Spatial analysis and machine learning prediction of forest fire susceptibility: a comprehensive approach for effective management and mitigation

Forest fires (FF) in tropical seasonal forests impact ecosystem. Addressing FF in tropical ecosystems has become a priority to mitigate impacts on biodiversity loss and climate change. The escalating frequency and intensity of FF globally have become a mounting concern. Understanding their tendencies, patterns, and vulnerabilities is imperative for conserving ecosystems and facilitating the development of effective prevention and management strategies. This study investigates the trends, patterns, and spatiotemporal distribution of FF for the period of 2001-2022, and delineates the forest fire susceptibility zones in Odisha State, India. The study utilized: (a) MODIS imagery to examine active fire point data; (b) Kernel density tools; (c) FF risk prediction using two machine learning algorithms, namely Support Vector Machine (SVM) and Random Forest (RF); (d) Receiver Operating Characteristic and Area Under the Curve, along with various evaluation metrics; and (e) a total of 19 factors, including three topographical, seven climatic, four biophysical, and five anthropogenic, to create a map indicating areas vulnerable to FF. The validation results revealed that the RF model achieved a precision exceeding 94 % on the validation datasets, while the SVM model reached 89 %. The estimated forest fire susceptibility zones using RF and SVM techniques indicated that 20.14 % and 16.72 % of the area, respectively, fall under the "Very High Forest Fire" susceptibility class. Trend analysis reveals a general upward trend in forest fire occurrences (R2 = 0.59), with a notable increase after 2015, peaking in 2021. Notably, Angul district was identified as the most affected area, documenting the highest number of forest fire incidents over the past 22 years. Additionally, forest fire mitigation plans have been developed by drawing insights from forest fire management strategies implemented in various countries worldwide. Overall, this analysis provides valuable insights for policymakers and forest management authorities to develop effective strategies for forest fire prevention and mitigation.

Spatiotemporal trends of cardiovascular disease burden attributable to low physical activity during 1990-2019: an analysis of the Global Burden of Disease Study 2019

OBJECTIVES

The epidemiological trends of cardiovascular disease (CVD) burden attributed to low physical activity (LPA) across various regions and countries are poorly understood. Hence, we assessed the global, regional, and national spatiotemporal trends of LPA-related CVD from 1990 to 2019.

STUDY DESIGN

We conducted a secondary analysis of the Global Burden of Disease Study 2019. The data on LPA-related CVD were examined with regard to sex, age, year, and Socio-Demographic Index (SDI).

METHODS

We assessed the temporal changes in age-standardized mortality rate (ASMR) and age-standardized death rate (ASDR) using the estimated annual percentage change (EAPC) over a 30-year period.

RESULTS

There were a staggering 0.64 million deaths and 9.99 million disability-adjusted life-years globally attributed to LPA-related CVD in 2019. The majority of the LPA-related CVD burden was observed in the population aged ≥80 years. It also indicated a high disease burden of LPA-related CVD in Central Asia, Arabian Peninsula, and North Africa. Although there has been a decline in ASMR and ASDR associated with LPA-related CVD on a global scale, the countries experiencing the most substantial increase in LPA-related CVD burden are Uzbekistan, Tajikistan, and Azerbaijan. The ASMR and ASDR remained stable in regions with low, low-middle, and middle SDI levels. The EAPCs of ASMR and ASDR were negatively linked with SDI in 2019.

CONCLUSIONS

From 1990 to 2019, LPA led to a significant and escalating burden of CVD in certain regions, namely, Uzbekistan, Tajikistan, and Azerbaijan. It is imperative for governments and policymakers to implement regulatory measures and strategic interventions aimed at mitigating this burden.

Retrospective spatiotemporal study of antidepressants in Slovenian wastewaters

This study utilizes wastewater-based epidemiology (WBE) to evaluate spatiotemporal changes in the consumption of antidepressants before and during the COVID-19 pandemic in Slovenia. Composite 24-h influent wastewater samples (n = 210) were collected from six wastewater treatment plants between summer 2019 and spring 2021. The samples were extracted using 96-well solid-phase extraction and analysed by liquid chromatography-tandem mass spectrometry. The measured concentrations of target antidepressant biomarkers were then converted to population-normalised mass loads (PNMLs), taking into account flow rate and catchment population. Ten biomarkers, including amitriptyline, bupropion, bupropion-OH, citalopram, norcitalopram, normirtazapine, venlafaxine, O-desmethylvenlafaxine, trazodone, and moclobemide, were above the lower limit of quantification and were included in the spatiotemporal temporal assessment. The highest PNMLs were detected for O-desmethylvenlafaxine (mean ± SD: 82.1 ± 21.2 mg/day/1000 inhabitants) and venlafaxine (38.0 ± 10.6 mg/day/1000 inhabitants), followed by citalopram (27.0 ± 10.7 mg/day/1000 inhabitants). In addition, the mean metabolite/parent compound ratios were comparable with other WBE studies indicating consumption rather than direct disposal. Overall, the results indicated significant spatiotemporal variations depending on the location, and the PNMLs of most biomarkers increased during the first wave of the COVID-19 pandemic (spring of 2020). However, no clear spatial patterns were revealed related to the pandemic.

Spatial and Temporal Trends in Pancreatic Cancer Burden Attributable to High Body Mass Index at the Global and National Levels

OBJECTIVES

To examine the spatiotemporal trends in pancreatic cancer (PC) disability-adjusted life years (DALYs) and mortality attributable to high body-mass index (BMI) by age, gender, and countries from 1990 to 2019.

METHODS

Data were extracted from the Global Burden of Disease Study 2019 results. We presented the annual number of PC DALYs and mortality, and corresponding age-standardized rates (ASDR and ASMR), which were further stratified by age, gender, and countries. The estimated annual percentage change (EAPC) was computed to assess the longitudinal trends in ASRs.

