Effects of effluent from a hospital in Mexico on the embryonic development of zebrafish, Danio rerio

Priority list of pharmaceutical active compounds in aquatic environments of Mexico considering their occurrence, environmental and human health risks

Pharmaceutical active compounds (PhACs) are detected pollutants in aquatic environments worldwide at concentrations ranging from ng L-1 to µg L-1. Currently, PhAC monitoring is poorly realized in Mexico. This study proposes a priority list of PhACs in Mexican aquatic environments, considering their occurrence and environmental and human health risks. Ecological risks were assessed as Risk Quotients (RQ) values using the PhAC concentrations detected in surface water, obtaining high risks (RQ > 1) against aquatic organisms, especially of naproxen, ibuprofen, diclofenac, acetaminophen, 17β-estradiol, carbamazepine, ketoprofen, caffeine. In contrast, potential human health risks (RQH) were assessed on the Mexican population using the concentrations quantified in groundwater, demonstrating potential risks (RQH > 0.2) on the population, particularly of DCF and CBZ. Thus, a priority list of PhACs can be used as a reference for environmental monitoring in Mexican water supplies as well as PhACs monitoring in countries of the Caribbean region and Central America.

Occurrence of emerging organic contaminants and endocrine disruptors in different water compartments in Mexico - A review

This review compiles the studies (2007-2021) regarding the occurrence of emerging organic contaminants (EOCs) and endocrine disruptors (EDs) in wastewater, surface water and groundwater in Mexico. A total of 174 compounds were detected, including pharmaceuticals, hormones, plasticizers, personal care products, sweeteners, drugs, and pesticides considered as EDs. The levels of EOCs and EDs varied from ng/L to 140 mg/L, depending on the compound, location, and compartment. Raw wastewater was the most studied matrix, showing a greater abundance and number of detected compounds. Nevertheless, surface waters showed high concentrations of bisphenol-A, butylbenzil-phthalate, triclosan, pentachlorophenol, and the hormones estrone, 17 α-ethinylestradiol, and 17 β-estradiol, which exceeded the thresholds set by international guidelines. Concentrations of 17 α-ethinylestradiol and triclosan exceeding the above-mentioned limits were reported in groundwater. Cropland irrigation with raw wastewater was the principal activity introducing EOCs and EDs into groundwater. The groundwater abundance of EOCs was considerably lesser than that of wastewater, highlighting the attenuation capacity of soils/aquifers during wastewater infiltration. However, carbamazepine and N,N-diethyl-meta-toluamide showed higher concentrations in groundwater than those in wastewater, suggesting their accumulation/concentration in soils/pore-waters. Although the contamination of water resources represents one of the most environmental concerns in Mexico, this review brings to light the lack of studies on the occurrence of EOCs in Mexican waters, which is important for public health policies and for developing legislations that incorporates EOCs as priority contaminants in national water quality guidelines. Consequently, the development of legislations will support regulatory compliance for wastewater and drinking water, reducing the human exposure.

Synthesis and Use of Silica Xerogels Doped with Iron as a Photocatalyst to Pharmaceuticals Degradation in Water

The main objective of this study was to assess the photoactive properties of iron-doped silica xerogels under solar radiation. For this purpose, silica xerogels (XGS) synthesized by the sol-gel method were doped with Fe (III) by two routes: impregnation and polymerization. XGS samples were texturally and chemically characterized by N2 adsorption, XRD, FTIR, Raman, SEM-EDX, DRS, and PL, evidencing the suitability of using XGS substrates to host iron clusters on their surface with total compatibility. Chlorphenamine (CPM), ciprofloxacin (CIP), and ranitidine (RNT) were used as model compounds. The degradation of the molecules was made under simulated solar radiation testing the synthesis pad, load, material size, and reuse. It was found that XGS doped with Fe by the impregnation route (XGS-Fe-Im) were able to completely degrade CPM and RNT in 30 min and 10 min, respectively, whilst for CIP it achieved the removal of 60% after 1 h of solar radiation exposure, outperforming parent materials and solar radiation by itself. The study of the degradation mechanism elucidated a major influence from the action of HO• radicals. The present investigation offers a potential route of application of XGS Fe-doped materials for the removal of emerging concern contaminants under near real-world conditions.

