The presence of microplastics in freshwater systems can have harmful effects on the food chain. Zooplankton, especially suspension and filter feeders, can ingest microplastics, which can cause adverse effects and transfer them to higher trophic levels. Here, we analyze the presence, abundance, and distribution of microplastics in surface water, zooplankton, and fish in two tropical lakes in central Mexico. We collected water samples in triplicate at three sites in each lake and 120 fish of the genus Chirostoma. From each water sample, 300 rotifers and 150 microcrustaceans were randomly isolated and processed independently. Of the particles found in the water, zooplankton, and fish from both lakes, the fragments were the predominant ones. The total abundance of microplastics in the water column of both lakes varied between 1.2 and 17.0 items L-1. In zooplankton, fragments were found predominantly with up to 0.1 items ind-1, while in fish, up to 4.5 items ind-1 was recorded. Our results confirm the presence of microplastics in different compartments of the food webs of freshwater bodies, water column, zooplankton, and fish. Further work is required on the possible effects of these stressors at the different trophic levels.

Microplastic contamination is a burgeoning environmental issue that poses serious threats to animal and human health. Microplastics enter the human body through nasal, dermal, and oral routes to contaminate multiple organs. Studies have advocated the existence of microplastics in human breast milk, sputum, faeces, and blood. Microplastics can find their ways to the sub-cellular moiety via active and passive approaches. At cellular level, microplastics follow clathrin and caveolae-dependent pathways to invade the sub-cellular environment. These environmental contaminants modulate the epigenetic control of gene expression, status of inflammatory mediators, redox homeostasis, cell-cycle proteins, and mimic the endocrine mediators like estrogen and androgen to fuel carcinogenesis. Furthermore, epidemiological studies have suggested potential links between the exposure to microplastics and the onset of chronic diseases. Microplastics trigger uncontrolled cell proliferation and ensuing tissue growth leading to various cancers affecting the lungs, blood, breasts, prostate, and ovaries. Additionally, such contamination can potentially affect sub-cellular signaling and injure multiple organs. In essence, numerous reports have claimed microplastic-induced toxicity and tumorigenesis in human and model animals. Nonetheless, the underlying molecular mechanism is still elusive and warrants further investigations. This review provides a comprehensive analysis of microplastics, covering their sources, chemistry, human exposure routes, toxicity, and carcinogenic potential at the molecular level.

Biological methods do not effectively remove pharmaceutical products (PPs) and antibiotic resistance genes (ARGs) from wastewater at low temperatures, leading to environmental pollution. Therefore, anaerobic-aerobic-coupled upflow bioelectrochemical reactors (AO-UBERs) were designed to improve the removal of PPs at low temperatures (10 ± 2 °C). The result shows that diclofenac (DIC) and ibuprofen (IBU) removals in the system with aerobic anodic and anaerobic cathodic chambers were 91.7% and 94.7%, higher than that in the control system (12.2 ± 1.5%, 36.5 ± 5.9%), and aerobic zone favors DIC and IBU removal; fluoroquinolone antibiotics (FQs) removals in the system with aerobic cathodic and anaerobic anodic chambers were 17.5-22.4% higher than that in the control system (9.1-22.4%), and anaerobic zone favors FQs removal. Analysis of microbial community structure and ARGs showed that different electrotrophic microbes (Flavobacterium, Acinetobacter, and Delftia) with cold-resistant ability to degrade PPs were enriched in different electrode combinations, and the aerobic cathodic chambers could remove certain ARGs. These results showed that AO-UBERs under intermittent electrical stimulation mode are an alternative method for the effective removal of PPs and ARGs at low temperatures.

Nitrogen-doped biochar as Fenton-like catalysts has been widely used to remove emerging pollutants in wastewater. However, the effect of in-situ and ex-situ nitrogen doping on the Fenton-like catalytic activity of biochar is unclear. In this study, the nitrogen-doped biochar was prepared by in-situ (NBC) and ex-situ (BC-N) nitrogen doping, and the Fenton-like catalytic activity of NBC and BC-N was compared for activating hydrogen peroxide (H2O2), peroxydisulfate (PDS) and peroxymonosulfate (PMS). The results showed that NBC had higher Fenton-like catalytic activity than BC-N, because the formation of carbon quantum dots (CQDs) significantly increased the adsorption capacity to H2O2, PDS and PMS. NBC could activate H2O2, PDS and PMS for degradation of sulfamethoxazole (SMX), but showed different catalytic activity and degradation mechanism. In the systems of NBC/H2O2 and NBC/PDS, CQDs played a key role in the activation of H2O2 and PDS, and surface-bound reactive species were mainly responsible for SMX degradation. In the system of NBC/PMS, NBC acted as both electron mediator and activator, direct electron transfer between PMS and SMX and surface-bound reactive species contributed to SMX degradation. This study provides an insight into the catalytic activity of NBC for H2O2, PDS and PMS.

