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Slope units (SUs) are sub-watersheds bounded by ridge and valley lines. A slope unit reflects the physical relationship between landslides and geomorphological features and is especially useful for landslide sensitivity modeling. There have been significant algorithmic advances in the automatic delineation of SUs. But the intrinsic difficulties of determining input parameters and correcting for unreasonable SUs have hindered their wide application. An improved method of the evaluation and local multi-scale optimization for the automatic extraction of SUs is proposed. The Sus' groups more consistent with the topographic features were achieved through a stepwise approach from a global optimum to a local refining. First, the preliminary subdivisions of multiple SUs were obtained based on the r.slopeunit software. The optimal subdivision scale was obtained by a collaborative evaluation approach capable of simultaneously measuring objective minimum discrepancies and seeking a global optimum. Second, under the selected optimal scale, unreasonable SUs such as over-subdivided slope units (OSSUs) and under-subdivided slope units (USSUs) were further distinguished. The local average similarity (LS) metric for each SU was designed based on calculating the SU's area, common boundary and neighborhood variability. The inflection points of the cumulative frequency curve of LS were calculated as the distinguishing intervals for those unrealistic SUs by maximum interclass variance threshold. Third, a new effective optimization mechanism containing the re-subdivision of USSUs and merging of OSSUs was put into effect. We thus obtained SUs composed of terrain subdivisions with multiple scales, which is currently one of the few available methods for non-single scales. The statistical distributions of density, size and shapes demonstrate the excellent performance of the refined SUs in capturing the variability of complex terrains. Benefiting from the sufficient integrating approach of diverse features for each object, it is a significant advantage that the processing object can be transferred from general entirety to each precise individual. [ABSTRACT FROM AUTHOR]

A 3.3-m-thick, 74.5-m-long ancient wood layer was discovered in Zhoushan Archipelago, East China Sea. The ancient woods were well preserved except for weak silicification of wood bark, and abundant amount of leaves, fruits and seeds were found therein. The distribution characteristics of the ancient woods and well-preserved ancient wood stumps indicated the native origin of these ancient woods. The ancient plants as well as their leaves, fruits and seeds were all preserved well, pointing to a possible sudden deposition event. As inferred from the radiocarbon dating results, the abrupt deposition of ancient wood layer was during the period 5900–5600 yr BP, when the palaeoclimatic records reveal intensified summer monsoon winds, strong winter monsoon winds, and very low ENSO activity. We suggest that the formation of the ancient wood layer was very likely caused by the coaction of a strong storm surge and rapid sea level rise, which became more frequent and intensive during this period. The findings of this study imply the potential risk of strong storm surges in the coastal area of the East China Sea, which should be considered in future planning and construction of buildings. [ABSTRACT FROM AUTHOR]

The glaciers act as an important proxy of climate changes; however, little is known about the glacial activities in Ny-Alesund during the Little Ice Age (LIA). In the present study, we studied a 118-cm-high palaeo-notch sediment profile YN in Ny-Alesund which is divided into three units: upper unit (0–10 cm), middle unit (10–70 cm) and lower unit (70–118 cm). The middle unit contains many gravels and lacks regular lamination, and most of the gravels have striations and extrusion pits on the surface. The middle unit has the grain size characteristics and origin of organic matter distinct from other units, and it is likely the glacial till. The LIA in Svalbard took place between 1500 and 1900 AD, the middle unit is deposited between 2219 yr BP and AD 1900, and thus the middle unit is most likely caused by glacier advance during the LIA. Glaciers during the LIA likely overran the sampling site, removed part of the pre-existing sediments, and contributed to the formation of diamicton in the middle unit. This study provides evidence for glacial deposits during the LIA in Ny-Alesund and improves our understanding about historical glacier dynamics and ice-sheet margins during the LIA in western Spitsbergen. [ABSTRACT FROM AUTHOR]