RESULTS

In 2019, 0.7 million DALYs and 31.9 thousand deaths worldwide were caused by PC attributable to high BMI, with the largest amount reported in high-income North America, Western Europe, and East Asia. The corresponding ASDR and ASMR were highest in females and in high SDI regions, while quite varied across countries. The global EAPC in ASDR and ASMR was 1.45 (95% uncertainty interval [UI]: 1.40, 1.50) and 1.44 (95% UI: 1.39, 1.49), respectively. Almost all involved countries demonstrated significant uptrends in ASRs from 1990 to 2019.

CONCLUSIONS

More productive efforts to reduce the impact of modifiable risk factors, such as overweight, should be undertaken, and thus effectively curb the rise of PC burden.

Spatiotemporal trends in global burden of rheumatic heart disease and associated risk factors from 1990 to 2019

BACKGROUND

The aim of this study was to estimate the burden of rheumatic heart disease (RHD) and its trends in different countries, regions, genders and age groups globally.

METHODS

Data were obtained from the Global Burden of Disease 2019 study. Age-standardized rates (ASRs) and the estimated annual percentage changes (EAPCs) in the ASRs were used to describe the burden of disease and its trends. Pearson's correlation was used to evaluate the correlation between sociodemographic index (SDI) values and the observed trends.

RESULTS

In 2019, the ASRs of the incidence, prevalence, mortality and disability-adjusted life years (DALYs) of RHD were 37.39/105 (95%UI, 28.59/105 to 46.74/105), 513.68/105 (95%UI, 405.01/105 to 636.25/105), 3.85/105 (95%UI, 4.29/105 to 3.29/105) and 132.88/105 (95%UI, 115.02/105 to 150.34/105), respectively. From 1990 to 2019, the incidence and prevalence of RHD showed upward trends and the mortality and DALYs showed downward trends. Countries or regions in Africa, South America and South Asia had a greater burden of RHD. The burden of RHD was greater in women, where as men showed more obvious increasing trends in the incidence and prevalence. The incidence of RHD was highest in adolescents, and the prevalence was highest in young and middle-aged. The mortality and DALYs rate associated with RHD increased with age. The EAPCs in the ASRs were negatively correlated with the SDI value.

CONCLUSION

Although the ASRs of mortality and DALYs attributable to RHD are decreasing globally, RHD remains an important public health problem that needs to be addressed urgently, especially in certain low- and middle-income countries and regions.

Generating daily high-resolution and full-coverage XCO2 across China from 2015 to 2020 based on OCO-2 and CAMS data

China has set a goal to achieve carbon neutrality by 2060, and satellite remote sensing allows for acquiring large-range and high-resolution carbon dioxide (CO₂) data, which can aid in achieving this goal. However, satellite-derived column-averaged dry-air mole fraction of CO₂ (XCO₂) products often suffer from substantial spatial gaps due to the impacts of narrow swath and clouds. Here, this paper generates daily full-coverage XCO₂ data at a high spatial resolution of 0.1° over China during 2015-2020, by fusing satellite observations and reanalysis data in a deep neural network (DNN) framework. Specifically, DNN constructs the relationships between Orbiting Carbon Observatory-2 satellite XCO₂ retrievals, Copernicus Atmosphere Monitoring Service (CAMS) XCO₂ reanalysis data, and environmental factors. Then, daily full-coverage XCO₂ data can be generated based on CAMS XCO₂ and environmental factors. Results show that a satisfactory performance is reported in multiform validations, with RMSE and R² of 0.99 ppm and 0.963 in terms of the sample-based cross-validation, respectively. The independent in-situ validation also indicates high consistency (R² = 0.866 and RMSE = 1.71 ppm) between XCO₂ estimates and ground measurements. Based on the generated dataset, spatial and seasonal distributions of XCO₂ across China are investigated, and a growth rate of 2.71 ppm/yr is found from 2015 to 2020. This paper generates long time series of full-coverage XCO₂ data, which helps promote our understanding of carbon cycling. The dataset is available from https://doi.org/10.5281/zenodo.7793917.

Spatiotemporal trends of cardiovascular disease burden attributable to ambient PM2.5 from 1990 to 2019: A global burden of disease study

There is little known about the global burden of CVD attributable to ambient PM_2.5 (referred to as CVD burden hereinafter) and its secular trend across different regions and countries. We aimed to evaluate the spatiotemporal trends in CVD burden at the global, regional and national levels from 1990 to 2019. Data on CVD burden including mortality and disability adjusted of life years (DALYs) from 1990 to 2019 were extracted from the Global Burden of Disease Study 2019. Cases, the age-standardized rate of mortality (ASMR) and DALYs (ASDR) were estimated by age, sex and sociodemographic index (SDI). Estimated annual percentage change (EAPC) was calculated to evaluate the temporal changing in ASDR and ASMR from 1990 to 2019. In 2019, 2.48 million deaths and 60.91 million DALYs of CVD were attributed to ambient PM_2.5 globally. Most CVD burden occurred in males, elderly and the middle SDI region. At national level, Uzbekistan, Egypt, and Iraq had the highest ASMR and ASDR. Despite remarkable increase in number of DALYs and deaths of CVD worldwide from 1990 to 2019, we observed nonsignificant change in ASMR (EAPC: 0.06, 95 % CI: -0.01, 0.13) and slight increment in ASDR (EAPC: 0.30, 95 % CI: 0.23, 0.37). The EAPCs of ASMR and ASDR were negatively associated with SDI in 2019, while the low-middle SDI region exhibited the fastest growth of ASMR and ASDR with EAPCs of 3.25 (95 % CI: 3.14, 3.37) and 3.36 (95 % CI: 3.22, 3.49), respectively. In conclusion, the global CVD burden attributable to ambient PM_2.5 has largely increased over the past three decades. The population growth, aging and SDI contributed to the heterogeneity of spatial and temporal distribution. Enforcing policy to improving air quality is required to halt the growing burden of PM_2.5 on health.

