Province South China Research Articles

The prevalence and correlates of unintended pregnancy among female sex workers in South China: a cross-sectional study

BackgroundFemale sex workers (FSW) are particularly vulnerable to unintended pregnancy. Research examining the experience of unintended pregnancy due to commercial sex among Chinese FSW, however, is limited. This study aimed to examine the prevalence and correlates of unintended pregnancy due to commercial sex among FSW in China.MethodsIn 2021, a cross-sectional study was conducted among 1257 FSW in five cities from Guangdong provinces in South China. Data were collected on social-demographic characteristics, sexual behaviors, experience of unintended pregnancy due to commercial sex and its pregnancy outcome, as well as experience of abortion in lifetime. Multivariable logistic regression analysis was employed to identify factors associated with unintended pregnancy.ResultsAmong the 1257 FSW, 19.3% reported having at least one unintended pregnancy due to commercial sex. Of those, 96.7% chose to terminate the pregnancy through induced abortion, and 40.5% reported undergoing multiple induced abortions in their lifetime. Multivariable logistic regression indicated that FSW working in current location over one year (adjusted Odds Ratio (aOR): 2.82, 95% CI 1.71–4.64) and having more than seven clients in the past week (aOR: 4.53, 95% CI 2.74–7.51) were more likely to have had unintended pregnancy due to commercial sex. Working in high tier (aOR: 0.21, 95% CI 0.14–0.30) and consistent condom use with clients in the past month (aOR: 0.16, 95% CI 0.10–0.23) were associated with a lower proportion of FSW having ever had unintended pregnancy.ConclusionsUnintended pregnancy are prevalent among FSW in South China. Interventions aimed at reducing the prevalence of unintended pregnancy and enhancing post-abortion care could be necessary among Chinese FSW.

Emerging digital inequality in early life: Parenting and differential usage of digital devices among urban preschoolers in China

AbstractObjectiveThis study aims to investigate the following questions: (1) how Chinese preschoolers’ usage of digital devices differ by their family socioeconomic status (SES), and (2) how socioeconomic differences in children's usage of digital devices can be accounted for by parents’ digital parenting attitudes and behaviors.BackgroundScholars in social stratification and inequality have warned about “Digital Inequality” and argued that the fact that people from different socioeconomic backgrounds differ in their access to digital equipment and their knowledge of how to use digital devices effectively would eventually contribute to social inequality. Unfortunately, most of the current studies on digital inequality focus on the population of adults or adolescents; whether and how digital inequality emerges in early life remains heavily understudied.MethodsWe use data from Early Childhood Study‐The Great Bay Area (ECS‐GB), a regional representative survey conducted in 2018 and designed to assess preschool children's social‐emotional and cognitive development in Guangdong, a coastal province in South China. Our analytical sample consists of 11,445 preschool children aged from 3 to 6 with urban hukou.ResultsOur results show that compared with children from lower‐SES families, preschoolers from higher‐SES families spend less time on digital devices daily, are less likely to use digital devices for prolonged time, and spend significantly less time on non‐education purposed and leisure activities. These socioeconomic differences in children's digital usage in terms of time and types of activities are attributable to the fact that parents of higher SES families impose more restrictions, provide more guidance to their children's digital activities, and are more conscious about their children's digital usage in daily life.ConclusionIn contemporary China, digital inequality emerges in early life and such inequality is closely related to family's digital parenting practices.

Tracking and optimizing toxic chemical exposure pathways through food trade: A case study in SCCPs contaminated seafood in China

Abstract Food safety is related to human health and sustainable development. International food trade poses food safety risks through the collateral transport of toxic chemicals that are detrimental to human health. Domestic interprovincial trade has similar effects within countries but has not been comprehensively investigated previously. Here we assessed the effects of interprovincial trade on food safety and human dietary exposure to short-chain chlorinated paraffins (SCCPs), a group of emerging persistent toxic chemicals, in seafood across China by synthesizing data from field observation and various models. Our findings indicate that there is a higher level of SCCPs exposure risk in coastal provinces compared to inland provinces. Approximately 70.3% of human exposure to SCCPs through seafood consumption in China was embodied in the interprovincial seafood trade in 2021. Specifically, the domestic trade led to a remarkable increase in SCCPs exposure in the coastal provinces in South China, attributable to low SCCPs pollution in these provinces and imported seafood from those provinces with high SCCPs pollution. In contrast, human exposure to SCCPs decreased in those coastal provinces in East China due to importing seafood from those provinces with low SCCPs concentrations. The interprovincial seafood trade routes were optimized by linear programming to minimize human exposure to SCCPs considering both shipping cost and health risk constraints. The optimized trade routes reduced the national per capita SCCPs exposure through seafood consumption by over 12%. This study highlights the importance of interprovincial food trade in the risk assessment of toxic chemicals.

