Environmental Risk Assessment Research Articles

Uptake, translocation, accumulation, and metabolism of fluroxypyr-meptyl and oxidative stress induction in rice seedling.

Fluroxypyr-meptyl (FLUME) is heterocyclic herbicide with internal absorption and transmission characteristics. Owing to its low cost and rapid efficacy, it has been widely used to control broad-leaved weeds in wheat, corn, and rice fields. However, the uptake, translocation, accumulation, and metabolism of FLUME in rice seedlings and the extent of oxidative stress induced by it remain largely unknown, which consequently restricts the comprehensive risk assessment of FLUME residues in the environment during rice production. Hence, we systematically investigated the growth and physiological responses of rice to FLUME and analyzed its uptake, translocation, accumulation, and metabolism in rice seedlings. The results indicated that under 0-0.12 mg/L FLUME treatment, only a small proportion of FLUME was translocated upward and accumulated in rice shoots following absorption via roots, with all the translocation factor values being < 1. Moreover, the distribution and enrichment ability of FLUME in rice seedlings were greater in roots than in shoots. Furthermore, we revealed that FLUME accumulation in rice seedlings evidently inhibited their growth and activated the defense system against oxidative stress, with an increase in the activity of antioxidant and detoxifying enzymes. In addition, multiple metabolic reactions of FLUME were observed in rice seedlings, including dehalogenation, hydroxylation, glycosylation, acetylation, and malonylation. Our study provides systematic insights into the uptake, translocation, accumulation, and metabolism of FLUME in rice seedlings as well as the oxidative stress induced by FLUME accumulation, which can help improve FLUME applications and environmental risk assessments in crops.

A contrast of emerging contaminants rac- and l-menthol toxicities to Microcystis aeruginosa through biochemical, physiological, and morphological investigations

Fragrances rac- and l-menthol extracted from peppermint are widely used and considered as emerging contaminants recently, which are persistent in the environment. Menthol has always been considered as a safe chemical for humans, but its potential adverse ecological effects on aquatic organisms and the toxic mechanisms have not yet been fully understood. The present study aims to investigate the physiological response of Microcystis aeruginosa after exposure to the two menthol isomers, and to explore the toxic mechanisms and ecological risks of these two chemicals. Results showed that rac-menthol exhibited a hormesis effect on the cell growth, chlorophyll a and protein contents; while l-menthol showed an inhibition effect. Adenosine triphosphate (ATP) content increased significantly at day 3 and then decreased markedly at day 6 after exposure to the two chemicals. Compared with rac-menthol, l-menthol can cause damage to the antioxidant system and plasmalemma more severely, promote the production and release of microcystins-LR (MC-LR) more dramatically, upregulate the expression of MC-transportation-related gene mcyH, and induce higher apoptosis rates. Overall results revealed that the toxic effects of l-menthol on cyanobacteria were significantly greater than those of rac-menthol. The significant increase in the malondialdehyde (MDA) content and the ultrastructural characteristics of the cells indicated that the plasma membranes were damaged. Thus, further attention should be paid to the scientific use, ecological and environmental risk assessment of chiral menthol. This study will also provide a scientific basis for future water quality criteria establishment on emerging contaminants such as fragrances.

Extrapolating Metal (Cu, Ni, Zn) Toxicity from Individuals to Populations Across Daphnia Species Using Mechanistic Models: The Roles of Uncertainty Propagation and Combined Physiological Modes of Action.

Mechanistic effect modeling is a promising tool to improve the ecological realism of environmental risk assessment. An open question for the mechanistic modeling of metal toxicity is whether the same physiological mode of action (PMoA) could be assumed for closely related species. The implications of various modeling choices, such as the use of parameter point estimates and assumption of simplistic toxicodynamic models, are largely unexplored. We conducted life-table experiments with Daphnia longispina, Daphnia magna, and Daphnia pulex exposed to the single metals Cu, Ni, and Zn, and calibrated toxicokinetic-toxicodynamic (TKTD) models based on dynamic energy budget theory. We developed TKTD models with single and combined PMoAs to compare their goodness-of-fit and predicted population-level sensitivity. We identified the PMoA reproduction efficiency as most probable in all species for Ni and Zn, but not for Cu, and found that combined-PMoA models predicted higher population-level sensitivity than single-PMoA models, which was related to the predicted individual-level sensitivity, rather than to mechanistic differences between models. Using point estimates of parameters, instead of sampling from the probability distributions of parameters, could also lead to differences in the predicted population-level sensitivity. According to model predictions, apical chronic endpoints (cumulative reproduction, survival) are conservative for single-metal population effects across metals and species. We conclude that the assumption of an identical PMoA for different species of Daphnia could be justified for Ni and Zn, but not for Cu. Single-PMoA models are more appropriate than combined-PMoA models from a model selection perspective, but propagation of the associated uncertainty should be considered. More accurate predictions of effects at low concentrations may nevertheless motivate the use of combined-PMoA models. Environ Toxicol Chem 2024;43:338-358. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Identification of polar organic chemicals in the aquatic foodweb: Combining high-resolution mass spectrometry and trend analysis

