This study presents a comparative assessment of the trace metal air pollutants of urban, peri-urban, and rural areas of the Brahmaputra Valley plain in the Eastern Himalayan region using biomonitoring of Pyxine cocoes. In situ collection of the thalli growing on Bombax sp. from representative locations was done, which was analyzed for Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn using ICP-OES. The metals, viz. Cd, Cr, Ni, Pb, and Zn, were highly enriched, indicating anthropogenic influences. The coefficients of variation (CV) of Co, Cr, and Ni were also high, pointing at their accumulation from local sources. Influence of local sources was also observed for Cd, Fe, and Mn in peri-urban and Cd in urban samples. Metals related to automobiles were accumulated in greater volume in samples of peri-urban locations, which implies the impact of the highway that runs through these locations and other associated human activities. The samples of urban areas were found to be enriched with metals originating from both vehicular emissions and road dust. Also, accumulations of Co, Cr, Cu, Fe, Mn, and Ni in the lichen thalli were found to be around tea gardens. Inter-species correlations were found to be positively significant for most of the elements. Principal component analysis (PCA) of the metal data revealed that vehicular emission and coal burning, street dust, and crustal dust were the major sources of trace metals in the ambient air of the region.
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http://dx.doi.org/10.1007/s10661-019-8007-x | DOI Listing |
Bioelectrochemistry
January 2025
School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China; Laboratory for Clinical Medicine, Capital Medical University, Beijing 100069, China. Electronic address:
A ratiometric electrochemical aptasensor was developed for ultra-sensitive detection of cortisol using aptamer (Apt) as recognition element, methylene blue (MB) as signal probe, and zirconium metal-organic framework (Zr-MOF) as carrier loaded with abundant MB for signal amplification. The carboxylated multi-walled carbon nanotubes (cMWCNTs)-modified Au electrode showed excellent electrochemical performance to immobilize complementary DNA (cDNA) for hybridizing with MB@Zr-MOF-Apt via amide bonds. In the presence of cortisol, it would compete with cDNA for binding the Apt, resulting in the detachment of MB@Zr-MOF-Apt complex from the electrode surface, and the electrochemical signal of MB was decreased, while that of [Fe(CN)] was basically unchanged.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055 China. Electronic address:
In the typical ionothermal synthesis of crystalline carbon nitride (CCN), alkali metal halides are usually used in large amounts. Here, we report a new method for synthesizing poly (heptazine imide) (PHI) using only a trace amount of NaF, which is 20 times less than the amount of NaCl typically required to achieve the PHI structure. Different from the prevailing view that salts function primarily as templates and chelating agents during polymerization, our research revealed the unique role that NaF plays in the polymerization of PHI.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Dept. of Science Education, Ewha Womans University, Seoul 03760, South Korea. Electronic address:
Although sulfur-bearing minerals are valuable resources, they pose significant environmental risks to river ecosystems by releasing hazardous leachate. Accurately tracing these sources is crucial but challenging due to overlapping chemical signatures and pollutant transport dynamics in river systems. This study investigates seasonal and spatial variations in sulfate (SO) and trace element contributions in mining districts of the upper Nakdong River basin, South Korea.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Mechanoresponsive colloidal photonic crystals embedded in elastic solid matrices exhibit tunable optical properties under mechanical force, showing great potential for various applications. However, the response of colloidal crystals embedded in a liquid matrix remains largely unexplored. In this study, we investigate the structural and optical transitions of colloidal crystals composed of particles suspended in a liquid oligomer under pressing and shear forces.
View Article and Find Full Text PDFAnal Chem
January 2025
Yunnan Key Laboratory of Modern Separation Analysis and Substance Transformation, College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming 650500, Yunnan Province, P. R. China.
Early and portable detection of pathogenic bacteria is crucial for ensuring food safety, monitoring product quality, and tracing the sources of bacterial infections. Moving beyond traditional plate-culture counting methods, the analysis of active bacterial components offers a rapid means of quantifying bacteria. Here, metal-organic framework (MOF)-derived NiCo-layered double hydroxide nanosheets (LDHs), synthesized via the Kirkendall effect, were employed as highly effective oxidase mimics to generate reactive oxygen species (ROS).
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