity of soils to immobilise contaminants and protect the quality of produce. Reuse of diluted or undiluted wastewaters improves crop productivity by 10-36% though production sustainability depends on soil type, climatic conditions, crop grown, irrigation techniques and socio-political factors. Disposal of wastewater in tree plantations and constructed wetlands with consequent removal of toxic metals/compounds using hyper-accumulators/accumulators plants provide for a possible alternative. Ignoring the associated risks, using pisciculture for sewage disposal is quite popular in high rainfall areas. With growing water scarcities, it is utmost important to recognise wastewaters as a valuable resource and formulate appropriate policy initiatives considering the health and livelihood issues of the per-urban farmers and consumers of food as well as risks to environment.

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.

Human health and ecological risk assessment of 98 pharmaceuticals and personal care products (PPCPs) detected in Indian surface and wastewaters

The release of pharmaceuticals and personal care products (PPCPs) in environmental waters has become an urgent issue due to their pseudo-persistent traits. The present study was undertaken to conduct a screening-level risk assessment of 98 PPCPs, detected in different water matrices (treated wastewater, surface water, and groundwater) of India, for evaluating ecological risk (risk to fish, daphnia, and algae), human health risk, and antimicrobial resistance (AMR) selection risk by following risk quotient (RQ) based methodology. In the present study, 47% of the detected PPCPs in Indian waters were found to exert a possible risk (RQ > 1) to either aquatic species and human health, or cause AMR selection risk. 17 out of 25 antibiotics detected in the environmental waters were found to pose a threat of AMR selection. 11 out of 49 pharmaceuticals were found to exert human health risk from ingesting contaminated surface water, whereas only 2 pharmaceuticals out of 25 were found to exert risk from the intake of groundwater. Very high RQs (>1000) for few pharmaceuticals were obtained, signifying a great potential of the detected PPCPs in causing severe health concern, aquatic toxicity, and AMR spread. Within India, special attention needs to be given to the pharmaceutical hubs, as the environmental waters in these regions were found to be severely contaminated with drug residues resulting in extremely high RQs. The present study will be helpful in prioritizing the detected PPCPs in the environmental waters of India, for which immediate attention and enforceable guidelines are required.

Environmental risk assessment of parabens in surface water from a Brazilian river: the case of Mogi Guaçu Basin, São Paulo State, under precipitation anomalies

Parabens are preservatives widely used by industry since these compounds have antifungal properties, relative low cost, and stability over a wide pH range. This study aims to quantify and assess the environmental risks of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) in surface water from a Brazilian River, Mogi Guaçu. The State of São Paulo, including the Mogi Guaçu River region, suffered from a period of intense drought and high temperatures, which caused anomalies in river flows and water supply problems. The water samples were collected from 14 locations, along 300 km of river extension, at four different seasons. Samples were previously extracted and pre-concentrated by dispersive liquid-liquid microextraction (DLLME) and later analyzed by ultra-performance liquid chromatography coupled with electrospray ionization in tandem with mass spectrometry (UPLC-ESI-MS/MS) detector. During the sampling period, PP was detected in 89.3% of the water samples, MP in 87.5%, EP in 73.2%, and BP in 48.2%. The sum of parabens' average levels was 42.2 μg L^-1 in Winter, 41.5 μg L^-1 in Summer, 36.6 μg L^-1 in Autumn, and 31.5 μg L^-1 in Spring. These levels can be attributed to the smaller dilution effect caused by the drought period. Also, ecological risk assessment indicated that parabens could take a low, medium, and high risk for target organisms in the measured aquatic environments, especially considering Pimephales promelas where 15% of the samples do not present potential risk, 84% of samples can present medium risk and only 1% have low risk. Besides, the risks for BP are also considerably higher, when almost 40% presents for high risks and 60% for medium risks. The present study indicates worrisome threats to the water source and to allegedly protected biodiversity and, therefore, urgent actions are needed to effectively protect.