Environmental risk assessment of chemical contaminants requires prioritizing of substances taken up by biota as it is a starting point for potential adverse effects. Although knowledge about the occurrence of known chemical pollutants in aquatic organisms has significantly improved during the last decade, there is still a poor understanding for a broad range of more polar compounds. To tackle this issue, we proposed an approach that identifies bioaccumulative and biomagnifiable polar chemicals using liquid chromatography coupled with electrospray ionization to high resolution tandem mass spectrometry (LC-HRMS/MS) and combine it with trend analysis using hierarchical clustering. As a proof-of-concept, this approach was implemented on various organisms and compartments (sediment, litter leaves, periphytic biofilm, invertebrates and fish) collected from a small urban river. HRMS/MS data measured via data-independent acquisition mode were retrospectively analysed using two analytical strategies: (1) retrospective target and (2) suspect/non-target screening. In the retrospective target analysis, 56 of 361 substances spanning a broad range of contaminant classes were detected (i.e. 26 in fish, 18 in macroinvertebrates, 28 in leaves, 29 in periphyton and 32 in sediments, with only 7 common to all compartments), among which 49 could be quantified using reference standards. The suspect screening approach based on two suspect lists (in-house, Norman SusDat) led to the confirmation of 5 compounds with standards (three xenobiotics at level 1 and two lipids at level 2) and tentative identification of seven industrial or natural chemicals at level 2 and 3 through a mass spectra library match. Overall, this proof-of-concept study provided a more comprehensive picture of the exposure of biota to emerging contaminants (i.e., the internal chemical exposome) and potential bioaccumulation or biomagnification of polar compounds along the trophic chain.

An Initial Survey on Occurrence, Fate, and Environmental Risk Assessment of Organophosphate Flame Retardants in Romanian Waterways.

Organophosphate ester flame retardants (OPFRs) are ubiquitous organic pollutants in the environment and present an important preoccupation due to their potential toxicity to humans and biota. They can be found in various sources, including consumer products, building materials, transportation industry, electronic devices, textiles and clothing, and recycling and waste management. This paper presents the first survey of its kind in Romania, investigating the composition, distribution, possible sources, and environmental risks of OPFRs in five wastewater treatment plants (WWTPs) and the rivers receiving their effluents. Samples from WWTPs and surface waters were collected and subjected to extraction processes to determine the OPFRs using liquid chromatography with mass spectrometric detection. All the target OPFRs were found in all the matrices, with the average concentrations ranging from 0.6 to 1422 ng/L in wastewater, 0.88 to 1851 ng/g dry weight (d.w.) in sewage sludge, and 0.73 to 1036 ng/L in surface waters. The dominant compound in all the cases was tri(2-chloroisopropyl) phosphate (TCPP). This study observed that the wastewater treatment process was inefficient, with removal efficiencies below 50% for all five WWTPs. The environmental risk assessment indicated that almost all the targeted OPFRs pose a low risk, while TDCPP, TCPP, and TMPP could pose a moderate risk to certain aquatic species. These findings provide valuable information for international pollution research and enable the development of pollution control strategies.

Atlas of Environmental Risks and Water Area Quality in Croatian Marinas

The lack of systematic mapping of water quality in the water areas of Croatian marinas hinders visualization and understanding of potential cumulative impact of marinas on the environment. The main goal of the research subject of this paper is forming an atlas of environmental risks and water area quality in Croatian marinas by implementing model of Marina Environmental Risk Assessment – MERA. Within the implemented model, input data are concrete and current data obtained through the questionnaire submitted to the management structures of Croatian marinas, which is an additional practical value of model and reasearch results. The implemented methodology and risk model of the impact of Croatian marinas on the environment in this paper provides an insight into the current situation and represents a significant basis for managing environmental risks and the quality of water areas in Croatian marinas.

