Toxicity Index Research Articles

Osteoporosis and Bone Deformities in Free-Living Geoffroy's Toadhead Turtles (Phrynops geoffroanus) Rescued from Urban Areas in the Metropolitan Region of Recife (Pernambuco, Brazil)

Abstract Organic pollutants have bioaccumulative effects and induce a high index of toxicity in aquatic ecosystems. The aim of our study was to report tomographic abnormalities found in free-living turtles (Geoffroy`s toadhead turtle, Phrynops geoffroanus) from an urban area near the Capibaribe and Beberibe river basins in Brazil, which are known to be contaminated by heavy metals as well solid waste. Clinical and tomographic evaluation of eight turtles was performed to assess their health status for subsequent release. Tomographic analysis revealed bone abnormalities including demineralization, coarse trabecular pattern, subperiosteal bone resorption, deformity of dorsal vertebrae and shell fracture. Considering that turtles are recognized as bioindicators of water quality, a high occurrence of bone abnormalities may suggest an association with environmental pollution in the studied area and signal that conservation initiatives are needed to safeguard the aquatic ecosystem of the metropolitan region of Recife.

Screening alcohol degrading function probiotics and protective effect of fermented apple juice on alcoholic liver injury in mice

In this study, we screened probiotics with alcohol degrading function and studied the antioxidant activity of fermented apple juice and its protective effect on alcoholic liver injury in mice. Lactobacillus helveticus CICC6064 was screened by the test of alcohol degradation and simulated gastrointestinal digestion in vitro. The antioxidant activity, polyphenol and flavonol concentrations of fermented apple juice were increased. Animal experiments showed that compared with other experimental groups, Lactobacillus helveticus CICC6064 fermented apple juice could reduce the concentration of alcohol in serum of mice significantly, meanwhile, it also can protect the liver by reducing the pro-inflammatory cytokines (TNF-α, IL-1β, IL-2, and IL-6), increasing anti-inflammatory cytokines (IL-10), reducing oxidative stress in the body (increasing SOD, GST, CAT, reducing NO), reducing liver toxicity index (ALT, AST, GGT, ALP), and reducing liver lipid accumulation.

Development and validation of a nomogram for radiation-induced hepatic toxicity after intensity modulated radiotherapy for hepatocellular carcinoma: a retrospective study.

This study aimed to construct a nomogram to predict radiation-induced hepatic toxicity in patients with hepatocellular carcinoma treated with intensity-modulated radiotherapy. This study reviewed the clinical characteristics and dose-volume parameters of 196 patients with hepatocellular carcinoma. Radiation-induced hepatic toxicity was defined as progression of the Child-Pugh score caused by intensity-modulated radiotherapy. Factors relevant to radiation-induced hepatic toxicity were selected using receiver operating characteristic and univariate logistic analysis. A risk assessment model was developed, and its discrimination was validated. Eighty-eight (44.90%) and 28 (14.29%) patients had radiation-induced hepatic toxicity ≥ 1 (Child-Pugh≥1) and radiation-induced hepatic toxicity ≥ 2 (Child-Pugh≥2). Pre-treatment Child-Pugh, body mass index and dose-volume parameters were correlated with radiation-induced hepatic toxicity ≥ 1 using univariate logistic analysis. V15 had the best predictive effectiveness among the dose-volume parameters in both the training (area under the curve: 0.763, 95% confidence interval: 0.683-0.842, P<0.001) and validation cohorts (area under the curve: 0.759, 95% confidence interval: 0.635-0.883, P<0.001). The area under the curve values of the model that was constructed by pre-treatment Child-Pugh, body mass index and V15 for radiation-induced hepatic toxicity ≥1 were 0.799 (95% confidence interval: 0.719-0.878, P<0.001) and 0.775 (95% confidence interval: 0.657-0.894, P<0.001) in the training and validation cohorts, respectively. Patients with a body mass index≤20.425, Barcelona clinic liver cancer=C, Hepatitis B Virus-positive, Eastern Cooperative Oncology Group=1-2 and hepatic fibrosis require lower V15 dose limits. Risk assessment model constructed from Pre-treatment Child-Pugh, V15 and body mass index can guide individualized patient selection of toxicity minimization strategies.