Spatio-temporal distribution of pharmaceutically active compounds in the River Cauvery and its tributaries, South India

Pharmaceutically active compounds (PhACs) present in the environment are a great threat to human well-being and the ecosystem. Eventhough recognized as the pharmacy of the world", studies addressing the distribution of PhACs in the Indian environment are scarce. Hence, in the current study, selected PhACs, heavy metals (HMs), and physicochemical parameters (PCPs) were measured from the surface waters of the River Cauvery during the pre- and post-monsoon. PhACs such as caffeine, carbamazepine, and diclofenac were detected in most samples, whereas topiramate, ibuprofen, and verapamil were found only in few stations. In contrast, the distribution of ciprofloxacin, atenolol, and isoprenaline was strongly influenced by the seasonal pattern (p < 0.05). PhACs such as loperamide, glafenine, erythromycin, and gemfibrozil were not detected during the study. Distribution of PhACs based on average concentration (ng/L) are, CBZ (205.62) > CAF (114.09) > DCF (28.51) > CIP (25.23) > ATL (18.86) > IPL (13.91) > PPL (11.26) > TCS (10.39) > IBF (7.34) > TPT (3.09) > VPL (1.16). Bivariate and multivariate statistical analyses have revealed a positive correlation expressed by the majority of the PhACs with PCPs (COD, TOC), nutrients (TN, TP), and HMs (Pb, Mn, Ni) in the range from 0.540** to 0.961**(p < 0.01). Whereas, DO revealed negative correlation with most of the parameters in the range from -0.559** to -0.831** (p < 0.01). A high average concentration of PhACs was recorded in the upstream (52.08 ng/L) and wastewater discharge points (55.60 ng/L). Further, the environmental risk assessment study has identified the higher risk exhibited by TCS (RQ: 3.29) and CAF (RQ: 38.82) on algae and Daphnia respectively. The study portrays the distribution of emerging contaminants in the River Cauvery and its tributaries and also delivers preliminary data about the distribution of isoprenaline, topiramate, verapamil, and perindopril in the Indian freshwater system.

Genomic markers for the biological responses of Triclosan stressed hatchlings of Labeo rohita

Triclosan (TCS) used commonly in pharmaceuticals and personal care products has become the most common pollutant in water. Three-day-old hatchlings of an indigenous fish, Labeo rohita, were given 96h exposure to a nonlethal (60 μg L^-1) and two moderately lethal concentrations (67 and 97 μg L^-1) of TCS and kept for 10 days of recovery for recording transcriptomic alterations in antioxidant/detoxification (SOD, GST, CAT, GPx, GR, CYP1a and CYP3a), metabolic (LDH, ALT and AST) and neurological (AchE) genes and DNA damage. The data were subjected to principal component analysis (PCA) for obtaining biomarkers for the toxicity of TCS. Hatchlings were highly sensitive to TCS (96h LC₅₀ = 126 μg L^-1 and risk quotient = 40.95), 96h exposure caused significant induction of CYP3a, AChE and ALT but suppression of all other genes. However, expression of all the genes increased significantly (except for a significant decline in ALT) after recovery. Concentration-dependent increase was also observed in DNA damage [Tail Length (TL), Tail Moment (TM), Olive Tail Moment (OTM) and Percent Tail DNA (TDNA)] after 96 h. The damage declined significantly over 96h values at 60 and 67 μg L^-1 after recovery, but was still several times more than control. TCS elicited genomic alterations resulted in 5-11% mortality of exposed hatchlings during the recovery period. It is evident that hatchlings of L. rohita are a potential model and PCA shows that OTM, TL, TM, TDNA, SOD and GR (association with PC1 during exposure and recovery) are the biomarkers for the toxicity of TCS. Graphical abstract.

Environmentally Relevant Concentrations of Triclosan Induce Cyto-Genotoxicity and Biochemical Alterations in the Hatchlings of Labeo rohita

