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Carbon nanostructures (CNSs) have sparked significant interest in modern science and industry due to their distinct properties and various carbon hybridization states. This makes them appealing for applications, including developing new energy storage devices, filtering systems, catalysts, sensors, and biomedical scaffolds. However, traditional methods' high production costs have prompted researchers to investigate more cost-effective manufacturing techniques. Among these, self-propagating high-temperature synthesis (SHS) has emerged as a promising option, using various carbon-based precursors as feedstock. This manuscript is the first comprehensive attempt to summarize and review a variety of carbon nanostructures synthesized using the SHS method. The review begins with an overview of carbon nanostructure characteristics and fabrication techniques, then delves into the main features of the SHS synthesis method and its suitability for CNS fabrication. It then looks at current approaches for CNS synthesis using the SHS, categorizing them based on the type of carbon precursors used. This analysis includes combustion thermodynamics, adiabatic temperatures and equilibrium phases; experimentally measured combustion temperatures and wave velocities; and combustion reaction chemistry. Simultaneously, we discuss the morphology, phase composition, and other physical-chemical properties of CNS synthesized using SHS. A dedicated section investigates the performance of CNSs in energy storage devices, catalysis, waste adsorption, and polymer reinforcement. Finally, we discuss methodological challenges, opportunities, and future research directions, offering a comprehensive overview of the current state and potential areas for research in this field. [Display omitted] [ABSTRACT FROM AUTHOR]

Sediment quality has been evaluated in a variety of ways since the early 1990s in studies from Europe. In South Korea, most studies have used an indicator value for benthic macroinvertebrates based on water quality, not sediment quality. To date, few studies have examined the biological integrity of benthic macroinvertebrate communities in South Korea. In the current study, the tolerance valency and value in samples and the indicator weight values were measured for 43 benthic macroinvertebrate taxa from 73 sampling units in South Korea from 2014 to 2016. Total organic carbon, the amount of heavy metals, and total ammonia nitrogen were analyzed. The average grade for each pollutant was used as the sediment quality index. A benthic macroinvertebrates sediment index was developed for bioassessment of freshwater sediment. The benthic macroinvertebrates sediment index, which is based on the relative frequency of occurrence of macroinvertebrates, was highly correlated with pollution levels in the sediment. This index can be used in the field to assess the contamination of freshwater sediment. As the sample size was small in the current study and there were taxonomic limitations of Chironomidae larvae, further research is needed to improve the reliability of the benthic macroinvertebrates sediment index. [ABSTRACT FROM AUTHOR]

We analyzed paired serum, urine, and hair samples from 94 Korean children and adults to investigate levels of 11 perfluoroalkyl acids (PFAAs). The effects of demographic factors and dietary habits on PFAA exposure were also assessed based on the paired samples. The total PFAA concentrations were 2.4–31 ng/mL in serum, not detected–9.5 ng/mL in urine, and 0.48–15 ng/g in hair. Levels of perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA), which have short carbon chains, were 1.5–5 fold higher in urine and hair than in serum. The PFAA concentrations in serum exhibited a decreasing trend with age from young childhood to adolescence, followed by an increasing trend after adolescence. For most PFAA species, concentrations in serum were higher in adult males than in adult females (p < 0.01). No sex difference was evident in the urine and hair samples. In addition, there was no age difference in the urine samples, but in the hair samples, we observed higher concentrations of PFAAs in children than in the other age groups (p < 0.01). The consumption rates of fish and water showed significant correlations with serum (positive correlation) and hair (negative) concentrations, respectively. No relationships between serum and hair/urine levels for most PFAAs were observed, except between serum and hair levels for perfluorooctanoic acid (PFOA). Image 1 • PFAAs concentrations in paired urine, hair and serum were assessed. • Short-chain PFAAs showed 1.5 times higher concentrations in urine and hair than in serum. • PFPeA and PFHxA were dominantly detected in urine and hair samples. • Consumption of fish and water showed negative correlation with PFOA in hair. • No correlation was observed for most of PFAAs between serum and hair or urine. Different perfluoroalkyl acid profiles were observed among serum, urine, and hair samples; in particular, higher proportions of perfluorocarboxylic acids (PFCAs) were present in urine and hair than in serum samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Daily intakes of PFASs on individual basis by multiple exposure sources are reported. • PFASs in dust showed most significant correlation with PFASs in serum. • Food ingestion was the main contributor of PFASs intake to human. • Indirect dust ingestion was the second contributor of PFASs intake to human. • Individual-based intake of PFASs was higher than the intake on group/scenario basis. Abstract Individual exposure of perfluoroalkyl substances (PFASs) was assessed by analyzing serum, food, dust, drinking water, and hand wipes from 50 individuals. The PFASs concentrations in serum were correlated most strongly with exposure to PFASs through the (direct and indirect) ingestion of dust (p < 0.01). Daily PFOA intakes were estimated to be 2.07 ng/kg/day from food, 0.003 ng/kg/day from dust, 0.053 ng/kg/day from hand-to-mouth activity, and 0.020 ng/kg/day from drinking water. Daily perfluorooctanesulfonic acid (PFOS) intakes were estimated to be 0.689 ng/kg/day from food, 0.001 ng/kg/day from dust, 0.018 ng/kg/day from hand-to-mouth activity, and 0.005 ng/kg/day from drinking water. The daily PFOA and PFOS intakes calculated for individuals in this study and in group/scenario based exposure assessment of previous studies were compared. The estimated PFOS intake on individual basis (0.695 ng/kg/day) was a little bit higher than the intake on group/scenario basis (0.652 ng/kg/day). However, the estimated daily PFOA intake on individual basis (1.41 ng/kg/day) was about four times higher than the intake on group/scenario basis (0.339 ng/kg/day). Among the exposure pathways, food ingestion was major contributor to the total daily PFOA and PFOS intakes on individuals (99% of total intake) and group/scenario basis (64% of total intake). [ABSTRACT FROM AUTHOR]

