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• O 3 reacts with KET to form Criegee intermediates through ring-opening. • HO· can greatly promote the degradation of KET in UV/O 3 process. • Kinetics modeling in UV/O 3 was performed to study the effect of parameters on efficiency. • Some products still have eco-toxicity effects on aquatic organisms. Ketoprofen (KET), as a non-steroidal anti-inflammatory drug frequently detected in aqueous environments, is a threat to human health due to its accumulation and low biodegradability, which requires the transformation and degradation of KET in aqueous environments. In this paper, the reaction process of ozone-initiated KET degradation in water was investigated using density functional theory (DFT) method at the M06-2X/6-311++g(3df,2p)//M06-2X/6-31+g(d,p) level. The detailed reaction path of KET ozonation is proposed. The thermodynamic results show that ozone-initiated KET degradation is feasible. Under ultraviolet irradiation, the reaction of ozone with water can also produce OH radicals (HO·) that can react with KET. The degradation reaction of KET caused by HO· was further studied. The kinetic calculation illustrates that the reaction rate (1.99 × 10−1 (mol/L)−1 sec−1) of KET ozonation is relatively slow, but the reaction rate of HO· reaction is relatively high, which can further improve the degradation efficiency. On this basis, the effects of pollutant concentration, ozone concentration, natural organic matter, and pH value on degradation efficiency under UV/O 3 process were analyzed. The ozonolysis reaction of KET is not sensitive to pH and is basically unaffected. Finally, the toxicity prediction of oxidation compounds produced by degradation reaction indicates that most of the degradation products are harmless, and a few products containing benzene rings are still toxic and have to be concerned. This study serves as a theoretical basis for analyzing the migration and transformation process of anti-inflammatory compounds in the water environment. [ABSTRACT FROM AUTHOR]

Cellulose nanofibers (CNFs) are nanomaterials with several potential applications in nanotechnology-based products, and their renewable origin and biodegradability property have attracted attention in sustainable product development; however, their environmental impacts still need to be fully understood as other nanoparticles. In this study, CNFs obtained from bleached cellulose pulp of Eucalyptus sp were evaluated regarding their potential to affect terrestrial and aquatic ecosystems. Thus, an ecotoxicity testing battery composed of phytotoxicity test, plant genotoxicity assay, earthworm acute toxicity test, algal chronic toxicity test, and Daphnia magna acute immobilization test was considered herein. Also, mean diameter and zeta potential were investigated in CNF exposure media to evaluate its aggregation behavior. CNFs did not present acute toxicity to aquatic organisms (algae and microcrustaceans) and did not cause lethal effects on earthworms. The results from plant test systems showed that CNFs did not inhibit seed germination or root development or cause cellular and genetic changes in plant cells. This later result does not agree with the scientific literature, which reported genotoxicity for other types of nanocellulose, which suggests that chemical identity and physicochemical properties can influence the toxicity of nanocelluloses. Thus, CNF kraft-bleached pulp is not toxic to key organisms of both aquatic and terrestrial ecosystems. Probably, larger aggregates precipitated in the aquatic toxicity tests, preventing the interaction of nanoparticles with the living organisms. Therefore, the findings presented here open a good perspective of applications of CNF kraft-bleached pulp on nanotechnology-based products as potential environmentally safe nanomaterial. [ABSTRACT FROM AUTHOR]

The release in aquatic environments of emergent contaminants such as copper oxide nanoparticles (CuO-NPs) has generated concerns on their short- and long-term toxicity and the potential risk for more vulnerable animal groups, such as amphibians. In this sense, the aim of this work was to evaluate the toxicity of CuO-NPs in comparison with its respective salt (CuCl2) in embryos and larvae of a native amphibian, Rhinella arenarum, by acute (96 h) and chronic (504 h) standardized bioassays. Lethality and sublethal effects such as developmental, morphological, and ethological alterations were assessed in a wide range of concentrations (0.001–100 mg/L). Neurotoxic effects by acetyl (AChE) and butyrylcholinesterase (BChE) activity levels and changes in the lipid content were also assessed at sublethal concentrations. Results showed that CuCl2 caused higher lethality than CuO-NPs in both developmental periods. Embryos were more sensitive than larvae with LC50-96 h = 0.080 mg CuCl2/L and 1.26 mg CuO-NPs/L and 0.21 mg CuCl2/L and 20.17 mg CuO-NPs/L, respectively. At acute exposure, embryos exhibited several developmental abnormalities such as developmental delay, edema, axial flexure, and microcephaly. Larvae presented spasmodic contractions and weak movements. Regarding neurotoxicity, a significant increase in AChE activity at low concentrations as well as an inhibition of BChE activity at all tested concentrations was evidenced for both substances at acute exposure. Moreover, an increment in phospholipid and triglyceride levels was observed at the highest concentration of CuO-NPs (10 mg/L) at chronic exposure. The chromatographic separation of lipids showed no apparent differences in acylglycerols and free fatty acid bands, between the treatments and the control. The differences in toxicity between CuO-NPs and CuCl2 could be due to structural and physicochemical characteristics that influence their bioavailability and toxicity. Considering the exponential growth in the production and use of these substances, it is expected that the levels of contamination will rise considerably in the future, so that wildlife, particularly aquatic organisms, will be more increasingly exposed, representing a potential risk for their populations. [ABSTRACT FROM AUTHOR]

