Propranolol degradation through processes based on the generation of hydroxyl free radical

Pharmaceutical substances such as propranolol (PRO) are an emerging class of aquatic contaminants that have increasingly been detected in ground and surface water. For this reason, the aim of this study was to evaluate the efficiency of advanced oxidation systems for the PRO degradation. The tests started with anodic oxidation (AO), using 0.01, 0.05, and 0.1 M Na2SO4 as the supporting electrolyte and 16, 32, 48, and 64 mA cm−2 as current density. Under the best conditions obtained in AO, the electro-Fenton (EF) process was reviewed, where the effect of Fe2+ was analyzed with 5, 10, 15, and 20 mg Fe2+ L−1. The Fenton reaction (FR) was studied using the Fe2+ concentration that promoted the highest percentage of PRO removal and initial concentration of 16 mg L−1 of H2O2, in addition to these conditions, in the photo-Fenton (PF) system, the effect of UV light with wavelengths 254 and 365 nm were evaluated. The results obtained showed that the degradation efficiency of the EF > AO > PF > FR system along with a percent removal of 94.52, 90.4, 25.97, and 4.4%, respectively. The results showed that PRO can be removed through the studied systems, with the EF system being the most efficient.

Effects of the Covid-19 Pandemic on the Environment

The emergence of the new coronavirus resulted in the COVID-19 pandemic, which led several countries to adopt restrictive measures, such as the lockdown. As a consequence, several changes were observed in social, commercial, industrial and environmental dynamics. Thus, the present study aimed to make a brief review of some of the main effects of the Pandemic on the environment, in different parts of the world, gathering this information in a single document. To this end, a qualitative method was adopted, in which bibliographical surveys from scientific articles were carried out, as well from articles, news and reports from reliable sources. According to the sources consulted, the impacts observed in the air were mostly positive, resulting in the reduction of the concentrations of most of the atmospheric contaminants. With regard to water resources, positive effects were detected, such as the improvement in water quality in several places in the world, as well as negative effects, portrayed in the increase of the insertion of new aquatic contaminants, of difficult synthesis, in addition to the increase of residues, harmful to the marine fauna. The increase in the volume of waste, due to the new consumption habits imposed by the Pandemic, has also shown to influence soil properties. Finally, it is possible to conclude that the health crisis is linked to the cultural habits of a society that should seek to establish more harmonious relationships with the environment.

Development of a Library of Responses for an Early-Warning Biomonitoring System to Detect and Identify Various Aquatic Contaminants

Biomonitors can be implemented in aquatic ecosystems to continuously assess water quality, but existing monitors are still reliant on a single species and unable to identify any stressor. A library of responses could potentially address these drawbacks by stereotyping the responses of several aquatic species to different contaminants. A model for the library was developed by conducting a bioassay on Pseudokirchneriella subcapitata and collecting the response data of Daphnia magna, Hyalella azteca and Lumbriculus variegatus from published ecotoxicological studies. Multivariate statistical tools were then employed to process the response data set and evaluate the ability of the model to distinguish contaminations by atrazine and tributyltin. Based on preliminary tests, the library was able to detect and identify each contaminant within 4 hours with an accuracy of 97%. These findings supported the integration of a library of responses in a biomonitoring system to provide a more comprehensive water quality assessment.

Development of a Library of Responses for an Early-Warning Biomonitoring System to Detect and Identify Various Aquatic Contaminants

Biomonitors can be implemented in aquatic ecosystems to continuously assess water quality, but existing monitors are still reliant on a single species and unable to identify any stressor. A library of responses could potentially address these drawbacks by stereotyping the responses of several aquatic species to different contaminants. A model for the library was developed by conducting a bioassay on Pseudokirchneriella subcapitata and collecting the response data of Daphnia magna, Hyalella azteca and Lumbriculus variegatus from published ecotoxicological studies. Multivariate statistical tools were then employed to process the response data set and evaluate the ability of the model to distinguish contaminations by atrazine and tributyltin. Based on preliminary tests, the library was able to detect and identify each contaminant within 4 hours with an accuracy of 97%. These findings supported the integration of a library of responses in a biomonitoring system to provide a more comprehensive water quality assessment.

