Spherical black carbon aggregates were frequently observed in dust dry deposition in Daejeon, Korea. They were tens of micrometers in diameter and presented a mixture of black carbon and several mineral phases. Transmission electron microscopy (TEM) observations with energy-dispersive X-ray spectroscopy (EDS) and selected area diffraction pattern (SADP) analyses confirmed that the aggregates were compact and included significant amounts of lead chromate (PbCrO). The compositions and morphologies of the nanosized lead chromate particles suggest that they probably originated from traffic paint used in roads and were combined as discrete minerals with black carbon. Based on Pb isotope analysis and air-mass backward trajectories, the dust in Daejeon received a considerable input of anthropogenic pollutants from heavily industrialized Chinese cities, which implies that long-range transported aerosols containing PbCrO were a possible source of the lead and hexavalent chromium levels in East Asia. Lead chromate should be considered to be a source of global atmospheric Pb and Cr(VI) pollution, especially given its toxicity.
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http://dx.doi.org/10.1038/srep36088 | DOI Listing |
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January 2025
School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China.
A key issue in photoelectrochemical applications is the modification of the behavior of photogenerated charge barriers. An effective strategy to improve the photoelectrochemical performance of semiconductor materials is to use the facet effect to promote spatial charge separation. In this work, three different morphologies of lead chromate (PbCrO) crystals are prepared by a simple hydrothermal method that used ammonium fluoride as the structure-directing agents.
View Article and Find Full Text PDFEnviron Pollut
December 2024
Analysis and Test Center, Guangdong University of Technology, Guangzhou, 510006, China. Electronic address:
The photo-dissolution of lead chromate pigments poses specific environmental hazards. In this study, we report that doping molybdenum in lead chromate pigments, resulting in commonly known molybdate red pigment, increases the risk of heavy metal leaching when exposed to light. Commercial molybdate red pigments undergo photo-dissolution when exposed to simulated sunlight and exhibit lower photostability compared to lead chromate pigments such as chrome yellow.
View Article and Find Full Text PDFSci Total Environ
November 2024
School of Medicine, Stanford University, Stanford, California, USA.
Food adulteration with toxic chemicals is a global public health threat. Lead chromate adulterated spices have been linked with lead poisoning in many countries, from Bangladesh to the United States. This study systematically assessed lead chromate adulteration in turmeric, a spice that is consumed daily across South Asia.
View Article and Find Full Text PDFMaterials (Basel)
May 2024
Engineering Research Center of Historical Cultural Heritage Conservation, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an 710119, China.
This study analyzes the pigments and binders used in the painted wooden structure of DaZhong Gate in the Confucius Temple in Qufu, Shandong Province, China. Five samples were collected from the building and analyzed using techniques such as polarized light microscopy (PLM), energy-dispersive X-ray spectroscopy (EDX), micro-Raman spectroscopy (m-RS), and Fourier-transform infrared spectroscopy (FT-IR). The findings reveal that the red, yellow, green, and blue pigments are identified as lead red, lead chromate yellow, emerald green, and ultramarine, respectively.
View Article and Find Full Text PDFEnviron Res
June 2024
Stanford King Center on Global Development, Stanford, CA, USA.
Spice adulteration using yellow lead chromate-based pigments has been documented as a growing global health concern. Spices from the Republic of Georgia with extremely high levels of lead, up to an order of magnitude higher than any other spices worldwide, have been implicated as sources of child lead poisoning. The objectives of this study were to 1) evaluate lead concentrations in spices sampled across the country of Georgia between 2020 and 2022, and 2) assess factors associated with spice adulteration, specifically the role of spice quality and regulatory enforcement.
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