Environmental Risk Assessment Research Articles

Environmental Risk Assessment of Time-Variable Toxicant Exposure with Toxicokinetic-Toxicodynamic Modeling of Sublethal Endpoints and Moving Time Windows: A Case Study with Ceriodaphnia dubia.

Toxicokinetic-toxicodynamic (TKTD) modeling has received increasing attention in terms of the regulatory environmental risk assessment of chemicals. This type of mechanistic model can integrate all available data from individual-level bioassays into a single framework and enable refined risk assessments by extrapolating from laboratory results to time-variable exposure scenarios, based, for instance, on surface water exposure modeling (e.g., FOCUS). Dynamic energy budget (DEB) models coupled with TKTD modules (DEB-TKTD) constitute the leading approach to assess and predict sublethal effects of chemicals on individual organisms. However, thorough case studies are rare. We provide a state-of-the-art example with the standard aquatic test species Ceriodaphnia dubia and the fungicide azoxystrobin, including all steps, from bespoke laboratory toxicity tests to model calibration and validation, through to environmental risk assessment. Following the framework proposed in the European Food Safety Authority Scientific Opinion from 2018, we designed bespoke good laboratory practice-compliant laboratory toxicity studies based on test guideline 211 of the Organisation for Economic Co-operation and Development and then identified robust parameter values from those data for all relevant model parameters through model calibration. The DEB-TKTD model, DEBtox2019, then informed the design of the validation experiment. Once validated, the model was used to perform predictions for a time-variable exposure scenario generated by FOCUS. A moving time-window approach was used to perform the environmental risk assessment. This assessment method reduces uncertainty in the risk assessment while maintaining consistency with the traditional measures of risk. Environ Toxicol Chem 2024;43:2409-2421. © 2024 Syngenta Crop Protection AG. ibacon GmbH and The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

A conceptual framework for landscape-based environmental risk assessment (ERA) of pesticides

While pesticide use is subject to strict regulatory oversight worldwide, it remains a main concern for environmental protection, including biodiversity conservation. This is partly due to the current regulatory approach that relies on separate assessments for each single pesticide, crop use, and non-target organism group at local scales. Such assessments tend to overlook the combined effects of overall pesticide usage at larger spatial scales. Integrative landscape-based approaches are emerging, enabling the consideration of agricultural management, the environmental characteristics, and the combined effects of pesticides applied in a same or in different crops within an area. These developments offer the opportunity to deliver informative risk predictions relevant for different decision contexts including their connection to larger spatial scales and to combine environmental risks of pesticides, with those from other environmental stressors. We discuss the needs, challenges, opportunities and available tools for implementing landscape-based approaches for prospective and retrospective pesticide Environmental Risk Assessments (ERA). A set of “building blocks” that emerged from the discussions have been integrated into a conceptual framework. The framework includes elements to facilitate its implementation, in particular: flexibility to address the needs of relevant users and stakeholders; means to address the inherent complexity of environmental systems; connections to make use of and integrate data derived from monitoring programs; and options for validation and approaches to facilitate future use in a regulatory context. The conceptual model can be applied to existing ERA methodologies, facilitating its comparability, and highlighting interoperability drivers at landscape level. The benefits of landscape-based pesticide ERA extend beyond regulation. Linking and validating risk predictions with relevant environmental impacts under a solid science-based approach will support the setting of protection goals and the formulation of sustainable agricultural strategies. Moreover, landscape ERA offers a communication tool on realistic pesticide impacts in a multistressors environment for stakeholders and citizens.

Assessment of Environmental Risks during the Implementation of Infrastructure Projects in the Arctic Region