Landuse and Water Quality Threats to Current and Historical Cryptobranchus Alleganiensis Streams Across Multiple Ecoregions

The hellbender (Cryptobranchus alleganiensis) is a large, long-lived, and fully aquatic salamander species endemic to streams and rivers across 15 states in the Midwest and Eastern United States. Hellbender populations have experienced drastic declines due to habitat degradation, accelerated sedimentation, aquatic contaminants, and infectious diseases. Although declining water quality is often suggested as a major contributing factor to hellbender population declines, few studies have evaluated the presence of aquatic contaminants at sites with current and historical C. alleganiensis populations. We used a novel passive sampling technique to assess the presence and concentration of two herbicides (glyphosate and atrazine) in the water and analyzed heavy metal (cadmium (Cd), mercury (Hg), and lead (Pb)) concentrations in stream sediment samples at 30 sites across a watershed development gradient throughout the C. alleganiensis range in Tennessee (TN) and North Carolina (NC). Our results indicated the presence of atrazine in 23% of our sites. All 30 sites contained Cd and Pb, and 26 sites contained Hg. Levels of glyphosate were too low to detect using our methods. Although percent watershed development was not significantly different among ecoregions, Blue Ridge watersheds were overall less developed than watersheds in the Ridge and Valley and Interior Plateau ecoregions. The model with greatest support suggested that percent watershed development and specific conductivity were negatively correlated with hellbender population status. Because this research focused on assessing the prevalence of commonly encountered aquatic contaminants, our results and study design are broadly applicable to C. alleganiensis populations across the species range.

TiO2-Photocatalyzed Water Depollution, a Strong, yet Selective Depollution Method: New Evidence from the Solar Light Induced Degradation of Glucocorticoids in Freshwaters

The photodegradation of the most prescribed glucocorticoids (GCs) was studied under relevant environmental conditions in the presence of suspended TiO2. The considered drugs included cortisone (CORT), hydrocortisone (HCORT), betamethasone (BETA), dexamethasone (DEXA), prednisone (PRED), prednisolone (PREDLO), and triamcinolone (TRIAM). The experiments were carried out at concentrations (50 µg L−1) close to the real ones in freshwater samples (tap and river) under simulated and natural sunlight, and their decomposition took place very efficiently under natural sunlight. The reactions were monitored by high-pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). According to a pseudo-first-order decay, all drugs underwent degradation within 15 min, following different paths with respect to the direct photolysis. The observed kinetic constants, slightly lower in river than in tap water, varied from 0.29 to 0.61 min−1 with modest differences among GCs in the same matrix. Among main matrix macro-constituents, humic acids (HAs) were the most interfering species involved in GCs degradation. The photogenerated primary products were identified by HPLC-ESI-MS/MS, allowing to elucidate the general photochemical path of GCs. Finally, a comparison with literature data obtained using different advanced oxidation processes (AOPs) highlights the treatment efficiency with TiO2/solar light for removing such persistent aquatic contaminants.

Plasticizers as Microplastics Tracers in Tunisian Marine Environment

The new knowledge on the bio-transformations to which the plastic material is subjected, raise concerns about their role as environmental contaminants. Microplastic have been reported to be responsible for the release and distribution of aquatic contaminants such organophosphorus esters, pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and phthalate esters. The occurrence, spatiotemporal trends, and ecological risk of phthalic acid esters (PAEs) and non-phthalate plasticizers (NPPs) released from microplastic were investigated in water and fish (Sparus aurata) from five sites along the coast of Mahdia governorate (Tunisia), during April 2018-March 2019. In seawater the most abundant and frequently detected congeners were dibutyl phthalate (DBP, 0.017 mg L–1 and 0.055 mg L–1), diisobutyl phthalate (DiBP, 0.075 mg L–1 and 0.219 mg L–1), di(2-ethylhexyl)phthalate (DEHP, 0.071 mg L–1 and 4.594 mg L–1), and di(2-ethylhexyl) terephthalate (DEHT, 0.634 mg L–1 and 2.424 mg L–1). (ΣPAEs: 1.416 mg L–1 and 5.581 mg L–1; ΣNPPs: 9.191 mg L–1 and 26.296 mg L–1), confirming that such compounds bioconcentrate through the food chain. DBP (0.389 and 0.817 mg L–1), DiBP (0.101 and 0.921 mg L–1), DEHP (0.726 and 1.771 mg L–1) and DEHT (9.191 and 23.251 mg L–1) were predominant also in S. aurata affirming that such compounds bioconcentrate through the food chain. Overall, Tunisian samples i) were much more contaminated than counterparts previously investigated for the same pollutants from other world areas, and ii) revealed NPPs at higher levels than PAEs, confirming that such plasticizers are increasingly replacing conventional PAEs.