Potential Ecotoxicity Research Articles

Comparison of different municipal sewage sludge products for potential ecotoxicity

Comparison of different municipal sewage sludge products for potential ecotoxicity

Sustainability analysis for scandium recovery from secondary sources

Primary aluminium industry is one of the largest industries associated with high greenhouse gas emissions. It is reported that in 2022, the aluminium production emitted nearly 270 Mt of direct CO2 in the atmosphere. To achieve the European goals of zero emissions by 2050, a reduction of 4% annually is essential. Τhe industry needs to take a turn towards less impactful production practices, focusing on the valorisation of residues for promoting sustainability. Bauxite residue from alumina production represents a remarkable source of Rare Earth Elements (REEs). This study offers valuable insights into the environmental and economic aspects of processes related to resource Scandium (Sc) extraction and processing in Greece, Romania and Turkey. In this frame, a comparative analysis of the environmental impact of the extraction process of REEs from Bauxite Residues (BR) in the regions mentioned above is presented. The results show that an up to 23% greenhouse gas emissions reduction can be achieved, while the environmental categories of human health risks, aquatic toxicity potential, and terrestrial ecotoxicity potential are improved by applying hydrothermal processes and direct leaching to BR. While the stages of Sc extraction remain consistent, variations in the chemical compositions of BR underscore the influence of local factors. The findings also emphasize the importance of tailoring extraction processes to local conditions and compositions for scandium extraction. These insights can guide industry decisions and contribute to responsible resource management in the future.

Insights into the Potential Effects of Micro(nano)plastic-Containing Nanoparticles in the Environment

Micro(nano)plastics (MNPs) can be generated from a variety of sources, including the breakdown of larger plastic items, the abrasion of synthetic textiles, and the fragmentation of plastic waste. These particles can become airborne and be transported by wind, potentially leading to their presence in the atmosphere. Due to their widespread applications, ZnO particles at the nanometer range have attractive proprieties that make them appropriate for being combined with polymers, especially PET (polyethylene terephthalate), the most commonly used polymer in the packaging sector. Nevertheless, ZnO NPs have a potential ecotoxicity that could be reflected in PET-ZnO composites reaching the environment in the form of micro(nano)plastics. To assess the potential release of PET-ZnO, as well as the ecotoxicity of ZnO NPs, PET-ZnO and weathered composites were analyzed. The ecotoxicity of PET-ZnO was tested in organisms representing different food-chain levels and compared to ZnO NPs’ ecotoxicity. The composite form contained a stable dispersion of around 3.7% of NPs uniformly scattered in the polymeric matrix. ZnO NPs were toxic to Vibrio fischeri and Brachionus calyciflorus. PET-ZnO did not exhibited any toxicity to the organisms studied, while a moderate level of toxicity was observed for the weathered forms.

Eco-friendly microalgae harvesting using lipid-cored particles with a comparative life-cycle assessment

This study proposed an innovative approach using lipid-cored particles (LCPs) aimed at addressing the efficiency, cost, and environmental impact challenges in microalgae harvesting. Cetyltrimethylammonium bromide (CTAB) and chitosan (CS) were used to modify LCPs and to optimize efficiency and investigate the mechanisms of harvesting with Chlorella vulgaris. Results showed that a maximum harvesting efficiency of 97.14 % was achieved using CS-LCPs. Zeta potential and microscopic images revealed the presence of embedded CS-LCPs within microalgal flocs. Fractal dimension data suggested looser aggregates of CS-LCPs and Chlorella vulgaris, corroborated by Excitation-emission matrices (EEM) analysis further confirmation the presence of bridging networks. Moreover, life cycle assessment of five harvesting methods pointed freshwater ecotoxicity potential (FEP) and terrestrial ecotoxicity potential (TEP) as major environmental impacts, mainly from flocculant use, carrier production, and electricity consumption. Notably, LCPs showed the lowest global warming potential (GWP) at 1.54 kg CO2 eq, offering a viable, low-carbon, cost-effective harvesting alternative.