Long-Term Monitoring of Polybrominated Diphenyl Ethers (PBDEs) in Indo-Pacific Humpback Dolphins (Sousa chinensis) from the Pearl River Estuary Reveals High Risks for Calves due to Maternal Exposure

Although many studies have documented the wide occurrence of polybrominated diphenyl ethers (PBDEs) in cetaceans, little evidence exists regarding the detrimental effects of PBDE exposure on calf death rates for free-ranging cetaceans. This study analyzed life-history-associated PBDE bioaccumulation patterns in 128 stranding Indo-Pacific humpback dolphin (Sousa chinensis) samples over an 18-year timespan from the Pearl River Estuary (PRE). In comparison to the records of PBDE levels in cetaceans worldwide, the median levels of PBDEs (median = 10600 ng g^-1 lw, range = 721-50900 ng g^-1 lw) in all samples were the highest to date. One-way analysis of variance (ANOVA) showed that adult males (median = 16100 ng g^-1 lw, range = 4070-50900 ng g^-1 lw) and calves (12000 ng g^-1 lw, range = 1250-35300 ng g^-1 lw) both had the highest levels of PBDEs compared to the rest of the age/sex groups (p < 0.05). Concentrations of PBDEs in noncalves significantly decreased over the studied period, while those in calves had a slightly increasing trend, which may be due to different exposure routes via fish or milk, respectively. A significant and positive relationship was found between annual calf stranding death rates and body-length-adjusted PBDE concentrations in calves (r = 0.62, p < 0.05), suggesting that maternal exposure of calves to elevated levels of PBDEs may have contributed to the high annual stranding death rates of calves in the last two decades.

Occurrences and potential lipid-disrupting effects of phthalate metabolites in humpback dolphins from the South China Sea

Phthalate esters (PAEs) are ubiquitous environmental contaminants, arising growing public concern. Nevertheless, information on the exposure and risks of PAEs in wildlife remains limited. Here, we conducted the first investigation of the occurrences, spatiotemporal trends, and potential risks of twelve metabolites of PAEs (mPAEs) in 74 humpback dolphins from the northern South China Sea during 2005-2020. All twelve mPAEs (∑₁₂mPAEs: 9.6-810.7 ng g^-1 wet weight) were detected in the dolphin liver, and seven major mPAEs showed increasing trends during the study period, indicating high PAE contamination in the coastal environment of South China. Monoethylhexyl phthalate accounted for over half of the ∑₁₂mPAE concentrations. The accumulation of mPAEs in the dolphins was neither age-dependent nor sex-specific. Compared to parent PAEs, mPAEs generally induced higher agonistic effects on the dolphin peroxisome proliferator-activated receptor alpha/gamma (PPARA/G) as master regulators of lipid homeostasis. Although short-term in vitro assays revealed no significant activation of dolphin PPARA/G by tissue-relevant doses of mPAEs, long-term in vivo evidence (i.e., correlations between hepatic mPAEs and blubber fatty acids) suggested that chronic exposure to mPAEs might have impacted lipid metabolism in the dolphin. This study highlighted the potential health risks of PAE exposure on marine mammals.

Spatiotemporal and life history related trends of per- and polyfluoroalkyl substances in Indo-Pacific finless porpoises from south China sea (2007-2020)

Per- and polyfluoroalkyl substances (PFASs) levels in Indo-Pacific finless porpoises (Neophocaena phocaenoides) in the Pearl River Estuary (PRE), near the most economically developed region in China, have not been characterized. We measured the hepatic concentrations of twelve PFASs, including nine perfluoroalkyl carboxylic acids (PFCAs) and three perfluoroalkane sulfonic acids (PFSAs) in the finless porpoises (n = 21) collected from the PRE between 2007 and 2020. The average level of PFSAs was more than 2-times higher than that of PFCAs. The order of six dominant PFASs was perfluorooctane sulfonate (PFOS) > perfluoroundecanoic acid (PFUdA) > perfluorodecanoic acid (PFDA) > perfluorotridecanoic acid (PFTrDA) > perfluorononanoic acid (PFNA) > perfluorododecanoic acid (PFDoDA). The levels of Hepatic PFOS of 29% samples exceeded the no observable adverse effect level (NOAEL) values. The concentration of PFASs in males was significant higher than in females. PFASs levels were significantly negatively correlated with body length in males and positively correlated in females. PFASs levels in the PRE finless porpoises were lower than in humpback dolphins possibly due to different foraging habitat toward the coast and the consumption of less fish. PFCAs levels in finless porpoises from the western PRE were higher compared to Hong Kong, possibly due to the high-intensity sources of terrestrial anthropogenic pollutants. Significant increasing spatiotemporal trends of PFSAs, PFCAs and PFASs were found in finless porpoises from 2007 to 2020, suggesting a continuously increased risk of PFASs exposure for PRE cetaceans in the last decade.

Meta-analysis on the epidemiology of gastroesophageal reflux disease in China

BACKGROUND

No large-scale epidemiological survey on the prevalence of gastroesophageal reflux disease (GERD) in China has been conducted. China has a large population and a complex geographical environment. It is important to understand the prevalence and spatial distribution of GERD in China.

AIM

To explore the prevalence and the spatial, temporal, and population distributions of GERD in the natural Chinese population.

METHODS

We searched Chinese and English databases for literature on the prevalence of GERD in the natural Chinese population. The prevalence of GERD was pooled using a random-effects meta-analysis model. Subgroup analysis was performed according to time, region, and population. We used ArcGIS software to draw statistical maps and trend analysis charts. Spatial autocorrelation analysis was carried out using Geoda software. Spearman correlation analysis was used to assess the spatial distribution relationship between GERD and upper digestive tract tumours.