Abstract Multi-species tests in bioassays offer a holistic view of the ecosystem’s response to toxicity, as different species display varying sensitivities to pollutants. This research aimed to assess the ability of toxicity tests’ to distinguish contamination levels, examine site-specific effects, and investigate seasonal variability. Using a multispecies approach (Nannochloropsis oceanica, Artemia franciscana, and Arbacia nigra), bioassays evaluated marine water quality from Callao Bay in Peru across four sampling areas (Naval School: PA1, Peruvian Marine Institute: PA2, Callao Pier: PA3, and San Lorenzo Island: PA4). These species, with varying sizes and morphologies, are relevant to marine systems and ideal for multispecies toxicity testing, contributing to broader environmental impact discussions. To conduct toxicity bioassays, seasonal evaluations were performed in fall, winter, spring, and summer. Brine shrimp displayed seasonal variations in toxicity values, with notable mortality rates during winter. Nannochloropsis oceanica was the most sensitive species, showing moderate toxicity across seasons. Areas impacted by pollution sources, such as wastewater and maritime traffic, exhibited the highest toxicity levels (PA3 and PA4). These fluctuations underscore the need to consider seasonal and local conditions when assessing organism sensitivity to seawater contaminants. Additionally, they reveal the complex interplay between environmental factors, water quality, and organism responses in marine ecosystems.

AbstractThe fast-increasing use of chemicals led to large numbers of chemical compounds entering the aquatic environment, raising concerns about their potential effects on ecosystems. Therefore, assessment of the ecotoxicological features of organic compounds on aquatic organisms is very important. Daphnia magna and Fathead minnow are two aquatic species that are commonly tested as standard test organisms for aquatic risk assessment and are typically chosen as the biological model for the ecotoxicology investigations of chemical pollutants. Herein, global quantitative structure–toxicity relationship (QSTR) models have been developed to predict the toxicity (pEC(LC)50) of a large dataset comprising 2106 chemicals toward Daphnia magna and Fathead minnow. The optimal descriptor of correlation weights (DCWs) is calculated using the notation of simplified molecular input line entry system (SMILES) and is used to construct QSTR models. Three target functions, TF1, TF2, and TF3 are utilized to generate 12 QSTR models from four splits, and their statistical characteristics are also compared. The designed QSTR models are validated using both internal and external validation criteria and are found to be reliable, robust, and excellently predictive. Among the models, those generated using the TF3 demonstrate the best statistical quality with R2 values ranging from 0.9467 to 0.9607, Q2 values ranging from 0.9462 to 0.9603 and RMSE values ranging from 0.3764 to 0.4413 for the validation set. The applicability domain and the mechanistic interpretations of generated models were also discussed. [ABSTRACT FROM AUTHOR]

Experiments are routinely conducted to evaluate the toxicity of water effluents or chemicals. In a Ceriodaphnia dubia reproduction test, organisms are exposed to varying concentration levels of the toxicant or other adverse treatment and the number of young produced after a given experiment period are recorded. To analyze the test outcomes, mean reproduction is modeled as a function of the concentration, and the estimated concentrations associated with specified levels of adverse effect often are used in risk management. While aquatic toxicity analyses often focus on outcomes from the current test, laboratories commonly have a history of conducting such tests using the same species, following a similar experimental protocol. So it seems reasonable to assume that the same underlying biological process generates the historical and current tests. In the present study, we propose using a calibrated power prior approach to incorporate historical control outcomes as prior input, and compare the behavior of the method when different congruence measures are used to determine the amount of historical input that will be incorporated. Simulation results show that three of the congruence measures can improve precision and reduce bias of the potency estimates.Supplementary material to this paper is provided online. [ABSTRACT FROM AUTHOR]

Climate changes linked to extreme events pose a threat to freshwater biodiversity, impacting organs, behaviour, and reproduction. Moreover, these changes can be amplified by pollution. Copper sulphate (CuSO4) is used in agriculture and aquaculture, so the copper can reach streams, rivers, and lakes impacting fish. This study evaluated the combined effects of temperature and copper on gills and liver histology biomarkers and in the behaviour of Mozambique tilapia over 28 days. Tilapias were exposed to different water temperatures (25 °C and 32 °C) and CuSO4 concentrations (1.1 and 3.6 mg/L). Fish from the control group were exposed to water without copper sulphate and at 25 °C (within their optimum range). Histopathological analysis revealed significant tissue lesions, namely aneurysms and bending of gill lamellae, and hyalinization and vacuolization in the liver at the higher temperature and CuSO4 level. Moreover, behavioural observations revealed increased stress changes under the same conditions. These findings highlight the effects of fast climate change, and rising temperatures on copper toxicity, underlining the necessity for strict monitoring and regulation of copper use due to future climate change scenarios to protect aquatic ecosystems, ichthyofauna population and trophic web dynamics. This data also alerts for similar problems with other toxic metals or chemicals, at short term, in streams and rivers, under rapid climate changes and more frequent extreme events. [ABSTRACT FROM AUTHOR]