Environmentally relevant concentrations of tris (2-chloroethyl) phosphate (TCEP) induce hepatotoxicity in zebrafish (Danio rerio): a whole life-cycle assessment.

Tris (2-chloroethyl) phosphate (TCEP), a typical organophosphate flame retardant, is of increasingly great concern considering their ubiquitous presence in aquatic environments and potential ecotoxicity. The present work was aimed to investigate the potential growth inhibition and hepatic stress induced by whole life-cycle exposure to TCEP (0.8, 4, 20 and 100μg/L) in zebrafish. The results revealed that the body length, body mass and hepatic-somatic index (HSI) of zebrafish were significantly declined after exposure to TCEP for 120days. GPx activity and GSH content were increased in the liver of zebrafish treated with low concentrations (0.8 and 4μg/L) of TCEP, while exposure to high concentrations (20 and 100μg/L) of TCEP reduced antioxidative capacity and elevated lipid peroxidation (LPO) levels. Gene transcription analysis demonstrated that the mRNA levels of nrf2 were altered in a similar manner to the transcription of the downstream genes nqo1 and hmox1, suggesting that Nrf2-Keap1 pathway mediated TCEP-induced oxidative stress in zebrafish liver. In addition, TCEP exposure might alleviate inflammatory response through down-regulating transcription of inflammatory cytokines (il-1β, il-6 and inos), and induce apoptosis via activating the p53-Bax pathway. Moreover, whole life-cycle exposure to TCEP caused a series of histopathological anomalies in zebrafish liver. Overall, our results revealed that lifetime exposure to environmentally relevant concentrations of TCEP could result in growth retardation and induce significant hepatotoxicity in zebrafish.

Ecotoxicity and rapid degradation of quaternary ammonium compounds (QACs) subjected to combined vacuum UV and UV-C treatment

Quaternary ammonium compounds (QACs) are active ingredients in a palette of commercially available disinfectants, sanitizers, and biocides. QACs are widely used because of their broad-spectrum antimicrobial properties but the ubiquitous uses have resulted in frequent detection in aquatic and terrestrial matrices including domestic wastewater, surface waters, urban soils and sediments. An increased domestic QACs consumption has increased the environmental occurrence, and investigation of mitigation methods and effects on non-target organisms are in demand. In this study, we examined the potential ecotoxicity of six QACs and investigated the effect of combined vacuum UV (185 nm) and UV-C (254 nm) irradiation (VUV/UVC) on degradation and mitigation of ecotoxicity of QACs. The study showed that combined VUV/UVC irradiation facilitated rapid degradation of benzalkonium chloride, benzethonium chloride, didecyldimethylammonium chloride, dodecyltrimethylammonium chloride, and hexadecyltrimethylammonium chloride. The estimated half-lives varied between 2 and 7 min, and degradation was affected by the initial QAC concentrations, the UV fluence, and the water matrix. The potential ecotoxicity of QACs and VUV/UVC treated QACs was examined using a battery of test organisms that included the luminescent bacterium Aliivibrio fischeri, the gram-negative and gram-positive bacteria Escherichiacoli and Enterococcus faecalis, the freshwater microalga Raphidocelis subcapitata, and the crustacean Daphia magna. The potential for trophic transfer of QACs was investigated in a simplified aquatic food web. Test organisms from different trophic levels were included to assess adverse effects of bioactive compounds in VUV/UVC treated samples including transformation products. The study showed that several QACs were highly toxic to aquatic test organisms with EC50 and/or EC20 values < 1 μM. VUV/UVC treatment of QACs resulted in substantial photolysis of the parent compounds and comprehensive mitigation of the ecotoxicity potential. VUV/UVC represent an attractive oxidation technology for abatement QACs in contaminated water because the process does not require addition of catalysts or precursors.

