Scientific Risk Assessment Research Articles

Human gingival fibroblast response on zirconia and titanium implant abutment: A systematic review.

The peri-implant region, where restoration interfaces with mucosal tissue, plays an essential role in overall implant success and is just as important as osseointegration. The implant abutment materials are in intimate contact with human gingival fibroblasts (HGFs). This study compares the proliferation of HGFs between zirconia and titanium abutments used in dental implants. An electronic search was performed using PubMed, EMBASE, and Web of Science databases. English articles based on in vitro studies testing HGFs proliferation on zirconia and titanium implant abutment materials were included. A quality assessment of the selected study was performed using the web-based Science in Risk Assessment and Policy (SciRAP) tool. The HGFs proliferation and cellular morphology tests on zirconia and titanium materials from the included studies were summarized, exploring the role of material surface characteristics. The electronic search yielded 401 studies, of which 17 were selected for inclusion. Zirconia exhibited comparable or superior efficacy in promoting the proliferation of HGFs compared to titanium. Observations on cellular morphology showed similar outcomes for both materials. Establishing a definitive relationship between contact angle, surface roughness, and their influence on cellular response remains challenging due to the varied methodological approaches in the reviewed studies. Based on the findings of this systematic review, zirconia shows comparable reliability to titanium as an abutment material for HGFs proliferation, with comparable or superior HGFs proliferative outcomes.

The Effectiveness of Curcumin Nanoparticle-Coated Titanium Surfaces in Osteogenesis: A Systematic Review.

(1) Background: This systematic review critically appraises and synthesizes evidence from in vitro studies investigating the effects of curcumin nanoparticles on titanium surface modification, focusing on cell adhesion, proliferation, osteogenic differentiation, and mineralization. (2) Methods: A comprehensive electronic search was conducted in PubMed, Cochrane Central Register of Controlled Trials, and Google Scholar databases, yielding six in vitro studies that met the inclusion criteria. The search strategy and study selection process followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A qualitative methodological assessment was performed using the SciRAP (Science in Risk Assessment and Policy) method, which evaluated the reporting and methodological quality of the included studies. (3) Results: All six studies consistently demonstrated that curcumin-coated titanium surfaces inhibited osteoclastogenesis and promoted osteogenic activity, evidenced by enhanced cell adhesion, proliferation, osteogenic differentiation, and mineralization. The mean reporting quality score was 91.8 (SD = 5.7), and the mean methodological quality score was 85.8 (SD = 10.50), as assessed by the SciRAP method. Half of the studies used hydroxyapatite-coated titanium as a control, while the other half used uncoated titanium, introducing potential variability in baseline comparisons. (4) Conclusions: This systematic review provides compelling in vitro evidence supporting the osteogenic potential of curcumin nanoparticle-coated titanium surfaces. The findings suggest that this surface modification strategy may enhance titanium implants' biocompatibility and osteogenic properties, potentially improving dental and orthopedic implant outcomes. However, the review highlights significant heterogeneity in experimental designs and a concentration of studies from a single research group. Further research, particularly in vivo studies and clinical trials from diverse research teams, is essential to validate these findings and comprehensively understand the translational potential of this promising surface modification approach.

Quality Risk Assessment of Prefabricated Steel Structural Components during Production Using Fuzzy Bayesian Networks

This study aims to address quality issues in the production of prefabricated steel structural components for buildings by investigating challenges in quality risk assessment. It identifies key factors contributing to quality problems and establishes an evaluation index system. Traditional methods encounter limitations in handling uncertainty and conducting quantitative analysis. Therefore, the fuzzy Bayesian network (FBN) theory is utilized to perform a probabilistic analysis of quality risks during the production phase. This research achieves a more accurate and dynamic risk assessment by integrating the strengths of fuzzy logic and Bayesian networks (BNs) and by utilizing expert knowledge, the similarity aggregation method (SAM), and the noisy-OR gate model. The study reveals that factors such as the “low professional level of designers”, “poor production refinement”, and “poor storage conditions for finished products” have a significant impact on quality risks. This study offers a scientific risk assessment tool designed to address the quality control challenges commonly experienced in the manufacturing of steel structural components. Identifying the critical risk factors that influence quality empowers actual production enterprises to develop risk management strategies and improvement measures in a more focused manner, thereby facilitating more effective resource allocation and risk prevention and control. Consequently, this approach has a significant impact on enhancing the overall production level and quality within the industry.