Changes in vegetation biomass have a great impact on many aspects of the Arctic ecosystem, and historical variations of biomass in Svalbard during the Holocene remain poorly understood. In this study, we collected a palaeo-notch sediment profile in Ny-Ålesund, Svalbard, performed organic biomarker and geochemical analysis on the sediments, reconstructed the photosynthetic biomass record during the interval of 9400–2200 BP, and examined the relationship between the photosynthetic biomass changes and Holocene temperature records in the Arctic region. The photosynthetic biomass production in Ny-Ålesund experienced four development periods. It rose steadily at the beginning of the Holocene and became stabilized at a high level during the Holocene thermal maximum. However, the photosynthetic biomass dropped sharply during the mid-Holocene transition. After that, it showed a small peak during the interval of 3000–2500 BP. The historical photosynthetic biomass record is in good agreement with the temperature records: the photosynthetic biomass production increases during warmer periods, and vice versa. Therefore, temperature is likely the driving factor controlling the photosynthetic biomass production. This study improves our understanding of the terrestrial ecosystem and its responses to climate change in the Arctic. [ABSTRACT FROM AUTHOR]

Abstract Fildes Peninsula, with a high density of scientific stations, has been significantly impacted by anthropogenic activities. However, the contamination from penguins, a biovector that transports pollutants from ocean to land, has seldom been assessed. In this study, 32 lacustrine surface sediment samples on Fildes Peninsula and 8 lacustrine surface sediment samples on Ardley Island were collected to determine Cu, Zn, Pb, Ni, Cr, Cd, Co, Sb, Hg and P levels. The results showed that the heavy metal contents of lacustrine sediments on Ardley Island are significantly higher than those on Fildes Peninsula. The contaminants on Fildes Peninsula are mainly derived from anthropogenic activities, while the contaminants on Ardley Island are transported to the lacustrine sediments in the form of penguin guanos after a series of biomagnification in the food chain. The results indicated that the impact of penguin-transported contamination on Antarctic environment outweighs human activities near scientific stations in some areas. Therefore, more attention should be paid to the impacts of Antarctic animals on the Antarctic environment. Graphical abstract Unlabelled Image Highlights • The contamination sources in Antarctica mainly include: penguins transport, human activities and bedrock weathering. • The impact of penguin-transported contamination on Antarctic environment outweighs human activities in some areas. • Penguins transport anthropogenic contaminants to Antarctica in the form of penguin droppings through marine food web. [ABSTRACT FROM AUTHOR]

The ferromanganese (Fe Mn) deposits could be found in many shallow water and deep-ocean places. Lots of studies have been performed to explore the occurrence, formation and economic value of Fe Mn nodules or crusts on the deep ocean floor. However, the occurrence and formation of Fe Mn beachrocks at the coastal zones has rarely been reported. In the present study, we collected two types of dendritic Fe Mn beachrock samples from an intertidal zone of Zhoushan Archipelago, East China Sea, where was significantly amended by an ancient wood layer formed during 5900–5600 cal. yr B.P. Then the microscale analysis including electron microprobe analyzer (EMPA), X-ray powder diffraction (XRD), and scanning electron microscopy-energy dispersive X-ray spectrometer (SEM-EDS) were performed to study the microscale characteristics on these Fe Mn beachrocks. Combined with our previous studies, a possible formation process was proposed: (1) Buried ancient woods produced enough organic acids to accelerate the weathering of nearby bedrock via chemical or biological reactions; (2) The seepage water could be regarded as a bridge to connect the ancients woods and the intertidal zones, and large amounts of dissolved Fe2+ and Mn2+ can be transported to the sandy beach and intertidal zones; (3) Precipitation of insoluble Fe Mn oxides occurred with the involvement of microbial processes and direct inorganic chemical sorption under mixing of seepage water and seawater; (4) After that, these Fe Mn oxides would experience nucleation, crystallization growth, and then diagenetic process to form the Fe Mn beachrocks. The present study spotted a light on the microscale features, formation process and biogeochemical cycling of nearshore/coastal diagenetic Fe-Mn deposits. • Accelerately formed ferromanganese rocks were discovered in an intertidal zone influenced by buried ancient wood layers; • The microscale characteristics on the intertidal ferromanganese rocks were described; • A complete formation processes on the present beachrocks were proposed. [ABSTRACT FROM AUTHOR]