In situ observations of rain rate and precipitation microphysics over the coastal area of South China: Perspectives for satellite validation

Abstract This study investigates precipitation observed by a set of collocated ground-based instruments in Zhuhai, a coastal city located at the southern tip of the Pearl River Delta of Guangdong Province in South China. Seven months of ground-based observations from a tipping-bucket rain gauge (RG), two laser disdrometers (PARSIVEL and PWS), and a vertically-pointing Doppler Micro Rain Radar-2 (MRR), spanning from December 2021 to July 2022, are statistically evaluated to provide a reliable reference for China’s spaceborne precipitation measurement mission. Rainfall measurement discrepancies are found between the instruments, though the collocated deployment mitigates uncertainties originating from spatial/temporal variabilities of precipitation. The RG underestimates hourly rain amounts at the observation site, opposite to previous studies, leading to 18.2% percent bias (Pbias) of hourly rain amounts when compared to the PARSIVEL. With the same measurement principle, the hourly-accumulated rain between the two laser disdrometers has a Pbias of 15.3%. Discrepancies between MRR and disdrometers are assumed to be due to different temporal/spatial resolution, instrument sensitivities and observation geometry, with a Pbias of mass-weighted mean diameter and normalized intercept parameter of gamma size distribution less than 9%. The vertical profiles of drop size distribution (DSD) derived from the MRR are further examined during extreme rainfalls in the East Asia monsoon season (May, June, and July). Attributed to the abundant moisture which favors the growth of raindrops, coalescence is identified as the predominant effective process and the raindrop mass-weighted mean diameter increases by 33.7% when falling from 2000 m to 600 m during the extreme precipitation event in May.

Predicting suitable habitat for the endangered tree Ormosia microphylla in China

Climate change has significantly influenced the growth and distribution of plant species, particularly those with a narrow ecological niche. Understanding climate change impacts on the distribution and spatial pattern of endangered species can improve conservation strategies. The MaxEnt model is widely applied to predict species distribution and environmental tolerance based on occurrence data. This study investigated the suitable habitats of the endangered Ormosia microphylla in China and evaluated the importance of bioclimatic factors in shaping its distribution. Occurrence data and environmental variables were gleaned to construct the MaxEnt model, and the resulting suitable habitat maps were evaluated for accuracy. The results showed that the MaxEnt model had an excellent simulation quality (AUC = 0.962). The major environmental factors predicting the current distribution of O. microphylla were the mean diurnal range (bio2) and precipitation of the driest month (bio14). The current core potential distribution areas were concentrated in Guangxi, Fujian, Guizhou, Guangdong, and Hunan provinces in south China, demonstrating significant differences in their distribution areas. Our findings contribute to developing effective conservation and management measures for O. microphylla, addressing the critical need for reliable prediction of unfavorable impacts on the potential suitable habitats of the endangered species.

Patterns of unhealthy lifestyle and their associations with depressive and anxiety symptoms among Chinese young adults: A latent class analysis

BackgroundThere is little evidence on the association between patterns of unhealthy lifestyle and mental health among young adults. MethodThis study included a total of 28,978 young adults aged 18 to 44 years old in Guangdong province in south China, which was conducted from September to December in 2022. We used latent class analysis to classify the patterns of unhealthy lifestyle among young adults and used multiple logistic regression to explore their associations with depressive and anxiety symptoms. ResultThe weighted prevalence of depressive and anxiety symptoms were 28.0 % and 19.5 %, respectively. The cumulative effect of unhealthy lifestyles on depressive and anxiety symptoms was significant. Five patterns of unhealthy lifestyle were classified. Compared to the relatively healthy lifestyle class, the class with more unhealthy lifestyles (OR = 6.54, 95 % CI: 5.70–7.51) and insufficient sleep (OR = 6.16, 95 % CI: 4.92–7.70) had higher risk for depressive and anxiety symptoms. Meaningfully, having adequate mental health literacy could reduce the risk of depressive and anxiety symptoms from unhealthy lifestyle by half. LimitationsThe cross-section design study limited causal inferences, and the self-report information may lead to recall bias. ConclusionsUnhealthy lifestyles have a negative impact on depressive and anxiety symptoms through independent, cumulative and combined effects, and they could be interrelated. Unhealthy lifestyle patterns differed in younger population by socio-demographic characteristics and mental health literacy. Health-care professionals and policymakers may provide programs to intervene multiple unhealthy lifestyles and improve mental health literacy by integrating healthy lifestyle education to promote youngers' mental health.

