Prednisolone impairs embryonic and posthatching development and shell formation of the freshwater snail, Physa acuta

Investigating the potential impacts of coal ash runoff on the freshwater Seminole ramshorn snail (Planorbella duryi) under laboratory conditions

Coal fly ash is an industrial waste product generated by coal fired powerplants which has been shown to contain elevated concentrations of several toxic trace metals. When stored in landfills or other repositories, these trace metals can enter nearby surface waters via a number of routes including leaching or runoff. Our study examined 1) the presence and concentration of eleven trace elements in a range of lab-created coal ash leachate solutions at neutral pH using ICP-OES, 2) the physiological effects of these leachate solutions on a freshwater gastropod (Planorbella duryi), and 3) the ability of these trace metals to bioaccumulate in the tissues of exposed individuals. As, Cd, Cu, Mg, Mn, and Pb were detected in solutions at increasing concentrations concurrent with ash concentration. Exposure to leachates caused significant delays in embryonic development, reduced juvenile shell growth, decreases in egg and clutch production, and the display of avoidance behaviors. Tissues of exposed snails contained elevated concentrations of As, Cd, Cu, and Cr, with bioconcentration factors 177,550 times higher in cadmium and 85,468 times higher in arsenic in the highest treatment compared to control organisms. Our results highlight the potential harmful effects of coal ash leachates on a novel freshwater invertebrate species using several unique methodologies, providing key information regarding their potential impacts on surrounding aquatic ecosystems.

Sulfate Radicals-Based Technology as a Promising Strategy for Wastewater

This study was focused on the generation of sulfate radicals and their applicability as powerful oxidants for degrading complex organic compounds with the final objective of operating in flow systems. To this end, the removal of two compounds from the pharmaceutical industry was assessed, lissamine green and prednisolone. Initially, sulfate radicals were generated by the activation of persulfate with iron as homogenous catalyst, and the key parameters involved in the process, as catalyst concentration and oxidant dosage, were evaluated. Furthermore, with the aim of preventing the secondary contamination due to metal leaching and to be operate in a continuous mode, a heterogeneous catalyst was developed. For it, the iron was fixed on a cationic resin as Amberlite IR120 Na+ form. It was demonstrated that the removal of both pollutants increases with greater catalyst dosages, achieving a decay of 85% within 25 min with 30 g·L−1 of catalyst. Moreover, the reuse capability of the catalyst was tested, illustrating that it is rough enough for its reuse. Conversely, in order to develop a continuous treatment in flow system, a fixed bed reactor was constructed and its feasibility was proven. Different experiments with residence times from 10 min to 60 min were performed, obtaining a removal level of ≈95% and 90% for prednisolone and lissamine green, respectively, at residence time of 60 min. In conclusion, the potential of sulfate radicals-based technology for degrading organic contaminants has been demonstrated.

Prednisolone degradation by UV/chlorine process: Influence factors, transformation products and mechanism

Prednisolone (PDNN) as an emergent micropollutant directly influences the regional ecological security. In this study, the degradation of PDNN by ultraviolet activated chlorine (UV/chlorine) oxidation process was comprehensively evaluated. The quenching experiment suggested that the PDNN degradation in UV/chlorine process was involved in the participation of hydroxyl radical (OH) and reactive chlorine species (RCS). Influence factors including chlorine dosage, pH, common anion and cation, fulvic acid (FA) on PDNN degradation via UV/chlorine process were investigated. A low chlorine (≤7.1 mg L^-1) promoted the PDNN degradation, while a high chlorine dosage (>7.1 mg L^-1) was adverse. The pH (4.0-10.0) showed negligible effect, while the investigated anions (Cl^-, Br^-, HCO₃^- and SO₄^2-), NH₄⁺ and FA exerted negative impact on PDNN degradation. An efficient process to minimize pharmaceutical micropollutants was the disposal of human urine containing a high concentration of pharmaceutical and potential toxic metabolites. An inhibitory effect was observed in the synthetic urine (fresh urine and hydrolyzed urine). The intermediates/products were identified and the mechanism of PDNN degradation was proposed. PDNN gone through three degradation routes, involving the direct addition of α, β-unsaturated ketone at C₁ or C₅, the photolysis of C₁₇ and H-abstraction of C₁₁. The main reactive sites were further determined by comparison of the frontier orbitals calculation and the proposed mechanism. Based on the toxicological tests for PDNN degradation, TP396 (TP396-C₁Cl and TP396-C₅Cl) and TP414-2-1 (TP414-C₁ClC₅OH) exhibited much higher toxicity than PDNN, and prolonging reaction time was necessary to achieve PDNN detoxification.