The Arctic Zone of Russia (AZR), due to its significant potential, for the implementation of which infrastructure projects and strategic plans are envisaged, is of great importance for the country. Particular attention is paid to the transport and related infrastructure development. The implementation of such projects requires the creation and implementation of modern integrated solutions based on new technical and technological solutions. The development of new territories is accompanied by problems such as urbanization and the disruption of ecosystems, which will have a particularly negative impact on the Arctic zone. The situation is complicated by the fact that the work must be carried out in difficult conditions, which are associated with a large number of risks, including environmental ones. Currently, many types of businesses are characterized by a transition to the implementation of the concepts of green and blue economy, as well as ESG principles when building strategic development plans that include risk reduction. Achieving this goal is possible through an environmental risk management system. To create a suchlike system, it is necessary to identify the most significant risk characteristics of each type of activity, taking into account their negative impact on the environment, after which it will be possible to plan measures to either prevent risks or minimize their consequences. Taking into account the above, we plan to develop the concept of an environmental risk management system (ERMS) as part of the region’s development strategy implementation. To reach this purpose, identifying the main groups of environmental risks depending on the danger source based on the scientific article review results, systematizing concepts aimed at improving the environmental situation under different types of anthropogenic impacts on the environment, developing an algorithm for implementing an environmental risk management system depending on the risk type, and proposing a concept for building an environmental risk management system are needed. The scientific novelty of the work lies in the fact that the main directions of negative anthropogenic impact on the environment are systematized, and possible ways to reduce environmental risks are outlined. The practical significance of the work lies in the fact that when implementing such a system, it will be possible to manage not only risks of a certain category, but also monitor the situation as a whole, identifying the consequences for related areas.

Effects of the insecticide acetamiprid and the fungicide azoxystrobin on locomotion activity and mushroom bodies of solitary bee Centris analis

Pesticide use is a major factor contributing to the global decline in bee populations. Sublethal effects, such as behavior alterations, are neglected in pesticide regulation for pollinators. However, these effects can bring important information to understanding the impacts of pesticides on bees' daily activities. In this study, we aimed to investigate the effects of the insecticide acetamiprid (7 ng/μL) and the fungicide azoxystrobin (10 ng/μL) on the behavior of the Neotropical solitary bee Centris analis. Female and male bees were exposed to these chemicals continuously for 48 h, followed by an additional 48 h without contaminated food, totaling 96 h of observation. We used five experimental groups: control, solvent control, insecticide, fungicide, and pesticide mixture (insecticide + fungicide). Behavioral alterations based on locomotion and light response were assessed by video tracking at 48 (end of pesticide exposure) and 96 h (end of bioassay). In addition, after recording bees at 96 h, the individuals were anesthetized for brain collection and histological evaluation of mushroom bodies to evaluate if pesticides can damage their neurons and impair the cognitive processes and responses of bees to sensory stimuli. Bees exposed to acetamiprid and pesticide mixture showed lethargic movements and impaired locomotion at 48 h. Notably, these behavioral effects were no longer evident after the bees consumed uncontaminated food for an additional 48 h, totaling 96 h from the start of pesticide exposure. Only fungicide exposure did not result in any behavioral or brain histological changes. Therefore, our study showed that acetamiprid at an estimated residual concentration, despite being classified as having low toxicity for bees, can cause significant initial locomotion disruption in solitary bees. These findings highlight the importance of considering sublethal effects in environmental risk assessment.

Reduced transcriptome analysis in zebrafish uncovers disruptors of spliceosome and ribosome biosynthesis

Abnormal biosynthesis of spliceosomes and ribosomes can lead to their dysfunction, which in turn disrupts protein synthesis and results in various diseases. While genetic factors have been extensively studied, our understanding of how environmental compounds interfere with spliceosome and ribosome biosynthesis remains limited. In the present study, we employed a Reduced Transcriptome Analysis (RTA) approach, integrating large-scale transcriptome data sets of zebrafish and compiling a specific zebrafish gene panel focusing on the spliceosome and ribosome, to elucidate the potential disruptors targeting their biosynthesis. Transcriptomic data sets for 118 environmental substances and 1400 related gene expression profiles were integrated resulting in 513 exposure signatures. Among these substances, several categories including PCB126, transition metals Lanthanum (La) and praseodymium (Pr), heavy metals Cd2+ and AgNO3 and atrazine were highlighted for inducing the significant transcriptional alterations. Furthermore, we found that the transcriptional patterns were distinct between categories, yet overlapping patterns were generally observed within each group. For instance, over 82 % differentially expressed ribosomal genes were shared between La and Pr within the equivalent concentration range. Additionally, transcriptional complexities were also evident across various organs and developmental stages of zebrafish, with notable differences in the inhibition of the transcription of various spliceosome subunits. Overall, our results provide novel insights into the understanding of the adverse effects of environmental compounds, thereby contributing to their environmental risk assessments.