Adverse outcome pathways as a tool for optimization of the biomarker-based assessment of pollutant toxicity: A case study of cadmium in the blue mussels Mytilus edulis

Technogenic metals like cadmium (Cd) are discharged into the environment posing significant ecological risks to wildlife and contributing to a decline in biodiversity. Recent developments in toxicity testing and environmental risk assessment have shifted the focus towards prioritizing biological effects. To ensure effective environmental risk assessment, it is essential to develop sensitive sub-organismal biomarkers correlated with ecologically relevant organismal-level responses. Our study proposes a novel approach to enhance the evaluation of biomarker-based toxicity based on adverse outcome pathways (AOP) concept. We exposed the blue mussels M. edulis to Cd concentrations ranging from 200 to 600 µg l−1 (10–30 % of LC50) for 14 days, and assessed a comprehensive panel of 26 biomarkers related to molecular initiation events (Cd uptake and binding), key cellular events (oxidative stress, metabolic disturbances, and cytotoxicity), and adverse organismal outcomes (survival, energy metabolism, and reef-building capacity) in the putative AOP of Cd. Tissue Cd burdens increased linearly with exposure concentrations in the mussels. Although the condition index of the mussels remained unaffected, their biofiltration activity was suppressed at the highest Cd concentration. The negative effects of Cd exposure on the mussels' feeding were linked to reduced energetic scope for growth, impaired byssus production, increased hemocyte mortality, and altered functional traits of hemocytes. Additionally, Cd exposure induced oxidative stress, as evidenced by lower total antioxidant capacity and thiol pool, along with increased lipid peroxidation, leading to enhanced autophagy. Through Random Forest Analysis, we identified a minimal set of sensitive Cd effect biomarkers, including hemocyte mortality (contributing ∼0.32 to classification accuracy), hemocyte acid phosphatase activity, nitric oxide and metallothionein levels in the digestive gland, and whole-organism clearance rate and scope for growth (each contributing ∼0.02–0.08 to classification accuracy). These biomarkers collectively achieved a high accuracy of 90–100 % in distinguishing between control and Cd-exposed groups. Increasing the number of biomarkers did not improve classification accuracy. These findings suggest that using a smaller number of optimized biomarkers based on Adverse Outcome Pathways (AOP) can enhance the assessment of contaminant-induced negative effects while reducing testing costs in environmental risk assessments.

Different VOC species derived from fugitive emissions at various altitudes around petrochemical plant

Volatile organic compounds (VOCs) emitted from fugitive sources are crucial for environmental and health risk assessments. However, monitoring these emissions at ground level, according to traditional technical specifications, has made it challenging to identify polluted air masses and collect purposeful samples. In this study, we focused on utilizing an unmanned aerial vehicle system to obtain air samples around a petrochemical industrial park. We conducted a quantitative analysis of 108 VOC species and compared the results between aerial and ground-level samples. The findings indicated a higher presence of reactive compounds in the aerial samples. The sample pairs exhibited relatively homogeneous compositions of hydrocarbons with fewer than eight carbon atoms, suggesting a well-mixed condition for light compounds. Conversely, the aerial samples exclusively exhibited high mixing ratios of C8–C15 compounds, including branched paraffins and aldehydes. Based on the quantified VOCs, we evaluated the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAP). The results highlighted aldehydes, alkenes, and aromatics, particularly propanal, 2-butene, m/p-xylene, and benzaldehyde, as priority control compounds. Additionally, the semiquantitative concentrations of these non-quantitative C8–C15 species ranged from 1 to 15 ppbv, with a total content exceeding 150 ppbv, it indicated the significant contribution to ambient secondary pollution. These results provide valuable insights into the identification of potential emission sources and the assessment of environmental repercussions attributed to these intermediate-volatile organic compounds from fugitive emissions around petrochemical plant.