Optimization of photo-Fenton process for the treatment of prednisolone

Prednisolone is a widely prescribed synthetic glucocorticoid and stated to be toxic to a number of non-target aquatic organisms. Its extensive consumption generates environmental concern due to its detection in wastewater samples at concentrations ranged from ng/L to μg/L that requests the application of suitable degradation processes. Regarding the actual treatment options, advanced oxidation processes (AOPs) are presented as a viable alternative. In this work, the comparison in terms of pollutant removal and energetic efficiencies, between different AOPs such as Fenton (F), photo-Fenton (UV/F), photolysis (UV), and hydrogen peroxide/photolysis (UV/H₂O₂), was carried out. Light diode emission (LED) was the selected source to provide the UV radiation. The UV/F process revealed the best performance, reaching high levels of both degradation and mineralization with low energy consumption. Its optimization was conducted and the operational parameters were iron and H₂O₂ concentrations and the working volume. Using the response surface methodology with the Box-Behnken design, the effect of independent variables and their interactions on the process response were effectively evaluated. Different responses were analyzed taking into account the prednisolone removal (TOC and drug abatements) and the energy consumptions associated. The obtained model showed an improvement of the UV/F process when treating smaller volumes and when adding high concentrations of H₂O₂ and Fe²⁺. The validation of this model was successfully carried out, having only 5% of discrepancy between the model and the experimental results. Finally, the performance of the process when having a real wastewater matrix was also tested, achieving complete mineralization and detoxification after 8 h. In addition, prednisolone degradation products were identified. Finally, the obtained low energy permitted to confirm the viability of the process.

Assessing multigenerational effects of prednisolone to the freshwater snail, Physa acuta (Gastropoda: Physidae)

Prednisolone (PDS), a potent synthetic glucocorticoid is widely prescribed for its exceptional anti-inflammatory properties. Several studies have detected the environmental presence of PDS in water bodies which has led to an ecological concern for its toxicity to non-target aquatic biota. The present study investigated the effects of exposure to PDS on different life-cycle stages and generations of the freshwater snail, Physa acuta. This continuous exposure over a period of multiple generations resulted in generational impairments at measured endpoints. LOEC values (p<0.001) for PDS exposure ranged from 32 to 4μg/L in exposed F0-F2 generations. Global DNA methylation (% 5-methyl cytosine) of adult progeny was found to be affected at higher test concentrations in comparison to the parent snails. Partially formed to completely missed growth components of shell structure and shell thinning in abnormally underdeveloped PDS exposed snails of F1 and F2 generation, was also observed in this multigenerational exposure experiment. The multigenerational study confirmed P. acuta as a promising bioindicator since critical effects of the long term glucocorticoid exposure opens up the way for further investigations on transgenerational toxicity in environmental toxicology and risk assessment and to monitor glucocorticoid pollution in aqueous ecosystem.

Multigenerational effects of two glucocorticoids (prednisolone and dexamethasone) on life-history parameters of crustacean Ceriodaphnia dubia (Cladocera)

Synthetic glucocorticoids (GCs) such as dexamethasone (DEX) and prednisolone (PDS) have been used since the 1940s to cure inflammatory and auto-immune disorders. Their use has been linked to a host of deleterious effects in aquatic ecosystems such as osteoporosis in vertebrates, developmental impairments in molluscs and reduced fecundity and growth in cladocerans. Apart from these handful of studies, the effects of GCs on aquatic biota are largely unknown. The present study is a first of its kind aiming to assess the multi-generational exposure effects of DEX and PDS on the life history parameters of Ceriodaphnia dubia (C. dubia). Multigenerational studies have proved to be an advantage in assessing the cumulative damage caused by aquatic toxicants at the population level of the exposed organisms over a period of successive generations using multiple biological endpoints. Test results demonstrated that C. dubia exhibited varied sensitivities towards both the studied chemicals however were more sensitive to DEX with 48-h EC₅₀ (95% confidence interval) of 0.75 mg/L (CI: 0.59-0.92) in comparison to PDS [19 mg/L (CI: 15-23)]. EC₁₀ values for F0 in a multigenerational chronic bioassays were 48 μg/L (CI: 37.4-61) for DEX and 460 μg/L (CI: 341-606) for PDS and in F3 were 2.2 μg/L (CI: 1.6-3.1) for DEX and 31 μg/L (CI: 19.4-46) for PDS. There was a positive trend of increased toxicity followed by reduced life history traits such as fecundity, brood size and time to first brood and intrinsic rate of population increase and body growth (length and area) of C. dubia in the case of both studied chemicals. The results from the current work highlighted the importance of multigenerational studies in identifying the evolutionary responses of stressed non-target aquatic organisms, and data obtained can be further used in developing water quality guidelines.