Acute Ecotoxicity Potential of Untreated Tannery Wastewater Release in Arequipa, Southern Peru

The centralized Rio Seco Industrial Park (RSIP) tannery collective in the Southern Peruvian city of Arequipa releases untreated tannery wastewater into a proximal creek that is a tributary of the Chili River. As industrial leather tanning wastewater contains high concentrations of metal(loid)s, salts, dyes, and organics, this complex mixture could exert a myriad of toxicological effects on the surrounding ecosystem. The RSIP effluent was analyzed to quantify the acute ecotoxicity and ecotoxicological status of this untreated industrial wastewater at multiple trophic levels with the following bioindicators: the floating macrophyte Lemna minor, invertebrates Daphnia magna and Physa venustula, and the amphibian Xenopus laevis. A physicochemical characterization of the RSIP effluent revealed a highly contaminated waste stream. In addition to chromium (10.4 ± 0.4 mg/L) and other toxic metals, the water harbored extremely high concentrations of total dissolved solids (67,770 ± 15,600 mg/L), biochemical oxygen demand (1530 ± 290 mg/L) and total nitrogen (490 ± 10 mg/L). The toxicological responses of certain bioindicator species tested were evaluated after exposure to 0, 1.5, 3.0, and 4.5% untreated tannery wastewater blended with dechlorinated tap water. L. minor experienced a significant decrease in the number of fronds, wet weight, and dry weight at the lowest blended wastewater of 1.5%. Bioassays with D. magna showed the effect on neonatal mortality with a calculated LC50 of 1.1% for 48 h. Bioassays with P. venustula embryos showed high sensitivity to diluted effluent with complete mortality at 3.0% wastewater and above. Finally, X. laevis showed a high sensitivity to the dilutions with an LC50 of 1.6 for embryos and 1.8% for tadpoles. Although RSIP wastewater contains many potentially toxic components, chromium and total dissolved solids, with a major contribution from sodium, are best correlated with acute toxicity variables. This suggests that conductivity or analogous measurements could provide a rapid and affordable forensic tool to query acute ecosystem pressures. Collectively, the results indicate that the release of untreated tannery wastewater from RSIP can exert pronounced acute impacts across trophic levels with the need for treatment or dilution to below 1% of total flow. As the assays addressed acute toxicity, the necessary treatment and/or dilution to mitigate chronic effects is likely much lower. In conclusion, untreated RSIP tannery wastewaters represent an ecological risk to downstream aquatic ecosystems; this needs to be addressed to prevent current and future environmental consequences.

Potential for high toxicity of polystyrene nanoplastics to the European Daphnia longispina

BackgroundCurrent regulatory discussions about microplastics are often questioned based on a lack of data indicating high ecotoxic hazards of these particles within standard and recognized definitions. Moreover, there is scientific debate on what metrics to report the micro-nanoplastics toxicity (i.e. mass or particle counts-based exposure). We present here the high potential sensitivity of three genotypically different clones of the European Daphnia longispina species complex exposed to non-functionalized polystyrene nanobeads of 50 nm and 100 nm in diameter according to adapted OECD 202 test protocol.ResultsEC50s 48 h varied from 0.2 to 8.9 mg L−1 (mean 2.49 mg L−1) for 50 nm beads, and from 32.7 to 90.3 mg L−1 (mean 59.39 mg L−1) for the 100 nm. EC10s 48 h varied from 0.0007 to 7.5 mg L−1 (mean 0.28 mg L−1) for 50 nm beads, and from 25.5 to 69.1 mg L−1 (mean 47.51 mg L−1) for the 100 nm. Inter-clonal variability was about tenfold. Therefore, several 1000 s-fold variations in mass-based ecotoxicity for these polystyrene beads was observed if particle size and Daphnia genotype are considered jointly.ConclusionsSuch ecotoxicity potential is comparable to highly toxic chemicals in global and EU-based regulatory classification and labelling. Ecotoxicity based on particle counts suggested convergence of EC50s, with effects generally observed around 1011 to1015 particles L−1. The present results highlight the potential high hazard of these particles and the relevance of particle size and exposure metrics on hazard conclusion.Graphical

In silico and in vitro evaluation of a safety profile of a cosmetic ingredient: 4-methoxychalcone (4-MC)