Outburst floods resulting from giant landslide dams can cause devastating damage to hundreds or thousands of kilometres of a river. Accurate and timely delineation of flood inundated areas is essential for disaster assessment and mitigation. There have been significant advances in flood mapping using remote sensing images in recent years, but little attention has been devoted to outburst flood mapping. The short-duration nature of these events and observation constraints from cloud cover have significantly challenged outburst flood mapping. This study used the outburst flood of the Baige landslide dam on the Jinsha River on 3 November 2018 as an example to propose a new flood mapping method that combines optical images from Sentinel-2, synthetic aperture radar (SAR) images from Sentinel-1 and a Digital Elevation Model (DEM). First, in the cloud-free region, a comparison of four spectral indexes calculated from time series of Sentinel-2 images indicated that the normalized difference vegetation index (NDVI) with the threshold of 0.15 provided the best separation flooded area. Subsequently, in the cloud-covered region, an analysis of dual-polarization RGB false color composites images and backscattering coefficient differences of Sentinel-1 SAR data were found an apparent response to ground roughness's changes caused by the flood. We carried out the flood range prediction model based on the random forest algorithm. Training samples consisted of 13 feature vectors obtained from the Hue-Saturation-Value color space, backscattering coefficient differences/ratio, DEM data, and a label set from the flood range prepared from Sentinel-2 images. Finally, a field investigation and confusion matrix tested the prediction accuracy of the end-of-flood map. The overall accuracy and Kappa coefficient were 92.3%, 0.89 respectively. The full extent of the outburst floods was successfully obtained within five days of its occurrence. The multi-source data merging framework and the massive sample preparation method with SAR images proposed in this paper, provide a practical demonstration for similar machine learning applications using remote sensing. [ABSTRACT FROM AUTHOR]

The carbon isotopic fractionation process in biogenic carbonate is very complex, and the mechanism for seasonal and long-term variations in biogenic carbonate δ13C remains a matter of debate. In this study, 5 Tridacnidae samples were collected from the South China Sea and analyzed in detail to study seasonal variations. The high-resolution δ13C records exhibited cyclic variations, likely related to seasonality in environmental parameters (e.g., Chl-a concentration, salinity, SST, rainfall). 57 Tridacnidae were collected and analyzed to study the millennium-scale changes of Tridacnidae δ13C during the mid- to late Holocene and the controlling mechanism. The Tridacnidae δ13C over the period 500–5500 BP is statistically significantly correlated with solar activity (TSI and sunspot number), likely attributed to the presence of symbiotic zooxanthellae within Tridacnidae 's mantle lobes. Solar activity could significantly affect the metabolic activity of zooxanthellae, Tridacnidae 's microenvironment, and thus Tridacnidae 's δ13C composition. The decoupling between the Tridacnidae δ13C and solar activity over the past 200 years is most likely due to increased amount of anthropogenic CO 2 and the oceanic δ13C Suess effect. This study improves our understanding about the seasonal and long-term variations of δ13C in Tridacnidae. • The first mid- to late Holocene Tridacnidae δ13C record in South China Sea was reconstructed. • Mid- to late Holocene carbon isotopic records of Tridacnidae is linked to solar activity. • Potential controlling mechanism of long-term Tridacnidae δ13C composition was proposed. [ABSTRACT FROM AUTHOR]

• Onshore deposits of the 1000-year-old tsunami were identified in Dongshan Bay, northeastern South China Sea. • This study further north is mutually corroborated with previous studies in the SCS. • This research provides examples and methods for the study of onshore tsunami deposits. A giant tsunami occurred in the South China Sea (SCS) approximately a thousand years ago, and various types of tsunami deposits were identified on the Xisha Islands, coastline of South China and Badoc Island, the Philippines. However, little is known about the extent of the affected SCS coastlines and the history of other giant tsunamis. Here, we identify tsunami deposits in the coastal sediment of Dongshan Bay, northeastern SCS. The tsunami deposit contains marine shell debris and coarse quartz grains, distinct from the muddy deposits in the upper and lower layers. Geochemical proxies, including Sr/Ba, Ca, Ti, Ca/Ti, and total organic carbon, indicate the marine intrusion of the event deposit. Radiocarbon ages of shells of the event layer are 970–1179 and 1137–1462 cal. yr BP (2σ range of calibrated 14C age). We suggest that the event layer was possibly deposited by the 1000-year-old tsunami. We found onshore tsunami deposits further north than previous studies, providing a new research example of onshore tsunami deposits and a reference for tsunami deposit research and tsunami disaster prevention. [ABSTRACT FROM AUTHOR]

