Occurrence of Pharmaceutically Active Compounds and Potential Ecological Risks in Wastewater from Hospitals and Receiving Waters in Sri Lanka

Wastewater reuse and pharmaceutical pollution in agriculture: Uptake, transport, accumulation and metabolism of pharmaceutical pollutants within plants

The presence of pharmaceutical pollutants in water sources has become a growing concern due to its potential impacts on human health and other organisms. The physicochemical properties of pharmaceuticals based on their intended therapeutical application, which include antibiotics, hormones, analgesics, and antidepressants, is quite diverse. Their presence in wastewater, sewerage water, surface water, ground water and even in drinking water is reported by many researchers throughout the world. Human exposure to these pollutants through drinking water or consumption of aquatic and terrestrial organisms has raised concerns about potential adverse effects, such as endocrine disruption, antibiotic resistance, and developmental abnormalities. Once in the environment, they can persist, undergo transformation, or degrade, leading to a complex mixture of contaminants. Application of treated wastewater, compost, manures or biosolids in agricultural fields introduce pharmaceutical pollutants in the environment. As pharmaceuticals are diverse in nature, significant differences are observed during their uptake and accumulation in plants. While there have been extensive studies on aquatic ecosystems, the effect on agricultural land is more disparate. As of now, there are few reports available on the potential of plant uptake and transportation of pharmaceuticals within and between plant organs. This review summarizes the occurrence of pharmaceuticals in aquatic water bodies at a range of concentrations and their uptake, accumulation, and transport within plant tissues. Research gaps on pharmaceutical pollutants' specific effect on plant growth and future research scopes are highlighted. The factors affecting uptake of pharmaceuticals including hydrophobicity, ionization, physicochemical properties (pKa, logKow, pH, Henry's law constant) are discussed. Finally, metabolism of pharmaceuticals within plant cells through metabolism phase enzymes and plant responses to pharmaceuticals are reviewed.

A Review of the Dissemination of Antibiotic Resistance through Wastewater Treatment Plants: Current Situation in Sri Lanka and Future Perspectives

The emergence of antibiotic resistance (AR) poses a significant threat to both public health and aquatic ecosystems. Wastewater treatment plants (WWTPs) have been identified as potential hotspots for disseminating AR in the environment. However, only a limited number of studies have been conducted on AR dissemination through WWTPs in Sri Lanka. To address this knowledge gap in AR dissemination through WWTP operations in Sri Lanka, we critically examined the global situation of WWTPs as hotspots for transmitting antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) by evaluating more than a hundred peer-reviewed international publications and available national publications. Our findings discuss the current state of operating WWTPs in the country and highlight the research needed in controlling AR dissemination. The results revealed that the impact of different wastewater types, such as clinical, veterinary, domestic, and industrial, on the dissemination of AR has not been extensively studied in Sri Lanka; furthermore, the effectiveness of various wastewater treatment techniques in removing ARGs requires further investigation to improve the technologies. Furthermore, existing studies have not explored deeply enough the potential public health and ecological risks posed by AR dissemination through WWTPs.

Hidden ecotoxicological dangers: Investigating pathogen circulation and non-toxic risks hazards in a crucial brazilian watershed

Numerous studies evaluate chemical contaminants released by human activities and their effects on biota and aquatic ecosystems. However, few of these studies address non-toxic agents and their potentially harmful effects, which, in a concealed manner, culminate in an increased ecotoxicological risk for aquatic life and public health. This study investigated the presence of toxic and non-toxic pollutants in one of the main watersheds in Northeast Brazil (Rio São Francisco) and proposed a model of dispersion and transfer of resistance among the analyzed bacteria, also assessing the health risks of individuals and aquatic organisms present there. The results are worrying because although most toxic parameters, including physical-chemical and chromatographic aspects, comply with Brazilian environmental standards, non-toxic (microbiological) parameters do not. This research reveals the circulation of pathogens in several points of this hydrographic basin, highlighting the hidden ecotoxicological potential of an aquatic environment considered unaffected by the usual patterns of toxic parameters.

