Environ Sci Technol
January 2025
There has been a sharp rise in the extent and scale of human activities since the mid-20th century, termed the "Great Acceleration", and nuclear activities are one of the defining technological processes for this period. Pu released by atmospheric nuclear weapons tests provides an ideal chronostratigraphic marker for labeling this change due to its global fallout feature, temporal mutation, and long half-lives. However, the accumulation dynamics of plutonium from atmospheric deposition to preservation in the sediment is still controversial.
View Article and Find Full Text PDFMicrostructure and deformation properties of both unaged and aged cladding material were studied at 400 °C for 10,000 h. The results indicated that carbide formation occurred in the cladding material, while thermal aging treatment resulted in spinodal decomposition and G-phase formation in the aged ferrite phase. Furthermore, intensive straight slip bands formed in both unaged and aged austenite phases.
View Article and Find Full Text PDFTo achieve dual optimization of the mechanical properties and environmental impacts of geopolymer concrete (GPC), this study proposes a high-strength geopolymer concrete (HSGPC) without coarse aggregate. The mix proportion of HSGPC was optimized using the response surface methodology, targeting compressive strength and splitting tensile strength to determine the optimal mix. Additionally, the carbon emission impact of HSGPC was assessed and compared with ordinary Portland cement concrete, ultra-high-performance concrete, and reactive powder concrete.
View Article and Find Full Text PDFThe geochemical composition of sediment cores can serve as a proxy for reconstructing past human and nature-driven environmental and climatic changes. We investigated the temporal variation in the concentrations and fluxes of polycyclic aromatic compounds (PACs) which include polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs, and azaarenes in the Sihailongwan Maar Lake and found that they remained low before 1950. The PAC concentrations and fluxes increased substantially since 1950, which was in good agreement with the fast socio-economic development, industrialization, and associated growth in fossil fuel consumption in China, particularly since the 1980s.
View Article and Find Full Text PDFShip emissions are a significant source of air pollution, and the primary policy to control is fuel oil quality improvement. However, the impact of this policy on particle size distribution and composition characteristics remains unclear. Measurements were conducted on nine different vessels (ocean-going vessels, coastal cargo ships, and inland cargo ships) to determine the impact of fuel upgrading ( < 0.
View Article and Find Full Text PDFLong-term deposition of atmospheric radioactive iodine-129 (I) is important for assessing the impact of human nuclear activities (HNAs), but still not well understood in East Asia. In this study, we quantitatively reconstructed the deposition history of airborne I using varved sediment from Sihailongwan Maar Lake (SHLW) in northeast China. Our results revealed significant increases in I concentrations and I/I atomic ratios since the 1950s, indicating the influence of HNAs on the environment and marking the onset of the Anthropocene.
View Article and Find Full Text PDFDwarfing rootstocks have transformed the production of cultivated apples; however, the genetic basis of rootstock-induced dwarfing remains largely unclear. We have assembled chromosome-level, near-gapless and haplotype-resolved genomes for the popular dwarfing rootstock 'M9', the semi-vigorous rootstock 'MM106' and 'Fuji', one of the most commonly grown apple cultivars. The apple orthologue of auxin response factor 3 (MdARF3) is in the Dw1 region of 'M9', the major locus for rootstock-induced dwarfing.
View Article and Find Full Text PDFAchieving rapid, efficient, and cost-effective anaerobic digestion (AD) of food waste is a key means to improve the efficiency of food waste treatment. However, in view of the shortage of historical anaerobic digestion data, the limitation of general neural networks in predicting biogas production, and its sensitivity to abnormal variation points, achieving accurate prediction of biogas production is not easy. This paper proposes a novel biogas production prediction model of food waste AD for energy optimization based on the mixup data augmentation integrating an improved global attention mechanism long short-term memory (LSTM).