Approximately half of the lubricants sold globally find their way into the environment. The need for Environmentally Acceptable Lubricants (EALs) is gaining increased recognition. A lubricant is composed of a base oil and multiple functional additives. The literature has been focused on EAL base oils, with much less attention given to eco-friendly additives. This study presents the tribological performance and aquatic toxicity of four short-chain phosphonium-phosphate and ammonium-phosphate ionic liquids (ILs) as candidate anti-wear and friction-reducing additives for EALs. The results are benchmarked against those of four commercial bio-derived additives. The four ILs, at a mere 0.5 wt% concentration in a synthetic ester, demonstrated a 30–40% friction reduction and >99% wear reduction, superior to the commercial baselines. More impressively, all four ILs showed significantly lower toxicity than the bio-derived products. In an EPA-standard chronic aquatic toxicity test, the sensitive model organism, Ceriodaphnia dubia, had 90–100% survival when exposed to the ILs but 0% survival in exposure to the bio-derived products at the same concentration. This study offers scientific insights for the future development of eco-friendly ILs as lubricant additives. [ABSTRACT FROM AUTHOR]

Rare earth elements (REEs) are widely used in various industries, such as electronics, renewable energy, and manufacturing, leading to their gradual accumulation in ecosystems, including water environments. As emerging pollutants, REEs find their way into water bodies through various channels, such as industrial discharge, mining runoff, and sewage. Despite their growing presence, the understanding of their toxicity in aquatic organisms is limited, representing a significant gap in current research. This review studies the bioaccumulation and toxicity of REEs in aquatic organisms, highlighting factors such as water chemistry, speciation, and organism characteristics that influence their uptake and effects. REEs can induce oxidative stress, ion imbalance, enzyme inhibition, and reproductive toxicity in aquatic species, leading to potential impairments in growth, survival, and reproduction. The ecological consequences of REE contamination extend beyond individual species and potentially affect community structures, disrupt food webs, and alter ecosystem functioning. This review emphasizes the urgent need for international regulatory guidelines to manage REE pollution in aquatic environments to protect biodiversity and ecosystem health.

In the present world, everyone is health, hygiene, and beauty conscious. Most households use different personal care products (PCPs) to keep themselves clean and hygienic. But when it comes to disposal, not much care is taken. PCPs are being liberated into the environment on a regular basis causing harm to the ecosystem. The prevalence of these PCPs as soaps, nail paints, hair dyes, fragrances, emulsifiers, antioxidants, ultraviolet absorbers, preservatives, disinfectants, etc. is posing severe health concerns. It has been studied that together these PCPs being biologically active and highly persistent, in turn impacts the lives of living beings. This review work aimed to elucidate and analyze the problems associated with personal care products when discharged into the aquatic system from different sources that cause detrimental effects on the organisms at different trophic levels and on human beings which has been included in this discussion, the variety of sources and how they impact the aquatic life as well as the movement of the emerging toxicants to the higher trophic levels through the food chain. This work also has analyzed the bioremediation of a few toxicants like, paraben, phthalate, sulphate by some potential microorganisms and the limitations in the microbial remediation process. [ABSTRACT FROM AUTHOR]

Tolfenpyrad, a highly effective and broad‐spectrum insecticide and acaricide extensively utilized in agriculture, presents a potential hazard to nontarget organisms. This study was designed to explore the toxic mechanisms of tolfenpyrad on zebrafish embryos. Between 24 and 96 h after exposure of the fertilized embryos to tolfenpyrad at concentrations ranging from 0.001 to 0.016 mg/L (96 h‐LC50 = 0.017 mg/L), lethal effects were apparent, accompanied with notable anomalies including pericardial edema, increased pericardial area, diminished heart rate, and an elongated distance between the venous sinus and the arterial bulb. Tolfenpyrad elicited noteworthy alterations in the expression of genes pertinent to cardiac development and apoptosis, with the most pronounced changes observed in the cardiac development‐related genes of bone morphogenetic protein 2b (bmp2b) and p53 upregulated modulator of apoptosis (puma). The findings underscore that tolfenpyrad induces severe cardiac toxicity and mitochondrial damage in zebrafish embryos. This data is imperative for a comprehensive assessment of tolfenpyrad risks to aquatic ecosystems, particularly considering the limited knowledge regarding its detrimental impact on aquatic vertebrates. [ABSTRACT FROM AUTHOR]