A Review of the Presence of SARS-CoV-2 in Wastewater: Transmission Risks in Mexico

The appearance of SARS-CoV-2 represented a new health threat to humanity and affected millions of people; the transmission of this virus occurs through different routes, and one of them recently under debate in the international community is its possible incorporation and spread by sewage. Therefore, the present work's research objectives are to review the presence of SARS-CoV-2 in wastewater throughout the world and to analyze the coverage of wastewater treatment in Mexico to determine if there is a correlation between the positive cases of COVID-19 and the percentages of treated wastewater in Mexico as well as to investigate the evidence of possible transmission by aerosol sand untreated wastewater. Methodologically, a quick search of scientific literature was performed to identify evidence the presence of SARS-CoV-2 RNA (ribonucleic acid) in wastewater in four international databases. The statistical information of the positive cases of COVID-19 was obtained from data from the Health Secretary of the Mexican Government and the Johns Hopkins Coronavirus Resource Center. The information from the wastewater treatment plants in Mexico was obtained from official information of the National Water Commission of Mexico. The results showed sufficient evidence that SARS-CoV-2 remains alive in municipal wastewater in Mexico. Our analysis indicates that there is a low but significant correlation between the percentage of treated water and positive cases of coronavirus r = -0.385, with IC (95%) = (-0.647, -0.042) and p = 0.030; this result should be taken with caution because wastewater is not a transmission mechanism, but this finding is useful to highlight the need to increase the percentage of treated wastewater and to do it efficiently. In conclusions, the virus is present in untreated wastewater, and the early detection of SAR-CoV-2 could serve as a bioindicator method of the presence of the virus. This could be of great help to establish surveillance measures by zones to take preventive actions, which to date have not been considered by the Mexican health authorities. Unfortunately, wastewater treatment systems in Mexico are very fragile, and coverage is limited to urban areas and non-existent in rural areas. Furthermore, although the probability of contagion is relatively low, it can be a risk for wastewater treatment plant workers and people who are close to them.

Application of Ultrasonic Intelligent Imaging in L-Selectin Regulating Embryo Implantation in Mongolian Sheep Endometrium

In order to explore the practical application of ultrasonic imaging in the pregnancy stage of Mongolian sheep and the role of L-selectin in the embryo implantation process of Mongolian sheep, this paper systematically observed the early embryonic development by B-mode ultrasonic imaging wave diagnostic instrument with 5 MHz rectal probe and detected the expression of sLex and L-selectin in embryonic cells (jar cells) and endometrial cells (RL95-2 cells) by immunoassay to show the role of L-selectin in embryonic adhesion. The results were as follows: the correct rate of fetal sex determination by ultrasound imaging increased with the increase of pregnancy days and reached 93% at 84 days; sLex/L-selectin on the surface of Jar/RL95-2 cells is involved in the adhesion between embryo and endometrium; and when the concentration of L-selectin was 30 μg/ml, the implantation success rate of fertilized eggs and embryos was the highest, reaching 95%. It is proved that ultrasonic intelligent imaging exploration can summarize the imaging characteristics of the early development law of sheep fetus, which provides a basis for B-ultrasound to monitor fetal growth and predict fetal age. While discussing the molecular mechanism of implantation, it provides a new idea and means for the clinical intervention of contraception and pregnancy assistance with oligosaccharide as the target.