Assessing Risks in Cross-Regional Tourism Corridors: A Case Study of Tibetan Plateau Tourism

Due to the frequent impact of external risks, scientific tourism risk assessment has become the primary task to be implemented in the process of tourism development. Especially with the development of self-driving travel, cross-regional tourism corridors have become an important tourism carrier. However, compared to traditional fixed-location tourism, cross-regional tourism introduces a more intricate landscape of risks. Therefore, there is a pressing need to assess the tourism risks inherent in these corridors. There are many cross-regional tourism corridors in the Tibetan Plateau, but the natural environment of the Tibetan Plateau brings great risks to these tourism corridors. That is why this study focuses on the Tibetan Plateau’s tourism corridors, employing methodologies such as the Analytic Hierarchy Process, entropy weight method, geographic information systems (GIS) spatial analysis, and others to delve into their tourism risk profiles and the influencing factors. Our findings reveal elevated tourism risks across the Tibetan Plateau’s corridors, notably concentrated along the Yunnan–Tibet Line, north Sichuan–Tibet Line, Xinjiang–Tibet Line, Tangfan Ancient Road, Qinghai–Tibet Line, and south Sichuan–Tibet Line. Furthermore, Geodetector was employed to scrutinize the factors influencing tourism risk within the Tibetan Plateau’s corridors, identifying tourism resource endowment, geographical location, precipitation patterns, and economic foundations as primary influencers. Notably, the interaction between these factors exacerbates the overall tourism risk. These insights significantly contribute to the field of tourism risk research and provide a scientific basis for formulating robust tourism safety management strategies within the Tibetan Plateau region.

Risk assessment of high-speed railway CTC system based on improved game theory and cloud model

PurposeIn order to solve the problem of inaccurate calculation of index weights, subjectivity and uncertainty of index assessment in the risk assessment process, this study aims to propose a scientific and reasonable centralized traffic control (CTC) system risk assessment method.Design/methodology/approachFirst, system-theoretic process analysis (STPA) is used to conduct risk analysis on the CTC system and constructs risk assessment indexes based on this analysis. Then, to enhance the accuracy of weight calculation, the fuzzy analytical hierarchy process (FAHP), fuzzy decision-making trial and evaluation laboratory (FDEMATEL) and entropy weight method are employed to calculate the subjective weight, relative weight and objective weight of each index. These three types of weights are combined using game theory to obtain the combined weight for each index. To reduce subjectivity and uncertainty in the assessment process, the backward cloud generator method is utilized to obtain the numerical character (NC) of the cloud model for each index. The NCs of the indexes are then weighted to derive the comprehensive cloud for risk assessment of the CTC system. This cloud model is used to obtain the CTC system's comprehensive risk assessment. The model's similarity measurement method gauges the likeness between the comprehensive risk assessment cloud and the risk standard cloud. Finally, this process yields the risk assessment results for the CTC system.FindingsThe cloud model can handle the subjectivity and fuzziness in the risk assessment process well. The cloud model-based risk assessment method was applied to the CTC system risk assessment of a railway group and achieved good results.Originality/valueThis study provides a cloud model-based method for risk assessment of CTC systems, which accurately calculates the weight of risk indexes and uses cloud models to reduce uncertainty and subjectivity in the assessment, achieving effective risk assessment of CTC systems. It can provide a reference and theoretical basis for risk management of the CTC system.

A Study of Insurance Company Underwriting Risk Based on EWM and TOPSIS Methods

This study proposes a risk assessment model called CPSF, which aims to assess insurance risk in areas where extreme weather is frequent. The model adopts a multidimensional and comprehensive assessment system, considering climate change, demographic and socio-economic, and financial conditions as the main factors, and constructs corresponding assessment indicators. The study establishes a scientific and reliable risk assessment system through the steps of data source, data pre-processing, indicator establishment, weight determination, and comprehensive assessment. By applying the model to two regions, namely, Southeast China and Southeast United States, where extreme weather often occurs, the insurance risk situation of these regions is analyzed and the future trend is predicted, which provides an important reference for insurance companies and policy making.