Deltamethrin (DLM), in combination with the synergist piperonyl butoxide (PBO), is extensively used in pest control programs due to its potent pesticidal properties and appreciable safety margin. However, various research studies report their adverse effects on non-target organisms. In this study, we investigated the toxicity of DLM, PBO, and a DLM-PBO (3:1) combination on Labeo rohita (L. rohita) fish fingerlings. Fish behavior and mortality rates were recorded at different time intervals up to 96 h for concentrations of 0.003, 0.007, 0.015, 0.031, and 0.062 µg/mL, respectively. Biochemical, hematological, and histopathological studies were carried out. High-performance liquid chromatography (HPLC) was used to detect and quantify residues in fish samples. The LC50 values after 48 h for DLM, PBO, and DLM-PBO exposed fish fingerlings were found to be 0.028, 0.066, and 0.007 µg/mL, respectively. At a concentration of 0.003 µg/mL of DLM, PBO, and DLM-PBO, the treated fish fingerlings exhibited similar behavior to the control group. Hematological parameters, such as red blood cell (RBC) and white blood cell (WBC) counts, were reduced in the treated groups compared to the control. Biochemical parameters showed increased levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), while total serum protein levels decreased in DLM, PBO, and DLM-PBO treated fingerlings. Histopathological examination of liver, gill, and heart tissues revealed lesions with hydropic degeneration in the liver and fusions of gill lamellae in the treated tissues. Fish fingerlings exposed to the DLM-PBO combination appeared highly prone to toxicity compared to those treated with DLM and PBO separately.

Background and purpose: Organic UV filters are commonly used in sunscreen and cosmetic formulations to protect against harmful UV radiation. However, concerns have emerged over their potential toxic effects on aquatic organisms. This study aims to investigate the acute aquatic toxicity of 13 organic UV filters and determine whether phospholipid binding, measured through biomimetic chromatographic methods, is a better predictor of toxicity than the traditionally used octanol-water partition coefficient (log P). Experimental approach: The chromatographic retention of the 13 UV filters was measured on an immobilized artificial membrane (IAM) stationary phase to assess phospholipid binding. These measurements were then applied to previously established predictive models, originally developed for pharmaceutical compounds, to estimate acute aquatic toxicity endpoints of 48-hour LC50 for fish and the 48-hour EC50 (immobilization) for Daphnia magna. Key results: Phospholipid binding was found to be a more reliable predictor of the acute aquatic toxicity of UV filters compared to log P. The toxicity was primarily driven by lipophilicity and charge, with negatively charged compounds exhibiting lower toxicity. Conclusion: The study demonstrates that phospholipid binding is a better descriptor of UV filter toxicity than log P, providing a more accurate method for predicting the environmental risk of these compounds. This insight can guide the development of more environmentally friendly sunscreens by reducing the use of highly lipophilic and positively charged compounds, thus lowering their aquatic toxicity.

Pesticides employed worldwide for crop protection easily reach aquatic systems, which act as the main reservoirs, and become a risk factor for aquatic fauna. Fipronil is a broad‐spectrum insecticide acting on the insect nervous system; however, other effects and systems unrelated to this mechanism could be affected in non‐target organisms. Thus, the present study aimed to assess the impact of fipronil on the suborganismal response (gene expression and enzymatic activity) of Chironomus riparius larvae as a model organism in ecotoxicology. To this end, short‐term toxicity tests were carried out with fourth‐instar larvae exposed to 0.001, 0.01, and 0.1 µg L−1 of fipronil for 24 and 96 h. Messenger RNA levels of 42 genes related to diverse metabolic pathways were analyzed by real‐time polymerase chain reaction, complemented with catalase (CAT), glutathione S‐transferase (GST), and acetylcholinesterase (AChE) activities. Few effects were observed at 24 h; however, after longer exposure (96 h), genes involved in the endocrine, detoxification, stress, and immune response pathways were altered. Moreover, fipronil at 96 h increased CAT and GST activity at 0.01 µg L−1 and AChE at the highest concentrations. The results demonstrate that even low environmentally relevant fipronil concentrations can modulate the molecular response of several cellular pathways in C. riparius after short‐term exposure. These results bring new information about the underlying response of fipronil and its mode of action on a key aquatic invertebrate. Despite no effects on mortality, strong modulation at the suborganismal level emphasizes the advantage of biomarkers as early damage responses and the harmful impact of this pesticide on freshwater organisms. Environ Toxicol Chem 2024;43:405–417. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Difenoconazole has a widespread agricultural use to control fungal diseases in crops, including rice. In edge-of-field surface waters the residues of this lipophilic fungicide may be toxic to both pelagic and benthic organisms. To allow an effect assessment we mined the regulatory and open literature for aquatic toxicity data. Since published sediment toxicity data were scarce we conducted 28 d sediment-spiked toxicity test with 8 species of benthic macroinvertebrates. Ecotoxicological threshold levels for effects were assessed by applying the species sensitivity distribution approach. Based on short-term L(E)C50’s for aquatic organisms from water-only tests an acute Hazardous Concentration to 5% of the species (HC5) of 100 µg difenoconazole/L was obtained, while the HC5 based on chronic NOEC values was a factor of 104 lower (0.96 µg difenoconazole/L). For benthic macroinvertebrates the chronic HC5, based on 28d-L(E)C10 values, was 0.82 mg difenoconazole/kg dry weight sediment. To allow a risk assessment for water- and sediment-dwelling organisms, exposure concentrations were predicted for the water and sediment compartment of an edge-of-field pond bordering rice paddies treated with difenoconazole using the Chinese Top-Rice modelling approach, the Chinese Nanchang exposure scenario and the Equilibrium Partitioning theory. It appeared that in the vast majority of the 20 climate years simulated, potential risks to aquatic and sediment organisms cannot be excluded. Although the HC5 values based on laboratory toxicity data provide one line of evidence only, our evaluation suggests population- and community-level effects on these organisms due to chronic risks in particular.