Chalcone is an important scaffold within medicinal and cosmetic chemistry. The structure enables multiple modifications which may result in obtaining compounds with desirable bioactivity. One of the chalcone derivatives, 4-methoxychalcone is a known cosmetic ingredient indexed in Cosing database as an antioxidant, bleaching, and skin conditioning substance. We investigated its in silico and in vitro safety profile. In silico study using Derek Nexus showed its potential of skin sensitisation, equivocal nature of chromosome damage in vitro in mammals, but also no mutagenic properties. In vitro research proved its activity as melanogenesis inhibitor in B16F10 cell line at the doses 12.5–3.125 μM. Evaluations performed in various cell lines showed that the cytotoxic doses were 50–25 μM. Tests in Episkin™ proved its ability to penetrate across epidermis and enabled classification of 2% formulation in PEG as non-irritant. In micronucleus tests it showed no genotoxicity. Studies in Cunninghamella echinulata model proved that 4-methoxychalcone was metabolised to less lipophilic products. 4-methoxychalcone showed phototoxic potential, its EC50(+UV) = 3.57 μg/mL, PIF = 10.19 and MPE = 0.428 were comparable to chlorpromazine. Moreover, 4-methoxychalcone showed ecotoxic potential in Microtox® assay with EC50(5 min) = 0.0047 mg/L and EC50(15 min) = 0.0033 mg/L. Although active doses were lower than toxic ones, some potential safety risks were noticed. Especially, due to the phototoxicity potential of 4-methoxychalcone, its use as depigmenting agent should involve avoidance of sunlight and use of appropriate photoprotection.

Simultaneous degradation of binary fluoroquinolone antibiotics by B and N in-situ self-doped guar gum hydrogel

Using guar gum (GG) as the raw material and borax (B) as the cross-linker, zeolitic imidazolate framework-8 (ZIF-8) was in-situ loaded into the 3D network of GG hydrogel, forming a highly efficient catalytic material GG-B-ZIF-8 combined with a subsequent low-temperature calcination process. In GG-B-ZIF-8 activated peroxymonosulfate (PMS) system, binary norfloxacin (NOR) and ciprofloxacin (CIP) could be removed simultaneously, with the degradation efficiency of >99.9% within 1 h. This system was adaptable to a wide pH range of 3.0–9.0, and was also highly resistant to 5–20 mM Cl− and 10–40 mg/L humic acid. The degradation process was dominated by free radical O2•-, non-radical 1O2 and electron transfer, with eleven degradation products identified for NOR and nine for CIP via eight possible degradation pathways. Finally, the potential eco-toxicity of NOR, CIP and degradation intermediates was evaluated using the ECOSAR method.

Red mud-based biochar activated peroxydisulfate under visible light for tetracycline removal: Synergistic effect of FeAl2O4 photocatalysis

Heterogeneous photocatalytic activation of persulfate (PDS) attracted much attention due to its positive environmental impact and efficacy in wastewater treatment. In this paper, a number of photocatalysts (RHRMX) were successfully synthesized by co-pyrolysis with rice husk (RH) using red mud (RM) as a precursor of Fe. Among them, RHRM50 exhibited excellent catalytic performance, with a high degradation rate of 99.5% for 20 mg/L tetracycline hydrochloride (TCH) in 60 min and its mineralization rate of 85.1% under the synthesized photocatalytic coupled PDS activation. In addition, the degradation efficiency under light conditioned remained above 95% after 5 cycles. The combination of the photoelectric properties and the Mott-Schottky spectrum of RHRM50 suggested that the photocatalysis was mainly attributable to FeAl2O4, with the energy band gap was determined to be 1.782 eV. Electron spin resonance (ESR) and burst experiments showed that under light, the FeAl2O4 generated holes mainly reacted with PDS to form 1O2, which was the main factor leading to the increase in the degradation rate. Based on density functional theory (DFT) calculations and identification of intermediates by liquid chromatography-mass spectrometry (LC-MS), hypothetical four potential pathways for TCH degradation were proposed. In addition, the potential ecotoxicity of TCH and its intermediates was evaluated using the ecological conformational relationship (ECOSAR). In conclusion, the green strategy of using RM to prepare RHRMX had a broad application prospect in the field of wastewater treatment and environmental protection.