Flood risk identification in high-density urban areas of Macau based on disaster scenario simulation

Currently, most of the world's economically developed and densely populated cities are built along coasts, and populations and industries tend to concentrate in coastal areas. However, with climate change, extreme weather events frequently occur in coastal areas. High-density urban spaces have changed the natural hydrological cycle, and the dense spatial layout, low-load municipal system planning, and inefficient management system of coastal cities have led to an increasing threat of flooding in these high-density urban areas, affecting their safety and sustainable development. In this context, the scientific and reasonable risk assessment of future flooding in coastal high-density urban areas has become an urgent problem and a key focus of urban disaster prevention and control efforts. In this paper, a flood identification tool is developed, a technical route for flood risk identification is established, identification scenarios under several disaster conditions are set, and classification criteria for flood risk identification are determined. An empirical study of high-density urban areas in Macau is carried out, the Infoworks Icm hydrological simulation software (Manufacturer: HR Wallingford (Shanghai) Co.,Ltd) is used to establish a flood hazard risk identification model for the Macau Peninsula, and flood hazard risk zones for the high-density urban areas in Macau are identified and delineated based on the simulation results.

Evaluation of multimodal data-driven financial risk prediction methods for corporate green credit

With the rapid economic development and increasingly serious environmental problems, many regions have launched green credit policies. Green credit can reduce the loan interest rate of the environmental protection industry and lower the financing threshold. Traditional risk prediction methods cannot comprehensively evaluate the green credit risk of the enterprise based on the degree of green environmental protection and the industry environment in which the enterprise is located, resulting in the inconsistency between the credit financial risk prediction and the actual results, which increases the bank credit risk. In order to strengthen the management level of green credit and reduce the probability of non-performing loans, a scientific risk assessment method was constructed by using a combination of automatic encoding network and bidirectional long short-term memory neural network model to predict the financial risks of green credit, driven by multi-modal data. Through the study of multimodal data, this paper took green credit financial risk as the research object, aggregated the information of various enterprises to improve the bank’s capital utilization rate, and also promoted enterprises to take the initiative to transform into the direction of green environmental protection. Finally, the experiment proved that multimodal data fusion model was more superior than random forest in risk prediction, reducing the bank’s non-performing loan rate by 3.1% and improving the bank’s risk control level.

Assessment of genetically modified maize MON 89034 × 1507 × NK603 for renewal authorisation under Regulation (EC) No 1829/2003 (application GMFF-2022-3670).

Following the submission of dossier GMFF-2022-3670 under Regulation (EC) No 1829/2003 from Corteva Agriscience Belgium BV and Bayer Agriculture BV, the Panel on genetically modified organisms of the European Food Safety Authority was asked to deliver a scientific risk assessment on the data submitted in the context of the renewal of authorisation application for the herbicide-tolerant and insect-resistant genetically modified maize MON 89034 × 1507 × NK603, for food and feed uses, excluding cultivation within the European Union. The data received in the context of this renewal application contained post-market environmental monitoring reports, a systematic search and evaluation of literature, updated bioinformatic analyses and a search for additional documents or studies performed by or on behalf of the applicant. The GMO Panel assessed these data for possible new hazards, modified exposure or new scientific uncertainties identified during the authorisation period and not previously assessed in the context of the original application. Under the assumption that the DNA sequences of the events in maize MON 89034 × 1507 × NK603 considered for renewal are identical to the sequences of the originally assessed events, the GMO Panel concludes that there is no evidence in renewal dossier GMFF-2022-3670 for new hazards, modified exposure or scientific uncertainties that would change the conclusions of the original risk assessment on maize MON 89034 × 1507 × NK603.

Assessment of genetically modified maize MON 89034 × 1507 × MON 88017 × 59122 and 8 out of 10 of its subcombinations for renewal authorisation under Regulation (EC) No 1829/2003 (dossier GMFF-2022-9170).