RESULTS

Altogether, 70 studies involving 276014 individuals from 24 provinces of China were included. The overall pooled prevalence of GERD was 8.7% (95%CI: 7.5%-9.9%) in mainland China. Over the past two decades, the prevalence of GERD in China has increased from 6.0% to 10.6%. GERD was more common in people aged 40-60, with body mass index ≥ 24, and of Uygur ethnicity. The prevalence was higher in the west and east than in the centre, and there may be a local spatial autocorrelation between the Qinghai-Tibet Plateau and the southeast. GERD was correlated with gastric (r = 0.421, P = 0.041) and oesophageal tumours (r = 0.511, P = 0.011) in spatial distribution.

CONCLUSION

GERD is becoming common in China. The prevalence differs by region and population. The development of appropriate strategies for the prevention and treatment of GERD is needed.

Efficacy of a large-scale integrated constructed wetland for pesticide removal in tail water from a sewage treatment plant

The higher and higher detection frequencies of micro-pollutants such as pesticides in water are nowadays intensifying the investigation for strategies to provide effective engineering methods that could mitigate such substances. Traditional sewage treatment plants (STP) do not design specific processes for micro-pollutants removal in water. As an environmentally-friendly measure, some laboratory-scale wetlands have been proved to be effective in the removal of pesticides in water, but such studies are rarely carried out in large-scale wetlands, especially when they are adopted as a polishing step of STPs. Therefore, the further removals of micro-pollutants in tail water of STPs through the large-scale wetlands and the relevant removal mechanism are still knowledge gaps. In this study, 44 target pesticides were detected in the water of a large-scale integrated constructed wetland (ICW) for four seasons. The ICW was established to further process the tail water from a STP, whose drainage was from domestic sewage of local residents. There were 19, 16, 17, and 19 pesticides detected in spring, summer, autumn, and winter, respectively. The removal values for Σ₁₉ pesticides ranged from 49.99% to 84.96% during the study period, and the removal of these pesticides followed significant seasonal trends, which was likely because the microorganisms responsible for biotic degradation were markedly influenced by seasonal temperature fluctuations. Proteobacteria, Chloroflexi, Acidobacteria, Planctomycetes, and Bacteroidetes were the dominant phyla, and might be associated with the biodegradation of organic pollutants in the ICW. Removal of pesticides by the ICW resulted in overall toxicity reductions in water, but butachlor and chlorpyrifos were still at non-ignorable ecological risks. This study highlights the potential of constructed wetlands for micro-pollutants removal in water as a polishing step in STPs.

The trends of maternal mortality ratios and cause pattern in 34 Chinese provinces, 1990-2017

Background

Understanding the trends and causes to the burden of maternal deaths is a key requirement to further reduce the maternal mortality ratio (MMR), and devise targeted intervention policy. We aimed to evaluate the spatiotemporal trends of MMRs and cause patterns across the 34 provinces of China during 1990–2017.

Methods

Using data from the Global Burden of Disease Study 2017, we calculated the levels and trends of total maternal deaths and MMR due to ten different causes through Bayesian multivariable regression model for pregnancies aged 10–54 years, and assessed the age and regional distribution over time.

Results

China has experienced fast decline in MMR, dropped from 95.2 (87.8–102.3) in 1990 to 13.6 (12.5–15.0) in 2017, with an annualised rate of decline of 7.0%. In 1990, the range of MMRs in mainland China was 31.1 in Shanghai, to 323.4 in Tibet. Almost all provinces showed remarkable decline in the last two decades. However, spatial heterogeneity in levels and trends still existed. The annualised rate of decline across provinces from 1990 to 2017 ranged from 0.54% to 10.14%. Decline accelerated between 2005 and 2017 compared with between 1990 and 2005. In 2017, the lowest MMR was 4.2 in Zhejiang; the highest was still in Tibet, but had fallen to 82.7, dropped by 74.4%. MMR was highest in the 40–49 years age group in both 1990 and 2017. In 2017, haemorrhage and hypertensive disorders were the leading two specific causes for maternal deaths.

Conclusions

MMRs have declined rapidly and universally across the provinces of China. Setting of associated interventions in the future will need careful consideration of provinces that still have MMR significantly higher than the national mean level.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13770-0.

Global and national burden and trends of mortality and disability-adjusted life years for silicosis, from 1990 to 2019: results from the Global Burden of Disease study 2019

Background

Silicosis, as an important type of pneumoconiosis, leads to progressive and irreversible conditions from the beginning of inflammation and fibrosis. However, the data on the global burden of silicosis and long-term trends were limited.

Methods

Derived from the Global Burden of Disease study 2019 (online publicly available: Global Health Data Exchange), data on both crude and age-standardized rates (ASR) per 100,00 people of mortality and disability-adjusted life years (DALYs) due to silicosis was collected and analyzed. The burden and trends of mortality and DALYs due to silicosis was assessed by 204 countries and territories, by 5-year interval of age group and by sex from 1990 to 2019. And all the regions were divided into 5 categories according to Sociodemographic Index (SDI). Temporal trends in mortality and DALY were evaluated only to ASR by the Joinpoint regression model.