Towards more sustainable and inclusive development corridors in Africa

Abstract Development corridors are linear programmes of infrastructure and agriculture aiming to facilitate rapid socio-economic development. In Africa, they are a major development activity, with 88 underway or planned corridors. Drawing from extensive literature and insights gleaned from a 4 year research programme, this review scrutinizes the impacts of development corridors on people, wildlife and ecosystems in Kenya and Tanzania, proposing solutions to achieve better outcomes. The overarching goal was to discern the principle challenges emerging from the practical execution of the prevailing corridor model. The holistic approach taken, assessing the development corridors paradigm through an integrated ecological, social, and economic lens, provides novel insights that have not been possible using more traditional—siloed—research approaches. Eight key challenge areas are identified: impact assessments processes; coherence across international, national and local planning; governance; inclusivity; equality; impacts on biodiversity and ecosystem services; incorporation of future climate risks; and integrated water resource management. Poorly planned and implemented corridors detrimentally impact livelihoods and ecosystems. They lack a sustainable development vision, detailed social, environmental or climate risk assessments, and develop incrementally in policy and corporate spaces. There is also often a disconnect between investors and recipient governments, with some investors funding what governments request without applying internationally-recognised safeguards, and governments lacking capacity and resources to enforce regulations. We make recommendations for addressing these challenge areas. These aim to enhance impact assessment efficacy; integrate local perspectives into effective and inclusive corridor planning; overcome siloed project development and implementation; anticipate future development projections; and prioritise landscape preservation for enhanced ecosystem services and climate resilience.

Comprehensive approach integrating water quality index and toxic element analysis for environmental and health risk assessment enhanced by simulation techniques

Due to water shortages and the potential impact of Ethiopia’s new dam on the Nile River, Egypt is seeking new water resources. This study assesses the drinking water quality and associated risks from potentially toxic elements (PTEs) in the Quaternary aquifer (QA) in Beni-Suef, Egypt. Using a comprehensive approach, including PHREEQC geochemical modeling, ionic ratios, multivariate statistical analyses, and the integrated weight water quality index (WQI), the study evaluated the sources of ion contamination and the mixing of Nile water with QA. Various indices, such as the Heavy Metal Pollution Index (HPI), ecological Risk Index (RI), Hazard Quotient (HQ), and Hazard Index (HI), were used to assess ecological and health risks. Monte Carlo simulations provided probabilistic assessments of non-carcinogenic risks for adults and children. GIS tools were used to map risk indices, identifying the most deteriorated locations for sustainable management. The hydrochemical analysis revealed water facies including Na–Cl, Ca–Mg–HCO3, and mixed types, influenced by carbonate dissolution, ion exchange, and silicate weathering. Contamination sources, particularly in the north and south, were linked to agricultural activities, irrigation return flow, municipal waste, and evaporation. The WQI indicated that 10.14% of samples were extremely poor, 21.7% were poor, 26% were medium, and 42% were good to excellent. PTE contamination varied, with HPI values indicating good water quality in the central area in 53.6% of the collected samples (HPI < 30), but contamination in the north and south is high (HPI > 51). Ecological Risk Index values were below the threshold in 100% of samples (RI < 30), confirming water safety regarding PTEs. In comparison, for hazard index (HI) through oral/ingestion, adults exhibited HI values ranging from 0.012 to 2.16, while children showed higher values, ranging from 0.045 to 8.25. However, the hazard index for oral/ingestion exceeded safe limits in the north and south (HI oral > 1), posing non-carcinogenic risks. Monte Carlo simulations revealed significant risks from oral exposure to manganese (HQ oral > 1), particularly in El-Wasta and El-Fashn, necessitating further treatment and management.