Identification of Clubroot-Resistant Germplasm in a Radish (Raphanus sativus L.) Core Collection

Clubroot disease, caused by Plasmodiophora brassicae, poses a significant global threat to cruciferous crops. The epidemic area of clubroot disease is expanding rapidly. In response to this pressing issue, there is a compelling need for the development of clubroot disease-resistant radish cultivars. China boasts an extensive array of radish varieties and germplasm resources. However, a comprehensive assessment of their resistance to clubroot has not yet been carried out, thereby impeding the effective utilization of germplasm and clubroot-resistant breeding. Therefore, it is urgent to systematically evaluate the clubroot resistance of the radish germplasm and identify resistant resources. In this study, clubroot resistance evaluations were conducted on 268 excellent radish varieties derived from 30 provinces in China, as well as seven accessions from Russia, North Korea, France, South Korea, and Germany. The resistance evaluation revealed a diverse range of resistance indices, with a mean disease index (DI) ranging from 0.6 to 58.5, showing significant disparities in clubroot resistance among these radish resources. A total of six accessions were characterized as highly resistant to clubroot, and a further 50 accessions were characterized as resistant. The disease-resistant radishes showed diversity in horticultural traits. Provinces in South China contributed significantly more resistance germplasm than those of North China. These materials are of great value for both genetic investigation and the crop breeding of clubroot resistance. Furthermore, we employed a previously established clubroot-resistance-linked SSR marker to analyze the clubroot-resistant resources. The accessions exhibited dissimilar genetic profiles from known clubroot-resistant germplasm, suggesting their potential status as novel sources of clubroot resistance. Conclusively, these newly identified accessions enriched the genetic diversity within the clubroot-resistant gene pool and may contribute to the future cloning of previously undiscovered clubroot-resistant genes.

LANGUAGE SITUATION IN THE CHAOSHAN COMMUNITY: A PILOT STUDY

Chaoshan, located on the east coast of Guangdong Province in South China, is a region with profound cultural and linguistic distinctiveness. This pilot study investigates the language situation in the Chaoshan region, focusing on the city of Shantou. It addresses key sociolinguistic issues such as language policy, attitude, identity, and mutual intelligibility among varieties of Teochew. Prior research mainly concentrated on language shift and maintenance, but this study delves deeper to explore sociolinguistic peculiarities within sub-communities and mutual intelligibility issues [Lin, 1994, 2005, 2017; F. Chen, 2017; H. Chen, 2020; Huang & Fang, 2021]. Results from 142 participants highlight significant intra-community differences in language practices, attitude, and identity among the three sub-communities. The South Shore sub-community - Haojiang, Chaoyang and Chaonan Districts and its variety stand out in interactions with other sub-communities: Downtown and Chenghai, primarily in language practices, attitudes and identity. The study also provides insights into the mutual intelligibility among three Teochew varieties, revealing the complexity of the language situation.

A qualitative study of food sociality in three provinces of South China: social functions of food and dietary behavior.