Results

More than 12.9 thousand [95% Uncertainty Intervals (UI): 10.9, 16.2] death cases occurred due to silicosis worldwide, and 655.7 thousand (95% UI: 519.3, 828.0) DALYs were attributed to silicosis in 2019. From 1990 to 2019, global number of mortality and DALYs in countries with high SDI quintile decreased by 0.35% (95% UI: − 0.45, − 0.17) and 0.32% (95% UI: − 0.45, − 0.01), respectively. There was a greater burden in low- and middle-income countries were estimated in 2019 according to ASRs. The global number of mortality and DALYs among males accounted for over 95% of all in 2019. Both age-sex-specific mortality and DALY rate were increasing with aging and reached their peak at 85–89 age group. During the past 30 years, ASR of mortality and DALYs showed a decreasing trend with average annual percentage change at -3.0% [95% Confidence Intervals (CI): − 3.2, − 2.9] and − 2.0 (95% CI: − 1.7, − 2.2), respectively.

Conclusions

Silicosis remains an important health issue and causes a potentially serious burden worldwide. Attention should be paid to making preventable, affordable and effective measures in lower SDI regions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02040-9.

Spatiotemporal trends in life expectancy and impacts of economic growth and air pollution in 134 countries: A Bayesian modeling study

Life expectancy (LE) varies across countries in space and time, and economic growth and air pollution are two important influence factors to LE. This study mainly aims to investigate spatiotemporal trends in LE in 134 countries from 1960 to 2016 by using Bayesian spatiotemporal modeling. Further, the relations between per capita gross domestic product (GDP_pc) and population-weighted fine particulate matter (pwPM_2.5) and LE are investigated from a global perspective from 1998 to 2016 by using the Bayesian regression model. The results illustrated the heterogeneity of spatiotemporal trends in LE globally. Specifically, Africa and South-East Asia show much lower LE levels, and the Americas, European, and Western Pacific exhibit a relatively higher LE level compared to the overall level. The countries with low overall levels of LE show a relatively stronger upward trend than the overall upward trend and vice versa. In addition, this study demonstrates that the spatial differences in effects of influence factors on LE in the six WHO regions in the 134 countries. Africa shows the highest positive regression coefficient of GDP_pc and lowest negative regression coefficient of pwPM_2.5 on LE than other regions in the world. Furthermore, it shows the complexity of the interaction between economic growth and air pollution on LE across six WHO regions. Our findings suggest the public policies to reduce the health damage caused by air pollution, especially in Africa, Eastern Mediterranean, and Europe where the pwPM_2.5 negatively affect the LE benefits from economic growth.

Concentration profile, spatial distributions and temporal trends of polybrominated diphenyl ethers in sediments across China: Implications for risk assessment

Polybrominated diphenyl ethers (PBDEs) in sediments of China have been extensively investigated; however, most studies conducted to date have focused on specific locations, and the pollution and risk posed by these chemicals in sediments at the national scale remain unknown. Therefore, we analyzed the concentrations and risks of PBDEs in sediments in China and their spatiotemporal variations based on available literature. Overall, the sediments across China contain moderate to high levels of PBDEs, with BDE-209 being the dominant congener, followed by BDE-47 and BDE-99. The sediment concentrations of PBDEs were highest in southern China and lowest in northeastern China. Additionally, based on their PBDE concentrations, 18.4%, 30.0%, and 11.9% of sediment samples from rivers, lakes, and coastal waters, respectively, posed low to moderate eco-toxicological risks, but 6.90% of river sediments posed high risks. Between 2001 and 2017, the concentrations and risks of PBDEs in the sediments from rivers and coastal waters tended to decrease gradually. Additionally, there were low to moderate risks from PBDEs in lake sediments, and the risks in 2012-2017 were 3.30 times higher than those in 2006-2011. However, more studies about the spatial and temporal trends in PBDEs in sediment across China and their impacts on aquatic organisms are needed because there is still a general lack of relevant information.

Spatiotemporal trends and influence factors of global diabetes prevalence in recent years

Diabetes is one of the most widespread global epidemics and has become the main component of the global disease burden. Based on data regarding the prevalence of diabetes in 203 countries and territories from 2013 to 2017, we employed the Bayesian space-time model to investigate the spatiotemporal trends in the global diabetes prevalence. The factors influencing the diabetes prevalence were assessed by the Bayesian LASSO regression model. We identified 77 (37.9%) hotspots with a higher diabetes prevalence than the global average, 10 (0.4%) warm spots with global average level and 116 (57.1%) cold spots with lower level than global average. Of the 203 countries and territories, 68 (33.5%), including 31 hotspots, 5 warm spots and 32 cold spots, exhibited an increasing trend. Of these, 60 experienced an annual increase of more than 0.25%, and 8 showed an increasing trend. Three populous countries, namely China, the USA and Mexico, exhibited a high prevalence and an increasing trend simultaneously. Three socioeconomic factors, body mass index (BMI), urbanization rate (UR) and gross domestic product per capita (GDP-PC), and PM_2.5 pollution were found to significantly influence the prevalence of diabetes. BMI was the strongest factor; for every 1% increase in BMI, the prevalence of diabetes increased by 2.371% (95% confidence interval (95% CI): 0.957%, 3.890%) in 2013 and by 3.045% (95% CI: 1.803%, 4.397%) in 2015 and 2017. PM_2.5 pollution could be a risk factor, and its influencing magnitude gradually increased as well. With an annual PM_2.5 concentrations increase of 1.0% in a country, the prevalence of diabetes increased by 0.196% (95% CI: 0.020%, 0.356%). The UR, on the other hand, was found to be inversely associated with the prevalence of diabetes; with each UR increase of 1%, the prevalence of diabetes decreased by 0.006% (95% CI: 0.001%, 0.011%).