Ammonia is deemed one of the most important pollutants in the freshwater environment because of its highly toxic nature and ubiquity in surface water. This study thus aims to derive the criteria for ammonia in freshwater to protect aquatic life because there are no water quality criteria for ammonia in Korea. Short-term lethal tests were conducted to perform the species sensitivity distribution (SSD) method. This method is widely used in ecological risk assessment to determine the chemical concentrations to protect aquatic species. Based on the species sensitivity distribution method using Korean indigenous aquatic biota, the hazardous concentration for 5% of biological species (HC 5 ) value calculated in this study was 44 mg/L as total ammonia nitrogen (TAN). The value of the assessment factor was set at 2. Consequently, the criteria for ammonia were derived as 22 mg/L at pH 7 and 20 °C. When the derived value was applied to the monitoring data nationwide, 0.51%, 0.09%, 0.18%, 0.20%, and 0.35% of the monitoring sites in Han River, Nakdong River, Geum River, Youngsan River, and lakes throughout the nation, respectively, exceeded this criteria. The Ministry of Environment in Korea has been considering introducing water quality standard of ammonia for protecting aquatic life. Therefore, our results can provide the basis for introducing the ammonia standard in Korea. [ABSTRACT FROM AUTHOR]

The combustion phenomenon is characterized by rapid self-sustaining reactions, which can occur in the solid, liquid, or gas phase. Specific types of these reactions are used to produce valuable materials by different combustion synthesis (CS) routes. In this article, all three CS approaches, i.e. solid-phase, solution, and gas-phase flame, are reviewed to demonstrate their attractiveness for fabrication of zero-, one-, two-, and three-dimensional nanostructures of a large variety of inorganic compounds. The review involves five sections. First, a brief classification of combustion synthesis methods is given along with the scope of the article. Second, the state of art in the field of solid-phase combustion synthesis is described. Special attention is paid to the relationships between combustion parameters and structure/properties of the produced nanomaterials. The third and fourth sections describe details for controlling material structures through solution combustion synthesis and gas-phase flame synthesis, respectively. A variety of properties (e.g., thermal, electronic, electrochemical, and catalytic) associated with different types of CS nanoscale materials are discussed. The conclusion focuses on the most promising directions for future research in the field of advanced nanomaterial combustion synthesis. [ABSTRACT FROM AUTHOR]