Ecotoxicological study of seven pharmaceutically active compounds: Mixture effects and environmental risk assessment

Pharmaceutically active compounds (PhACs) have been detected in several aquatic compartments, which has been of environmental concern since PhACs can cause adverse effects on the aquatic ecosystem at low concentrations. Despite the variety of PhACs detected in surface water, ecotoxicological studies are non-existent for many of them, mainly regarding their mixture. In addition, water bodies can continuously receive the discharge of raw or treated wastewater with micropollutants. Thus, PhACs are subject to mixture and interactions, potentiating or reducing their toxicity. Therefore, the present study evaluated the toxicity on Aliivibrio fischeri of seven PhACs, which still needs to be explored in the literature. The effects were evaluated for the PhACs individually and for their binary and tertiary mixture. Also, the experimental effects were compared with the concentration addition (CA) and independent action (IA) models. Finally, an environmental risk assessment was carried out. Fenofibrate (FEN), loratadine (LOR), and ketoprofen (KET) were the most toxic, with EC50 of 0.32 mg L-1, 6.15 mg L-1 and 36.8 mg L-1, respectively. Synergistic effects were observed for FEN + LOR, KET + LOR, and KET + FEN + LOR, showing that the CA and IA may underestimate the toxicity. Environmental risks for KET concerning algae, and LOR e 17α-ethynylestradiol (EE2) for crustaceans and fish were high for several locations. Besides, high removals by wastewater treatment technologies are required to achieve the concentrations necessary for reducing KET and LOR risk quotients. Thus, this study contributed to a better understanding of the toxic interactions and environmental risks of PhACs.

Developing a dynamic energy budget model to project potential effects of deep-sea mining plumes on the Atlantic deep-sea mussel, Bathymodiolus azoricus

Due to the consistent lack of Environmental Risk Assessment (ERA) for deep-sea mining scenarios, the potential impacts of this industry on marine ecosystems remain largely unknown. In order to fill this gap, a Dynamic Energy Budget (DEB) model was developed to study the consequences of toxic sediment plumes derived from deep-sea mining on the energy budget of the Atlantic deep-sea mussel, Bathymodiolus azoricus. Model calibration was based on environmental conditions observed at the Menez Gwen (MG) vent field (Mid-Atlantic Ridge- MAR), assuming a B. azoricus lifespan of 10 years and a maximum shell length of 119 mm. Scenario simulations were conducted to mimic the effects of increased concentrations of toxic sediment plumes on mussel filtration rates, the absorption of reduced substrates by their endosymbionts, and the energetic costs associated with metal toxicity. Data were sourced from B. azoricus and, when necessary, from proxy species. One disturbance scenario (EF1) incorporated measured rates and realistic parameters, while the other (EF2) was intentionally designed to encompass cumulative effects and uncertainties, representing a potential worst-case scenario. Both disturbance scenarios were initiated at three different timings (0, 1200 and 2400 days) to accommodate the mining effects at different stages of the mussels' life cycle. Results indicate that B. azoricus is significantly impacted by toxic sediment plumes, particularly during earlier life stages, potentially leading to severe growth impairment and mortality. These results were integrated into a food web model of the MG vent field, revealing that disruptions to the energetic balance of the vent mussel have widespread consequences for the entire ecosystem. Overall, we argue that this numerical framework offers a valuable tool for conducting ERA and Environmental Impact Assessments (EIA) in the context of industrial deep-sea mining.

Does it run in the family? - Improving radiological risk assessment in the coastal environment using taxonomic and phylogenetic perspectives in macroalgae species

Marine macroalgae are widely used indicator species for monitoring environmental radioactivity. Empirical studies have demonstrated a range in radionuclide transfer coefficients, or concentration ratios (CRs), between taxonomic groups, however the CR values used for dose estimation assume that macroalgae are a homogenous group, represented by a single CR. This study demonstrates the presence of a taxonomic signal in macroalgae CRs for multiple anthropogenic and naturally occurring radionuclides (137Cs, 241Am, 239+240Pu, 210Po) based on a collation of available data. A Residual Maximum Likelihood (REML) mixed model was applied, producing relative estimate CRs specific to each species within the datasets. The collated data was also analysed for a phylogenetic signal, but only a weak signal was found for one radionuclide in one group (239+240Pu in Phaeophyceae). A theoretical case study using the estimated CRs and the ERICA tool was carried out to demonstrate the implications of these findings in a real-world scenario.