The Arctic region is very sensitive to climate change and important in the Earth’s climate system. However, proxy datasets for Arctic climate are unevenly distributed and especially scarce for Svalbard because glaciers during the Little Ice Age, the most extensive in the Holocene, destroyed large quantities of sediment records in Svalbard. Fortunately, palaeo-notch sediments could withstand glaciers and be well-preserved after deposition. In this study, we reconstructed a mid-to-late Holocene record of climate changes in a palaeo-notch sediment sequence from London Island. Multiple weathering indices were determined, they all showed consistent weathering conditions in the study area, and they were closely linked to climate changes. Total organic carbon (TOC) and total nitrogen (TN) were also determined, and their variation profiles were similar to those of weathering indices. The climate change record in our sediment sequence is consistent with ice rafting record from North Atlantic and glacier activity from Greenland, Iceland and Svalbard, and four cold periods are clearly present. Our study provides a relatively long-term climate change record for climate conditions from mid-to-late Holocene in Svalbard. [ABSTRACT FROM AUTHOR]

The El Niño-Southern Oscillation (ENSO) is the principal climatic system in the modern Pacific Ocean, and it potentially influences the global climate. The South China Sea (SCS), in the western tropical Pacific, is significantly affected by ENSO activity. We have conducted a high-resolution oxygen isotope study of the shells of one modern and four fossil Tridacna from the Xisha Islands in the SCS. The results for the modern sample reveal that the shells of Tridacna are a good proxy of ENSO variability. We used the results of the oxygen isotope composition of four fossil Tridacna to produce high-resolution records of ENSO activity during four time slices in the Holocene. The results indicate that ENSO variability in the early Holocene was comparable to that of today, and that a minimum in the frequency and intensity of ENSO activity occurred in the mid Holocene. These findings are consistent with paleoclimatic results from corals, mollusks and sedimentary records. However, the observed extremely low frequency and moderate ENSO intensity at 4.7 ka indicate an anomalous pattern of ENSO changes within this interval of climatic transition. In addition, seasonal temperature variations during the Holocene were different from those of today and extreme seasonality may also occur during warmer periods. [ABSTRACT FROM AUTHOR]

As an emerging environmental contaminant, di (2-ethylhexyl) phthalate (DEHP) is widely present in the aquatic environment, however, the effects and underlying mechanisms of DEHP on the aquatic organisms are poorly understood. This study systematically investigated the ecotoxicity induced by chronic exposure to environmental relevant concentrations of DEHP (0.03 mg/L, 0.1 mg/L, and 0.3 mg/L) on zebrafish brain. Results indicated that DEHP exposure significantly increased the levels of ROS and disturbance of the antioxidant enzymes activities in the brain, which may further enhance lipid peroxidation and DNA damage. Furthermore, acetylcholinesterase activity was first stimulated and inhibited by exposure to DEHP, and the antioxidant and apoptosis related genes were mainly upregulated. Risk assessment indicated that the ecotoxicity of DEHP on the zebrafish showed an "enhancement-reduction" trend as the exposure time was prolonged. Overall, these results provided new insights and useful information to ecological risk assessment and environmental management of DEHP pollution. • DEHP elevated the ROS levels and disturbed antioxidant homeostasis in zebrafish brain. • DEHP induced lipid peroxidation and DNA damage in brain of zebrafish. • DEHP caused hazardous effects on brain at the neural and genetic levels. • The ecotoxicological risk of DEHP to zebrafish brain first increased and then decreased with the increase of exposure time. [ABSTRACT FROM AUTHOR]

Nitrogen immobilization usually leads to nitrogen retention in soil and, thus, influences soil nitrogen supply for plant growth. Understanding soil nitrogen immobilization is important for predicting soil nitrogen cycling under anthropogenic activities and climate changes. However, the global patterns and drivers of soil nitrogen immobilization remain unclear. We synthesized 1350 observations of gross soil nitrogen immobilization rate (NIR) from 97 articles to identify patterns and drivers of NIR. The global mean NIR was 8.77 ± 1.01 mg N kg−1 soil day−1. It was 5.55 ± 0.41 mg N kg−1 soil day−1 in croplands, 15.74 ± 3.02 mg N kg−1 soil day−1 in wetlands, and 15.26 ± 2.98 mg N kg−1 soil day−1 in forests. The NIR increased with mean annual temperature, precipitation, soil moisture, soil organic carbon, total nitrogen, dissolved organic nitrogen, ammonium, nitrate, phosphorus, and microbial biomass carbon. But it decreased with soil pH. The results of structural equation models showed that soil microbial biomass carbon was a pivotal driver of NIR, because temperature, total soil nitrogen, and soil pH mostly indirectly influenced NIR via changing soil microbial biomass. Moreover, microbial biomass carbon accounted for most of the variations in NIR among all direct relationships. Furthermore, the efficiency of transforming the immobilized nitrogen to microbial biomass nitrogen was lower in croplands than in natural ecosystems (i.e., forests, grasslands, and wetlands). These findings suggested that soil nitrogen retention may decrease under the land use change from forests or wetlands to croplands, but NIR was expected to increase due to increased microbial biomass under global warming. The identified patterns and drivers of soil nitrogen immobilization in this study are crucial to project the changes in soil nitrogen retention. [ABSTRACT FROM AUTHOR]