Glucocorticoid toxicity index in patients with systemic lupus erythematosus (preliminary data)

Objective: to investigate the contribution of glucocorticoids (GC) to the development of irreversible organ damage in patients with systemic lupus erythematosus (SLE) using the GC toxicity index (GTI).Material and methods. The study included 65 patients with SLE who met the 2012 SLICC classification criteria. GTI, disease activity according to the SLEDAI-2K index and the SLICC damage index (DI) were determined in all patients, and standard laboratory and immunological tests were performed.Results and discussion. Patients were predominantly female (n=56, 86%), median disease duration was 76 [2; 288] months, SLEDAI-2K – 8.8 [0; 26], DI SLICC – 1.0 [0; 5], DI SLICC &gt;0 was found in 28 (43%) patients. The median duration of GC therapy during the disease period was 66.0 [0; 288] months, maximum dose of GC – 32.7 [0; 80] mg, median of total GC dose during intravenous administration was 2942 [0; 17 812.5] mg, GTI at the time of enrolment in the study – 19 [0; 37] points. GTI &gt;0 was present in 47 (72%) of 65 patients. GTI correlated with disease duration (r=0.33; p&lt;0.008); maximum dose of oral GCs (r=0.31; p&gt;&lt;0.012); duration of GC use (r=0.35; p&gt;&lt;0.005); DI SLICC (r=-0.43; p&gt;&lt;0.0001). In patients with an average disease duration of more than 3 years, GTI&gt;˂0.008); maximum dose of oral GCs (r=0.31; p˂0.012); duration of GC use (r=0.35; p˂0.005); DI SLICC (r=-0.43; p˂0.0001). In patients with an average disease duration of more than 3 years, GTI was significantly higher than in patients with a disease duration of 1–3 years (p=0.023).Conclusion. An GTI&gt;0 was found in 72% of SLE patients, which increased significantly with disease duration. The GTI value was influenced by the duration of SLE, the duration of GC treatment and the maximum GC dose during the disease period. A statistically significant correlation was found between the GTI and the SLICC DI, allowing the GTI value to be used as an additional component in the assessment of the contribution of GCs to the development of irreversible organ damage in patients with SLE. It is recommended that GTI is assessed in all patients with SLE receiving long-term GC treatment for the purpose of dose adjustment.

Cationic effect in the formation of toxic and antiviral properties of Keggon heteropoly compounds

The Cytotoxicity indices (IC50) of Keggin’s phosphorus-molybdenum heteropoly acids (HPCAs) and their sodium and potassium salts on dog kidney cells (MDSC) were determined. The antiviral activity of these compounds against topical strains of influenza A (H3N2 and H1N1) was revealed. The dependence of the biological properties of polyoxometalates (POMs) on the elemental composition of their molecules has been confirmed. It has been shown that when some of the molybdenum atoms are replaced by vanadium atoms, HPCA and their salts acquire higher cytotoxicities, which increase monotonically as the number of substitutions increases. For the first time, the dependence of the biological activity of HPCA and their salts on the mass of cations has been established and interpreted. In vivo (on white outbred mice) the values of semi-lethal doses (DL50) of these compounds were established. For aqueous solutions of sodium and potassium salts of GPCA in a wide range of concentrations (from 0.05 μM to 15 μM), the values of the toxicity index (It) were determined on the model of motile cells. It has been established that GPCA and their salts are classified as moderately dangerous toxic substances and have selective antiviral activity, which at low concentrations (less than 15 μM) for influenza A strains is manifested mainly by a decrease in hemagglutination activity (HA).

Potentially toxic elements in sediments near mines-a comprehensive approach for the assessment of pollution status and associated risk for the surface water environment.