The ability to employ waste products, such as vegetable scraps, as raw materials for the synthesis of new promising adsorbing materials is at the base of the circular economy and end of waste concepts. Dextrin-based nanosponges (D_NS), both cyclodextrin (CD) and maltodextrin (MD), have shown remarkable adsorption abilities in the removal of toxic compounds from water and wastewater, thus representing a bio-based low-cost solution which is establishing itself in the market. Nevertheless, their environmental safety for either aquatic or terrestrial organisms has been overlooked, raising concern in terms of potential hazards to natural ecosystems. Here, the environmental safety (ecosafety) of six newly synthesized batches of D_NS was determined along with their full characterization by means of dynamic light scattering (DLS), thermogravimetric analysis (TGA), Fourier transformed infrared spectroscopy with attenuated total reflection (FTIR-ATR) and transmission electron microscopy (SEM). Ecotoxicity evaluation was performed using a battery of model organisms and ecotoxicity assays, such as the microalgae growth inhibition test using the freshwater Raphidocelis subcapitata and the marine diatom Dunaliella tertiolecta, regeneration assay using the freshwater cnidarian Hydra vulgaris and immobilization assay with the marine brine shrimp Artemia franciscana. Impact on seedling germination of a terrestrial plant of commercial interest, Cucurbita pepo was also investigated. Ecotoxicity data showed mild to low toxicity of the six batches, up to 1 mg/mL, in the following order: R. subcapitata > H. vulgaris > D. tertiolecta > A. franciscana > C. pepo. The only exception was represented by one batch (NS-Q+_BDE_(GLU2) which resulted highly toxic for both freshwater species, R. subcapitata and H. vulgaris. Those criticalities were solved with the synthesis of a fresh new batch and were hence attributed to the single synthesis and not to the specific D_NS formulation. No effect on germination of pumpkin but rather more a stimulative effect was observed. To our knowledge this is the first evaluation of the environmental safety of D_ NS. As such we emphasize that current formulations and exposure levels in the range of mg/mL do not harm aquatic and terrestrial species thus representing an ecosafe solution also for environmental applications.

Synthetic surfactant products are continuously released into the aquatic environment in large quantities, posing a burden on ecosystems as a “pseudo–persistent” organic pollutant. Threshold derivation for protecting aquatic ecosystems is challenging due to the various homologous components of surfactants. In this study, five commercially available products were chosen as representative major types of surfactants. Corresponding quantitative structure–activity relationships (QSAR) were screened and subsequently combined with interspecific correlation estimation (ICE) to develop species sensitivity distributions (SSDs) for each component. Then, the 5th percentile hazard concentrations (HC5s) were calculated. The results indicated that the developed QSAR–ICE models demonstrated good toxicity prediction performance. The HC5 of each component showed a negatively correlation with alkyl chain length and a positive correlation with the amount of ethylene oxide. The HC5s of surfactants correlate with variations in their charged properties. Quaternary ammonium compounds (QAC) exhibited the lowest HC5s (8.5 ± 18.3 μg/L), followed by alcohol ethoxylates (AE), linear alkylbenzene sulfonates (LAS), and alcohol ethoxylated sulfates (AES); and alkyl oxide (AO) exhibited the highest HC5s (15784.2 ± 21552.6 μg/L). For cationic surfactants, the HC5s in the invertebrates were significantly lower than those in the fish; conversely, for anionic surfactants, the opposite was true, indicating a difference in the toxic mechanisms of surfactants with different charged properties across species taxa. Additionally, among invertebrates, shellfish demonstrated heightened sensitivity to surfactants, owing to their high accumulation and low metabolism of pollutants. Salmoniformes were the most sensitive among all species, indicating the necessity of prioritizing these species for aquatic ecological conservation in surfactant-contaminated waters.

Microplastics (MPs), which are small plastic particles measuring less than 5 mm in size, have emerged as a significant environmental concern in marine ecosystems worldwide. The presence of MPs in aquatic environments has increased due to the contributions from anthropogenic and terrestrial sources, raising concerns about their abundance in aquatic organisms. MPs primarily originate from the photo-degradation of larger plastic debris (macroplastics), with their release into the environment often occurring through the breakdown of additive compounds. The ingestion of MPs poses eco-toxicological risks to marine organisms, causing damage to the gastrointestinal (GI) tracts and stomachs of affected organisms. Approximately 80 % of MPs originate from terrestrial sources, which can be classified as either primary sources, such as those generated during the production of skincare products, tires, and the use of MPs as carriers for pharmaceutical products, or secondary sources resulting from the improper disposal of plastics near coastal areas and water bodies. The issue of MPs and their potential effects on the marine ecosystem demands significant attention. In conclusion, this review provides a comprehensive overview of the vulnerability of microplastics in marine environments, consolidating the current understanding of their sources, distribution, fate, and ecological impacts. It emphasizes the urgent need for ongoing research and proactive measures to mitigate the potential long-term consequences of microplastic pollution on marine ecosystems and the essential services they provide.