Efficient removal of high concentration dyes from water by functionalized in-situ N-doped porous biochar derived from waste antibiotic fermentation residue

Using biochar for dye wastewater treatment is attracting interest due to its excellent adsorption properties and low costs. In this work, a novel biochar derived from oxytetracycline fermentation residue (functionalized OFR biochar, FOBC) was investigated as a efficient adsorbent for typical dyes removal. At 25 °C, the maximum adsorption capacity calculated by Langmuir model of FOBC-3-600 for methylene blue (MB), malachite green (MG), and methyl orange (MO) reached 643.97, 617.89, and 521.03 mg/g, respectively. The kinetics and isotherm model fitting showed that the chemisorption and physisorption both occurred during the adsorption process. Dyes were efficiently adsorbed through pore filling, electrostatic attraction, π-π interactions, and surface complexation. And the cycling experiment and environmental risk assessment indicated that the FOBC-3-600 had excellent recyclability and utilization safety. Overall, this study provides a practical method to simultaneously treat the dyeing wastewater and utilize the antibiotic fermentation residue.

Application of Business Intelligence Technology Model to Sustainable Supply Chain

Under the backdrop of globalization, sustainable supply chains are becoming one of the most important directions for commercial development in the future. The efficiency of supply chain management (SCM) will be significantly improved when business intelligence is used in the supply chain. Sustainable supply chain refers to the integration of sustainable development elements on the basis of traditional supply chain management, introducing the assessment and management of social, environmental, economic benefits and other risks. The aim of this paper is to look at how different BI techniques affect different business models. Most of this paper is a summary of previous scholars work. The most successful and widespread application of BI is the final outcome of the technology acceptance model. These three BI models have different effects on sustainable supply chains, but in general, BI is very helpful for sustainable supply chain development in all aspects. Future results would be much more accurate and effective if three techniques were actually able to monitor and compare the sustainability of supply chains.

Using the Fuzzy Version of the Pearl’s Algorithm for Environmental Risk Assessment Tasks

In risk assessment, numerous subfactors influence the probabilities of the main factors. These main factors reflect adverse outcomes, which are essential in risk assessment. A Bayesian network can model the entire set of subfactors and their interconnections. To assess the probabilities of all possible states of the main factors (adverse consequences), complete information about the probabilities of all relevant subfactor states in the network nodes must be utilized. This is a typical task of probabilistic inference. The algorithm proposed by J. Pearl is widely used for point estimates of relevant probabilities. However, in many practical problems, including environmental risk assessment, it is not possible to assign crisp probabilities for relevant events due to the lack of sufficient statistical data. In such situations, expert assignment of probabilities is widely used. Uncertainty in expert assessments can be successfully modeled using triangular fuzzy numbers. That is why this article proposes a fuzzy version of this algorithm, which can solve the problem of probabilistic inference on a Bayesian network when the initial probability values are given as triangular fuzzy numbers.

ECOTOXr: An R package for reproducible and transparent retrieval of data from EPA's ECOTOX database

The US EPA ECOTOX database provides key ecotoxicological data that are crucial in environmental risk assessment. It can be used for computational predictions of toxicity or indications of hazard in a wide range of situations. There is no standardised or formalised method for extracting and subsetting data from the database for these purposes. Consequently, results in such meta-analyses are difficult to reproduce. The present study introduces the software package ECOTOXr, which provides the means to formalise data retrieval from the ECOTOX database in the R scripting language. Three cases are presented to evaluate the performance of the package in relation to earlier data extractions and searches on the website. These cases demonstrate that the package can reproduce data sets relatively well. Furthermore, they illustrate how future studies can further improve traceability and reproducibility by applying the package and adhering to some simple guidelines. This contributes to the FAIR principles, credibility and acceptance of research that uses data from the ECOTOX database.

Impact of several sludge dewatering conditioners on municipal sludge pyrolysis properties, kinetics, by-products, and environmental risk assessment