Life cycle assessment of fermentative xylitol production from wheat bran: A comparative evaluation of sulphuric acid and chemical-free wet air oxidation-based pretreatment

Xylitol, a sugar alcohol is a low-calorie sweetener has wide applications in food and pharmaceutical industry and hence considered as a high value premium product. The conventional methods for fermentative xylitol production uses chemicals (acid/alkali) which generates inhibitors affecting fermentation and downstream purification of xylitol. In the present study, wet air oxidation was evaluated as a chemical-free pretreatment option of wheat bran for xylose release which is subsequently fermented to xylitol. Life cycle assessment was used as a tool to compare wet air oxidation with conventional methods like dilute acid pretreatment for valorization of wheat bran, a model agro-industrial remnant. A comparative evaluation of wet air oxidation and dilute acid pretreatment was investigated for fermentative production of xylitol (1 g/L as functional unit) with the aim of identifying the process involved with the lowest environmental impact, while also demonstrating the higher xylose recovery of 13.52 g/L coupled with FO based concentration unit. The inputs and outputs of the process involving energy use, chemicals employed, and emissions produced were evaluated with respect to food and environment perspective. Environmental impacts of wet air oxidation and dilute acid pretreatment with fermentative xylitol production of 6.134 and 1.42 g/L, respectively showed emission results of 1.476 and 5.288 kg CO2 equivalent, respectively. Though, primary energy demand of wet air oxidation was almost found to be equivalent to dilute acid, due to energy penalty for reactor mixing was higher in wet air oxidation. However, energy demand of wet air oxidation-based pretreatment was found to be energy efficient by 30% as compared to dilute acid. Coupling biogas reduces energy demand by 3.5%. The reduction in impacts relevant to food safety namely, marine aquatic and freshwater ecotoxicity potential were found by 74.29% and 84.97% substantially lower in wet air oxidation as compared to dilute acid based xylitol production. The effect of sulphate, as input form of sulphuric acid in dilute acid showed an impact of 3.83 folds higher on human toxicity potential as compared to wet air oxidation pretreatment process.

Assessing the impact of heavy metal pollution in Nike River using a life cycle approach

The threat of heavy metals contamination in the aquatic environment is more serious than those of other pollutants due to their non-bio-degradable nature and accumulative properties. This research project investigated some water quality parameters and heavy metals present in Nike Lake. In this study, three different water and sediment samples was collected from the upstream mid-stream and downstream of Nike Lake by submerging the sample bottle at about 0.5ft below the water surface and transferred into metal-free bottle that was used for all the analysis. The results of the physiochemical respectively forupstream, midstream and downstream were pH 5.49, 4.94, 5.41, conductivity was 72.3 µs/cm, 72.1 µs/cm, 72.0 µs/cm respectively, dissolve oxygen was 9.4mg/l, 9.6 mg/l, 10.4 mg/l, biochemical oxygen demand was 4.6 mg/l, 6.0 mg/l, 5.8 mg/l, nitrate was 0.28 mg/l, 0.31 mg/l, 0.32 mg/l and sulphate was 10.40 mg/l, 9.71 mg/l, 9.72. The water and sediment analysis showed that the heavy metals deviated slightly above their respective permissive levels when compared to WHO standard majorly at the upstream. The ecotoxicity potential of the heavy metal in the water sample at the upstream, mid-stream and downstream of Nike Lakewere 274.04 mg, 23.651 and 243.542 while that of the sediment sample were 0.03546 mg, 0.00015 mg and 0.0288 mg respectively. A higher impact of the ecotoxicity implies a higher source of the heavy metals at the points concerned, and higher negative health consequences directly to the aquatic organisms and indirectly to humans through consumption.