Revealing the toxicity of lopinavir- and ritonavir-containing water and wastewater treated by photo-induced processes to Danio rerio and Allivibrio fischeri

In coronavirus disease 2019 (COVID-19), among many protocols, lopinavir and ritonavir in individual or combined forms with other drugs have been used, causing an increase in the concentration of antiviral drugs in the wastewater and hospital effluents. In conventional wastewater treatment plants, the removal efficiency of various antiviral drugs is estimated to be low (<20%). The high values of predicted no-effect concentration (PNEC) for lopinavir and ritonavir (in ng∙L^-1) reveal their high chronic toxicity to aquatic organisms. This indicates that lopinavir and ritonavir are current priority antiviral drugs that need to be thoroughly monitored and effectively removed from any water and wastewater samples. In this study, we attempt to explore the impacts of two photo-induced processes (photolysis and photocatalysis) on the toxicity of treated water and wastewater samples containing lopinavir and ritonavir to zebrafish (Danio rerio) and marine bacteria (Allivibrio fischeri). The obtained results reveal that traces of lopinavir in water under photo-induced processes may cause severe problems for Danio rerio, including pericardial edema and shortening of the tail, affecting its behavior, and for Allivibrio fischeri as a result of the oxygen-depleted environment, inflammation, and oxidative stress. Hence, lopinavir must be removed from water and wastewater before being in contact with light. In contrast, the photo-induced processes of ritonavir-containing water and wastewater reduce the toxicity significantly. This shows that even if the physicochemical parameters of water and wastewater are within the standard requirements/limits, the presence of traces of antiviral drugs and their intermediates can affect the survival and behavior of Danio rerio and Allivibrio fischeri. Therefore, the photo-induced processes and additional treatment of water and wastewater containing ritonavir can minimize its toxic effect.

Pharmaceuticals as emerging pollutants: Case naproxen an overview

Nonsteroidal anti-inflammatory drugs (NSAIDs), including naproxen (NP), diclofenac, ibuprofen, etc., are widely used for fever and pain relief. NP is one of the most widely consumed drugs in the world, because it is available over the counter in many countries. Many studies have proven that NP is not eliminated in conventional water treatment processes and its biodegradation in the environment is also difficult compared to other drugs. Along these lines, we are aware that both the original compound and its metabolites can be found in different destinations in the environment. To assess the environmental exposure and the risks associated with NP, it is important to understand better the environment where they finally reach, the behavior of its original compounds, its metabolites, and its transformation products. In this sense, the purpose of this review is to summarize the current state of knowledge about the introduction and behavior of NP in the environments they reach and highlight research needs and gaps. Likewise, we present the sources, environmental destinations, toxicology, environmental effects, and quantification methodologies.

Effects of oxidative stress induced by environmental relevant concentrations of fluoxetine on the embryonic development on Danio rerio

Fluoxetine (FLX) is a psychoactive drug that acts as an antidepressant. FLX is one of the world's best-selling prescription antidepressants. FLX is widely used for the treatment of various psychiatric disorders. For these reasons, this drug may eventually end up in the aquatic environment via municipal, industrial, and hospital discharges. Even though the occurrence of FLX in aquatic environments has been reported as ubiquitous, the toxic effects that this drug may induce, especially at environmentally relevant concentrations, on essential biological processes of aquatic organisms require more attention. In the light of this information, this work aimed to investigate the influence that fluoxetine oxidative stress-induced got over the embryonic development of Danio rerio. For this purpose, D. rerio embryos (4 h post fertilization) were exposed to environmentally relevant concentrations (5, 10, 15, 20, 25, 30, 35, and 40 ng L^-1) of fluoxetine, until 96 h post fecundation. Along the exposure, survival, alterations to embryonic development, and teratogenic effects were evaluated using a stereomicroscope. Furthermore, oxidative stress biomarkers (superoxide dismutase, catalase, glutathione peroxidase, lipid peroxidation, hydroperoxide, and carbonyl content) were evaluated at 72 and 96 h post fecundation. LC₅₀, EC_50m, and teratogenic index were 30 ng L^-1, 16 ng L^-1, and 1.9, respectively. The main teratogenic effects induced by fluoxetine were pericardial edema, hatching retardation, spine alterations and craniofacial malformations. Concerning oxidative stress, our integrated biomarkers (IBR) analysis demonstrated that as the concentration increased, oxidative damage biomarkers got more influence over the embryos than antioxidant enzymes. Thus, fluoxetine induces an important oxidative stress response on the embryos of D. rerio. Collectively, our results allow us to concluded that FLX is a dangerous drug in the early life stages of D. rerio due to its high teratogenic potential and that FLX-oxidative stress induced may be involved in this toxic process.