Satellite-derived spatiotemporal PM2.5 concentrations and variations from 2006 to 2017 in China

The PM_2.5 concentration is an important evaluation index for the global Sustainable Development Goals (SDGs) for its negative impacts on human health. Last decade, several fine particulate pollution episodes occurred in the vast area of China. In response to this, the Chinese government has stepped up efforts to tackle air pollution. In this paper, the temporal trends of PM_2.5 and the quantitative potential impact of environmental governance on PM_2.5 are analyzed for China. Due to the lack of historical records, a two-stage model was used to estimate the historical PM_2.5 concentrations, combined with the newly released satellite-based aerosol optical depth (AOD) product (MODIS Collection 6.1) and other data. The estimated PM_2.5 concentrations showed strong consistency with the surface observations. Furthermore, significant seasonal variations existed in the PM_2.5 concentrations and the temporal trends were captured, especially in city clusters. Then eight major city clusters were selected as typical samples. All the city clusters showed decrease trends in recent years, with PM_2.5 concentrations in these regions decreased by 0.269-1.604 μg m^-3 year^-1. From 2006 to 2017, the annual PM_2.5 concentrations decreased by 7.83%-26.35% in the major city clusters among China. Technological innovation and environmental governance play an important role in the decrease of PM_2.5. In order to quantify the influence of governance, environmental regulation intensity and synergy were applied as the indicators of the internal governance and co-governance in each city cluster. In most city clusters, PM_2.5 concentrations were significantly negatively correlated with regional internal governance and co-governance (R = -0.596 to -0.930, p < 0.05), and the effect on PM_2.5 lasted for several years. However, 1- to 2-year lagged effect was found for governance, which means that the regulatory measures should be enhanced to decrease PM_2.5 in the future to achieve the SDGs in China.

Globally analysing spatiotemporal trends of anthropogenic PM2.5 concentration and population's PM2.5 exposure from 1998 to 2016

Air pollution in the form of particulate matter (PM) is becoming one of the greatest current threats to human health on a global scale. This paper firstly presents a Bayesian space-time hierarch piecewise regression model (BSTHPRM) which can self-adaptively detect the transitions of local trends, accounting for spatial correlations. The spatiotemporal trends of the approximately anthropogenic PM_2.5 removed natural dust (PM_{2.5_No Dust}) concentrations and the corresponding population's PM_{2.5_No Dust} exposure (PPM_2.5E) in the global continent from 1998 to 2016 were investigated by the presented BSTHPRM. The total areas of the high and higher PM_{2.5_No Dust}-polluted regions, whose spatial relative magnitude of PM_{2.5_NoDust} pollution to the global continental overall level was between 1.89 and 14.68, accounted for about 13.4% of the global land area, and the corresponding exposed populations accounted for 56.0% of the global total population. The spatial heterogeneity of the global PM_{2.5_NoDust} pollution increased generally from 1998 to 2016. The areas of hot, warm, and cold spots with increasing trends of PM_{2.5_NoDust} concentration initially contracted and then later expanded. The local trends of the global continental PM_{2.5_NoDust} concentrations and PPM_2.5E can be parted into three changing stages, early, medium, and later stages, using the BSTHPRM. The area proportions of the regions experiencing a decreasing trend of PM_{2.5_NoDust} concentrations and PPM_2.5E were greater in the medium stage than in the early and later stages. The local trends of PM_{2.5_NoDust} concentration and PPM_2.5E in the two higher PM_{2.5_NoDust} polluted areas, northern India and eastern and southern China, increased in the early stage and then decreased in the medium stage. In the later stage (recent years), northern India displayed a stronger increasing trend; nevertheless, the follow-up decreasing trend still occurred in eastern and southern China. In the first two stages, more than half of the areas in Europe experienced a decreasing trend of PM_{2.5_NoDust} concentration and PPM_2.5E; later, more than half of areas in Europe exhibited increasing trends in the later stage. North America and South America experienced a similar local trend of PPM_2.5E to Europe. The PPM_2.5E trend in Africa generally increased during the study period.

Bioaccumulation behavior and spatiotemporal trends of per- and polyfluoroalkyl substances in Indo-Pacific humpback dolphins from the Pearl River Estuary, China

Sixteen per- and polyfluoroalkyl substances (PFASs) were measured in liver (n = 52) and kidney (n = 18) tissues of Indo-Pacific humpback dolphins (Sousa chinensis) stranded in the Pearl River Estuary (PRE) of China between 2004 and 2016. The average concentrations of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and most of other PFASs in the liver samples were respectively greater than any records previously reported in cetaceans globally. PFOS levels in 46% of dolphin liver samples exceeded the hepatic toxicity threshold in cetaceans. For the first time, we found a U-shaped trend for the distribution pattern of perfluorinated carboxylic acids (PFCAs) between liver and kidney with increasing carbon chain lengths (C5-C16), whereas a descending trend (C4-C10) was found for perfluoroalkane sulfonic acids (PFASs), which may be explained by binding efficiencies of PFAS analogues to proteins. Dolphins with the highest levels of ∑PFASs (age-corrected) were clustered near the river outlets in Lingdingyang area, which agrees with the spatial distribution of PFASs in the environment. Significant temporal trends were observed for many PFASs. Concentrations of PFOA, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA) and perfluoroheptanoic acid (PFHpA) all peaked in year 2011, followed by a decreasing trend, while a consistently descending trend was shown for perfluoroundecanoic acid (PFUdA) and perfluorodecane sulfonate (PFDS). Our findings contribute to the knowledge of tissue distribution and spatiotemporal trends of PFASs in the PRE dolphins, which are valuable for us to understand the PFASs exposure risk and their industrial emission in Southern China.

