Different types of background music have varying effects on classroom teaching. In this study, a focus on the attention analysis of 72 elementary school students revealed that slow-paced classical ...music significantly enhances students' attention. The experiment demonstrated a clear positive correlation between choosing this type of music and improved learning outcomes. Furthermore, the research delved into the different reactions of students across various age groups to the same background music, providing a robust foundation for multimodal teaching. This discovery not only offers valuable insights into the field of education but also guides the design of personalized teaching and learning environments. It urges educators to pay closer attention to the potential impact of music on students' learning experiences, facilitating better adaptation to the learning needs of students across different age groups.
Dangerous goods are particularly hazardous, as they can be flammable, explosive, and toxic. These characteristics make them vulnerable to accidents, and such mishaps during port operations can lead ...to massive economic losses and even deaths. It is, therefore, necessary and important to analyze and study the dangerous goods accidents at ports, so as to identify major factors and prevent them. Formal concept analysis (FCA) is a powerful tool for rule extraction. This paper introduces FCA along with relevant documents and case studies to analyze the dangerous goods accidents at China’s ports, building a concept lattice model of dangerous goods accidents at China’s ports, and reduces the condition attributes to come up with three key attributes of dangerous goods accidents at China’s ports: warehousing management, facilities and equipment, goods registration and extract four effective diagnostic rules for dangerous goods accidents at ports. This paper proposes corresponding governance strategies to the rules of dangerous goods accidents, which can significantly prevent and manage dangerous goods accidents at China’s ports in the future. In the future, the concept scale can be introduced to study the problem that the influencing factor is multi-valued attribute so as to expand the scope of research.
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•Dangerous goods accidents at ports are small sample events.•Dangerous goods accidents in China’s ports are divided into three types.•Rules exist between dangerous goods accidents and influence factors.•Targeted measures can be taken to reduce dangerous goods accidents.
Soil secondary minerals are important scavengers of rare earth elements （REEs） in soils and thus affect geochemical behavior and occurrence of REEs. The fractionation of REEs is a common geochemical ...phenomenon in soils but has received little attention, especially fractionation induced by secondary minerals. In this study, REEs （La to Lu and Y） associated with soil-abundant secondary minerals Fe-, Al-, and Mn-oxides in 196 soil samples were investigated to explore the fractionation and anomalies of REEs related to the minerals. The results show right-inclined chondrite-normalized REE patterns for La-Lu in soils subjected to total soil digestion and partial soil extraction. Light REEs （LREEs） enrichment features were negatively correlated with a Eu anomaly and positively correlated with a Ce anomaly. The fractionation between LREEs and heavy REEs （HREEs） was attributed to the high adsorption affinity of LREEs to secondary minerals and the preferred activation/leaching of HREEs. The substantial fractions of REEs in soils extracted by oxalate and Dithionite-Citrate-Bicarbonate buffer solutions were labile （10 %-30 %）, which were similar to the mass fraction of Fe （10 %-20 %）. Furthermore, Eu was found to be more mobile than the other REEs in the soils, whereas Ce was less mobile. These results add to our understanding of the distribution and geochemical behavior of REEs in soils, and also help to deduce the conditions of soil for- mation from REE fractionation.
Soil secondary minerals are important scavengers of rare earth elements(REEs) in soils and thus affect geochemical behavior and occurrence of REEs. The fractionation of REEs is a common geochemical ...phenomenon in soils but has received little attention, especially fractionation induced by secondary minerals. In this study, REEs(La to Lu and Y) associated with soil-abundant secondary minerals Fe-, Al-, and Mn-oxides in 196 soil samples were investigated to explore the fractionation and anomalies of REEs related to the minerals. The results show right-inclined chondrite-normalized REE patterns for La–Lu in soils subjected to total soil digestion and partial soil extraction. Light REEs(LREEs) enrichment features were negatively correlated with a Eu anomaly and positively correlated with a Ce anomaly. The fractionation between LREEs and heavy REEs(HREEs) was attributed to the high adsorption affinity of LREEs to secondary minerals and the preferred activation/leaching of HREEs.The substantial fractions of REEs in soils extracted byoxalate and Dithionite-Citrate-Bicarbonate buffer solutions were labile(10 %–30 %), which were similar to the mass fraction of Fe(10 %–20 %). Furthermore, Eu was found to be more mobile than the other REEs in the soils, whereas Ce was less mobile. These results add to our understanding of the distribution and geochemical behavior of REEs in soils, and also help to deduce the conditions of soil formation from REE fractionation.