Pyrethroid and neonicotinoid pesticides control an array of insect pests in leafy greens, but there are concerns about the off-site movement and potential water quality impacts of these chemicals. Effective on-farm management practices can eliminate aquatic toxicity and pesticides in runoff. This project evaluated an integrated vegetated treatment system (VTS), including the use of polyacrylamide (PAM), for minimizing the toxicity of imidacloprid and permethrin pesticides in runoff. The VTS incorporated a sediment trap to remove coarse particles, a grass-lined ditch with compost swales to remove suspended sediment and insecticides, and granulated activated carbon (GAC) or biochar to remove residual insecticides. Runoff was sampled throughout the VTS and analyzed for pesticide concentrations, and aquatic toxicity using the midge Chironomusdilutus and the amphipod Hyalella azteca. In simulated runoff experiments, the VTS reduced suspended sediment load by 88%, and imidacloprid and permethrin load by 97% and 99%, respectively. In runoff events from a conventionally grown lettuce field, suspended sediment load was reduced by 98%, and insecticide load by 99%. Toxicity was significantly reduced in approximately half of the simulated runoff events, and most of the lettuce runoff events. Integrated vegetated treatment systems that include components for treating soluble and hydrophobic pesticides are vital tools for reducing pesticide load and occurrence of pesticide-related toxicity.

Ecotoxicological safety assessment of chemicals requires toxicity data on multiple species, despite the general desire of minimizing animal testing. Predictive models, specifically machine learning (ML) methods, are one of the tools capable of solving this apparent contradiction as they allow to generalize toxicity patterns across chemicals and species. However, despite the availability of large public toxicity datasets, the data is highly sparse, complicating model development. The aim of this study is to provide insights into how ML can predict toxicity using a large but sparse dataset. We developed models to predict LC50-values, based on experimental LC50-data covering 2431 organic chemicals and 1506 aquatic species from the ECOTOX-database. Several well-known ML techniques were evaluated and a new ML model was developed, inspired by recommender systems. This new model involves a simple linear model that learns low-rank interactions between species and chemicals using factorization machines. We evaluated the predictive performances of the developed models based on two validation settings: 1) predicting unseen chemical-species pairs, and 2) predicting unseen chemicals. The results of this study show that ML models can accurately predict LC50-values in both validation settings. Moreover, we show that the novel factorization machine approach can match well-tuned, complex, ML approaches. [ABSTRACT FROM AUTHOR]

Initially, density approximations and generalised gradient approximations (GGA) functional of DFT were executed to determine the electronic structure where the non-local functionals of GGA obtained more close value of reference value, so that GGA method was used to calculate the band structures, DOS, PDOS and optical properties of ZrO2, Zr0.93Si0.07O2 and Zr0.86Si0.14O2 using the Perdew–Burke–Ernzerhof (PBE), Revised Perdew–Burke–Ernzerhof (RPBE), Perdew Wang (PW91), and Wu-Cohen. The transferability of electrons is completely related to PseudoPotential (PP), where four methods, such as OTFG ultra-soft, OTFG norm-conserving, ultra-soft, and norm-conserving, were used in this study. Finally, the norm-conserving PP has been selected as the most accurate method for determination of electronic structure. In addition, to assess the nature of orbital, the DOS and PDOS were additionally simulated and even the optical properties of crystals were calculated. Furthermore, the chemical reactivity, such as HOMO and LUMO, quantum properties, is justified where doping can have a vast effect as well as the open circuit voltage (Voc) is increased after doping. Finally, the toxicity data from in silico study refers to us that these are non-toxic or non-carcinogenic materials with not readily biodegradable status. [ABSTRACT FROM AUTHOR]