This study investigates the current situation and possible health risks due to pharmaceutically active compounds (PhACs) including analgesics, antibiotics, antifungals, anti-inflammatories, psychiatric and cardiovascular drugs, and metabolites, in indoor environments. To achieve this objective, a total of 85 dust samples were collected in 2022 from three different Spanish indoor environments: homes, classrooms, and offices. The analytical method was validated meeting SANTE/2020/12830 and SANTE/12682/2019 performance criteria. All indoor dust samples except one presented at least one PhAC. Although concentration levels ranged from < LOQ to 18 µg/g, only acetaminophen, thiabendazole, clotrimazole, and anhydroerythromycin showed quantification frequencies (Qf %) above 19% with median concentrations of 166 ng/g, 74 ng/g, 25 ng/g and 14 ng/g, respectively. The PhAC distribution between dust deposited on the floor and settled on elevated (> 0.5 m) surfaces was assessed but no significant differences (p > 0.05, Mann-Whitney U-test) were found. However, concentrations quantified at the three types of locations showed significant differences (p < 0.05, Kruskal-Wallis H-test). Homes turned out to be the indoor environment with higher pharmaceutical concentrations, especially acetaminophen (678 ng/g, median). The use of these medicines and their subsequent removal from the body were identified as the main PhAC sources in indoor dust. Relationships between occupant habits, building characteristics, and/or medicine consumption and PhAC concentrations were studied. Finally, on account of concentration differences, estimated daily intakes (EDIs) for inhalation, ingestion and dermal adsorption exposure pathways were calculated for toddlers, adolescents and adults in homes, classrooms and offices separately. Results proved that dust ingestion is the main route of exposure, contributing more than 99% in all indoor environments. Moreover, PhAC intakes for all studied groups, at occupational locations (classrooms and offices) are much lower than that obtained for homes, where hazard indexes (HIs) obtained for acetaminophen (7%-12%) and clotrimazole (4%-7%) at the worst scenario (P95) highlight the need for continuous monitoring.

Contamination with traces of pharmaceutical compounds, such as ciprofloxacin, has prompted interest in their removal via low-cost, efficient biomass-based adsorption. In this study, classical models, a mechanistic model, and a neural network model were evaluated for predicting ciprofloxacin breakthrough curves in both laboratory- and pilot scales. For the laboratory-scale (d = 2.2 cm, Co = 5 mg/L, Q = 7 mL/min, T = 18 °C) and pilot-scale (D = 4.4 cm, Co = 5 mg/L, Q = 28 mL/min, T = 18 °C) setups, the experimental adsorption capacities were 2.19 and 2.53 mg/g, respectively. The mechanistic model reproduced the breakthrough data with high accuracy on both scales (R2 > 0.4 and X2 < 0.15), and its fit was higher than conventional analytical models, namely the Clark, Modified Dose-Response, and Bohart-Adams models. The neural network model showed the highest level of agreement between predicted and experimental data with values of R2 = 0.993, X2 = 0.0032 (pilot-scale) and R2 = 0.986, X2 = 0.0022 (laboratory-scale). This study demonstrates that machine learning algorithms exhibit great potential for predicting the liquid adsorption of emerging pollutants in fixed bed.