A critical review of the quantification, analysis and detection of radionuclides in the environment using diffusive gradients in thin films (DGT): advances and perspectives

Abstract This critical review explores the quantification, analysis, and detection of radionuclides in the environment using the diffusive gradients in thin films (DGT) technique. Radionuclides, unstable isotopes emitting ionising radiation, are present in the environment due to natural and anthropogenic sources for which concerns are raised about their impact on human health and ecosystems. DGT offers a unique passive sampling approach for understanding the behaviour of radionuclides and other trace elements. This review provides insights into method development, real case scenarios, advantages, limitations, and future perspectives of DGT in radionuclide analysis. In terms of method development, various isotopes have been analysed with varying significance based on origin, concentration, risks, and persistence. Notably, U, Th, Pu, Am, Cm, 99Tc, 226Ra, 137Cs, 134Cs, 232U, 237Np, and 152Eu have been measured, revealing their diverse roles in environmental radioactivity. Real case scenarios illustrate applications in uranium mining, water quality monitoring, and metal speciation studies, shedding light on mobility, bioavailability, and ecological impacts. DGT’s advantages include in-situ monitoring, time-averaged mean concentrations, and comprehensive speciation insights. Challenges include potential influences from biofouling, temperature changes and specifically the possible degradation of the binding and diffuse layer due to ionising radiation in long term exposures. In addition, the distinction between fully labile free metal ions and partially labile metal-ligand complexes introduces a potential limitation in the DGT technique, hence being an opportunity for future studies. Looking forward, DGT is expected to contribute to radiation dose modelling, environmental risk assessment, and water quality monitoring, with ongoing developments enhancing its utility and accuracy.

Incorporating environmental capacity considerations to prioritize control factors for the management of heavy metals in soil

Heavy metals (HMs) pollution threatens food security and human health. While previous studies have evaluated source-oriented health risk assessments, a comprehensive integration of environmental capacity risk assessments with pollution source analysis to prioritize control factors for soil contamination is still lacking. Herein, we collected 837 surface soil samples from agricultural land in the Nansha District of China in 2019. We developed an improved integrated assessment model to analyze the pollution sources, health risks, and environmental capacities of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn. The model graded pollution source impact on environmental capacity risk to prioritize control measures for soil HMs. All HMs except Pb exceeded background values and were sourced primarily from natural, transportation, and industrial activities (31.26%). Approximately 98.92% (children), 97.87% (adult females), and 97.41% (adult males) of carcinogenic values exceeded the acceptable threshold of 1E-6. HM pollution was classified as medium capacity (3.41 kg/hm2) with mild risk (PI = 0.52). Mixed sources of natural backgrounds, transportation, and industrial sources were identified as priority sources, and As a priority element. These findings will help prioritize control factors for soil HMs and direct resources to the most critical pollutants and sources of contamination, particularly when resources are limited.

Assessment of performance and environmental friendliness of a sorbent-based remediation method for heavy metal and metalloid contaminated soils

The contamination of natural ecosystems with heavy metals and metalloids (HMMs) primarily results from anthropogenic activities. Consequently, ongoing efforts are dedicated to the development of technologies aimed at restraining the mobility of HMMs and expediting chemical reactions that convert pollutants from mobile to immobile states. Addressing the reclamation issue always necessitates the selection of the most promising and effective type of reclamation work, as well as justification of land prioritization for reclamation purposes. In terms of performance and future potential, the sorbent-oriented approach, grounded in the concept of “green” utilization of man-made waste as a raw material for creating novel composite sorbents, is gaining traction for land reclamation in disturbed areas. In international practice, diverse environmental risk assessment methods are employed to substantiate the necessity for and prioritize reclamation efforts.The aim of the present study is to evaluate established conventional methods for assessing the risks associated with environmental harm. Additionally, this research aims to assess the efficacy and ecological compatibility of the composite sorbents developed by the author. This evaluation will be conducted by assessing and comparing the levels of potential environmental risks or risks of environmental damage subsequent to the application of these sorbents.The objectives of this study are as follows: 1) to explore the theoretical aspects of HMMs: including the formulation of a definition, investigation onto the origins of HMMs, examination of HMMs’ toxicity, and identification of prevalent methods for evaluating the environmental risks associated with HMMs; 2) to evaluate the effectiveness of established methods for assessing the environmental risks posed by HMMs; 3) to assess the efficacy and environmental sustainability of the composite sorbents developed by the author. This evaluation will involve an examination and comparison of the levels of potential environmental risks and the risks of environmental damage subsequent to the a pplication of these sorbents.The research subject: the mining allotment within the Levikhinskoye mine (classified as an environmental disaster site) is investigated as a disturbed land ecosystem, encompassing industrial waste dumps containing HMMs.The research hypothesis aims to establish the viability of “green” waste utilization from industrial sources as a raw material for composite sorbents used in land reclamation, without escalating the environmental damage. The conducted experiments revealed that sorbents composed of peat/water treatment sludge (at a ratio of 20/80 wt. % with natural moisture content) and peat/diatomite/water treatment sludge (at a ratio of 5/15/80 wt. % with natural moisture content) exhibited the highest level of performance, surpassing an overall efficiency of 89%. A sorbent composed of peat/diatomite (at a ratio of 25/75 wt. % with natural moisture content) demonstrated an overall efficiency of 67.7%. The estimated environmental risks (ER and ED) after the application of the proprietary composite sorbents, which include water treatment sludge, exhibited an average reduction of 89.5% and 88%, respectively.