Modeling and optimization of advanced oxidation treatment of dexamethasone from aquatic solutions using electro-peroxone/ultrasonic process: Application for real wastewater, electrical energy consumption and degradation pathway

Dexamethasone (DXM) is a widely used anti-inflammatory corticosteroid that is frequently detected in the water bodies due to its immense consumption and incomplete removal during wastewater treatment. The potential eco-toxicity of pharmaceutical pollutants and their insufficient removal in conventional wastewater treatments have provoked researchers to investigate and develop novel and highly efficient treatment systems. The present study aimed to develop a synergistic advanced oxidation system based on electro-peroxone coupled with ultrasonic irradiation (EP/US process) for the degradation of dexamethasone (DXM) from water medium and an EP/US process assisted with granular activated carbon (GAC) for the remediation of real pharmaceutical wastewater. The effects of various experimental parameters such as pH, operating time, US power, applied current, and supporting electrolyte (Na2SO4) were systematically investigated by using response surface methodology based on central composite design (RSM-CCD), and results established that the complete degradation of DEX was attained at pH 9, operating time 25 min, US power 300 W/L, applied current 420 mA, and supporting electrolyte 0.05 M. The results of analysis of variance and regression analysis revealed that the second-order polynomial equation is more suitable (R2 = 0.9981 and p-value = 0.0004) to predict removal efficiency and describe the oxidation process. Under optimized experimental condition, the integrated EP/US process provided synergy and lessenergyconsumption compared to individual EP and US processes. The removal efficiency of TOC and COD reached 44.2% and 70.8% after 25 min reaction and increased to 78.7 % and 94.4%, respectively, as contact time increased to 50 min. Also, average oxidation state (AOS) and carbon oxidation state (COS) values increased from 0.22 to 3.28 and 3.78, respectively. Scavenger tests disclosed that HO• radical is the predominant reactive free radical generated in the EP/US system, and LC-MS analysis indicated that different intermediates are produced during DEX decomposition. The EP/US system increased the BOD/COD ratio of real pharmaceutical wastewater from 0.27 to 0.5 during 100 min treatment time, while in the presence of GAC, the EP/US process showed better results. Overall, the present study highlights that the coupling of EP/US processes noticeably improves the DEX abatement rate from water medium, and GAC can improve the efficiency of this process for pharmaceutical wastewater treatment. The findings of the present study propose the EP/US and EP/US/GAC systems as promising efficient alternatives for treating persistentpharmaceutical wastewater.

Integrated microbiome and multi-omics analysis reveal the molecular mechanisms of Eisenia fetida in response to biochar-derived dissolved and particulate matters

At present, most ecotoxicological studies are still confined to focusing on the harmful effects of biochar itself on soil fauna. However, the potential ecotoxicity of different components separated from biochar to terrestrial invertebrates remains poorly understood. In this study, the dissolved matter (DM) and particulate matter (PM) were separated from biochar (BC) and then introduced into the soil-earthworm system to investigate the response mechanism of earthworms at the molecular level. The results showed that BC and DM exposure caused an increase in the abundance of Proteobacteria in the cast bacterial community, suggesting the dysbiosis of intestinal microbiota. It was also observed that the cast bacterial communities were more sensitive to DM exposure than PM exposure. Transcriptomic analysis showed that BC and DM exposure induced significant enrichment of functional pathways related to infectious and neuropathic diseases. Metabolomic profiling manifested that DM exposure caused metabolic dysfunction, antioxidant and detoxification abilities recession. Furthermore, significant differences in the responses of earthworms at transcriptomic and metabolic levels confirmed that DM exhibited greater ecotoxicity than PM. This study highlighted the significant contributions of dissolved matter to the ecotoxicity of biochar from the perspective of transcriptomic and metabolomic profiles.