Clay minerals are important soil components and usually coexist with organic matter, forming mineral-organic associations (MOAs), which control the speciation, mobility, and bioavailability of heavy ...metals. However, the adsorption mechanism of cadmium (Cd) by MOAs is still unclear, especially for the associations of amphotericorganic matter and clay minerals. In this study, 12-aminododecanoic acid (ALA) and montmorillonite (Mt) were chosen to prepare MOAs via intercalation (Mt-ALA composite) and physical mixing (Mt-ALA mixture). Batch experiments were conducted to investigate the adsorption mechanism of Cd(II) by MOAs under different pH values and initial Cd(II) concentrations. The results showed that the Cd(II) adsorption capacities followed as Mt > Mt-ALA mixture > Mt-ALA composite under acidic conditions, Mt-ALA mixture > Mt > Mt-ALA composite under neutral conditions, and Mt-ALA mixture > Mt-ALA composite > Mt under alkaline conditions, suggesting the adsorption behaviors of Cd(II) by MOAs were primarily constrained by the speciation of ALA and solution pH. Under acidic conditions, cationic HALA+ could intercalate into the interlayer of Mt and occupy the adsorption sites, reducing the adsorption capacity of Cd(II). As pH increased to neutral, HALA+ decreased and changed to a zwitterionic state, which caused ALA to release out from the interlayer of Mt-ALA composite or not easily enter into Mt-ALA mixture and promoted Cd(II) adsorption. Under alkaline conditions, the increase of anion ALA- would cause ALA to be mainly adsorbed on the surface of Mt and chelate with Cd(II), enhancing the adsorption of Cd(II). Further analysis by Fourier transform infrared and X-ray photoelectron spectroscopy indicated that the carboxyl and amino groups of ALA both participated in the adsorption of Cd(II). These findings could extend the knowledge on the mobility and fate of Cd in clay-based soils and be used as a basis for understanding the biogeochemical behavior of Cd in the environment.
•ALA attachment to clay mineral surface was dynamic and sensitive to solution pH.•Cd adsorption on Mt was larger than MOAs at pH < 7 while less than MOAs at pH > 7.•ALA could enter the interlayer of Mt at pH< 7 but be released at pH > 7.•The adsorption of Cd(II) was constrained by the associations between Mt and ALA.•The carboxyl and amino groups of ALA participated in the adsorption of Cd(II).
Understanding the degradation of pentachlorophenol (PCP) by indigenous microorganisms stimulated by an electron donor and shuttle in paddy soil, and the influences of PCP/electron donor/shuttle on ...the native microbial community are important for biodegradation and ecological and environmental safety. Previous studies focused on the kinetics and the microbial actions of PCP degradation, however, the effects of toxic and antimicrobial PCP and electron donor/shuttle on the microbial community diversity and composition in paddy soil are poorly understood. In this study, the effects of PCP, an electron donor (lactate), and the electron shuttle (anthraquinone-2, 6-disulfonate, AQDS) on the microbial community in paddy soil were investigated. The results showed that the presence of PCP reduced the microbial diversity compared to the control during PCP degradation, while increased the microbial diversity was observed in response to lactate and AQDS. The addition of PCP stimulated the microorganisms involved in PCP dechlorination, including Clostridium, Desulfitobacterium, Pandoraea, and unclassified Veillonellaceae, which were dormant in raw soil without PCP stress. In all of the treatments with PCP, the addition of lactate or AQDS enhanced PCP dechlorination by stimulating the growth of functional groups involved in PCP dechlorination and by changing the microbial community during dechlorination process. The microbial community tended to be uniform after complete PCP degradation (28 days). However, when lactate and AQDS were present simultaneously in PCP-contaminated soil, lactate acted as a carbon source or electron donor to promote the activities of microbial community, and AQDS changed the redox potential because of the production of reduced AQDS. These findings enhance our understanding of the effect of PCP and a biostimulation method for PCP biodegradation in soil ecosystems at the microbial community level, and suggest the appropriate selection of an electron donor/shuttle for accelerating the bioremediation of PCP-contaminated soils.
•PCP decreased the microbial community diversity of the paddy soil.•Dechlorinating bacteria were stimulated with the stress of PCP.•Electron donor had a greater impact on the microbial community than electron shuttle.•The microbial community tended to be uniform after PCP complete degradation.