View Article and Find Full Text PDFFine particulate matter (PM) has health effects that may depend on its sources and chemical composition. In this study, characteristics of PM chemical composition and health risk assessment from Songyuan, China, were investigated during day and night in indoor and outdoor from February 4 to 19, 2021. Relative high concentrations of PM were obtained in indoor environment than outdoor, with 503.
View Article and Find Full Text PDFFuel usage is an important catalyst for socio-economic development and human well-being. Human activities have resulted in significant increases in emissions from biomass burning (BB) and fossil fuel (FF) combustion which have significantly adversely affected human, ecosystem, and planetary health in this era of the Anthropocene. Sanjiaolongwan Maar Lake (SJLW), as a typical crater lake, uniquely receives atmospheric deposition from long-distance transport, and thus, its sediments reflect environmental change and human impacts on a broad scale.
View Article and Find Full Text PDFAll light or heavy water reactors fabricated with carbon steels suffer from flow-accelerated corrosion (FAC). The FAC degradation of SA106B with different flow velocities was investigated in terms of microstructure. As flow velocity increased, the major corrosion type changed from general corrosion to localized corrosion.
View Article and Find Full Text PDFReconstructing historical black carbon (BC) variations based on sedimentary records are significant for understanding long-term BC emissions, tracing sources, and establishing effective strategies for pollution control. By comparing BC profiles between four lake sediment cores, historical BC variations were reconstructed on the southeastern Mongolian Plateau in North China. Except one, the other three records show close fluxes and similar temporal trends of soot, indicating their repetitiveness on revealing historical variations at a regional scale.
View Article and Find Full Text PDFIn this study, field measurement was conducted using an integrated online monitoring system to characterize heterogeneous properties and light absorption of refractory black carbon (rBC). rBC particles are mainly from the incomplete combustion of carbonaceous fuels. With the data collected from a single particle soot photometer, thickly coated (BC) and thinly coated (BC) particles are characterized with their lag times.
View Article and Find Full Text PDFFood safety is important for sustainable social and economic development and people's health. The traditional single risk assessment model is one-sided to the weight distribution of food safety factors including physical-chemical and pollutant indexes, which cannot comprehensively assess food safety risks. Therefore, a novel food safety risk assessment model combining the coefficient of variation (CV) integrating the entropy weight (EWM) (CV-EWM) is proposed in this paper.
View Article and Find Full Text PDFThe ideal conditions for anaerobic digestion experiments with biochar addition are challenging to thoroughly study due to different experimental purposes. Therefore, three tree-based machine learning models were developed to depict the intricate connection between biochar properties and anaerobic digestion. For the methane yield and maximum methane production rate, the gradient boosting decision tree produced R values of 0.
View Article and Find Full Text PDFNowadays, the world has achieved tremendous economic development at the expense of the long-term habitability of the planet. With the rapid economic development, the global greenhouse effect caused by excessive carbon dioxide (CO) emissions is also accumulating, which generates the negative impact of global warming on nature and human beings. Meanwhile, economy and CO emissions prediction methods based on traditional neural networks lead to gradient disappearance or gradient explosion, making the economy and CO emissions prediction inaccurate.
View Article and Find Full Text PDFIn this study, the environmental fate of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in tropical lake sediments and their potential sources have been discussed. 15 PAHs (i.e.
View Article and Find Full Text PDFThe parameters from full-scale biogas plants are highly nonlinear and imbalanced, resulting in low prediction accuracy when using traditional machine learning algorithms. In this study, a hybrid extreme learning machine (ELM) model was proposed to improve prediction accuracy by solving imbalanced data. The results showed that the best ELM model had a good prediction for validation data (R = 0.
View Article and Find Full Text PDFHuman activities have profoundly transformed the natural environment and the Earth system, leading to the concept of the Anthropocene. This paper summarizes the effects of human activities on the environment in China as recorded in sedimentary archives. China is divided into core and marginal areas based on their natural and societal conditions, and changes in selected proxies for four stages since 2.
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