Re-designing environmentally persistent pharmaceutical pollutant through programmed inactivation: The case of methotrexate

Municipal wastewater as an ecological trap: Effects on fish communities across seasons

Contamination of aquatic ecosystems by microplastics (MPs) is mainly due to the release of high levels of MP particles from treated effluents by wastewater treatment plants (WWTPs). Due to the lack of policies and regulations establishing criteria for the control and elimination of MPs from WWTP effluents, this research evaluates the presence of 38 and 150 µm MPs in influents and effluents from three WWTPs in the port of Acapulco, Mexico. Optical microscopy and Fourier transform infrared spectroscopy revealed that the MPs were polyethylene, polypropylene, polyethylene terephthalate, and polyvinyl chloride. MP removal efficiencies of 82.5–98.7% (38 µm) and 86.8–97.5% (150 µm) were achieved. Moreover, the MP average daily emissions to the receiving bodies of the three WWTPs ranged from 9.5 × 106 to 4.70 × 108 particles, while the annual emissions ranged from 3.05 × 109 to 1.72 × 1011 particles. This work reveals the urgency of implementing regulatory policies to avoid the continuous emission of MPs into aquatic ecosystems from WWTPs in Acapulco, Mexico.

Are environmental levels of gabapentin (GBP) a cause for concern? Chronic reproductive effects of GBP in zebrafish.

Pharmaceutical residues are not completely removed in wastewater treatment plants (WWTPs) becoming contaminants in aquatic ecosystems. Thereby, it is important to investigate their concentrations in the environment and the possible consequences of their occurrence, including for human health. Here, we briefly reviewed the paths of pharmaceuticals to reach the environment, their behavior and fate in the environment, and the possible consequences of their occurrence. Moreover, we synthetized all the studies about the detection of pharmaceuticals in Brazilian water bodies and the available ecotoxicological knowledge on their effects. In this study, when we compare the data found on these compounds worldwide, we observed that Brazilian surface waters present considerable concentrations of 17α-ethinylestradiol, 17β-estradiol, and caffeine. In general, concentrations found in aquatic systems worldwide seems to be low; however, ecotoxicological tests showed that even these low concentrations can cause sublethal effects in biota. The knowledge about the effects of continuous exposure and mixtures is sparse. In summary, new research is urgently required about the effects of these compounds in biota-including long-term exposition and mixture tests-and on specific technologies to remove these compounds in water bodies and WWTPs, besides the introduction of new policies for pharmaceutical use.

Pharmaceutical and personal care products (PPCPs) are increasingly recognized as emerging contaminants in aquatic ecosystems due to their persistence, bioaccumulation potential, and adverse effects on both human health and aquatic life. In Malaysia, particularly in the state of Selangor, the rapid growth in population and healthcare demand has led to rising pharmaceutical consumption and subsequent contamination of surface water, tap water, and drinking water sources. Recent studies have detected compounds such as diclofenac, triclosan, ciprofloxacin, caffeine, and sulfamethoxazole in local water bodies, with concentrations often exceeding those reported in developed countries such as Australia and Taiwan. This trend highlights the inefficiency of conventional wastewater treatment plants (WWTPs) in removing pharmaceutical residues. The persistence of these contaminants poses potential health risks, including antibiotic resistance, endocrine disruption, and long-term toxicity to aquatic organisms and humans. Current treatment technologies in Malaysia, including adsorption, bioremediation, and activated sludge systems, have shown partial removal efficiency but remain inadequate for complete elimination of PPCPs. To address this limitation, emerging research recommends integrating hybrid treatment systems that combine biological and physicochemical processes to enhance contaminant removal efficiency. The aim of this study is to assess the occurrence and distribution of pharmaceutical contaminants in Selangor’s aquatic system, evaluate their potential risks, and discuss the limitations of existing wastewater treatment technologies while proposing sustainable alternatives for improved water quality management. Overall, the findings emphasize the urgent need for policy revision, technological innovation, and stricter monitoring to safeguard public health and environmental integrity in Malaysia.