Trends in bacterial and fungal communities in ant nests observed with Terminal-Restriction Fragment Length Polymorphism (T-RFLP) and Next Generation Sequencing (NGS) techniques-validity and compatibility in ecological studies

Microbes are ubiquitous and often occur in functionally and taxonomically complex communities. Unveiling these community dynamics is one of the main challenges of microbial research. Combining a robust, cost effective and widely used method such as Terminal Restriction Fragment Length Polymorphism (T-RFLP) with a Next Generation Sequencing (NGS) method (Illumina MiSeq), offers a solid alternative for comprehensive assessment of microbial communities. Here, these two methods were combined in a study of complex bacterial and fungal communities in the nest mounds of the ant Formica exsecta, with the aim to assess the degree to which these methods can be used to complement each other. The results show that these methodologies capture similar spatiotemporal variations, as well as corresponding functional and taxonomical detail, of the microbial communities in a challenging medium consisting of soil, decomposing plant litter and an insect inhabitant. Both methods are suitable for the analysis of complex environmental microbial communities, but when combined, they complement each other well and can provide even more robust results. T-RFLP can be trusted to show similar general community patterns as Illumina MiSeq and remains a good option if resources for NGS methods are lacking.

Remote sensing of the urban heat island effect in a highly populated urban agglomeration area in East China

Increasingly urban agglomeration, representing a group of cities with a compact spatial organization and close economic links, can rise surface temperature in a continuous area due to decreasing distance between cities. Significant progress has been made in elucidating surface urban heat island intensity (SUHII) of a single city or a few big cities, but the SUHII's patterns remain poorly understood in urban agglomeration regions. Using Aqua/Terra MODIS data over 2010-2015, we examined the SUHII variations and their drivers in Yangtze River Delta Urban Agglomeration (YRDUA) of east China. Instead of using the widely-used suburban/rural areas as references, this study predicted the unaffected reference temperature wall-to-wall from natural forests by a simple planar surface model. Results indicated that urbanization warmed the land surface regardless of urban area size in YRDUA, with the SUHII clearly larger in the day (2.6±0.9°C) than night (0.7±0.4°C). The SUHII varied markedly by cities, yet the largest did not happen in the presumed core cities. Also, the SUHII differed greatly in a seasonal cycle, with summer-winter difference of 4.2±0.9°C and 2.0±0.5°C in the day and night, respectively. Particularly, cooling effects of urban areas were observed in winter for the majority of cities at night. These spatiotemporal patterns depend strongly on the background climate (precipitation and air temperature), vegetation activity, surface albedo, and population density, with contrast mechanisms during the day and night. Further, we showed that ignoring urban agglomeration effect (using suburban/rural areas as the unaffected references) would lead to large biases of SUHII estimates in terms of magnitude and spatial distribution. Our results emphasize the necessity of considering cities altogether when assessing the urbanization effects on climate in an urban agglomeration area.

Levels and trends of polycyclic aromatic hydrocarbons in the Indo-Pacific humpback dolphins from the Pearl River Estuary (2012-2017)

We investigated the levels and trends of the 16 USEPA priority PAHs in the blubber of 37 Indo-Pacific humpback dolphins sampled during the period 2012-2017 from the Pearl River Estuary (PRE), China. Σ₁₆PAHs concentrations (17.6-6080 ng g^-1 wet weight) were at median level compared to dolphin species worldwide. Humpback dolphins affiliated with the hotspots of PAHs, had significantly higher levels of Σ₁₆PAHs than individuals from the other areas in the PRE. Moreover, dolphins stranded on the coast of Lingdingyang are significantly more contaminated by Σ₁₆PAHs than those in the West-four region of the PRE, which appears to reflect the heterogeneous distribution of PAHs in the environment. A marked decline in blubber Σ₁₆PAHs levels is observed over the studied period, with the control of a range of confounding factors. The trend is strongly and statistically significant (p < 0.0001), indicating that the loading of PAHs are gradually being reduced.

Epidemiological shift and geographical heterogeneity in the burden of leptospirosis in China

Background

Leptospirosis morbidity and mortality rates in China have decreased since the 2000s. Further analyses of the spatiotemporal and demographic changes occurring in the last decade and its implication on estimates of disease burden are required to inform intervention strategies. In this study, we quantified the epidemiological shift and geographical heterogeneity in the burden of leptospirosis during 2005–2015 in China.

Methods

We used reported leptospirosis case data from 1st January 2005 to 31st of December 2015 that routinely collected by the China Information System for Disease Control and Prevention (CISDCP) to analyze the epidemiological trend and estimate the burden in terms of disability-adjusted life-years (DALYs) over space, time, and demographical groups.

Results

A total of 7763 cases were reported during 2005–2015. Of which, 2403 (31%) cases were the laboratory-confirmed case. Since 2005, the notified incidence rate was gradually decreased (P < 0.05) and it was relatively stable during 2011–2015 (P > 0.05). During 2005–2015, we estimated a total of 10 313 DALYs were lost due to leptospirosis comprising a total of 1804 years-lived with disability (YLDs) and 8509 years-life lost (YLLs). Males had the highest burden of disease (7149 DALYs) compared to females (3164 DALYs). The highest burden estimate was attributed to younger individuals aged 10–19 years who lived in southern provinces of China. During 2005–2015, this age group contributed to approximately 3078 DALYs corresponding to 30% of the total DALYs lost in China. Yet, our analysis indicated a declining trend in burden estimates (P < 0.001) since 2005 and remained relatively low during 2011–2015. Low burden estimates have been identified in the endemic regions where infections principally distributed. Most of the changes in DALY estimates were driven by changes in YLLs.

Conclusions

In the last 11-years, the burden estimates of leptospirosis have shown a declining trend across the country; however, leptospirosis should not be neglected as it remains an important zoonotic disease and potentially affecting the young and productive population in economically less-developed provinces in southern of China. In addition, while in the last five years the incidence has been reported at very low-level, this might not reflect the true incidence of leptospirosis. Strengthened surveillance in the endemic regions is, hence, substantially required to capture the actual prevalence to better control leptospirosis in China.

Electronic supplementary material

The online version of this article (10.1186/s40249-018-0435-2) contains supplementary material, which is available to authorized users.