This research is focused on the assessment of the pollution status of river and lake sediments near Pb, Zn, and Cu mines and tailings in the southeastern part of Serbia-Krajište area. The study is based on hypothesis that investigated rivers and lakes in the Krajište area could be polluted by potentially toxic elements (PTEs) and that these elements could pose considerable ecological risk to the studied surface water environment. High PTE contents are detected in studied river sediments (up to 7892mgkg-1 for Zn, 3224mgkg-1 for Cu, 36,790mgkg-1 for Pb, 64.2mgkg-1 for Cd, and 1444mgkg-1 for As). Given that the contents of the studied elements in most of the river sediments exceeded the background values, values prescribed by regulations of the Republic of Serbia, as well as probable effect concentration (PEL), it is possible to conclude that sediments were heavily polluted and that detrimental effects can be expected. Contamination indices including the enrichment factor (EF), contamination factor (CF), index of geoaccumulation (Igeo), potential ecological risk index (Eri), ecological risk index (RI), pollution load index (PLI), and aggregative toxicity index (ATI) were used to assess the degree of pollution by PTEs. The ecological risk assessment revealed that there is a significant risk observed for toxic elements (primarily Pb, Cu, Cd, and As) at this moment. The highest contamination indices (EF, Igeo, CF, PLI, and ATI) are mainly associated with historical and current mining activities. The Monte Carlo analysis based on the risk assessment indices was used to evaluate the uncertainty. The most pronounced toxic risk is found for the Pb, Cu, Cd, and As which assessment was in the range of high and extremely high-risk probabilities. The obtained results suggest that levels of toxic elements pose a significant ecological risk to the surface water environment near Pb, Zn, and Cu mines in the Krajište area. The methodology applied in this paper could be very useful for other researchers dealing with the problem of environmental pollution by toxic elements.

Prospective study of complications and sequelae of glucocorticoid therapy in ANCA-associated vasculitis

ObjectiveGlucocorticoids (GC) are a cornerstone in treating antineutrophil cytoplasmic antibodies-associated vasculitides (AAV), however, they add to morbidity and mortality. To date, GC toxicity in AAV has rarely been systematically investigated.MethodsPatients...

Qualitative interviews to support development of a patient-reported companion measure to the Glucocorticoid Toxicity Index

IntroductionGlucocorticoids (GCs) are associated with multiple toxicities that have substantial impact on patients. We conducted qualitative interviews with patients to identify the toxicities that are most relevant from their perspective, with the goal of creating a patient-reported companion measure to the Glucocorticoid Toxicity Index (GTI), a clinician-facing instrument. MethodsThirty-one patients with recent or current GC use participated in concept elicitation interviews. Participants received GC treatment for myasthenia gravis, chronic inflammatory demyelinating polyradiculoneuropathy, vasculitis, or systemic lupus erythematosus. Transcripts were coded following a thematic analysis approach. ResultsParticipants reported more than 100 toxicities they believed to be associated with their GC medications. Common toxicities included weight gain (87%), increased appetite (84%), insomnia/sleep problems (77%), cognitive impairment/brain fog (71%), easy bruising (68%), anxiety (65%), irritability/short temper (65%), and osteoporosis (39%). These toxicities often centered on self-esteem, neuropsychiatric effects, skin toxicities, and musculoskeletal function. They can be categorized into domains such emphasizing neuropsychiatric, metabolic/endocrine, musculoskeletal, and dermatological effects, highlighting aspects of GC toxicity that patients are uniquely positioned to appreciate and report. ConclusionOur results confirm that the toxicities associated with GCs are pervasive and diverse, with substantial impact on patients' lives. These data will be used to inform the development of a patient-reported outcome measure assessing GC toxicity. This patient-reported instrument will be designed to complement the clinician-reported GTI, facilitating a more detailed understanding of the nuances of change in GC toxicity.