Pb and Cd accumulation in riparian soils and river sediments in river basins is a challenging pollution issue due to the persistence and bioaccumulation of these two trace metals. Understanding the ...migration characteristics and input sources of these metals is the key to preventing metal pollution. This study was conducted to explore the contents, geochemical fractionation, and input sources of Pb and Cd in riparian soils and river sediments from three lower reaches of the Pearl River Delta located in the Guangdong-Hong Kong-Macao Greater Bay Area. The total concentration of all Pb and Cd values exceeded the background values to varying degrees, and the exchangeable fraction of Cd in riparian soils and river sediments accounted for the largest proportion, while that of Pb was dominated by the residual fraction. Geoaccumulation index calculations showed that in the riparian soils, the average accumulation degree of Pb (0.52) in the Beijiang River (BJR) was the highest, while that of Cd (2.04) in the Xijiang River (XJR) was the highest. Unlike that in riparian soils, the maximum accumulation of Pb (0.76) and Cd (3.01) in river sediments both occurred in the BJR. Furthermore, the enrichment factor results also showed that Pb and Cd in the riparian soils and river sediments along the BJR were higher than those in the XJR and Dongjiang River (DJR). The relationship between enrichment factors and nonresidual fractions further proved that the enrichment factors of Cd were significantly correlated with the nonresidual fractions of Cd, which may imply various anthropogenic sources of Cd in the three reaches. Moreover, source identification based on principal component analysis (PCA) and Pb isotope ratio analysis indicated that riparian soils and river sediments have inconsistent pollution source structures. The PCA results showed that Pb and Cd were homologous inputs in the DJR, and there were significant differences only in the riparian soils and river sediments. Pb isotope tracing results further showed that the bedrock of high geological background from upstream may be the main reason for Cd accumulation in the XJR. However, the ultrahigh accumulation of Cd in the BJR is mainly caused by the input of the upstream mining and metallurgy industry. The control of upstream input sources will be the key to the prevention of trace metal pollution in these regions.
Soil secondary minerals are important scavengers of rare earth elements (REEs) in soils and thus affect geochemical behavior and occurrence of REEs. The fractionation of REEs is a common geochemical ...phenomenon in soils but has received little attention, especially fractionation induced by secondary minerals. In this study, REEs (La to Lu and Y) associated with soil-abundant secondary minerals Fe-, Al-, and Mn-oxides in 196 soil samples were investigated to explore the fractionation and anomalies of REEs related to the minerals. The results show right-inclined chondrite-normalized REE patterns for La–Lu in soils subjected to total soil digestion and partial soil extraction. Light REEs (LREEs) enrichment features were negatively correlated with a Eu anomaly and positively correlated with a Ce anomaly. The fractionation between LREEs and heavy REEs (HREEs) was attributed to the high adsorption affinity of LREEs to secondary minerals and the preferred activation/leaching of HREEs. The substantial fractions of REEs in soils extracted by oxalate and Dithionite-Citrate-Bicarbonate buffer solutions were labile (10 %–30 %), which were similar to the mass fraction of Fe (10 %–20 %). Furthermore, Eu was found to be more mobile than the other REEs in the soils, whereas Ce was less mobile. These results add to our understanding of the distribution and geochemical behavior of REEs in soils, and also help to deduce the conditions of soil formation from REE fractionation.
The interaction between aqueous Fe(II) (Fe(II)aq) and iron minerals is an important reaction of the iron cycle, and it plays a critical role in impacting the environmental behavior of heavy metals in ...soils. Metal substitution into iron (hydr)oxides has been reported to reduce Fe atom exchange rates between Fe(II)aq and metal-substituted iron (hydr)oxides and inhibit the recrystallization of iron (hydr)oxides. However, the environmental behaviors of the substituted metal during these processes remain unclear. In this study, Fe(II)aq-induced recrystallization of Cr-substituted goethite (Cr-goethite) was investigated, along with the sequential release behavior of substituted Cr(III). Results from a stable Fe isotopic tracer and Mössbauer characterization studies show that Fe atom exchange occurred between Fe(II)aq and structural Fe(III) (Fe(III)oxide) in Cr-goethites, during which the Cr-goethites were recrystallized. The Cr substitution inhibited the rates of Fe atom exchange and Cr-goethite recrystallization. During the recrystallization of Cr-goethites induced by Fe(II)aq, Cr(III) was released from Cr-goethite. In addition, Cr-goethites with a higher level of Cr-substituted content released more Cr(III). The highest Fe atom exchange rate and the highest amount of released Cr(III) were observed at a pH of 7.5. Under reaction conditions involving a lower pH of 5.5 or a higher pH of 8.5, there were substantially lower rates of Fe atom exchange and Cr(III) release. This trend of Cr(III) release was similar with changes in Fe atom exchange, suggesting that Cr(III) release is driven by Fe atom exchange. The release and reincorporation of Cr(III) occurred simultaneously during the Fe(II)aq-induced recrystallization of Cr-goethites, especially during the late stage of the observed reactions. Our findings emphasize an important role for Fe(II)aq-induced recrystallization of iron minerals in changing soil metal characteristics, which is critical for the evaluation of soil metal activities, especially those in Fe-rich soils.
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