Environmental Risk Assessment of the Harbin Section of the Songhua River Basin Based on Multi-Source Data Fusion

Surface water is a vital resource for human survival. However, economic and social development has resulted in significant pollutants from human activities, causing environmental pollution in watersheds. This pollution has had a profound impact on the surface water environment. However, limited studies have been conducted on the environmental risk evaluation of the watershed. In this study, we accounted for agricultural, industrial, and domestic source discharges in the districts and counties of the Harbin section of the Songhua River Basin for 2021. Data were collected from Statistical Yearbooks and governmental departments, and the characteristics of pollutant discharges in Harbin’s districts and counties were analyzed. Subsequently, we employed the Back Propagation neural network optimization method, combining remote sensing data, accounting data, pollution discharge data from each district and county, and economic and social data from the Statistical Yearbook and literature. This fusion of multiple data sources facilitated the construction of a watershed environmental risk evaluation system. The analysis considered four levels: economic and social, resource load, environmental infrastructure, and pollution discharge. Via this comprehensive evaluation, we identified the reasons for environmental risks in the water environment of the Harbin section of the Songhua River Basin. The evaluation results indicate that Nangang District, Xiangfang District, and Pingfang District face a higher risk to the water environment. Consequently, recommendations for mitigating water environment risks in these areas and across Harbin City are presented. The research methods and findings in this paper contribute valuable insights for developing control strategies to manage water quality in critically polluted areas of the Harbin section of the Songhua River Basin, providing a scientific foundation for regional river water quality management studies.

Bioaccumulative chemicals are either too hard or too soft: Conceptual density functional theory as a screening tool for emerging pollutants

Conceptual density functional theory (CDFT) descriptors were computed to predict the environmental fate of approximately 6,000 widely used industrial chemicals. CDFT descriptors aligned with a molecule’s possible bioaccumulation mechanism, i.e., soft chemicals are lipophilic, whereas hard chemicals may bioaccumulate by other mechanisms such as protein binding. The results have provided us with a new “rule of thumb” to guide risk assessment of chemical hazards: suspected persistent organic pollutants are either too hard (η > 0.40 hartree) or too soft (α > 200 Å3). This offers a novel approach to environmental risk assessment using two fundamental properties of a molecule.

Co-occurrence of organophosphate esters and phosphorus fractions in river sediments: Implications for pollution prediction and environment risk assessment

Organophosphate esters (OPEs) and phosphorus (P) are widespread pollutants in aquatic ecosystems, presenting potential ecological risks. However, there is still a lack of comprehensive understanding of their relationships in sediments. In this study, we investigated the co-occurrence and behaviors of the OPEs and P in urban river sediments. The results indicated serious OPE and P pollution in the study area, with substantial spatial variations in the contents and compositions. The OPE congeners and P fractions exhibited different correlations, particularly more significant linear relationships (R = 0.455 - 0.816, p < 0.05) were observed between the aryl-OPEs and P fractions, potentially due to the influence from sources, physicochemical properties, and total organic carbon. About 56 to 71% of variability in predicting the concentrations of aryl-OPE can be explained by the multiple linear regression model using the Fe/Al- and Ca-bound P contents. The study regions exhibited greater aryl-OPEs ecological risks were consistent with the regions with more serious Total P pollution levels. This study represents the first report demonstrating the potential of Fe/Al-P and Ca-P contents in predicting aryl-OPE contents in heavily polluted sediments, providing a useful reference to comprehensively assess the occurrence and environmental behaviors of aryl-OPEs in anthropogenic polluted sediments.