Xenobiotic Triclosan (TCS) is of great concern because of its existence in a variety of personal, household and healthcare products and continuous discharge in water worldwide. Excessive use of TCS-containing sanitizers and antiseptic products during the COVID-19 pandemic further increased its content in aquatic ecosystems. The present study deals with the cyto-genotoxic effects and biochemical alterations in the hatchlings of Labeo rohita on exposure to environmentally relevant concentrations of TCS. Three-days-old hatchlings were exposed to tap water, acetone (solvent control) and 4 environmentally relevant concentrations (6.3, 12.6, 25.2 and 60 µg/L) of TCS for 14 days and kept for a recovery period of 10 days. The significant concentration-dependent decline in cell viability but increase in micronucleated cells, nucleo-cellular abnormalities (NCAs) and DNA damage parameters like tail length, tail moment, olive tail moment and percent of tail DNA after exposure persisted till the end of recovery period. Glucose, triglycerides, cholesterol, total protein, albumin, total bilirubin, uric acid and urea (except for an increase at 60 µg/L) showed significant (p ≤ 0.05) concentration-dependent decrease after 14 days of exposure. The same trend (except for triglycerides, albumin and total bilirubin) continued till 10 days post exposure. In comparison to control, transaminases (alanine and aspartate aminotransferases) increased (p ≤ 0.05) after exposure as well as the recovery period, while a decline in alkaline phosphatase after exposure was followed by a significant increase during the recovery period. The results show that the environmentally relevant concentrations of TCS cause deleterious effects on the hatchlings of L. rohita.

Pharmaceuticals and personal care products' (PPCPs) impact on enriched nitrifying cultures

The impact of pharmaceutical and personal care products (PPCPs) on the performance of biological wastewater treatment plants (WWTPs) has been widely studied using whole-community approaches. These contaminants affect the capacity of microbial communities to transform nutrients; however, most have neither honed their examination on the nitrifying communities directly nor considered the impact on individual populations. In this study, six PPCPs commonly found in WWTPs, including a stimulant (caffeine), an antimicrobial agent (triclosan), an insect repellent ingredient (N,N-diethyl-m-toluamide (DEET)) and antibiotics (ampicillin, colistin and ofloxacin), were selected to assess their short-term toxic effect on enriched nitrifying cultures: Nitrosomonas sp. and Nitrobacter sp. The results showed that triclosan exhibited the greatest inhibition on nitrification with EC₅₀ of 89.1 μg L^-1. From the selected antibiotics, colistin significantly affected the overall nitrification with the lowest EC₅₀ of 1 mg L^-1, and a more pronounced inhibitory effect on ammonia-oxidizing bacteria (AOB) compared to nitrite-oxidizing bacteria (NOB). The EC₅₀ of ampicillin and ofloxacin was 23.7 and 12.7 mg L^-1, respectively. Additionally, experimental data suggested that nitrifying bacteria were insensitive to the presence of caffeine. In the case of DEET, moderate inhibition of nitrification (<40%) was observed at 10 mg L^-1. These findings contribute to the understanding of the response of nitrifying communities in presence of PPCPs, which play an essential role in biological nitrification in WWTPs. Knowing specific community responses helps develop mitigation measures to improve system resilience.

Toxicity and removal of parabens from water: A critical review

Parabens are biocides used as preservatives in food, cosmetics and pharmaceuticals. They possess antibacterial and antifungal activity due to their ability to disrupt cell membrane and intracellular proteins, and cause changes in enzymatic activity of microbial cells. Water, one of our most valuable natural resource, has become a huge reservoir for parabens. Halogenated parabens from chlorination/ozonation of water contaminated with parabens have shown to be even more persistent in water than other types of parabens. Unfortunately, there is dearth of data on their (halogenated parabens) presence and fate in groundwater which serves as a major source of drinking water for a huge population in developing countries. An attempt to neglect the presence of parabens in water will expose man to it through ingestion of contaminated food and water. Although there are reviews on the occurrence, fate and behaviour of parabens in the environment, they largely omit toxicity and removal aspects. This review therefore, presents recent reports on the acute and chronic toxicity of parabens, their estrogenic agonistic and antagonistic activity and also their relationship with antimicrobial resistance. This article further X-rays several techniques that have been employed for the removal of parabens in water and their drawbacks including adsorption, biodegradation, membrane technology and advanced oxidation processes (AOPs). The heterogeneous photocatalytic process (one of the AOPs) appears to be more favoured for removal of parabens due to its ability to mineralize parabens in water. However, more work is needed to improve this ability of heterogeneous photocatalysts. Perspectives that will be relevant for future scientific studies and which will drive policy shift towards the presence of parabens in our drinking waters are also offered. It is hoped that this review will elicit some spontaneous actions from water professionals, scientists and policy makers alike that will provide more data, effective technologies, and adaptive policies that will address the growing threat of the presence of parabens in our environment with respect to human health.