Effect-directed analysis (EDA) was performed to identify the major aryl hydrocarbon receptor (AhR) agonists in sediments collected from a highly industrialized area (Lake Shihwa, Korea). Great AhR-mediated potencies were found in fractions containing aromatic compounds with log K ow values of 5–8, and relatively great concentrations of styrene oligomers (SOs) and polycyclic aromatic hydrocarbons (PAHs) were detected in those fractions. Until now, there was little information on occurrences and toxic relative potencies (RePs) of SOs in coastal environments. In the present study; i) distributions and compositions, ii) AhR binding affinities, and iii) contributions of SOs to total AhR-mediated potencies were determined in coastal sediments. Elevated concentrations of 10 SOs were detected in sediments of inland creeks ranging from 61 to 740 ng g −1 dry mass (dm), while lesser concentrations were found in inner (mean = 33 ng g −1 dm) and outer regions (mean = 25 ng g −1 dm) of the lake. Concentrations of PAHs in sediments were comparable to those of SOs. 2,4-diphenyl-1-butene (SD3) was the predominant SO analogue in sediments. SOs and PAHs were accumulated in sediments near sources, and could not be transported to remote regions due to their hydrophobicity. RePs of 3 SOs could be derived, which were 1000- to 10,000-fold less than that of one representative potent AhR active PAH, benzo[ a ]pyrene. Although concentrations of SOs in sediments were comparable to those of PAHs, the collective contribution of SOs to total AhR-mediated potencies were rather small (<1%), primarily due to their smaller RePs. Overall, the present study provides information on distributions and AhR binding affinities for SOs as baseline data for degradation products of polystyrene plastic in the coastal environment. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify how hydrologic factors (e.g., rainfall, maximum depth, reservoir and catchment area, and water residence time) and water chemistry factors (e.g., conductivity, pH, suspended particulate matter, chlorophyll-a, dissolved organic carbon, and sulfate) interact to affect the spatial variance in monomethylmercury (MMHg) concentration in nine artificial reservoirs. We hypothesized that the MMHg concentration of reservoir water would be higher in eutrophic than in oligotrophic reservoirs because increased dissolved organic matter and sulfate in eutrophic reservoirs can promote in situ production of MMHg. Multiple tools, including Pearson correlation, a self-organizing map, and principal component analysis, were applied in the statistical modeling of Hg species. The results showed that rainfall amount and hydraulic residence time best explained the variance of dissolved Hg and dissolved MMHg in reservoir water. High precipitation events and residence time may mobilize Hg and MMHg in the catchment and reservoir sediment, respectively. On the contrary, algal biomass was a key predictor of the variance of the percentage fraction of unfiltered MMHg over unfiltered Hg (%MMHg). The creation of suboxic conditions and the supply of sulfate subsequent to the algal decomposition seemed to support enhanced %MMHg in the bloom reservoirs. Thus, the nutrient supply should be carefully managed to limit increases in the %MMHg/Hg of temperate reservoirs. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the cumulative risks of Di(2-ethylhexyl) phthalate (DEHP), Di-n-butyl phthalate (DBP), and Benzyl-butyl phthalate (BBP) to 2-year-old children in two countries: one European (Denmark) and one Asian (South Korea) were compared. Denmark does not produce phthalates as a raw material, while Korea produces more than 0.4milliontons of the three above-mentioned phthalates each year. First, a comparative review of the existing phthalate regulations in the two countries was performed. Next, the level of childhood phthalate exposure from environmental and food sources was estimated using an exposure scenario approach. Then, the scenario based exposure level was compared with back-calculated exposure levels based on biomonitored urinary phthalate metabolite concentrations. The result verifies the existence of varying territorial human background exposure levels and the gap between exposure estimations based on exposure modeling and biomonitoring data. Cumulative childhood risk levels in Denmark were lower than in Korea. For both countries, risk levels from back calculation were higher than those from scenario estimation. The median cumulative risk levels from scenario estimation and back calculation respectively were 0.24 and up to 0.5 in Denmark while 0.52 and up to 0.95 in Korea. Food and indoor dust were the main exposure sources for all three phthalates. In order to protect human health from cumulative risks of these phthalates, the exposure scenarios in existing regulations such as the EU REACH need to be strengthened. Moreover, based on the contributions from different exposure sources, national specific risk management tools need to be developed and strengthened, applying a systemic approach to promote sustainable material flows. [Copyright &y& Elsevier]

Highlights: [•] We monitored toxicity of intertidal sediments for 5years after Hebei Spirit oil spill. [•] Toxicity of sandy beaches decreased within 8months after the spill. [•] Sediment toxicity remained at heavily contaminated sites 5years after the spill. [•] Ecological impact and weathering process of residual oils are ongoing. [Copyright &y& Elsevier]