Quantile modeling for environmental risk: SAARC's journey with green finance, policies, and regulations

Environmental risk assessment and management have become critical issues facing global climate change and its multifaceted consequences. The 2030 United Nations Sustainable Development Goal (SDG) 13 prioritizes a sustainable environment and urgent climate change mitigation. The present study aimed to make accountability of environmental risk through green finance, financial development, policies, and regulations in SAARC countries. Using data from 2005 to 2022, the panel quantile regression (PQR) approach is applied to estimate the long-run coefficients at lower, middle, and upper quantiles. Overall, the study results indicate heterogeneity in the parameters impacting the environmental risk in SAARC. The findings from the PQR unveiled that green finance contributes to mitigating environmental risk in higher quantiles. Financial development contributes to environmental risk in the middle (40th to 60th) and higher quantiles (70th to 90th). It is concluded that the appropriate business regulatory framework reduces environmental risk in higher quantiles, and poor and low-rated policies increase it in the middle, and higher quantiles. Nevertheless, foreign direct investments increase environmental risk in lower and middle quantiles. Overall, there is a heterogeneity in the results; however, the amplitude of their parameters varied substantially. The quantile slope equality (QSE), symmetric quantile (SQ) tests, and fully modified ordinary least square (FMOLS), also confirmed the robustness of the results. Finally, the empirical findings of this study have prudent policy implications for the stakeholders concerning environmental risk.

Degradation of micropollutants by gamma irradiation: Insight of transformation product formation explored by suspect and non-target screening using LC-HRMS

Conventional wastewater treatment systems have limitations in removing diverse micropollutants present with the complex matrix. As an alternative, advanced oxidation processes such as gamma-irradiation have been proposed. The aim of the study was to get insight into the decomposition of persistent pharmaceuticals (carbamazepine, cetirizine, tramadol) by gamma irradiation in pure water and effluent, and the formation and pathway of transformation products (TPs) identified via suspect/non-target screening using LC-HRMS. For TPs, the environmental risk assessment was also conducted with Quantitative Structure Activity Relationship (QSAR) based estimations. The decomposition effect was estimated with the removal rate and radiation chemical yield (G-value). The results indicated that the removal rate increased as the absorbed dose increased, up to 5 kGy, completely eliminating the target pharmaceuticals (initial nominal concentration: 10 mg/L) in pure water. However, the degradation in effluent was negatively affected by the organic matrix. By employing suspect/non-target screening techniques, a tentative identification of 30 transformation products (TPs) was achieved, providing insights into the degradation pathway. They were mainly formed through hydroxylation reaction by OH⸱. As a result of the QSAR estimation for the hazard of TPs, most of the TPs showed a lower risk than the parent compound. It indicates that the gamma-irradiation can be used as an alternative process to eliminate hardly degradable micropollutants in conventional wastewater treatment plant in a way to mitigate the environmental risk.

Short-term exposure to environmental levels of nicotine and cotinine impairs visual motor response in zebrafish larvae through a similar mode of action: Exploring the potential role of zebrafish α7 nAChR

The current view is that environmental levels of nicotine and cotinine, commonly in the ng/L range, are safe for aquatic organisms. In this study, 7 days post-fertilization zebrafish embryos have been exposed for 24 h to a range of environmental concentrations of nicotine (2.0 ng/L-2.5 μg/L) and cotinine (50 pg/L–10 μg/L), as well as to a binary mixture of these emerging pollutants. Nicotine exposure led to hyperactivity, decreased vibrational startle response and increased non-associative learning. However, the more consistent effect found for both nicotine and cotinine was a significant increase in light-off visual motor response (VMR). The effect of both pollutants on this behavior occurred through a similar mode of action, as the joint effects of the binary mixture of both chemicals were consistent with the concentration addition concept predictions. The results from docking studies suggest that the effect of nicotine and cotinine on light-off VMR could be mediated by zebrafish α7 nAChR expressed in retina. The results presented in this study emphasize the need to revisit the environmental risk assessment of chemicals including additional ecologically relevant sublethal endpoints.