Food sociality refers to the exploration of food production, exchange, distribution, and consumption and influences on cultural communication and social meaning. This study aimed to investigate food sociality in three provinces of South China to provide theoretical and practical evidence of food sociality in the region and to revise nutrition policies. We conducted a qualitative study comprising 25 experts in the fields of nutrition, sociology, food science, and agriculture from Hainan, Guangdong, and Guangxi Province by using a semi-structured in-depth interview, which included 28 pre-determined questions covering six topics. The interviews were conducted between November 2020 and March 2021. Verbatim transcripts were analyzed thematically using NVivo 11.0. Of the 25 experts, the mean age was 50.6 (SD = 8.4) years, 15 (60%) were male, and 22 (88%) held a master's degree or above. The analysis showed that food sociality in three provinces of South China mainly comprises social functions of food and dietary behavior. Regarding social functions of food, the experts expressed that food represents local culture (72%, 18 experts), presents social status and economic power (40%, 10 experts), and is central to special occasions, traditional customs, and etiquette activities (60%, 15 experts). In terms of social functions of dietary behaviors, the majority of experts indicated that food is a social communication tool (72% experts), has geographical characteristics (80% experts), and, to some extent, is used as a proxy for reward or punishment. Furthermore, festivals are one of the core elements of food sociality in the region, although food safety is a major concern. Some dietary behaviors, such as overindulgence in afternoon tea and encouraging drinking, may increase the risk of chronic diseases. Food sociality in three provinces of South China is mainly related to the social function of food and dietary behavior. It is a combination of local culture, social status and economic power, traditional customs, rewards and punishments, geographical food preference, and social communication tools. The authors recommend increasing food safety at festivals and promoting healthy eating behaviors in order to improve the overall health of the population in this region.

Association of age at menarche with gestational hypertension and preeclampsia: A large prospective cohort in China.

This study explored the potential association between age at menarche and the risks of gestational hypertension and preeclampsia in Chinese women. Data were sourced from the China-US Collaborative Project for Neural Tube Defects Prevention, a large population-based cohort study. Our study consisted of 209411 women pre-registered for pregnancy in two provinces in South China. Trained healthcare workers measured blood pressure at registration and recorded other pertinent health information. Using logistic regression, we assessed the correlations between age at menarche and the likelihood of developing gestational hypertension and preeclampsia, considering confounders such as maternal age, body mass index, ethnicity, parity, folic acid supplementation, education level, and occupation. The observed incidences for gestational hypertension and preeclampsia were 9.65% and 2.54%, respectively. The adjusted odds ratios (ORs) for gestational hypertension, based on age at menarche, were as follows: ≤13 years, 1.18 (95% confidence interval: 1.11-1.26); 14 years, 1.09 (1.04-1.15); 15 years, 1.11 (1.06-1.16); 16 years, 1.06 (1.01-1.12); and ≥17 years, 1.00 (reference; P for trend<.001). The correlation between age at menarche and preeclampsia varied across age groups, with the following respective ORs: 1.35 (1.20-1.52), 1.21 (1.09-1.34), 1.27 (1.15-1.39), 1.14 (1.03-1.26), and 1.00 (reference; P for trend<.001). This association appeared to be more pronounced in women with no folic acid supplementation and those with a lower education level. In conclusion, an earlier age at menarche seems to be linked to increased risks of gestational hypertension and preeclampsia.

Key factors influencing arsenic phytotoxicity thresholds in south China acidic soils

Arsenic (As) toxicity threshold values (TTVs) for plants are fundamental to both establishing regional As reference values in soil and performing risk assessment. However, TTVs vary with plant species and soil types. In this study, a hydroponic experiment with 16 plant species was conducted to screen the most As-sensitive plant species. The results showed that the EC20 (available As concentration at which shoot biomass or height is inhibited by 20%) values were 1.38–104.4 mg L−1 for shoot height and 0.24–42.87 mg L−1 for shoot fresh biomass. Rice was more sensitive to As toxicity than the other species. Therefore, it was chosen as the ecological receptor in the pot experiment on As phytotoxicity in nine types of soils collected from Fujian Province in South China. The EC10 and EC20 with respect to rice shoot height were 3.72–29.11 mg kg−1 and 7.12–45.60 mg kg−1, respectively. Stepwise regression analysis indicated that free iron oxide concentration is the major factor that affects As bioavailability in soil, and ECx (x = 10, 20, and 50) of soil available As for shoot height was positively related to free iron oxide concentration in soil. In addition, soil cation exchange capacity, clay (<0.002 mm) content, and exchangeable magnesium content are also important factors influencing As phytotoxicity in acidic soils. The regression models can be used to predict As phytotoxicity in acidic soils.