Acute exposure to 17-α-ethinylestradiol disrupt the embryonic development and oxidative status of Danio rerio

17-Alpha-ethinylestradiol (EE2) is an estrogen derived from estradiol (E2). This compound and is one of the most widely used drugs both in humans and animals. Numerous studies have reported the ability of EE2 to alter sex determination and delay sexual maturity, but there are toxic effects that need to be explored. In this work, we analyzed the effect of EE2 on embryonic development and oxidative stress biomarkers in Danio rerio. For this effect, zebrafish embryos in the blastula period (2.5 h post fecundation) were exposed to different concentrations of EE2 (36-106 ng L^-1) until 96 hpf. Survival, alterations to embryonic development, and teratogenic effects were evaluated using a stereomicroscope. Furthermore, oxidative stress biomarkers: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) activities, lipid peroxidation (LPX), hydroperoxide content (HPX), and protein carbonyl content (POX) were evaluated at 72 and 96 hpf using spectrophotometric methods. LC₅₀ and EC₅₀ of malformations got values of 82 ng L^-1 and 57.7 ng L^-1, respectively. The main teratogenic effects found were: chorda malformation, body malformation, and developmental delay. These alterations occurred at 86, 96, and 106 ng L^-1. Integrated biomarker index showed that the oxidative stress biomarkers that had the most influence on embryos were SOD, CAT, GPX, and LPX. Overall, our results allow us to conclude that low concentrations of EE2 may potentially alter the development and oxidative status in the early life stages of zebrafish. Therefore, this bio-active estrogen can be considered a hazardous substance for fish.

Developmental alterations, teratogenic effects, and oxidative disruption induced by ibuprofen, aluminum, and their binary mixture on Danio rerio

Several studies highlighted the ubiquitous presence of ibuprofen and aluminum in the aquatic environment around the world and demonstrated their potential to induce embryotoxic and teratogenic defects on aquatic species individually. Although studies that evaluate developmental alterations induced by mixtures of these pollutants are scarce; and, since environmental contamination presented in the form of a mixture of toxicants with different chemical properties and toxicity mechanisms capable of generating interactions; the objective of this study was to evaluate the developmental defects, teratogenic alterations, and oxidative stress induced by individual forms and the mixture of ibuprofen (IBU) and aluminum (Al) on zebrafish embryos. Oocytes exposed to environmentally relevant concentrations of IBU (0.1-20 μg L-1) and Al (0.01-8 mg L-1) and one binary mixture. The LC50 and EC50 were obtained to calculate the teratogenic index (TI). The IBU LC50, EC50, and TI were 8.06 μg L-1, 2.85 μg L-1 and 2.82. In contrast, Al LC50 was 5.0 mg L-1with an EC50 of 3.58 mg L-1 and TI of 1.39. The main alterations observed for individual compounds were hatching alterations, head malformation, skeletal deformities, hypopigmentation, pericardial edema, and heart rate impairment. The mixture also showed significant delays to embryonic development. Moreover, oxidative stress biomarkers of cellular oxidation and antioxidant defenses at 72 and 96 hpf significantly increased. Results show that environmentally relevant concentrations of ibuprofen (IBU), aluminum (Al), and their mixture promote a series of developmental defects, teratogenic effects, and oxidative disruption on D. rerio embryos, and the interaction of both substances altered the response. In conclusion, morphological and biochemical tests are suitable tools for assessing the health risk of aquatic wildlife by exposure to individual and mixed pollutants in freshwater bodies.