Following the joint submission of dossier GMFF-2022-9170 under Regulation (EC) No 1829/2003 from Bayer Agriculture B.V. and Corteva Agriscience Belgium B.V., the Panel on genetically modified organisms of the European Food Safety Authority was asked to deliver a scientific risk assessment on the data submitted in the context of the renewal of authorisation application for the herbicide tolerant and insect resistant genetically modified maize MON 89034 × 1507 × MON 88017 × 59122 and 8 out of 10 of its subcombinations, for food and feed uses, excluding cultivation within the European Union. The data received in the context of this renewal application contained post-market environmental monitoring reports, an evaluation of the literature retrieved by a scoping review, a search for additional studies performed by or on behalf of the applicant and updated bioinformatics analyses. The GMO Panel assessed these data for possible new hazards, modified exposure or new scientific uncertainties identified during the authorisation period and not previously assessed in the context of the original application. Under the assumption that the DNA sequences of the events in maize MON 89034 × 1507 × MON 88017 × 59122 and 8 out of 10 of its subcombinations considered for renewal are identical to the sequences of the originally assessed events, the GMO Panel concludes that there is no evidence in renewal dossier GMFF-2022-9170 for new hazards, modified exposure or scientific uncertainties that would change the conclusions of the original risk assessment on maize MON 89034 × 1507 × MON 88017 × 59122 and 8 out of 10 of its subcombinations.

An integrated risk assessment method for urban areas due to chemical leakage accidents

Chemical parks which hold large inventories of hazardous materials have become one important type of urban critical infrastructure. The hazardous chemical leakage such as toxic gas leakage has emerged in recent years, resulting in not only serious environmental pollution but also catastrophic consequences to certain urban areas. It is critical to make scientific risk assessment for such events to reduce negative effects. To address this issue, an integrated urban risk assessment (IURA) method coupling consequences of chemical leakage accidents and the vulnerability of local population is proposed in this work. The threat zones and hazard maps of toxic gas dispersion are present by using the ALOHA software. The population vulnerability is decided by three indicators including exposure, sensitivity, and adaptive capacity of residents in affected areas, the Grey Correlation-TOPSIS (GC-TOPSIS) method is used to rank the vulnerability of different regions. The ArcGIS software is applied to generate an integrated risk map through superimposing the hazard map and the population vulnerability map. The original risk matrix evaluation results were subdivided using the Borda count method. A case about an industrial city in Hubei, China is analyzed to test the method. Result shows the new integrated risk assessment method is more accurate and effective, which is beneficial for the government to develop emergency plans and enhance the safety of people.

Research on Safety Risk Assessment of Prefabricated Building Construction Based on Disaster Sociology

Nowadays, with the development of the economy and the needs of people's lives, the industrialization and informatization of construction have begun to develop rapidly. the rapid development of China's market economy. The original cast-in-place construction technology has become increasingly difficult to adapt to the new requirements of market economy and social construction development. However, prefabricated buildings are increasingly accepted by society due to their advantages of green environmental protection, low consumption, improved labor efficiency, and standardized production. With the promotion of a series of national policies, prefabricated buildings have begun to develop rapidly. However, in the actual construction process, safety accidents such as high-altitude falls, object strikes, lifting injuries, and collapses are constantly occurring. How to effectively reduce safety accidents has become one of the major problems that urgently need to be solved. Therefore, this article aims to establish a comprehensive and scientific safety risk assessment index system for prefabricated buildings by comprehensively analyzing the characteristics of safety accidents in prefabricated buildings and combining disaster sociology theory for similar projects.

Derivation of human health and odor risk control values for soil ammonia nitrogen by incorporating solid-liquid partitioning, ammonium/ammonia equilibrium: A case study of a retired nitrogen fertilizer site in China

Nitrogen fertilizer supports agricultural intensification, but its manufacturing results in substantial contaminated sites. Ammonia nitrogen is the main specific pollutant in retired nitrogen fertilizer sites with potential human health and odor risks. However, few studies focus on ammonia nitrogen risk assessment at contaminated sites, particularly considering its solid-liquid partitioning process (Kd) and ammonium/ammonia equilibrium process (R) in the soil. This study took a closed nitrogen fertilizer factory site as an example and innovatively introduced Kd and R to scientifically assess the human health and odor risk of ammonia nitrogen. The risk control values (RCVs) of ammonia nitrogen based on human health and odor risk were also derived. The maximum concentration of ammonia nitrogen was 3380 mg/kg in the unsaturated soil, which was acceptable for human health because the health RCVs were 5589 ∼ 137,471 mg/kg in various scenarios. However, odor risk was unacceptable for RCVs were 296 ∼ 1111 mg/kg under excavation scenarios and 1118 ∼ 35,979 mg/kg under non-excavation scenarios. Of particular concern, introducing Kd and R in calculation increased the human health and odor RCVs by up to 27.92 times. Despite the advancements in ammonia risk assessment due to the introduction of Kd and R, odor risk during excavation remains a vital issue. These findings inform a more scientific assessment of soil ammonia risk at contaminated sites and provide valuable insights for the management and redevelopment of abandoned nitrogen fertilizer plant sites.