High-resolution shallow crustal shear wave velocity structure of Anyuan mining area and its adjacent region in Jiangxi Province, China

High-resolution seismic image is critically important for mining minerals. In this study, we collected seismic data from a local dense seismic array consisting of 154 stations around the Anyuan mining area and its adjacent region of Pingxiang City, Jiangxi Province in South China, and applied the ambient noise tomography (ANT) method to image the shear wave velocity structure in the study area. Shallow crustal velocities at depths less than 3.3 km were determined by direct inversion of Rayleigh wave group velocity dispersion curves at the period range of 0.5–5.0 s. Overall, the S-wave velocity structure has a tight correlation with surface geological and tectonic features in the study area. The shear wave velocity structure in the shallow crust of the Anyuan Mine and its adjacent areas displayed distinct low-velocity anomalies, which can be attributed to the depression of sedimentary structures and coal mining activities in the Pingxiang-Leping region. The zones surrounding the Anyuan fault (AYF) and Wangkeng fault (WKF) zones exhibited low-velocity anomalies from the ground surface to ~ 3.3 km underground. And the low-velocity anomalies at depths less than 1.2 km could be related to the sedimentary environment of coal mine and the coal mining activities, while the low-velocity anomalies at depths below 1.2 km are caused by the presence of fracture medium, oil and gas in the fault zone. The shear wave velocity changes sharply across the AYF, and the characteristics of the velocity change interface indicate that the AYF is inclined toward the northwest, with its extension reaching depths of approximately 3 km underground.Graphical

Ecosystem carbon storage considering combined environmental and land-use changes in the future and pathways to carbon neutrality in developed regions

Assessing the carbon storage capacity of terrestrial ecosystems is crucial for land management and carbon reduction policymaking. There is still a knowledge gap regarding how ecosystem carbon storage will be impacted by combined environmental and land-use factors and their spatial-temporal changes, especially in developed regions where urbanization has slowed down. This study investigated how developed regions in subtropical and tropical areas might increase carbon storage and achieve carbon neutrality, using Guangdong Province in South China as an example. Based on the sustainable development assumption, three land-management scenarios were developed and simulated for 2020–2060 using the Patch-generating Land Use Simulation model. Without considering disturbance and natural losses, carbon storage was estimated by net ecosystem productivity (NEP)—the difference between net primary productivity (NPP) and heterotrophic respiration (HR). NPP was predicted using an artificial neural network model trained by historical NPP data and 16 environmental and land-use variables. HR was predicted using soil respiration models from previous research. Based on the balance between carbon storage and emissions, we predicted the allowable fossil fuel consumption to achieve net-zero CO2 emissions in 2060. The results show that Guangdong's total carbon storage changes from 73.7 MtC in 2020 to 70.6–74.8 MtC in 2060 under different scenarios. Nonlinear relationships exist between the carbon stored and the areas of different land-use types. Topography, temperatures, and land-use configurations jointly lead to significantly varied carbon storage between croplands and between forests in space and time. Protecting and regenerating forests in subtropical areas and forest edges is more effective than afforestation in lowland tropical areas for storing carbon. Net-zero CO2 emissions rely more on reducing emissions than land management. To achieve this, the proportion of fossil energy in total energy consumption should be lowered from 75.5 % in 2020 to ~25 % in 2060.

A novel uncertainty analysis method to improve the accuracy of agricultural grey water footprint evaluation considering the influence of production conditions

Agricultural grey water footprint (GWF) is an important index for quantitatively describing the impact of agricultural production on water environment, which can help evaluate regional water pollution risk (WPR). However, changes in agricultural production conditions lead to strong uncertainties in agricultural GWF. Therefore, advanced methods to deal with these uncertainties for improving the accuracy of regional WPR assessment are required. By combining min–max/max-max programming models with a GWF assessment framework, an integrated uncertainty analysis method for agricultural GWF affected by production conditions was proposed in this study. Based on the method, extreme scenarios of GWF evaluation were established to obtain lower and upper bounds of agricultural GWF. The proposed method was applied in the Guangdong Province in South China, and the following results were obtained. Agricultural GWFs in the Guangdong Province were [124.67, 237.37], [110.63, 204.90], and [104.04, 178.01] Gm3 in 2005, 2010, and 2015, respectively. Different contributing factors of agricultural GWF were shown in the minimum and maximum GWF scenarios. For crop planting, the contribution of dryland and paddy fields to GWF was larger than that of garden land in the minimum GWF scenario, whereas the contribution of garden land was greatest in the maximum GWF scenario. For livestock and poultry breeding, the contribution of livestock raised under dry cleaning condition to the GWF was larger than that under flushing condition in the minimum GWF scenario, whereas the opposite situation was observed in the maximum GWF scenario. Based on the interval values of agricultural GWF, the WPR of the cities of Zhanjiang, Maoming, Yunfu, Chaozhou, Foshan, and Dongguan were identified as unacceptable. By identifying the uncertainties within agricultural GWF evaluation induced by the variability of production conditions, the proposed method can provide helpful information for agricultural planning in the context of sustainable agricultural development.