Occurrence, Fate, Effects, and Risks of Dexamethasone: Ecological Implications Post-COVID-19

The recent outbreak of respiratory syndrome-coronavirus-2 (SARS-CoV-2), which causes coronavirus disease (COVID-19), has led to the widespread use of therapeutics, including dexamethasone (DEXA). DEXA, a synthetic glucocorticoid, is among the widely administered drugs used to treat hospitalized COVID-19 patients. The global COVID-19 surge in infections, consequent increasing hospitalizations, and other DEXA applications have raised concerns on eminent adverse ecological implications to aquatic ecosystems. Here, we aim to summarize published studies on DEXA occurrence, fate, and effects on organisms in natural and engineered systems as, pre-COVID, the drug has been identified as an emerging environmental contaminant. The results demonstrated a significant reduction of DEXA in wastewater treatment plants, with a small portion, including its transformation products (TPs), being released into downstream waters. Fish and crustaceans are the most susceptible species to DEXA exposure in the parts-per-billion range, suggesting potential deleterious ecological effects. However, there are data deficits on the implications of DEXA to marine and estuarine systems and wildlife. To improve DEXA management, toxicological outcomes of DEXA and formed TPs should entail long-term studies from whole organisms to molecular effects in actual environmental matrices and at realistic exposure concentrations. This can aid in striking a fine balance of saving human lives and protecting ecological integrity.

Long-term exposure to environmentally relevant concentrations of ibuprofen and aluminum alters oxidative stress status on Danio rerio

Despite the ubiquitous presence of multiple pollutants in aqueous environments have been extensively demonstrated, the ecological impact of chemical cocktails has not been studied in depth. In recent years, environmental studies have mainly focused on the risk assessment of individual chemical substances neglecting the effects of complex mixtures even though it has been demonstrated that combined effects exerted by pollutants might represent a greater hazard to the biocenosis. The current study evaluates the effects on the oxidative stress status induced by individual forms and binary mixtures of ibuprofen (IBU) and aluminum (Al) on brain, gills, liver and gut tissues of Danio rerio after long-term exposure to environmentally relevant concentrations (0.1-11 μg L^-1 and 0.05 mg L^-1- 6 mg L^-1, respectively). Lipid peroxidation (LPO), Protein carbonyl content (PCC) and activity of Superoxide Dismutase (SOD), Catalase (CAT), and Glutathione Peroxidase (GPX) were evaluated. Moreover, concentrations of both toxicants and the metabolite 2-OH-IBU were quantified on test water and tissues. Results show that ibuprofen (IBU) and aluminum (Al) singly promote the production of radical species and alters the oxidative stress status in all evaluated tissues of zebrafish, nevertheless, higher effects were elicited by mixtures as different interactions take place.

Sensitivity of Zebrafish (Danio rerio) Embryos to Hospital Effluent Compared to Daphnia magna and Aliivibrio fischeri

The Fish Embryo Acute Toxicity (FET) Test was adopted by the Organisation for Economic Co-operation and Development as OECD TG 236 in 2013. The test has been designed to determine acute toxicity of chemicals on embryonic stages of fish and proposed as an alternative method to the Fish Acute Toxicity Test performed according to OECD TG 203. In recent years fish embryos were used not only in the assessment of toxicity of chemicals but also for environmental and wastewater samples. In our study we investigated the acute toxicity of treated wastewater from seven hospitals in the Czech Republic. Our main purpose was to compare the suitability and sensitivity of zebrafish embryos with the sensitivity of two other aquatic organisms commonly used for wastewater testing – Daphnia magna and Aliivibrio fischeri. For the aim of this study, in addition to the lethal endpoints of the FET test, sublethal effects such as delayed heartbeat, lack of blood circulation, pericardial and yolk sac edema, spinal curvature and pigmentation failures were evaluated. The comparison of three species demonstrated that the sensitivity of zebrafish embryos is comparable or in some cases higher than the sensitivity of D. magna and A. fischeri. The inclusion of sublethal endpoints caused statistically significant increase of the FET test efficiency in the range of 1-12 %. Based on our results, the FET test, especially with the addition of sublethal effects evaluation, can be considered as a sufficiently sensitive and useful additional tool for ecotoxicity testing of the acute toxicity potential of hospital effluents.