The levels of six perfluorocarboxylates (PFCAs), four perfloroalkylsulfonates (PFASs), and one sulfonamide were measured in paired samples of maternal serum, umbilical cord serum, and breast milk. The maternal and cord sera were strongly correlated with each other for all measured compounds (r > 0.5 and p < 0.01). Nevertheless, there was a significant difference in compound composition profile between the two sera matrices, with a more depletion of the longer chain compounds in cord serum. The transfer efficiency values from maternal to cord serum (TFCS/MS) decreased by 70% with each increasing unit of –CF2 chain within a PFCA group, and for perfluorooctanesulfonate (PFOS), by a half compared to perfluorooctanoate (PFOA). In contrast to the strong correlation in concentrations between the two sera matrices, the pattern of compounds in breast milk differed considerably with those in sera. Accordingly, compound- and matrix-specific transfer must be considered when assessing prenatal and postnatal exposure. [Copyright &y& Elsevier]

Abstract: Fetal and maternal exposure levels of two emerging pollutants, polybrominated diephenyl ethers (PBDEs) and synthetic musks, were measured in Korean general population to assess prenatal and postnatal exposures in infants. For this purpose, paired samples of breast milk, maternal and cord blood were collected from 20 Korean women in 2007. In comparison to data from other countries and previous data from Korea, relatively higher and gradually increasing concentrations for PBDEs were found in Korean breast milk (

Abstract: Laboratory microcosm experiments were conducted to investigate the influence of acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) in sediments on the bioavailability and toxicity of Cd, Ni, and Zn in sediments to polychaete worms Neanthes arenaceodentata. Cohorts of juvenile N. arenaceodentata were exposed to sediments spiked with metal mixtures containing Cd, Ni, and Zn (0.5–15 μmol·g−1 of total SEM) with Low- (∼1 μmol·g−1), Medium- (∼5 μmol·g−1), and High-AVS concentrations (∼10 μmol·g−1) for 20 days to determine mortality, growth rate, and metal bioaccumulation. Tissue Cd and Zn concentrations at the end of the exposure were significantly higher in sediments with the low-AVS concentration at a given SEM concentration due to the increased dissolved metal concentrations in overlying water (OW). However, tissue Ni concentrations were not related to dissolved Ni in the OW. AVS concentrations also influenced the toxicity of metals to the worms. Significant mortality was observed only at the highest SEM treatments at Low-AVS series. Most individuals survived at the highest SEM treatments at Medium- and High-AVS series. Similarly, the growth rates of worms were reduced in treatments having higher molar differences between SEM and AVS ([SEM−AVS]). Overall, the bioavailability and toxicity of metals in sediments was not well predicted by sediment metal concentrations only, but considering the influence of geochemical factors (AVS) on the metal bioavailability improved the prediction of toxicity. Also, the relationship between tissue metal concentration and toxicity was used to determine which contaminant was most responsible for the observed toxicity of the metal mixture. [Copyright &y& Elsevier]

• Clearance level of radioactive metal waste by electrolytic decontamination assessed. • LiCl-KCl eutectic-4 wt.% NiCl 2 with max. 8 wt.% CoCl 2 electrolyte at 500 °C used. • For Co conc.< 167 ppm, 3 decontamination cycles required to meet clearance level. • Electrolytic decontamination can be used to treat nuclear waste. Many countries are in the process of decommissioning their nuclear power plants. These power plants contain valuable metals, including Inconel alloys, which are often only contaminated on the surface. Metals are typically decontaminated using laser ablation. However, electrolytic decontamination is a simpler and less expensive solution. Our investigation aimed to develop a method for decontaminating Inconel alloy contaminated with Co to clearance level for recycling and reuse. This study focused on the electrolytic decontamination of Ni-0.2 wt.% Co alloy, identified as a potential replacement for the radioactively contaminated material. Molten LiCl-KCl-NiCl 2 -CoCl 2 (500 °C) was used as the electrolyte in the experiments and the potential recyclability of the used electrolyte was examined. In the absence of CoCl 2 in the electrolyte, the decontamination factor is 1.38E8 after the third cycle of electrolytic decontamination. Considering that the decontamination factor corresponding to the clearance level is 1.27E7, three cycles of electrolytic decontamination are considered to be sufficient. Additionally, an investigation of the possibility of recycling the used electrolyte showed that the solidified products formed after vacuum distillation were LiCl, KCl, and Co oxide with traces of Ni oxide. ICP analysis of the LiCl and KCl collected after vacuum distillation revealed that the concentration of Co was less than 0.1 ppm, which suggests that the used electrolyte can be recycled. These findings are expected to offer valuable insights into the electrolytic decontamination process, its limitations, and potential applications in the processing of nuclear waste. [Display omitted] [ABSTRACT FROM AUTHOR]