In this study, laboratory-scale cultivation of T. chuii and D. tertiolecta was conducted using Conway, F/2, and TMRL media to evaluate their biochemical composition and economic costs. The highest cell density (30.36 × 106 cells/mL) and dry weight (0.65 g/L) for T. chuii were achieved with Conway medium. This medium also produced biomass with maximum lipid content (25.65%), proteins (27.84%), and total carbohydrates (8.45%) compared with F/2 and TMRL media. D. tertiolecta reached a maximum cell density of 17.50 × 106 cells/mL in F/2 medium, which was notably lower than that of T. chuii. Furthermore, the media cost varied from US$0.23 to US$0.74 for each 1 L of media, primarily due to the addition of Na3PO4, KNO3, and cyanocobalamin. Thus, biomass production rates varied between US$38.81 and US$128.80 per kg on a dry weight basis. These findings comprehensively compare laboratory conditions and the costs associated with biomass production in different media. Additionally, this study explored the potential of T. chuii and D. tertiolecta strains, as well as their consortia with bacteria, for the degradation of various emerging pollutants (EPs), including caffeine, salicylic acid, DEET, imidacloprid, MBT, cimetidine, venlafaxine, methylparaben, thiabendazole, and paracetamol. Both microalgal strains demonstrated effective degradation of EPs, with enhanced degradation observed in microalgae-bacterial consortia. These results suggest that the symbiotic relationship between microalgae and bacteria can be harnessed for the bioremediation of EPs, thereby offering valuable insights into the environmental applications of microalgal cultivation.

Microplastics are emerging sources of environmental pollutants that are increasingly of concern because of their harmful impacts on aquatic life and thereby humans. Their accumulation in the environment is in direct proportion to global plastic production; their being nondegradable, recalcitrant and of a persistent nature creates an urgent need to address this issue on a global scale. Recent reports have demonstrated the presence of microplastics in marine life, and directly becoming a part of the food chain when seafood is ingested by humans. The repercussions of these studies point to an even larger scale presence of microplastics across varied habitats, which are yet to be sampled. Bioremediation, using various microorganisms such as bacteria, algae and fungi, alone or as consortia or in biofilm form can be used as an effective remediation tool. Genetically modified microorganisms for focused removal of microplastics and metagenomics studies, providing taxonomic details of uncultured organisms, are also expected to provide an additional catalogue of technologies in this field. This review offers a comprehensive overview of microplastic sources, existing technologies for treating microplastics and an in-depth analysis of bioremediation mechanisms, its components, and the results from various studies which provide sufficient clues as to the directions to be chosen to address microplastics pollution and can facilitate and instruct researchers to further investigate the more practical approaches and create new and innovative strategies for advanced remediation of microplastic in the future.

BACKGROUND: Several countries\' most incorrectly discarded medicines are acetaminophen (ACM), metamizole (MTZ), and nimesulide (NMS). These xenobiotics easily reach the aquatic environment; such contamination is very important for the health of humans and other species, yet little explored.
OBJECTIVE: To evaluate the cocktail effect of ACM, MTZ, and NMS during zebrafish\'s initial development.
METHODS: Zebrafish embryos 6-8 h post-fertilization (hpf) were exposed to different concentrations of ACM, MTZ, and NMS, separately, to obtain the 50% lethal concentrations (LC50). Next, the embryos were exposed to distinct concentrations of the cocktail (LC50/2, LC50/5, LC50/10, and LC50/20) in a semi-static system. Samples were analyzed 0, 24, 48, and 96 h after exposure, and the drugs\' concentrations in E3 medium were assessed by high-performance liquid chromatography. For embryotoxicity evaluation, the mortality, hatching, and heart rates; total length; and pericardial and yolk sac areas were determined. In addition, body malformations, edemas, presence of pigmentation, and histopathological assessments were also recorded.
RESULTS: The LC50 values obtained for MTZ, ACM, and NMS were 4.69 mgmL-1, 799.98 μgmL-1, and 0.92 μgmL-1, respectively. No difference was observed between the drugs\' nominal and observed concentrations at each time point. The cocktail significantly induced mortality and decreased hatching in the LC50/10, LC50/5, and LC50/2 groups. Additionally, body malformations, pigmentation loss, and yolk sac and pericardial edemas were observed in the cocktail groups. The cocktail groups\' larvae had decreased total length and slower heart rates compared to the controls (p < 0.05). The histopathological assessment showed that yolk sac edema promoted severe histological changes in the esophageal-intestine junction and intestine in larvae treated with cocktails. Moreover, PAS-positive structures decreased in the esophageal-intestine junction, intestine, and liver in larvae exposed to pharmaceutical cocktails.
CONCLUSIONS: This study\'s findings suggest the cocktail of ACM, MTZ, and NMS may be hazardous to aquatic organisms in case of environmental contamination.