Anticancer drugs (ADs) have been detected in the environment and represent a risk to aquatic organisms, necessitating AD removal in drinking water and wastewater treatment. In this study, ozonation of the most commonly used antimetabolite ADs, namely 5-fluorouracil (5-FU) and its prodrug capecitabine (CAP), was investigated to determine reaction kinetics, oxidation mechanisms, and residual toxicity. The specific second-order rate constants between aqueous ozone and 5-FU, 5-FU−, 5-FU2−, CAP, and CAP− were determined to be 7.07(±0.11)×104 M−1·s−1, 1.36(±0.06)×106 M−1·s−1, 2.62(±0.17)×107 M−1·s−1, 9.69(±0.08)×103 M−1·s−1, and 4.28(±0.07)×105 M−1·s−1, respectively; furthermore, the second-order rate constants for •OH reaction with 5-FU and CAP at pH 7 were determined to be 1.85(±0.20)×109 M−1·s−1 and 9.95(±0.26)×109 M−1·s−1, respectively. Density functional theory was used to predict the main ozone reaction sites of 5-FU (olefin) and CAP (olefin and deprotonated secondary amine), and these mechanisms were supported by the identified transformation products. Carboxylic acids constituted a majority of the residual organic matter for 5-FU ozonation; however, carboxylic acids and aldehydes were important components of the residual organic matter generated by CAP. Ozone removed the toxicity of 5-FU to Vibrio fischeri, but the residual toxicity of ozonated CAP solutions exhibited an initial increase before subsequent removal. Ultimately, these results suggest that ozone is a suitable technology for treatment of 5-FU and CAP, although the residual toxicity of transformation products must be carefully considered.

The elimination of the pesticide imazalil (IMZ) spiked into ultrapure water as well as into wastewater applying ozone (O3) and the identification of transformation products was investigated. O3 under hydroxyl radical suppression conditions reacted rapidly with the aliphatic double bond or the imidazole ring in IMZ, yielding several transformation products by partial oxidation. The structures of four oxidation products not yet described were characterized and identified after liquid chromatography coupled with high resolution, high mass accuracy, mass and tandem mass spectrometry (LC/MS and -MSn) in ultrapure water. For two identified transformation products, generated via direct ozone attack on IMZ, formation pathways were proposed. In wastewater, only two of those transformation products were observed. Kinetics studies for the reaction of IMZ with O3, evaluated by the competition kinetic method, resulted in a second-order rate constant kO3,IMZ ∼ (1.02 ± 0.03) × 105 M−1 s−1 at pH 6.6 ± 0.2, indicating that IMZ is completely transformed during the ozonation process. Tests of acute toxicity were performed applying a solution of IMZ in ultrapure water or treated wastewater to Daphnia magna. In both cases the decrease of toxicity was observed after ozone treatment.

The present study addressed the dissipation of the insecticidechlorantraniliprole in tomatoes treated with Altacor 35 WG under laboratoryand greenhouse conditions, as well as the identification of transformationproducts (TPs) and coformulants, performing suspect screening analysis.Analyses were performed by ultra-high-performance liquid and gas chromatographycoupled to quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap-MSand GC-Q-Orbitrap-MS). In all cases, chlorantraniliprole was fittedto a biphasic kinetic model, with R2 valuesgreater than 0.99. Dissipation was noticeably faster in greenhousestudies, in which even 96% dissipation was achieved over 53 days.One TP, IN-F6L99, was tentatively identified in both greenhouse andlaboratory studies and was semiquantified by using chlorantraniliproleas the analytical standard, yielding a top value of 354 μg/kgfor laboratory studies, whereas values for greenhouse studies fellunder the limit of quantitation (LOQ). Finally, a total of 15 volatilecoformulants were identified by GC-Q-Orbitrap-MS.

Abiotic oxidative transformation of 6-PPD and 6-PPD quinone from tires and occurrence of their products in snow from urban roads and in municipal wastewater

Aerobic activated sludge transformation of methotrexate: Identification of biotransformation products

Enhanced degradation of para-nitrophenol during the UV/chlorine process with the addition of Fe(III): Performance, reaction mechanisms, and DBPs formation

Revealing the underestimated risks of pharmaceutical transformation products in wastewater by suspect and targeted screening.