Effect of common low-molecular-weight organic acid on the photodegradation of sertraline by ferrihydrite

Sertraline is one of the most commonly used antidepressant pharmaceuticals with ubiquitous distribution in the aqueous environment. However, the environmental behavior of sertraline in the co-presence of low-molecular-weight organic acid (LMWOA) and iron oxide mineral is still poorly understood. In this study, the photodegradation of sertraline was systematically investigated in a common photosensitizing system (ferrihydrite (Fh)-LMWOA). Six LMWOAs, including citrate acid (CA), tartrate acid (TA), malate acid (MA), lactate acid (LA), succinate acid (SA) and malonic acid (MOA) were chosen as the representatives. Our results implied that the different Fe3+ dissolution rates would lead to rather different sertraline degradation patterns following the order of Fh-CA > Fh-TA > Fh-MA > Fh-LA > Fh-SA > Fh-MOA. The reaction was initiated by the interaction between LMWOA and Fh via ligand-promoted-dissolution mechanism. Furthermore, the Fe3+ dissolution rates also showed a strong correlation with the metal-organic complexation constants, indicating that the photodegradation process is strongly related to the complexation ability of LMWOA with Fe3+. •OH, O2•- and CO2•- were detected, indicating that they contributed to the photodegradation of sertraline. •OH was demonstrated to be the dominant Reactive oxygen species (ROS) for the degradation of sertraline, and the detailed transformation pathways were proposed based on the product analysis and theoretical calculation. According to the ecological structure activity relationship estimation, the photodegradation products of sertraline possessed lower toxicity compared to the parent compound. These findings contribute to a more comprehensive understanding of the environmental fate of sertraline and evaluate its potential ecotoxicity in natural systems.

Aerobic degradation of parent triisobutyl phosphate and its metabolite diisobutyl phosphate in activated sludge: Degradation pathways and degrading bacteria

Although organophosphate esters (OPEs) degradation has been widely studied, the degradation of their metabolites is always ignored. Triisobutyl phosphate (TiBP), a typical alkyl-OPEs, is of emerging concern because of its potential ecotoxicity in the environment. This study provides comprehensive understanding about the degradation of TiBP and one of its metabolites, diisobutyl phosphate (DiBP) using activated sludge (AS). The results showed that TiBP and DiBP were degraded mainly through hydrolysis, dehydrogenation, and hydroxylation. The degradation kinetics indicated that DiBP had similar transformation rates to its parent TiBP in AS, highlighting the importance of metabolite DiBP study. Dehydrogenase, hydroxylase, phosphotriesterase, phosphodiesterase, and phosphomonoesterase played an important role in contributing to TiBP and its metabolites degradation via enzyme activity analysis. Besides, the expression of genes encoding these enzymes in bacteria and the relative abundance change of bacterial populations indicated that Sphingomonas and Pseudomonas may be the degrading bacteria of TiBP and Pseudomonas may be the main degrading bacteria of DiBP. This study provides new perspectives for metabolite DiBP and its parent TiBP degradation. It highlights that the formation and degradation of metabolites must be considered into the future researches.

Exposure of Lemna minor (Common Duckweed) to Mixtures of Uranium and Perfluorooctanoic Acid (PFOA).

A variety of processes, both natural and anthropogenic, can have a negative impact on surface waters, which in turn can be detrimental to human and environmental health. Few studies have considered the ecotoxicological impacts of concurrently occurring contaminants, and that is particularly true for mixtures that include contaminants of emerging concern (CEC). Motivated by this knowledge gap, the present study considers the potential ecotoxicity of environmentally relevant contaminants in the representative aquatic plant Lemna minor (common duckweed), a model organism. More specifically, biological effects associated with exposure of L. minor to a ubiquitous radionuclide (uranium [U]) and a fluorinated organic compound (perfluorooctanoic acid [PFOA], considered a CEC), alone and in combination, were monitored under controlled laboratory conditions. Lemna minor was grown for 5 days in small, aerated containers. Each treatment consisted of four replicates with seven plants each. Treatments were 0, 0.3, and 3 ppb PFOA; 0, 0.5, and 5 ppb U; and combinations of these. Plants were observed daily for frond number and signs of chlorosis and necrosis. Other biological endpoints examined at the conclusion of the experiment were chlorophyll content and antioxidant capacity. In single-exposure experiments, a slight stimulatory effect was observed on frond number at 0.3 ppb PFOA, whereas both concentrations of U had a detrimental effect on frond number. In the dual-exposure experiment, the combinations with 5 ppb U also had a detrimental effect on frond number. Results for chlorophyll content and antioxidant capacity were less meaningful, suggesting that environmentally relevant concentrations of PFOA and U have only subtle effects on L. minor growth and health status. Environ Toxicol Chem 2023;42:2412-2421. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