Threats of nano/microplastics to reproduction and offspring: Potential mechanisms and perspectives

Due to the ubiquitous occurrence in the aquatic environment and terrestrial ecosystem and underlying eco-environmental risks, nano/microplastics (NPs/MPs) have sparked great public concerns. The purpose of this work is aimed to summarize the harmful influence of NPs/MPs on reproduction and offspring health and further explore the potential mechanisms of action, thereby facilitating the more comprehensive understanding of NPs/MPs features. Literature search databases included EMBASE, Web of Science, and PubMed. The study selection and data extraction were implemented according to the inclusion criteria. NPs/MPs could accumulate and trigger reproductive toxic responses and thereafter generate deleterious effects on the offspring health. Accordingly, the reproductive toxicity of NPs/MPs was characterized as the sperm deformity, decline in sperm count and motility, follicular growth tardiness, ovarian fibrosis, granulosa cell death, disorder of reproductive hormone secretion, as well as the fetal growth restriction, glycolipid metabolism disorder, and inflammatory responses of the next generation. Additionally, mechanism research revealed that NPs/MPs exposure brought about inflammatory responses and oxidative stress and thereafter, destroyed the blood-testis barrier (BTB) integrity, motivated spermatogenic cell apoptosis by activating the JNK and p38/MAPK-Nrf2/NF-κB pathways, and induced ovarian granulosa cell pyroptosis and apoptosis and subsequent ovarian fibrosis via the Wnt/β-Catenin and NLRP3/Caspase-1 pathways. Nevertheless, this work also highlighted the imperative requirements for scientific and systematic risk assessments of NPs/MPs, so as to identify the feasible risk mitigation strategies.

Prioritization of the ecotoxicological hazard of PAHs towards aquatic species spanning three trophic levels using 2D-QSTR, read-across and machine learning-driven modelling approaches

Polycyclic aromatic hydrocarbons (PAHs) represent a common group of environmental pollutants that endanger various aquatic organisms via various pathways. To better prioritize the ecotoxicological hazard of PAHs to aquatic environment, we used 2D descriptors-based quantitative structure-toxicity relationship (QSTR) to assess the toxicity of PAHs toward six aquatic model organisms spanning three trophic levels. According to strict OECD guideline, six easily interpretable, transferable and reproducible 2D-QSTR models were constructed with high robustness and reliability. A mechanistic interpretation unveiled the key structural factors primarily responsible for controlling the aquatic ecotoxicity of PAHs. Furthermore, quantitative read-across and different machine learning approaches were employed to validate and optimize the modelling approach. Importantly, the optimum QSTR models were further applied for predicting the ecotoxicity of hundreds of untested/unknown PAHs gathered from Pesticide Properties Database (PPDB). Especially, we provided a priority list in terms of the toxicity of unknown PAHs to six aquatic species, along with the corresponding mechanistic interpretation. In summary, the models can serve as valuable tools for aquatic risk assessment and prioritization of untested or completely new PAHs chemicals, providing essential guidance for formulating regulatory policies.

Construction of Intelligent Financial Supervision Mechanism for Colleges and Universities Based on RPA Technology

Abstract The RPA financial monitoring mechanism utilizes a predictive model to capture and store university data in preprocessing, and adopts a decision tree algorithm to construct a specific predictive model with good classification ability, and its logical structure is very similar to the decision-making ideas of human beings in the natural environment. CNN-LSTM financial risk assessment model is also utilized to carry out scientific risk assessment, the output of CNN is used as the input of LSTM, combining the advantages of the two to improve the learning ability of the financial fraud risk assessment model, and dynamic early warning can be accomplished beforehand for potential risk points. By analyzing the accuracy and coverage of the financial violation prediction model, 10.28% of violations were found with 96.7% accuracy. The accuracy is lower when the proportion of financial violations is higher. Risk assessment of fundraising activities and working capital of universities can be found that Z private universities have a relatively single source of income, tuition income is dominant, and in 2019, 2020 and 2022, the proportion of constructive expenditures of Z private universities reaches more than 20%, while the expenses of scientific research costs are less, however, the university’s comprehensive early warning status is relatively good. The financial risk is not significant and is in a safer range. In the university research fund violation supervision, the weight of researchers still have balance funds after two years after the completion of the project is 0.073, which indicates that the research project fund management supervision is not in place.