Temporal change of potential toxic element contamination, ecological and toxicological risk in holocene in Southern Black Sea coasts (Türkiye)

This study was carried out to evaluate the temporal variation of the potential toxic element concentration and ecological risk level during the Holocene along the Southern Black Sea coasts. Ecological and ecotoxicological indices such as enrichment factor (EF), modified ecological risk index (mRI), modified potential ecological risk index (mPER) and toxic risk index (TRI) were used in the study. Anthropogenic effects were determined to be more dominant in the western and middle parts of the Southern Black Sea Region. As, Cu, Pb, Zn, Cd, Hg, Ni enrichments were observed in the last 200 – 300 years and the potential risk index values related to them increased. Source of enrichment detected in the cores was found to be related to the volcanic activities that occurred in different geological periods. It was determined that the increases in PTE concentration observed specifically in the middle parts of the cores coincided with the dates of the volcanic activities observed in Anatolia.

Efficacy and safety of avacopan in patients with ANCA-associated vasculitis receiving rituximab in a randomised trial

ObjectivesTo evaluate the efficacy and safety of avacopan in the subgroup of patients with antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis receiving background induction therapy with rituximab in the phase 3 ADVOCATE...

A Bispecific Modeling Framework Enables the Prediction of Efficacy, Toxicity, and Optimal Molecular Design of Bispecific Antibodies Targeting MerTK

Inhibiting MerTK on macrophages is a promising therapeutic strategy for augmenting anti-tumor immunity. However, blocking MerTK on retinal pigment epithelial cells (RPEs) results in retinal toxicity. Bispecific antibodies (bsAbs) containing an anti-MerTK therapeutic and anti-PD-L1 targeting arm were developed to reduce drug binding to MerTK on RPEs, since PD-L1 is overexpressed on macrophages but not RPEs. In this study, we present a modeling framework using in vitro receptor occupancy (RO) and pharmacokinetics (PK) data to predict efficacy, toxicity, and therapeutic index (TI) of anti-MerTK bsAbs. We first used simulations and in vitro RO data of anti-MerTK monospecific antibody (msAb) to estimate the required MerTK RO for in vivo efficacy and toxicity. Using these estimated RO thresholds, we employed our model to predict the efficacious and toxic doses for anti-MerTK bsAbs with varying affinities for MerTK. Our model predicted the highest TI for the anti-MerTK/PD-L1 bsAb with an attenuated MerTK binding arm, which was consistent with in vivo efficacy and toxicity observations. Subsequently, we used the model, in combination with sensitivity analysis and parameter scans, to suggest an optimal molecular design of anti-MerTK bsAb with the highest predicted TI in humans. Our prediction revealed that this optimized anti-MerTK bsAb should contain a MerTK therapeutic arm with relatively low affinity, along with a high affinity targeting arm that can bind to a low abundance target with slow turnover rate. Overall, these results demonstrated that our modeling framework can guide the rational design of bsAbs.Graphical

Bioassay-guided isolation of leishmanicidal cucurbitacins from Momordica charantia.

Leishmaniasis, a neglected tropical parasitic disease, is regarded as a major public health problem worldwide. The first-line drugs for leishmaniasis suffer from limitations related to toxicity and the development of resistance in certain parasitic strains. Therefore, the discovery of alternative treatments for leishmaniasis is imperative, and natural products represent a valuable source of potential therapeutic agents. The present study aimed at finding new potential antileishmanial agents from the aerial parts of the medicinal plant Momordica charantia. This study was based on bioassay-guided fractionation of the M. charantia extract against promastigotes and amastigotes of Leishmania (Leishmania) amazonensis. The cytotoxicity of the extract, fractions, and isolated compounds were evaluated against peritoneal murine macrophages by employing the MTT assay for assessing cell metabolic activity. Antileishmanial assay-guided fractionation of the M. charantia extract led to the bioactive cucurbitacin-enriched fraction and the isolation of four bioactive cucurbitacin-type triterpenoids, which exhibited significant antileishmanial activity, with IC50 values between 2.11 and 3.25μg.mL-1 against promastigote and amastigote forms, low toxicity and selectivity indexes ranging from 8.5 to 17.2. Our findings demonstrate that the fractions and cucurbitacin-type triterpenoids obtained from the aerial parts of M. charantia are promising natural leishmanicidal candidates.

The cardiovascular safety of tricyclic antidepressants in overdose and in clinical use.