Unveiling combined ecotoxicity: Interactions and impacts of engineered nanoparticles and PPCPs

Emerging contaminants such as engineered nanoparticles (ENPs), pharmaceuticals and personal care products (PPCPs) are of great concern because of their wide distribution and incomplete removal in conventional wastewater and soil treatment processes. The production and usage of ENPs and PPCPs inevitably result in their coexistence in different environmental media, thus posing various risks to organisms in aquatic and terrestrial ecosystems. However, the existing literature on the physicochemical interactions between ENPs and PPCPs and their effects on organisms is rather limited. Therefore, this paper summarized the ecotoxicity of combined ENPs and PPCPs by discussing: (1) the interactions between ENPs and PPCPs, including processes such as aggregation, adsorption, transformation, and desorption, considering the influence of environmental factors like pH, ionic strength, dissolved organic matter, and temperature; (2) the effects of these interactions on bioaccumulation, bioavailability and biotoxicity in organisms at different trophic levels; (3) the impacted of ENPs and PPCPs on cellular-level biological process. This review elucidated the potential ecological hazards associated with the interaction of ENPs and PPCPs, and serves as a foundation for future investigations into the ecotoxicity and mode of action of ENPs, PPCPs, and their co-occurring metabolites.

Machine learning coupled with causal inference to identify COVID-19 related chemicals that pose a high concern to drinking water

Various synthetic substances were utilized in large quantities during the recent coronavirus pandemic, COVID-19. Some of these chemicals could potentially enter drinking water sources. Persistent, mobile, and toxic (PMT) substances have been recognized as a threat to drinking water resources. It has not yet been assessed how many COVID-19 related substances could be considered PMT substances. One reason is the lack of high-quality experimental data for the identification of PMT substances. To solve this problem, we applied a machine learning model to identify the PMT substances among COVID-19 related chemicals. The optimal model achieved an accuracy of 90.6% based on external test data. The model interpretation and causal inference indicated that our approach understood causation between PMT properties and molecular descriptors. Notably, the screening results showed that over 60% of the COVID-19 chemicals considered are candidate PMT substances, which should be prioritized to prevent undue pollution of water resources.

A review of hybrid enzymatic-chemical treatment for wastewater containing antiepileptic drugs

Epilepsy is one of the most common neurological diseases worldwide and requires treatment with antiepileptic drugs for many years or for life. This fact leads to the need for constant production and use of these compounds, placing them among the four pharmaceutical classes most found in wastewater. Even at low concentrations, antiepileptics pose risks to human and environmental health and are considered organic contaminants of emerging concern. Conventional treatments have shown low removal of these drugs, requiring advanced and innovative approaches. In this context, this review covers the results and perspectives on (1) consumption and occurrence of antiepileptics in water, (2) toxicological effects in aquatic ecosystems, (3) enzymatic and advanced oxidation processes for degrading antiepileptics drugs from a molecular point of view (biochemical and chemical phenomena), (4) improvements in treatment efficiency by hybridization, and (5) technical aspects of the enzymatic-AOP reactors.

Carbamazepine, venlafaxine, tramadol, and their main metabolites: Toxicological effects on zebrafish embryos and larvae

Pharmaceutical compounds and their metabolites are found in natural and wastewater. However, investigation of their toxic effects on aquatic animals has been neglected, especially for metabolites. This work investigated the effects of the main metabolites of carbamazepine, venlafaxine and tramadol. Zebrafish embryos were exposed (0.1-100 µg/L) for 168hpf exposures to each metabolite (carbamazepine-10,11-epoxide, 10,11-dihydrocarbamazepine, O-desmethylvenlafaxine, N-desmethylvenlafaxine, O-desmethyltramadol, N-desmethyltramadol) or the parental compound. A concentration-response relationship was found for the effects of some embryonic malformations. Carbamazepine-10,11-epoxide, O-desmethylvenlafaxine and tramadol elicited the highest malformation rates. All compounds significantly decreased larvae responses on a sensorimotor assay compared to controls. Altered expression was found for most of the 32 tested genes. In particular, abcc1, abcc2, abcg2a, nrf2, pparg and raraa were found to be affected by all three drug groups. For each group, the modelled expression patterns showed differences in expression between parental compounds and metabolites. Potential biomarkers of exposure were identified for the venlafaxine and carbamazepine groups. These results are worrying, indicating that such contamination in aquatic systems may put natural populations at significant risk. Furthermore, metabolites represent a real risk that needs more scrutinising by the scientific community.