The pyrolysis characteristics of four different types of conditioned sludge were ascertained, and PAM, CaO, K2FeO4, and K2FeO4-CaO-PAM (KCP) conditioners were employed as sludge dewatering conditioners. The sludge pyrolysis reaction's activation energy (E) dropped with the addition of four conditioners. CaO, PAM, KCP, and K2FeO4 were the sequences of E needed for the pyrolysis of four different types of conditioned sludge. The addition of K2FeO4, CaO, and KCP resulted in an increase in the yields of H2 and CO. Except for the K2FeO4 conditioning sludge carbon, the pyrolytic carbon of the other three groups of samples showed an increase in S contents, while the pyrolytic carbon of the four groups of samples treated with conditioners clearly showed lower C and N contents compared to the raw sludge carbon. Protein-N made up the majority of N in sludge pyrolytic carbon. After adding conditioner, the level of organic sulfur decreased. Organic sulfur could then be broken down by K2FeO4 and CaO. The four conditioners efficiently mitigated the ecological and environmental risks posed by heavy metals. Alkynes were the most abundant result in pyrolytic volatiles of sludge pyrolysis; the other products included acids, alcohols, lipids, furans, ketones, phenols, hydrocarbons, N-components, and so on. All samples' acids, alcohols, and ketones from pyrolysis were decreased once the conditioner was added. The acid reduction rate reached 66.7 %, and the alkynes clearly increased during the KCP conditioned sludge's pyrolysis. The sulfur level of the bio-oil was decreased by all four conditioners. Everything mentioned above indicated that the KCP aided in the subsequent pyrolysis of the sludge, leading to the production of an advantageous pyrolysis bio-oil.

Polystyrene nanoplastics alter intestinal toxicity of 2,4-DTBP in a sex-dependent manner in zebrafish (Danio rerio)

Nanoplastics (NPs) and 2,4-di-tert-butylphenol (2,4-DTBP) are ubiquitous emerging environmental contaminants detected in aquatic environment. While the intestinal toxicity of 2,4-DTBP alone has been studied, its combined effects with NPs remain unclear. Herein, adult zebrafish were exposed to 80 nm polystyrene nanoplastics (PS-NPs) or/ and 2,4-DTBP for 28 days. With co-exposure of PS-NPs, impact of 2,4-DTBP on feeding capacity and intestinal histopathology was enhanced in males while attenuated in females. Addition of PS-NPs significantly decreased the uptake of 2,4-DTBP in females, while the intestinal concentrations of 2,4-DTBP were not different between the sexes in co-exposure groups. Furthermore, lower intestinal pH and higher contents of digestive enzymes were detected in male fish, while bile acid was significantly increased in co-exposed females. In addition, co-exposure of PS-NPs stimulated female fish to remodel microbial composition to potentially enhance xenobiotics degradation, while negative Aeromonas aggravated inflammation in males. These results indicated that in the presence of PS-NPs, the gut microenvironment in females can facilitate the detoxification of 2,4-DTBP, while exaggerating toxiciy in males. Overall, this study demonstrates that toxicological outcomes of NPs-chemical mixtures may be modified by sex-specific physiology and microbiota composition, furthering understanding for environmental risk assessment and management of aquatic environments.

Insight into simultaneously sludge dewatering and antiviral drugs removal by integrated particle electrodes assisted electrochemical oxidation

Given the widespread occurrence of pandemic influenza, antiviral drugs (ATVs) as emerging pollutants which are ubiquitously present in wastewater and become concentrated in sewage sludge (SS). Therefore, achieving the simultaneous elimination of ATVs during sludge dewatering holds significant importance. Herein, six representative ATVs including amantadine, rimantadine, memantine hydrochloride, imiquimod, oseltamivir, and morpholidine were detected in sewage sludge. Their partitioning between solid and liquid phases was also examined under simultaneous sludge conditioning by particle electrodes-assisted electrochemical process (3D-SAC). The findings indicated that 3D-SAC significantly enhanced sludge dewaterability, achieving a moisture content reduction to 64.22 %. The total removal rates of the six ATVs ranged from 17.97 % to 66.22 %, closely associated with the degree of sludge cells cracking. Sludge lysis resulted in the destruction of protein-like EPS structures, exposing hydrophobic bonding sites, finally releasing more bonded water and ATVs into filtrate. The ·OH induced hydroxylation, backbone cleavage, and ring-opening of ATVs occurred concurrently as the sludge flocs disrupted and structural transformed. Environmental risk assessment revealed that the ecological risks and potential toxicity associated with the sludge filtrate were significantly diminished following electrochemical conditioning (EC). This process achieved the dual objectives of contaminant degradation and enhanced sludge dewatering.