The ecotoxicological impact of pharmaceuticals has received considerable attention, primarily focusing on active pharmaceutical ingredients (APIs) while largely neglecting the potential hazards posed by pharmaceutical excipients. Therefore, we analyzed the ecotoxicity of 16 commonly used pharmaceutical excipients, as well as 26 API–excipient and excipient–excipient mixtures utilizing the Microtox® test. In this way, we assessed the potential risks that pharmaceutical excipients, generally considered safe, might pose to the aquatic environment. We investigated both their individual ecotoxicity and their interactions with tablet ingredients using concentration addition (CA) and independent action (IA) models to shed light on the often-overlooked ecotoxicological consequences of these substances. The CA model gave a more accurate prediction of toxicity and should be recommended for modeling the toxicity of combinations of drugs with different effects. A challenge when studying the ecotoxicological impact of some pharmaceutical excipients is their poor water solubility, which hinders the use of standard aquatic ecotoxicity testing techniques. Therefore, we used a modification of the Microtox® Basic Solid Phase protocol developed for poorly soluble substances. The results obtained suggest the high toxicity of some excipients, i.e., SLS and meglumine, and confirm the occurrence of interactions between APIs and excipients. Through this research, we hope to foster a better understanding of the ecological impact of pharmaceutical excipients, prompting the development of risk assessment strategies within the pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Fullerene derivatives (FDs) are widely used in nanomaterials production, the pharmaceutical industry and biomedicine. In the present study, we focused on the potential toxic effects of FDs on the aquatic environment. First, we analyzed the binding affinity of 169 FDs to 10 human proteins (1D6U, 1E3K, 1GOS, 1GS4, 1H82, 1OG5, 1UOM, 2F9Q, 2J0D, 3ERT) obtained from the Protein Data Bank (PDB) and showing high similarity to proteins from aquatic species. Then, the binding activity of 169 FDs to the enzyme acetylcholinesterase (AChE)—as a known target of toxins in fathead minnows and Daphnia magna, causing the inhibition of AChE—was analyzed. Finally, the structural aquatic toxicity alerts obtained from ToxAlert were used to confirm the possible mechanism of action. Machine learning and cheminformatics tools were used to analyze the data. Counter-propagation artificial neural network (CPANN) models were used to determine key binding properties of FDs to proteins associated with aquatic toxicity. Predicting the binding affinity of unknown FDs using quantitative structure–activity relationship (QSAR) models eliminates the need for complex and time-consuming calculations. The results of the study show which structural features of FDs have the greatest impact on aquatic organisms and help prioritize FDs and make manufacturing decisions. [ABSTRACT FROM AUTHOR]

• Over 70% of FIPs were bound to DOC in aqueous phase. • Fipronil sulfone was more predominant in urban stream than its parent compound. • FIPs exhibited greater affinity to DOC in surface water than OC in sediment. • Freely dissolved concentrations of FIPs significantly improved toxicity estimation. Environmental fate and ecological impacts of fipronil and its transformation products (FIPs) in aquatic environment have caused worldwide attention, however, the influence of dissolved organic carbon (DOC) on multimedia distribution, bioavailability, and toxicity of FIPs in field waterways was largely unknown. Here, we collected 11 companion water and sediment samples along a lotic stream in Guangzhou, South China. FIPs were ubiquitous with total water concentrations ranging from 1.22 to 43.2 ng/L (14.8 ± 12.9 ng/L) and fipronil sulfone was predominant in both water and sediment. More than 70% of FIPs in aqueous phase were bound to DOC and the K DOC values of FIPs were approximately 1–2 orders of magnitude higher than K d-s / K OC , emphasizing the significance of DOC in phase partitioning and transport of FIPs in aquatic environment. Water and sediment samples were more toxic to Chironomus dilutus than Hyallela azteca , and FIPs (especially fipronil sulfone) pronouncedly contributed toxicity to C. dilutus. Toxic units (TU) based on freely dissolved concentrations in water determined by solid phase microextraction significantly improved toxicity estimation of FIPs to the invertebrates compared to TUs based on aqueous concentrations. The present study highlights the significance of DOC association on fate and ecological risk of hydrophobic insecticides in lotic ecosystem. [Display omitted] [ABSTRACT FROM AUTHOR]

Nanoparticles are man-made materials defined as materials smaller than 100 nm in at least one dimension. Titanium oxide nanoparticles are of great interest because of their extensive use in self-care products. There is a lack of nanotoxicological studies of TiO2 NPs in benthic organisms to have evidence about the effects of these pollutants in freshwater ecosystems. Atya lanipes is a scraper/filter that can provide a good nanotoxicological model. This study aims to determine how the TiO2 NPs can develop a toxic effect in the larvae of the Atya lanipes shrimp and to document lethal and sublethal effects after acute exposures to TiO2 NP suspensions of: 0.0, 1.0, 10.0, 50.0, 100.0, and 150.0 mg/L. The results show that early exposure to TiO2 NPs in Atya lanipes creates an increase in mortality at 48 and 72 h exposures, hypoactivity in movements, and morphological changes, such as less pigmentation and the presence of edema in exposed larvae. In conclusion, TiO2 NPs are toxic contaminants in the larval stage of the Atya lanipes. It is necessary to regulate these nanoparticles for purposes of the conservation of aquatic biodiversity, especially for freshwater shrimp larvae and likely many other larvae of filter-feeding species.

Styrene oligomers (SOs) are ubiquitous contaminants that appear in the environment, sometimes to significant extent (see section 3.1). Despite the ongoing international debate on the human health risks posed by SOs, to the best of my knowledge, there are no studies on the aquatic toxicity and environmental fates (biodegradation and atmospheric degradation) of SOs in the environment. This study is to predict the aquatic toxicity and environmental fate of SOs by using the US EPA EPI suite program as an in-silico method. For better understanding, the risks and fates of SOs are compared with those of the well-known bisphenol A (BPA) and styrene monomer (SM or styrene). As a result of this study, SOs are predicted to be relatively more toxic than BPA and SM to aquatic and terrestrial organisms in the freshwater, marine, and terrestrial environments. In particular, the biodegradability of SOs is predicted to be relatively very slow in the environment, and most SOs are more likely to be effectively decomposed by hydroxyl radicals than by ozone in the atmosphere. As a result, this study can contribute to motivating understanding of the aquatic toxicity and fate of ubiquitous SOs in the environment.