An Environmental Impact Assessment of Largemouth Bass (Micropterus salmoides) Aquaculture in Hangzhou, China

With the rapid increase in aquaculture production, its role in food safety and nutritional security has become increasingly important, but this has also given rise to environmental problems that cannot be ignored. The largemouth bass (Micropterus salmoides) has become a widely cultivated and highly economic freshwater farmed species since it was introduced to China in 1983; however, the environmental impacts of its freshwater pond aquaculture process have not yet been elucidated. Here, life cycle assessment (LCA), a decision-making tool that can evaluate and identify environmental issues during production processes, was used to evaluate the environmental performance of the largemouth bass freshwater pond aquaculture process, and a large-scale, commercial company was selected as an example in Hangzhou, China. The results showed that the pond-farming stage and marine aquatic ecotoxicity potential (MAETP) had the largest environmental impacts on the entire aquaculture process. An environmental contribution analysis indicated that electricity (48%) and emissions (23%) were two key factors in the seed-rearing stage, and electricity (60%) and feeds (26%) were two main impact contributors in the pond-farming stage. Improvement measures based on emerging technologies in aquaculture were discussed, namely, clean energies, industrial pond farming, and intelligent feeding strategies, to help with decision making for continuous improvement in the environmental performance of largemouth bass pond farming. Moreover, suggestions for further aquaculture LCA studies in China were summarized, as they will provide a useful reference for promoting the development of China’s aquaculture LCA research and the enrichment of the world’s aquaculture life cycle inventory databases.

Facemasks: An insight into their abundance in wetlands, degradation, and potential ecotoxicity

Disposable facemasks represent a new form of environmental contamination worldwide. This study aimed at addressing the abundance of facemasks in an overlooked natural environment with high ecological and economic value – the wetlands (Ria de Aveiro, Portugal, as study case), evaluating their potential biodegradation using naturally occurring fungi and assessing the potential ecotoxicity of released microfibres on local bivalves.All masks collected within 6500 m2 area of Aveiro wetland were 100 % disposable ones (PP-based, confirmed by Fourier transform infrared spectroscopy - FTIR) with an initial abundance of 0.0023 items/m2 in Sept. 2021, which was reduced by ∼40 % in Apr. 2022 and ∼87 % in Sept. 2022, as a reflection of the government policies. Analysis of the carbonyl index (0.03 to 1.79) underlined their state of degradation, primarily due to sun exposure during low tides. In laboratory conditions, 1 mm2 microplastics obtained from new disposable facemasks were prone to biodegradation by Penicillium brevicompactum and Zalerion maritimum inferred from microplastics mass loss (∼22 to −26 % and ∼40 to 50 %, respectively) and FTIR spectra (particularly in the hydroxyl and carbonyl groups). In addition, microfibres released from facemasks induced sublethal effects on the clam, Venerupis corrugata, mostly in their UV-aged form when compared to pristine ones, characterised by a decrease in cellular energy allocation (CEA) and an increase in aerobic energy metabolism (ETS). Concomitantly, clams exposed to 1250 items/L of UV-aged microplastics (similar to field-reported concentrations) expressed greater clearance capacity, indicating a need to compensate for the potential energy unbalance.This study provides the first baseline monitoring of facemasks in wetlands while bringing new evidence on their biodegradation and ecotoxicity, considering environmentally relevant conditions and keystone organisms in such environments. Such studies require scientific attention for rapid regulatory action against this emerging and persistent pollutant, also targeting remediation and mitigation strategies considering these items under pandemic scenarios.