Occurrence, dissipation kinetics and environmental risk assessment of antibiotics and their metabolites in agricultural soils

Antibiotics are among the emerging contaminants of greatest concern to the scientific community. However, the occurrence and behaviour of their metabolites in soils have been scarcely studied. To address this research gap, this study investigates the occurrence, sorption, dissipation kinetics, and environmental risk of highly important antibiotics (sulfamethazine, sulfadiazine, sulfamethoxazole, trimethoprim) and their main metabolites in Mediterranean agricultural soils. Batch experiments were conducted under natural conditions for 120 days. Five different dissipation kinetics models were applied to elucidate antibiotics degradation. The sorption isotherms were evaluated by three different models. Most of the antibiotics and metabolites tested showed a good fit with the Linear Isotherm model (R2 >0.96) and biphasic dissipation kinetic models (R2 >0.90). The dissipation and the endpoints values (DT50 and DT90) depended on the soil type properties. A Lixisol soil demonstrated reduced degradation of the investigated compounds. Trimethoprim showed the highest persistence, followed by sulfamethazine, sulfamethoxazole, and sulfadiazine. Parent compounds exhibited lower degradation rates than their metabolites. Remaining antibiotic concentrations were found to be below the predicted no-effect concentration in soil, suggesting that they may not pose a risk to terrestrial biota. This study provides valuable insights into the behaviour of these antibiotics and their metabolites in soil.

Unravelling the mechanisms of PFAS toxicity to submerged macrophytes and epiphytic biofilms at metabolic and molecular levels

Per- and poly-fluoroalkyl substances (PFAS) are an emerging class of persistent organic pollutants that are widespread in aquatic ecosystems and pose a serious threat to aquatic organisms. It is thus crucial to explore the toxicity mechanisms of PFAS to submerged macrophytes and biofilms. In this study, Vallisneria natans (V. natans) was exposed to environmentally relevant concentrations of perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS). Results showed that PFAS induced the excessive production of reactive oxygen species, triggering antioxidant responses. V. natans exhibited an improved stress tolerance by altering the biosynthesis of several plant secondary metabolites and the histidine, arginine, proline pathways in response to PFAS exposure. Moreover, PIP1–1, PIP2–2, SLAH1 and SLAH2 genes were upregulated, indicating the activation of aquaporins and slow-type anion channels. The uptake of PFOA and PFOS by V. natans was 41.74 % and 52.31 %, respectively. Notably, PFAS bound to functional proteins (GSTF10), promoting the detoxification of plants. Exposure to PFAS also altered the structure of biofilms by inducing the synthesis of large amounts of polysaccharides and proteins. The diversity and richness of the microbial community within periphytic biofilms changed significantly. These results provide a comprehensive description of the responses of aquatic plants and periphytic biofilms to PFAS and the removal mechanism of PFAS, contributing to the environmental risk assessments and removal of PFAS in aquatic ecosystems.

Evaluation of Bisphenol S (BPS) toxicity on the reproductive system of Channa striatus: Insights for environmental risk assessment

Aquatic ecosystems face significant exposure to endocrine-disrupting chemicals (EDCs), which can mimic, block, or alter the synthesis of endogenous hormones. Bisphenol A (BPA), a widely known EDC, has been phased out from consumer products due to concerns about its potential impacts on human health. In its place, bisphenol S (BPS), an organic compound, has been increasingly used in the production of polycarbonate plastics, epoxy resins, thermal receipt papers, and currency. Vitellogenin (Vtg), a yolk precursor protein synthesized in the liver and present in oviparous fish, particularly males, serves as a pertinent biomarker for studying the effects of estrogenic EDCs on fish. This study aimed to assess the impact of BPS on reproductive parameters and hepatic vitellogenin expression in Channa striatus. The LC50 of BPS was determined to be 128.8 mg/L. Experimental groups included control and BPS-exposed fish, with sub-lethal concentrations of BPS (1 mg/L, 4 mg/L, and 12 mg/L) administered and effects monitored at seven- and twenty-one-day intervals. Significant decreases in gonadosomatic index (GSI), ova diameter, and fecundity were observed in BPS-exposed Channa striatus. Hepatic Vtg mRNA expression was downregulated in female and upregulated in male following BPS exposure. Serum hormone analysis confirmed the estrogenic activity of BPS. These findings underscore BPS's ability as an endocrine disruptor to interfere with hormone synthesis and disrupt spermatogenesis and oogenesis processes in Channa striatus. This research contributes to understanding the endocrine-disrupting effects of BPS on aquatic organisms, highlighting potential ecological implications and the need for continued monitoring and regulatory considerations.