ABSTRACTPharmaceutical pollutants in aquatic environments have become a growing concern worldwide due to their persistence and potential ecological and human health impacts. In Malaysia, the rapid expansion of urban areas, increasing population, and rising healthcare demands have contributed to the growing influx of pharmaceutical pollutants into water bodies. These pollutants, including antibiotics, analgesics, and hormones, enter aquatic ecosystems primarily through wastewater discharge, agricultural runoff, and improper disposal of unused medications. The Malaysian water treatment infrastructure, designed to target conventional pollutants, often fails to adequately remove these pharmaceutical pollutants, leading to their accumulation in rivers, lakes, and coastal waters. This review explores the current state of pharmaceutical pollution in Malaysia's aquatic environments, focusing on the sources, types, and concentrations of pharmaceuticals detected in surface and wastewater systems. Additionally, the study investigates the ecological impacts, particularly on aquatic organisms, and the potential for bioaccumulation and trophic transfer, which could affect both wildlife and human populations. Existing mitigation efforts, such as policy initiatives, advancements in wastewater treatment technologies, and public awareness campaigns, are also discussed. However, significant challenges remain regarding regulatory enforcement and the need for more effective, cost‐efficient removal technologies. This paper highlights the urgency of addressing pharmaceutical pollutants in Malaysia's aquatic systems. It suggests avenues for future research, including advanced treatment solutions and collaborative policy frameworks, to safeguard the environment and public health from these emerging contaminants.

This study investigates the remarkable potential of living Mixed Indigenous Microalgae (MIMA) for mercury bioremediation in aquatic environments at environmentally relevant concentrations (10-100μg/L). Our research demonstrates high mercury removal efficiency (89-94%) across all tested concentrations, with rapid kinetics achieving equilibrium within just 2min of contact time. The maximum biosorption capacity reached 0.10mg/g at 100μg/L initial concentration. Notably, MIMA maintained both viability and removal efficiency when exposed to Hg for 3 days without any addition of nutrients suggesting resilience under nutrient-limited conditions. Comprehensive isotherm analysis revealed the Dubinin-Radushkevich model provided the best fit (R2=0.998), indicating physical adsorption as the predominant mechanism, as the calculated mean free energy (E=5.00kJ/mol) falls within the 1-8kJ/mol range characteristic of physical adsorption. Kinetic studies showed superior correlation with the pseudo-second-order model (R2>0.996), with rate constants decreasing systematically from 767.5 to 216.0g/mg·min as concentration increased, suggesting secondary chemical interactions may also contribute to the overall mechanism. Advanced characterization revealed significant surface modifications, with Scanning Electron Microscopy (SEM) showing increased surface roughness, Fourier Transform Infrared Spectroscopy (FTIR) indicating involvement of hydroxyl, protein, and carbohydrate functional groups, and X-ray Photoelectron Spectroscopy (XPS) confirming Hg(II) binding to oxygen-containing moieties with distinctive Hg 4f peaks at 101.78 and 105.8eV. Optical microscopy revealed the formation of sudden spherical-shell boundaries around individual cells providing visual evidence of an immediate physico-chemical response at the cell-mercury interface, correlating with the observed rapid kinetics. This research addresses critical knowledge gaps regarding living microalgae-mediated mercury removal and demonstrates MIMA's potential as a sustainable, efficient solution for mercury contamination in aquatic ecosystems, maintaining viability even under nutrient-limited conditions while effectively reducing mercury concentrations to near guideline values at the lowest initial level (10μg/L).

Gabapentin is a drug used to treat epilepsy and peripheral neuropathic pain. It is an analog of gamma-aminobutyric acid, and it is a selective blocker of voltage-gated calcium channels. The drug is excreted unmetabolized; it is stable in the environment and is classified as a persistent mobile organic contaminant. Because wastewater treatment plants (WWTPs) are not completely efficient, some bioactive molecules may be released unaltered into the environment. The aim of this study was to provide information about degradation pathways of gabapentin in water by studying its photoinduced transformation products (TPs) through laboratory simulation experiments. Gabapentin and its TPs were monitored in influent and effluent water samples from WWTPs in Germany and Italy. The laboratory simulation used heterogeneous photodegradation mediated by titanium dioxide (TiO2 ). Chromatographic separation was achieved using a C18 reverse-phase column, and the structural identification of TPs was performed using high-resolution electrospray ionization high-resolution mass spectrometry (ESI-HRMS) and multistage MSn experiments. Several TPs were observed during TiO2 photodegradation. Nine new compounds were detected, and potential structures were assigned by studying the fragmentation pathways of the [M + H]+ ions of these TPs and gabapentin. Gabapentin and some of the newly identified TPs were found in environmental samples from WWTPs. The developed high-performance liquid chromatography/high-resolution mass spectrometry method was used to identify TPs from gabapentin. It was then successfully applied to real environmental samples to monitor the TPs as potential environmental pollutants.