Occurrence and the potential ecological risk of veterinary antimicrobials in swine farm wastewaters in Japan: Seasonal changes, relation to purchased quantity and after termination of oxytetracycline usage

This study provides the first comprehensive investigation of the residual concentrations of eight classes of antimicrobial agents (AMs, 20 compounds) in 13 swine wastewater treatment facilities in Japan. These facilities implemented the aerobic activated sludge (AS) or its alternative methods. The maximum concentrations before treatment were found at the level of 7100, 6900, 6000, 3600, 3400, and 1400 µg/L for tilmicosin, oxytetracycline (OTC), chlortetracycline, lincomycin , sulfamethoxazole, and trimethoprim, respectively. The highest detection rate (96.3%) in influents was noted for the morantel, which was a feed additive. The seasonal difference in residual concentration was much greater for tetracyclines (TCs) and macrolides (MLs) when their residual concentrations were high, especially in the cold season. There was a positive correlation between the purchased quantity of TCs and fluoroquinolones (FQs) and their residue levels detected in the effluents (p < 0.01). The estimated removal rate of AMs was greater than 80%. In contrast, on a few occasions, it was diminished due to failing operating conditions, such as water temperature and AS rate in the aeration tank. The estimated ecological risks of AMs in effluents based on risk quotients (RQs) considered to enhance the selection pressure for drug resistance (RQs-AMR) were high for TCs and FQs, whereas ecotoxicological effects (RQs-ENV) to aquatic organisms were higher for sulfonamides and MLs. When OTC usage ceased, its concentration in wastewater decreased rapidly; however, it remained longer period in the effluents, probably due to OTC desorption from the AS. The concentrations (and respective RQs) of TCs were decreased by >99.8% and >92% in the influents and effluents, respectively. This data suggested that it is essential to reduce the amount used and introduce more efficient methods and operating conditions to constantly remove AMs during the treatment to reduce the risk of AM discharge from swine farms.

Occurrence and risk assessment of pharmaceuticals in surface waters of the Middle East and North Africa: A review

Pharmaceutical compounds in surface water are perceived as contaminants of emerging concern due to their impacts on the aquatic environment and human health. The risk associated with these compounds has not been quantified in the Middle East and North Africa (MENA). This review identified that 210 pharmaceutical compounds have been analyzed in MENA water compartments between 2008 and 2022. In fact, 151 of these substances were detected in at least one of 13 MENA countries where occurrence studies had been conducted. Antibiotics claimed the highest number of pharmaceuticals detected with concentrations ranging between 0.03 and 66,400 ng/L (for Thiamphenicol and Spiramycin respectively). To investigate whether any of these compounds exert an ecological, human health, or antibiotic resistance risk, a screening-level risk assessment was performed in surface water matrices using maximum, median, and minimum concentrations. 39 and 8 detected pharmaceuticals in MENA surface waters posed a possible risk on aquatic ecosystems and human health respectively. Extremely high risk quotients (>1000) for six pharmaceuticals (17β estradiol, spiramycin, diclofenac, metoprolol, ethinylestradiol, and carbamazepine) were enumerated based on maximal concentrations implying an alarming risk on aquatic toxicity. Moreover, hormones posed the highest possible risk on human health whether ingested through drinking water or fish (e.g., 17β-estradiol had a health risk quotient of 2880 for children). Spiramycin showed a high risk of antibiotic resistance with a risk quotient of 133. This review serves as a basis for future prioritization studies and regulatory guidelines in the MENA region to minimize the risks of the identified compounds.

Solution blow spinning polysulfone-Aliquat 336 nanofibers: synthesis, characterization, and application for the extraction and preconcentration of losartan from aqueous solutions

Nanofibers are materials used in a wide range of applications due to their unique physicochemical properties. As an alternative to the most common method of its manufacturing (electrospinning) blow spinning has been used since it has greater production efficiency and simplicity. A wide variety of polymers is used for its preparation and can be modified to improve the interaction and selectivity toward specific analytes. Thereby nanofibers have been used for the extraction or removal of organic compounds such as drugs but there are still few reports of drug extractions like losartan. In this work polysulfone-Aliquat 336 nanofibers were prepared using the blow spinning method to extract and preconcentrate losartan. The studies showed that Aliquat 336 incorporation significantly improve the extraction of losartan with polysulfone fibers. Adsorption process was thermodynamically favorable with an adsorption capacity of 15.45 mg·g−1. Thus, it was possible to extract more than 92% of initial losartan using 10 mg of polysulfone-Aliquat 336 fibers (9 and 3.5% (w/v)), at pH 6 from deionized water and synthetic wastewater. Finally, losartan preconcentration was evaluated to facilitate its quantification using ultraviolet–visible spectrometry (UV-Vis), which allowed the determination of this drug at concentrations below the detection limit.