Spatial and temporal trends of short- and medium-chain chlorinated paraffins in sediments off the urbanized coastal zones in China and Japan: A comparison study

To examine the impacts of urbanization and industrialization on the coastal environment, and assess the effectiveness of control measures on the contamination by chlorinated paraffins (CPs) in East Asia, surface and core sediments were sampled from the urbanized coastal zones in China and Japan (i.e., Pearl River Delta (PRD), Hong Kong waters and Tokyo Bay) and analyzed for short-chain (SCCPs) and medium-chain CPs (MCCPs). Much higher concentrations of CPs were found in the industrialized PRD than in adjacent Hong Kong waters. Significant correlation between CP concentration and population density in the coastal district of Hong Kong was observed (r² = 0.72 for SCCPs and 0.55 for MCCPs, p < 0.05), highlighting the effect of urbanization. By contrast, a relatively lower pollution level of CPs was detected in Tokyo Bay. More long-chain groups within SCCPs in the PRD than in Hong Kong waters and Tokyo Bay implied the effect of industrialization. Comparison of temporal trends between Hong Kong outer harbor with Tokyo Bay shows the striking difference in historical deposition of CPs under different regulatory situations in China and Japan. For the first time, the declining CP concentrations in Tokyo Bay, Japan, attest to the effectiveness of emissions controls.

Compositing climate change vulnerability of a Mediterranean region using spatiotemporally dynamic proxies for ecological and socioeconomic impacts and stabilities

The study presents a new methodology to quantify spatiotemporal dynamics of climate change vulnerability at a regional scale adopting a new conceptual model of vulnerability as a function of climate change impacts, ecological stability, and socioeconomic stability. Spatiotemporal trends of equally weighted proxy variables for the three vulnerability components were generated to develop a composite climate change vulnerability index (CCVI) for a Mediterranean region of Turkey combining Landsat time series data, digital elevation model (DEM)-derived data, ordinary kriging, and geographical information system. Climate change impact was based on spatiotemporal trends of August land surface temperature (LST) between 1987 and 2016. Ecological stability was based on DEM, slope, aspect, and spatiotemporal trends of normalized difference vegetation index (NDVI), while socioeconomic stability was quantified as a function of spatiotemporal trends of land cover, population density, per capita gross domestic product, and illiteracy. The zones ranked on the five classes of no-to-extreme vulnerability were identified where highly and moderately vulnerable lands covered 0.02% (12 km²) and 11.8% (6374 km²) of the study region, respectively, mostly occurring in the interior central part. The adoption of this composite CCVI approach is expected to lead to spatiotemporally dynamic policy recommendations towards sustainability and tailor preventive and mitigative measures to locally specific characteristics of coupled ecological-socioeconomic systems.

Comparing methods of measuring geographic patterns in temporal trends: an application to county-level heart disease mortality in the United States, 1973 to 2010

PURPOSE

To demonstrate the implications of choosing analytical methods for quantifying spatiotemporal trends, we compare the assumptions, implementation, and outcomes of popular methods using county-level heart disease mortality in the United States between 1973 and 2010.

METHODS

We applied four regression-based approaches (joinpoint regression, both aspatial and spatial generalized linear mixed models, and Bayesian space-time model) and compared resulting inferences for geographic patterns of local estimates of annual percent change and associated uncertainty.

RESULTS

The average local percent change in heart disease mortality from each method was -4.5%, with the Bayesian model having the smallest range of values. The associated uncertainty in percent change differed markedly across the methods, with the Bayesian space-time model producing the narrowest range of variance (0.0-0.8). The geographic pattern of percent change was consistent across methods with smaller declines in the South Central United States and larger declines in the Northeast and Midwest. However, the geographic patterns of uncertainty differed markedly between methods.

CONCLUSIONS

The similarity of results, including geographic patterns, for magnitude of percent change across these methods validates the underlying spatial pattern of declines in heart disease mortality. However, marked differences in degree of uncertainty indicate that Bayesian modeling offers substantially more precise estimates.

Influences of groundwater extraction on the distribution of dissolved As in shallow aquifers of West Bengal, India

Here we report temporal changes of As concentrations in shallow groundwater of the Bengal Delta Plain (BDP). Observed fluctuations are primarily induced by seasonally occurring groundwater movement, but can also be connected to anthropogenic groundwater extraction. Between December 2009 and July 2010, pronounced variations in the groundwater hydrochemistry were recorded in groundwater samples of a shallow monitoring well tapping the aquifer in 22-25 m depth, where Astot concentrations increased within weeks from 100 to 315 μg L(-1). These trends are attributed to a vertically shift of the hydrochemically stratified water column at the beginning of the monsoon season. This naturally occurring effect can be additionally superimposed by groundwater extraction, as demonstrated on a local scale by an in situ experiment simulating extensive groundwater withdrawal during the dry post-monsoon season. Results of this experiment suggest that groundwater extraction promoted an enduring change within the distribution of dissolved As in the local aquifer. Presented outcomes contribute to the discussion of anthropogenic pumping influences that endanger the limited and yet arsenic-free groundwater resources of the BDP.

Urban BTEX Spatiotemporal Exposure Assessment by Chemometric Expertise

Normative regulations on benzene in fuels and urban management strategies are expected to improve air quality. The present study deals with the application of self-organizing maps (SOMs) in order to explore the spatiotemporal variations of benzene, toluene, ethylbenzene, and xylene levels in an urban atmosphere. Temperature, wind speed, and concentration values of these four volatile organic compounds were measured after passive sampling at 21 different sampling sites located in the city of Trieste (Italy) in the framework of a multi-year long-term monitoring program. SOM helps in defining pollution patterns and changes in the urban context, showing clear improvements for what concerns benzene, toluene, ethylbenzene, and xylene concentrations in air for the 2001-2008 timeframe.