Toxicological effects induced by two carbamates on earthworms (Eisenia fetida): Acute toxicity, arrested regeneration and underlying mechanisms

Eisenia fetida is recognised as advantageous model species in ecotoxicological and regeneration investigations. The intensive utilization of carbamate pesticides (CARs) imposes heavy residue burdens and grave hazards on edaphic environments as well as soil fauna therein. However, precise mechanisms whereby the specific CAR exerted toxic effects on earthworms remain largely elusive, notably from regenerative perspective. Herein, acute responses and regenerative toxicity of two carbamates (metolcarb, MEB and fenoxycarb, FEB) against E. fetida were dissected using biochemical, histological as well as molecular approaches following OECD guidelines at the cellular, tissue and organismal level. The acute toxicity data implied that MEB/FEB were very toxic/medium to extremely toxic, respectively in filter paper contact test and low to medium toxic/low toxic, respectively in artificial soil test. Chronic exposure to MEB and FEB at sublethal concentrations significantly mitigated the soluble protein content, protein abundance while enhanced the protein carbonylation level. Moreover, severely retarded posterior renewal of amputated earthworms was noticed in MEB and FEB treatments relative to the control group, with pronouncedly compromised morphology, dwindling segments and elevated cell apoptosis of blastema tissues, which were mediated by the rising Sox2 and decreasing TCTP levels. Taken together, these findings not only presented baseline toxicity cues for MEB and FEB exposure against earthworms, but also yielded mechanistic insights into regenerative toxicity upon CAR exposure, further contributing to the environmental risk assessment and benchmark formulation of agrochemical pollution in terrestrial ecosystem.

Reproductive toxicity in birds predicted by physiologically-based kinetics and bioenergetics modelling

Effects on the growth and reproduction of birds are important endpoints in the environmental risk assessment (ERA) of pesticides. Toxicokinetic-toxicodynamic models based on dynamic energy budget theory (DEB) are promising tools to predict these effects mechanistically and make extrapolations relevant to ERA. However, before DEB-TKTD models are accepted as part of ERA for birds, ecotoxicological case studies are required so that stakeholders can assess their capabilities.We present such a case-study, modelling the effects of the fluopyram metabolite benzamide on the northern bobwhite quail (Colinus virginianus). We parametrised a DEB-TKTD model for the embryo stage on the basis of an egg injection study, designed to provide data for model development. We found that information on various endpoints, such as survival, growth, and yolk utilisation were needed to clearly distinguish between the performance of model variants with different TKTD assumptions. The calibration data were best explained when it was assumed that chemical uptake occurs via the yolk and that benzamide places stress on energy assimilation and mobilisation.To be able to bridge from the in vitro tests to real-life exposure, we developed a physiologically-based toxicokinetic (PBK) model for the quail and used it to predict benzamide exposure inside the eggs based on dietary exposure in a standard reproductive toxicity study. We then combined the standard DEB model with the TKTD module calibrated to the egg injection studies and used it to predict effects on hatchling and 14-day chick weight based on the exposure predicted by the PBK model. Observed weight reductions, relative to controls, were accurately predicted. Thus, we demonstrate that DEB-TKTD models, in combination with suitable experimental data and, if necessary, with an exposure model, can be used in bird ERA to predict chemical effects on reproduction.

Cadmium accumulation in tropical island paddy soils: From environment and health risk assessment to model prediction

Cultivated soil quality is crucial because it directly affects food safety and human health, and rice is of primary concern because of its centrality to global food networks. However, a detailed understanding of cadmium (Cd) geochemical cycling in paddy soils is complicated by the multiple influencing factors present in many rice-growing areas that overlap with industrial centers. This study analyzed the pollution characteristics and health risks of Cd in paddy soils across Hainan Island and identified key influencing factors based on multi-source environmental data and prediction models. Approximately 27.07% of the soil samples exceeded the risk control standard screening value for Cd in China, posing an uncontaminated to moderate contamination risk. Cd concentration and exposure duration contributed the most to non-carcinogenic and carcinogenic risks to children, teens, and adults through ingestion. Among the nine prediction models tested, Extreme Gradient Boosting (XGBoost) exhibited the best performance for Cd prediction with soil properties having the highest importance, followed by climatic variables and topographic attributes. In summary, XGBoost reliably predicted the soil Cd concentrations on tropical islands. Further research should incorporate additional soil properties and environmental variables for more accurate predictions and to comprehensively identify their driving factors and corresponding contribution rates.