Tricyclic antidepressants (TCAs) remain widely prescribed for depression and many other conditions. There may be important differences between individual TCA in regard to their overdose toxicity and their cardiac toxicity in clinical use. We conducted a systematic review to compare the toxicity of individual TCA in overdose and the risk of serious adverse cardiac events occurring with therapeutic doses. We used the fatal toxicity index (FTI) and case fatality ratio as markers of fatality in overdose, and hazard ratios or odds ratios for the risk of cardiovascular adverse events during normal clinical use. In all, 30 reports of mortality in overdose and 14 observational studies assessing the risk of cardiovascular adverse events in clinical use were included. FTI values were of the same order of magnitude (101-102) for all TCAs except lofepramine. Desipramine appears to be somewhat more likely than other TCAs to lead to death in overdose. Amitriptyline, clomipramine, dothiepin/dosulepin, doxepin, trimipramine and imipramine showed broadly similar toxicity and were usually reported to be less toxic than desipramine. Data on nortriptyline were contradictory. Lofepramine had the lowest risk of death in overdose. The rank order of overdose toxicity was broadly consistent between different FTI definitions and between markers used. With respect to the risk of cardiovascular events at clinically relevant exposure, amitriptyline, nortriptyline and lofepramine were associated with a greater risk of in-use cardiotoxicity. All measures of overdose toxicity were subject to external influences and confounding. The continued use of TCAs in depression and other conditions should be minimized when considering their undoubted toxicity in overdose and possible toxicity in normal clinical use.

Chemical composition of four essential oils and their adulticidal, repellence, and field oviposition deterrence activities against Culex pipiens L. (Diptera: Culicidae)

Effective mosquito repellents can limit the transmission of vector-borne diseases to humans. Consequently, there is an urgent need to develop mosquito control strategies that prioritize eco-friendly and cost-effective repellents. Essential oils (EOs) have enormous potential for mosquito repellency. Here, cinnamon, basil, eucalyptus, and peppermint EOs were investigated for adulticide and repellency properties against Culex pipiens as well on the oviposition behavior of gravid females from laboratory (lab test) and field (field test) populations. Cinnamon oil was an effective oviposition deterrent regardless of the population and had high adulticidal activity with toxicity index of 75.00% at 24 h of exposure, relative to deltamethrin. In addition, it exhibited effective repellency at 98.01% and 71.22% at 6.67 and 1.71 µl/cm2, respectively. Peppermint oil had the least adulticidal activity with toxicity index of 6.2% at 24 h, and it resulted in low repellency at 70.90% and 50.64% at 6.67 and 1.71 µl/cm2, respectively. On average, basil and eucalyptus oils showed some adulticidal efficiency, repellency, and oviposition deterrent activity. For all treatments, the oviposition deterrent index values of gravid females from natural populations (field test) were lower than those from lab-reared (lab test) females. Different ratios of monoterpenoids, phenylpropanoids, and fatty acids in the EOs tested likely account for the activity variations observed. Our results suggest cinnamon, basil, eucalyptus, and peppermint EOs, which are widely available, economical, and eco-friendly, with good potential for mosquito control strategies.

Novel Combined Toxicity Indices (CTI) to assess the ecological risk of metals in sediments dependent on fractions and total metal content, application on Qarun Lake sediment, case study

Fractions and total contents of 21 heavy metals were evaluated in Qarun Lake sediment, a closed and shallow turbid saline lake. The metal contents in the sediments were in the following order: Fe > Al > Ti > Mn > Sr > Zn > Cr > Pb > Ba > Ni > B > Cu > Li > Co > As > Ga > Cd > Se > Bi > Ag > Hg. Several indices based on the total content (T-indices) or the fraction ratios (F-indices) assessed the pollution degree of the sediment. All the indices used revealed that the sediment of Qarun Lake suffers from different degrees of metal pollution. The T-indices evaluate the pollution or potential risk depending on the total content of metals, regardless of the species of these metals (hazardous mobile or non-mobile forms). Also, the F-indices evaluate pollution depending on the fraction ratios of metals, regardless of their metal content (even if at a deficient level). This study suggested a new combined toxicity index (CTI) and mean CTI (m-CTI) to combine T-indices and F-indices to assess the potential toxicity of metals and the pollution levels of sites, respectively. Based on integrated T-indices, all selected sites in Qarun Lake were extremely or highly polluted. Also, the GCF (as F-index) revealed that the investigated metals highly contaminated all sites. In contrast, according to the m-CTI, sites 1, 3, and 4 were highly polluted, while sites 2, 5, and 6 were moderately polluted. The present study's findings indicate that using CTI and m-CTI may be more favorable and accurate in assessing the metal pollution status of sediment than using T-indices or F-indices separately.