Influence of consumption of the food additive carrageenan on the gut microbiota and the intestinal homeostasis of mice.

The safety of the carrageenan (CGN) consumption as a food additive is under debate, with negative effects being associated with the products of hydrolysis of CGN. Moreover, there is an increasing need to integrate gut microbiome analysis in the scientific risk assessment of food additives. The objective of this study was to test the effects of CGN consumption on the gut microbiota and the intestinal homeostasis of young male and female mice. Female and male ICR-CD1 mice (8 weeks old) orally received 540 mg kg-1 day-1 of CGN, representing the maximum-level exposure assessment scenario surveyed for children, over the course of two weeks. Fecal material and peritoneal immune cells were analyzed to determine changes in the fecal microbiota, based on the analysis of bacterial 16S rRNA gene amplicon sequences and short-chain fatty acid (SCFA) concentrations, and some immune functions and redox parameters of peritoneal leukocytes. Non-significant microbiota taxonomical changes associated with CGN intake were found in the mouse stools, resulting the housing time in an increase in bacterial groups belonging to the Bacteroidota phylum. The PICRUSt2 functional predictions showed an overall increase in functional clusters of orthologous genes (COGs) involved in carbohydrate transport and metabolism. A significant increase in the cytotoxicity of fecal supernatants was observed in CGN-fed mice, which correlated with worsening of immune functions and oxidative parameters. The altered immunity and oxidative stress observed in young mice after the consumption of CGN, along with the fecal cytotoxicity shown towards intestinal epithelial cells, may be associated with the gut microbiota's capacity to degrade CGN. The characterization of the gut microbiota's ability to hydrolyze CGN should be included in the risk assessment of this food additive.

Risk management of supply chain finance in the new energy vehicle industry: A comprehensive evaluation model

In recent years, the new energy vehicle (NEV) industry has rapidly grown and become a vital part of the automotive sector. Supply chain finance plays a critical role in the NEV industry as it affects the operation and development of the entire industry chain. The supply chain of NEVs is different from the traditional automobile industry due to its complexity, fragility, and forecasting difficulties. Managing the risks associated with supply chain finance in the NEV industry presents new challenges. Commercial banks need to establish scientific risk assessment models and take preventive measures to ensure the provision of financial services while safeguarding their funds. This study focuses on the supply chain financial services of NEVs provided by commercial banks. It employs various methods to assess financial risks, establishes a risk index model, and uses the analytic hierarchy process, entropy weight method, and fuzzy comprehensive evaluation to determine weights and provide risk assessment opinions. The proposed evaluation model effectively assesses risks and provides preventive measures with potential practical applications. Future research can further refine and apply this model to benefit enterprises and financial institutions in the NEV industry.

Assessment of genetically modified maize MON 810 for renewal authorisation under Regulation (EC) No 1829/2003 (dossier GMFF-2022-9450).

Following the submission of dossier GMFF-2022-9450 under Regulation (EC) No 1829/2003 from Bayer Agriculture BV, the Panel on Genetically Modified Organisms of the European Food Safety Authority was asked to deliver a scientific risk assessment on the data submitted in the context of the renewal of authorisation application for the insect protected genetically modified maize MON 810, for food and feed uses (including pollen), excluding cultivation within the European Union. The data received in the context of this renewal application contained post-market environmental monitoring reports, an evaluation of the literature retrieved by a scoping review, additional studies performed by or on behalf of the applicant and updated bioinformatics analyses. The GMO Panel assessed these data for possible new hazards, modified exposure or new scientific uncertainties identified during the authorisation period and not previously assessed in the context of the original application. Under the assumption that the DNA sequence of the event in maize MON 810 considered for renewal is identical to the sequence of the originally assessed event, the GMO Panel concludes that there is no evidence in dossier GMFF-2022-9450 for new hazards, modified exposure or scientific uncertainties that would change the conclusions of the original risk assessment on maize MON 810.

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.