The contamination of uranium in aquatic ecosystems has raised growing global concern. However, the understanding of its chronic effects on aquatic organisms is limited, particularly with regards to transgenerational toxicity. In this study, we evaluated the maternal transfer risk of uranium using zebrafish. Sexually mature female zebrafish were exposed to 2 and 20 ng/g of uranium-spiked food for 28 days. The induced bioconcentration, thyroid disruption, and oxidative stress in both the adults (F0) and their embryos (F1) were further investigated. Element analysis showed that uranium was present in both F0 and F1, with higher concentrations observed in F1, indicating significant maternal offloading to the offspring. Meanwhile, an increased malformation and decreased swim speed were observed in the F1. Thyroid hormone analysis revealed significant decreases in the levels of triiodothyronine (T3) in both the F0 adults and F1 embryos, but thyroxine (T4) was not significantly affected. Additionally, the activities of antioxidant defenses, including catalase (CAT) and superoxide dismutase (SOD), and the expression of glutathione (GSH) and malondialdehyde (MDA) were significantly altered in the F0 and F1 larvae at 120 hpf. The hypothalamic-pituitary-thyroid (HPT) axis, oxidative stress, and apoptosis-related gene transcription expression were also significantly affected in both generations. Taken together, these findings highlight the importance of considering maternal transfer in uranium risk assessments.

Antimony tin oxide (Sb2O5/SnO2) is effective in the absorption of infrared radiation for applications, such as skylights. As a nanoparticle (NP), it can be incorporated into films or sheets providing infrared radiation attenuation while allowing for a transparent final product. The acute toxicity exerted by commercial Sb2O5/SnO2 (ATO) NPs was studied in adults and embryos of zebrafish (Danio rerio). Our results suggest that these NPs do not induce an acute toxicity in zebrafish, either adults or embryos. However, some sub-lethal parameters were altered: heart rate and spontaneous movements. Finally, the possible bioaccumulation of these NPs in the aquacultured marine mussel Mytilus sp. was studied. A quantitative analysis was performed using single particle inductively coupled plasma mass spectrometry (sp-ICP-MS). The results indicated that, despite being scarce (2.31 × 106 ± 9.05 × 105 NPs/g), there is some accumulation of the ATO NPs in the mussel. In conclusion, commercial ATO NPs seem to be quite innocuous to aquatic organisms; however, the fact that some of the developmental parameters in zebrafish embryos are altered should be considered for further investigation. More in-depth analysis of these NPs transformations in the digestive tract of humans is needed to assess whether their accumulation in mussels presents an actual risk to humans. [ABSTRACT FROM AUTHOR]

The present study examined the histopathological changes and some parameters of oxidative stress in the testes of the freshwater leech Limnatis nilotica, following their exposure to 50 µg l−1 of cadmium (Cd). The protective effects of salicylic acid (SA) in mitigating Cd-induced oxidative and histopathological injury were also investigated. We found that Cd exposure caused several histopathological changes in leech testes, such as vacuolisation of spermatogenic cysts which were strongly destroyed and disorganised. Biochemical study showed oxidative stress damage marked by a substantial increase in malondialdehyde and hydrogen peroxidase levels as well as disturbance in the activity of the leech antioxidant system. Interestingly, the testes from the Cd and SA leech-exposed group exhibited increased enzymatic and nonenzymatic antioxidant mechanism defenses, including superoxide dismutase, catalase, glutathione peroxidase, glutathione, oxidized glutathione, thiols, and ascorbic acid, in comparison with the testes of leeches exposed to Cd alone. Thus, SA supplementation considerably attenuated the histopathological lesions induced by Cd exposure, thereby restoring the normal appearance of the testes. In summary, the findings of this study indicate that SA treatment ameliorated the testicular histopathological and oxidative stress-induced damages caused by exposure to Cd through enhancing the antioxidant defense system. [ABSTRACT FROM AUTHOR]

Metal oxides comprise a large group of chemicals used in water treatment to adsorb organic pollutants. The ability of titanium dioxide (TiO2) and iron (III) oxide (Fe2O3) to reduce the chronic toxicity of (phenolic) C6H6(OH)2 isomers, namely hydroquinone (HQ) and catechol (CAT) to Ceriodaphnia dubia and Pimephales promelas (less than 24 h-old) were investigated. The toxic endpoints following metal oxide treatment were compared to endpoints of untreated CAT and HQ. In chronic toxicity testing, HQ resulted in greater toxicity than CAT for both test organisms; the median lethal concentrations (LC50) for CAT were 3.66 to 12.36 mg.L−1 for C. dubia and P. promelas, respectively, while LC50 for HQ were 0.07 to 0.05 mg.L−1, respectively. Although both treated solutions presented lower toxic endpoints than those in the untreated solutions, Fe2O3 had a better potential to reduce the toxic effects of CAT and HQ than TiO2. [ABSTRACT FROM AUTHOR]