Nature and timing of Sn mineralization in southern Hunan, South China: Constraints from LA-ICP-MS cassiterite U-Pb geochronology and trace element composition

Abstract Accurately determining the timing and mechanism of metallogenesis of ore deposits is essential for developing a robust genetic model for their exploration. In this paper, we analyze the formation conditions of cassiterite in five major deposits of southern Hunan Province, one of the most important tungsten-tin (W-Sn) provinces in South China, using a combination of cathodoluminescence imaging, in situ U-Pb geochronology, and trace-element concentration data. In situ cassiterite U-Pb geochronology constrains the main period of Sn mineralization to between 155.4 and 142.0 Ma, demonstrating a temporal and genetic relationship to silicic intrusive magmatism in the same area. Three stages of magmatic activity and metallogenic evolution are recognized: (1) Early Paleozoic and Triassic: the initial enrichment stage of tungsten and tin; (2) Jurassic: the metasomatic mineralization stage; and (3) Cretaceous: the magmatic-hydrothermal superposition stage. The cassiterite in these deposits takes four forms, i.e., quartz vein-type, greisen-skarn-type, greisen-type, and granite-type, representing a progression characterized by the increasing content and decreasing range of variation of high field strength elements (HFSEs), and reflecting a general increase in the degree of evolution of the associated granites. Rare earth element (REE) concentrations suggest that precipitation of cassiterite was insensitive to the redox state of the fluid and that precipitation of cassiterite in the southern Hunan Sn deposits did not require a high-fO2 environment. These findings provide new insights into tin mineralization processes and exploration strategies.

Multistage W-Sn metallogenic processes in the Xitian ore field, South China: Evolution from skarn-type to vein-type mineralization

The Nanling Metallogenic Belt is a major W-Sn province in South China containing numerous ore deposits formed during a complex history of magma emplacement and mineralization. The Xitian ore field in Hunan Province is a typical example of a late magmatic-metallogenic system. In this study, garnets from skarn-type ores in the Xitian ore field yield a U-Pb age of 231.7 ± 1.3 Ma (n = 33), whereas cassiterite grains from quartz vein-type ores give U-Pb ages of 158 to 154 Ma (n = 72) and 140.7 ± 3.3 Ma (n = 6), suggesting three stages of W-Sn mineralization (Late Triassic, Late Jurassic, and Early Cretaceous). In the Late Triassic skarn-type ores, the REE patterns of scheelite change from MREE-enriched to LREE-enriched with time, whereas the REE patterns of scheelite shift from MREE-enriched to MREE-depleted in the Late Jurassic quartz vein-type ores, indicating diverse metallogenic processes. Differences in the Y/Ho ratios and Sr-O isotope compositions of scheelite further confirm discrete metallogenic pathways for the Late Triassic skarn-type W ore and the Late Jurassic quartz vein-type ore, with fluid-rock interaction of the former dominated by magmatic-hydrothermal fluids whereas the latter was influenced by large amounts of meteoric water. A model emphasizing the evolution from skarn-type to vein-type metallogeny is proposed to account for the complex genesis of multistage W–Sn deposits related to the Xitian granite complex. More generally, this study demonstrates that in-situ LA-ICP(MC)-MS U-Pb dating and isotopic analysis of hydrothermal minerals are powerful tools to decipher the nature, timing, and evolution of multistage W-Sn metallogenic systems.