Financial Toxicity and Its Associated Factors in Cancer Patients: A Cross-sectional Study in Indonesia

Background: Financial toxicity has been shown to negatively affect cancer patients’ quality of life, depression, anxiety, and even mortality rates. However, there is only limited data on financial toxicity and its associated factors, which are needed to address this problem in Indonesia. Purpose: This study aimed to identify factors associated with financial toxicity in cancer patients in Indonesia.Methods: This study was a cross-sectional study that recruited respondents at a cancer health center in Indonesia using a convenience sampling method. A total of 110 adult cancer patients undergoing treatment took part in the study. The questionnaires comprised sociodemographic data, clinical characteristics, and the Comprehensive Score for Financial Toxicity (COST). Logistic regression was performed to achieve the study's aim.Results: The median value of the financial toxicity index was 3.01 (min-max=1-5), indicating a medium level of financial toxicity. Occupational status was the only factor found to be associated with financial toxicity in this study. The participants who were unemployed were 2.389 more likely to have a higher financial toxicity level compared to those who were employed (OR=2.389; p=0.048).Conclusion: Unemployment was identified to be associated with financial toxicity among cancer patients. Nurses should assess and assist patients in utilizing financial resources and develop strategies to manage extra costs that burden them financially. Future nationwide studies are essential to provide more robust evidence on multifaceted factors influencing financial toxicity and inform policy-making aimed at effectively addressing financial toxicity.

Leaching behavior and comprehensive toxicity evaluation of heavy metals in MSWI fly ash from grate and fluidized bed incinerators using various leaching methods: A comparative study

Municipal solid waste incineration fly ash (MSWI FA) is a kind of hazardous waste that contains a substantial amount of heavy metals. To facilitate the appropriate treatment of MSWI FA, the leaching behavior of heavy metals was evaluated in MSWI FA from various sources using different leaching methods. Nine kinds of MSWI FA were investigated using three kinds of batch leaching tests (TCLP, HJ/T 300, and EN12457-2). The chemical form distributions of heavy metals in MSWI FA were obtained by sequential extraction procedures (SEPs) and the environmental risk posed by MSWI FA was comprehensively evaluated. The results showed that the grate and fluidized bed MSWI FA performed differently in various leaching methods, which was mainly dependent on the leachate pH and the chemical form distributions of the heavy metals. In addition, the BCR SEP was more suitable for the fractionation of heavy metals and the environmental risk assessment of MSWI FA when compared with Tessier's SEP. The overall pollution toxicity index allowed a comprehensive risk assessment specific to the leaching environment, thereby offering valuable guidelines for the stabilization or resource-based treatment of MSWI FA.

Human health risk assessment and carcinogenicity due to exposure to potentially toxic elements on soil pollution in Southwest Iran

Background/objectives: Potentially toxic elements (PTEs) are one of the dangerous pollutants in the environment that can cause morbidity and mortality in humans. This study was designed to evaluate the concentration of PTEs, assessment its human health risk assessment and carcinogenicity in the north of Ahvaz, the southwest of Iran. MethodsThe soil samples were collected from the agricultural fields and riversides for investigating the health effects of the selected PTEs on the soil of the Weiss and Arab Assad regions in Ahvaz. ResultsAccording to the result of this study, the highest level of Fe was observed in the soil samples of the Weiss and Arab Assad regions, 9013.70 and 9208.93 mg/kg, while Cd showed the lowest concentration in the soils of Weiss and Arab Assad fields, 1.58 and 1.56 mg/kg, respectively. Potentially toxic elements hazard quotient (HQ), non-carcinogenic risk (HI), and risk index (RI)) in the soil of agricultural fields in the Arab Assad and Weiss regions showed that Cd, Pb, Ni, Cu, Cr, Zn, Fe, Mn, and Co posed a significant risk to human health. Thus, it is recommended to observe health issues due to the non-carcinogenic risk index of metals. ConclusionGenerally, the excessive use of agricultural fertilizers (phosphate and nitrate), industrial, and human activities can increase the contamination of the resources and products, which has irreversible effects on human health, especially in carcinogenic risk.