DFT investigation of SiO2 nanotube for adsorption of methyl- and propyl-paraben

A huge number of parabens, esters of p-hydroxybenzoic acid, are used in cosmetic and personal care products as preservative substances. Due to their detrimental effects on ecosystem and human health, taking precautionary measures to remove these compounds is an important task regarding the environmental issues. In this study, a silica (SiO2) nanotube has been selected as a novel sensor to adsorb the most common parabens which are methyl paraben and propyl paraben molecules. To this aim, density functional theory (DFT) calculations were used to evaluate the properties for investigated compounds. The calculated adsorption energies of the most stable configurations for methyl parban@SiO2 and propyl paraben@SiO2 complexes were found to be –0.238 and –0.242 eV, respectively. The electronic properties of nanotubes experienced dramatic changes in case of interactions with parabens, which led to declining the HOMO/LUMO energy gap of the nanotube to its original value. Such adsorption could also enhance the electrical conductivity of the nanotubes meaning that the utilized SiO2 nanotube could detect the existence of methyl and propyl parabens molecules in the environment. As a concluding remark, the investigated SiO2 nanotube could work as a possible sensor for hazardous paraben with the importance of environmental issues.

Biomarkers for assessing chronic toxicity of carbamazepine, an anticonvulsants drug on Pangasianodon hypophthalmus (Sauvage, 1878)

In recent times, carbamazepine (CBZ) as an anticonvulsants drug has raised attention because of its safety concern in the aquatic environment. The present study aimed to evaluate the sub-lethal effects of CBZ (1%, 0.1 % and 0.01 % of 96 h LC₅₀) on P. hypophthalmus for 60 days based on haematological, biochemical, and genotoxicity biomarkers. Chronic exposure of CBZ altered blood profiles (total erythrocyte count, packed cell volume, haemoglobin) and serum biomarkers such as alkaline phosphates, cholesterol, lactate dehydrogenase and transaminase enzymes. Oxidative stress biomarkers such as superoxide dismutase (SOD) and catalase (CAT) activity were also substantially affected in all treatments. Genotoxicity study revealed the formation of micronucleus in erythrocytes of exposed fish. Integrated Biomarker Response (IBR) study showed cholesterol, serum glutamic oxaloacetic transaminase (SGOT) in serum and SOD, CAT in liver tissue are the best organ-based enzyme biomarkers. The present report concludes that an environmentally realistic concentration of CBZ can pose a serious threat to aquatic organisms.

Simple and effective removal of psychiatric pharmaceuticals from wastewater treatment plant effluents by magnetite red mud nanoparticles

Psychological disorders due to the COVID-19 pandemic have increased the consumption of psychiatric pharmaceuticals on a global scale in last year. These compounds reach wastewater treatment plants (WWTP) through sewerage system and are not sufficiently removed by using conventional treatment process. Psychiatric drugs released with WWTP effluent may cause possible risks to the receiving aquatic environment. Also, two antidepressants have been included in the "watch list" in 2020. Therefore, simple and relatively cost effective removal of psychiatric drugs from wastewaters becomes important. Magnetite red mud nanoparticles (RM-NPs) synthesized was applied for the removal of psychiatric drugs (fluoxetine, paroxetine, carbamazepine, diazepam, and lorazepam) in WWTP effluent first time in this study. The adsorption of carbamazepine as a model compound was fitted well with pseudo-second-order kinetic model. The Freundlich isotherm model better represented the sorption data than the Langmuir model. High adsorption capacity (90.5 mg/g) was reached at 30 min contact time at pH 6.5-7.0 at 25 °C. The adsorption rate was described by the pseudo second order model and its rate control mechanism was controlled by film diffusion. The magnetite RM-NPs were efficiently used for the removal of carbamazepine from real WWTP effluents. The adsorption capacity and the magnetic separability of the regenerated magnetite RM-NPs were unaffected five cycles. Due to its simple application, low cost and high adsorption capacity, magnetite RM-NPs can be recommended as a better adsorbent comparing to commercial adsorbents to remove psychiatric drugs from WWTP effluents.