Seismically imaged lithospheric delamination and its controls on the Mesozoic Magmatic Province in South China

The current lithospheric root of the South China Block has been partly removed, yet what mechanisms modified the lithospheric structure remain highly controversial. Here we use a new joint seismic inversion algorithm to image tabular high-velocity anomalies at depths of ~90–150 km in the asthenosphere beneath the convergent belt between the Yangtze and Cathaysia blocks that remain weakly connected with the stable Yangtze lithosphere. Based on obtained seismic images and available geochemical data, we interpret these detached fast anomalies as partially destabilized lower lithosphere that initially delaminated at 180–170 Ma and has relaminated to their original position after warming up in the mantle by now. We conclude that delamination is the most plausible mechanism for the lithospheric modification and the formation of a Mesozoic Basin and Range-style magmatic province in South China by triggering adiabatic upwelling of the asthenosphere and consequent lithospheric extension and extensive melting of the overlying crust.

Tracing the sources of PM2.5-related health burden in China

Fine particulate matter (PM2.5) poses a major environmental risk to human health. We estimated PM2.5-related premature deaths in 30 Chinese provinces in 2020 using an integrated exposure response model based on monitored concentrations and obtained regional and sectoral contributions based on the atmospheric transport of the atmospheric transport contribution matrix. From the perspective of regional- and sectoral-scale effects, the results revealed that 740,140 [95% confidence interval (CI):646,538–839,968] premature deaths were related to PM2.5 in 2020, mainly in East (30%), Central (18%), and North (15%) China. Manufacturing activity was found to be the major cause of PM2.5-related premature deaths, accounting for over 50% of the deaths. From the perspective of the interregional atmospheric transport effect, although local emissions were the major source of PM2.5-related premature deaths in all regions, non-local emissions contributed approximately 30%. The overall trend in the net atmospheric transport direction was from north to south. In particular, the Guangdong, Guangxi, and Hainan provinces of South China received contributions of more than 40% from non-local provinces, mainly from the East and Central China. Combined with economic data, the regions and sectors with the highest PM2.5-related premature deaths per unit output or consumption include the manufacturing and household sectors in North and Northeast China and transportation, agriculture, and electricity in Central China. Therefore, from the perspective of the above three impacts, although the potential impact of PM2.5 pollution on health in China has decreased with the decrease in PM2.5 concentration in the past decade owing to strict air pollution control, the central and northern parts of China are still the key areas requiring air pollution control. The health impacts of air pollution associated with the rapid development of China's manufacturing industry in the post-pandemic era cannot be ignored.

Climate and soil management factors control spatio-temporal variation of soil nutrients and soil organic matter in the farmland of Jiangxi Province in South China

Climate and soil management factors control spatio-temporal variation of soil nutrients and soil organic matter in the farmland of Jiangxi Province in South China

Counterfeiting activities during the Tang Dynasty (618–907 CE) revealed by the special alloy coins in the Chenzhou hoard, Hunan, China

Kaiyuan Tongbao coin was the primary circulation currency during the Tang Dynasty. It defined the Chinese coinage model for over a thousand years afterward. Despite repeated government prohibition, coin counterfeiting prevailed through Tang Dynasty. Such activities resulted in a large amount of counterfeit coins entering the market, which undermined economy and led to social instability. However, as a key to exploring the issue of counterfeiting, information on the alloy composition, provenance and the production mode of the counterfeit coins are not yet clear. This paper presents the first comprehensive scientific study on counterfeit coins from a hoard in Hunan Province in South China (a total of 39 kg and approximately 8000 coins were found). Radiocarbon dating of the bamboo weaving wrapped coins indicated that the hoard dated from 668 to 874 CE (Tang Dynasty). Chemical composition analysis, morphological and metallographic images and lead isotope analysis of 78 hoarded Kaiyuan Tongbao coins had been obtained. Combined with historical records, ore materials probably originated from the local Huangshaping and Baoshan polymetallic deposits in the Nanling metallogenic belt in South China. Results showed that there were 16 types of alloy materials, primarily cast alloys of the Cu-Fe-As system. Most of the coins were minted using a Cu-Pb syngenetic ore rich in many elements from Fe, As, Sb, and Sn. One discovery is the utilizing of a by-product of local ore smelting which was called the speiss. The hoard coins studied in this paper provide the first evidence of the use of speiss for coinage in ancient China. Such material sources and manufacture technique made convenience for coin counterfeiting, which explains repeated failures of central government’s attempts to eliminate coin counterfeiting, especially for those mining areas.