Nanopolystyrene size effect and its combined acute toxicity with halogenated PAHs on Daphnia magna

Nanoplastics (NPs, diameter <1 μm) not only have toxicity but also change the toxicity of other pollutants in water. To date, the nanopolystyrene (nano-PS) size effect and its combined toxicity with halogenated polycyclic aromatic hydrocarbons (HPAHs) remain unclear. In this study, the single toxicity, combined toxicity, and mode of action of the binary mixture of polystyrene (PS) and HPAH were examined. At the same time, the nano-PS size effect on combined toxicity was also discussed. According to our results, the 48 h acute toxicity test results showed that 30 nm PS was highly toxic (EC50–48 h = 1.65 mg/L), 200 nm PS was moderately toxic (EC50–48 h = 17.8 mg/L), and 1 μm PS was lowly toxic (EC50–48 h = 189 mg/L). The NP toxicity decreased with increasing size. HPAHs were highly toxic substances to Daphnia magna (EC50–48 h = 0.12–0.22 mg/L). The mode of action of PS and HPAHs was antagonistic according to the toxicity unit method (TU), additive index method (AI), and mixture toxicity index method (MTI). The size effect of nano-PS operates via two mechanisms: the inherent toxicity of nano-PS and the sorption of pollutants by nano-PS. The former impacts the combined toxicity more than the latter. In the binary mixed system, the larger the particle size and the higher the proportion of NPs in the system, the less toxic the system was. Linear interpolation analysis can be used to predict the combined toxicity of a mixed system with any mixing ratio.

Manufacture and Combustion Characteristics of Cellulose Flame-Retardant Plate through the Hot-Press Method.

This study focuses on the increased risk of high heat release and asphyxiation (toxic gas poisoning) in the event of a fire involving polyurethane (PU)- and MDF-based building materials, which are commonly used in buildings. Among them, polyurethane (PU) building materials are very commonly used in buildings, except in Europe and some other countries, due to their excellent thermal insulation performance. Still, problems of short-term heat release and the spread of toxic gases in the event of a fire continue to occur. To overcome these problems, researchers are actively working on introducing various flame retardants into building materials. Therefore, in this study, we produced a laboratory-sized (500 mm × 500 mm) plate-like flame-retardant board that can be utilized as a building material with a lower heat release rate and a lower toxicity index. The material was made by mixing expanded graphite and ceramic binder as flame retardants in a material that is formulated based on the cellulose of waste paper, replacing the existing building materials with a hot-press method. According to the ISO-5660-1 test on the heat release rate of the plate-like flame-retardant board, the Total Heat Release (THR) value was 2.9 (MJ/m2) for 10 min, showing an effect of reducing the THR value by 36.3 (MJ/m2) compared to the THR value of 39.2 (MJ/m2) of the specimen made using only paper. In addition, the toxicity index of the flame-retardant board was checked through the NES (Naval Engineering Standards)-713 test. As a result, the test specimen showed a toxicity index of 0.7, which is 2.4 lower than the toxicity index of 3.1 of MDF, which is utilized as a conventional building material. Based on the results of this study, the cellulose fire-retardant board showed the effect of reducing the heat release rate and toxicity index of building materials in a building fire, which reduces the risk of rapid heat spread and smoke toxicity. This has the potential to improve the evacuation time (A-SET) of evacuees in fires. It is also important to show that recycling waste paper and utilizing it as the main material for building materials can be an alternative in terms of sustainable development.