On Oct. 10 and Nov. 3, 2018, two landslides, i.e., the "10.10" and "11.3" rockslides, occurred successively at Baige Village, Jiangda County, Tibetan Autonomous Region, P. R. China. The two landslides are located in the upper reaches of the Jinsha River and both dammed the river. Immediately since the slides, the authors have been working on the slides and help disaster reduction. Based on the data collected by April 2020, this paper is aimed at clarifying the geological condition of the slides and at explaining why the slides occurred and what the whole sliding process was. Conclusions are summarized as follows. First, the two landslides occurred in the suture belt of the Jinsha River and the rocks are composed of tectonic mélange slices of mainly gneiss intermingled with carboniferous slate and marble and with intruded serpentine and granite porphyry. The gneiss generally bears a schistosity plane with an averaged attitude of N47° W/47°, dipping into the slope. Secondly, long-term geomorphological evolution of the bank slope due to river incision contributed to the progressive slope deformation for the development of the "10.10" rockslide. No preferential joints exist in the slope, but alteration and weathering played important roles in its occurrences. Rainfall and earthquakes may also accelerate its deformation. Thirdly, the "10.10" rockslide is of high-speed wedge-like slope failure with a high-position and a high-shear outlet. Its sliding and deposition process demonstrate special features as initial speed, collision between debris, surging waterjet, and second slipping. Fourthly, the whole process of the "10.10" rockslide can be divided into 6 steps, i.e., startup of the major sliding and sliding resistance zones, sliding initiation of the trailing zone, formation of debris-eroded zones, collision of debris and triggering waterjet and mist, secondary slip of the landslide dam, and surface flush in the deposition area. The estimated speed may reach as high as 67 m/s. Fifthly, the "11.3" rockslide follows a different mode, i.e., wedge cleaving effect. And finally, the cracked zones still have the risk to constitute a potential landslide and to dam the river again. [ABSTRACT FROM AUTHOR]

[Display omitted] • A machine learning method assisted by auto hyperparameter optimization was developed. • TPE-XGBoost model has the best performance for spatial prediction of soil heavy metals. • Air quality and hyperspectral variables have the high contributions for prediction accuracy. • There is a source-receptor coupling path for the accumulation of soil heavy metals. • Soil heavy metals with high concentrations are concentrated around rivers. Machine learning (ML) models have been widely used for predicting spatial variability of soil heavy metals. However, it is impossible to explore the entire hyperparameter space of ML models by artificially trial-and-error experimentation. Here, an auto hyperparameter optimization-based machine learning (HPO-ML) method with three search algorithms and random forest (RF) and extreme gradient boosting (XGBoost) models was developed to predict the heavy metal content in soil with multiple environmental variables. The tree-structured Parzen estimator (TPE) algorithm outperformed other search algorithms in identifying the optimal hyperparameters of RF and XGBoost models. The model prediction results showed that the TPE-XGBoost had the highest accuracy for predicting the As (RMSE = 3.06 mg kg−1 and R2 = 70.35%), Cd (RMSE = 0.10 mg kg−1 and R2 = 75.43%), Cr (RMSE = 13.86 mg kg−1 and R2 = 82.11%), Ni (RMSE = 3.19 mg kg−1 and R2 = 75.20%), Pb (RMSE = 3.75 mg kg−1 and R2 = 74.79%), and Zn (RMSE = 6.83 mg kg−1 and R2 = 70.05%) contents. The TPE-XGBoost mapping result showed that areas with high concentrations of soil heavy metals were concentrated in the central and eastern areas (As), the mainstream of the Yellow River (Cd), the northeast area (Cr), the ancient watercourse of the Yellow River (Ni and Pb), and the central and northeastern areas (Zn). The SHapley additive explanation (SHAP) and structural equation model (SEM) were used to interpret the drivers of environmental variables. It is found that the variables with the highest contributions were CO, PM 2.5 , O 3 , PC3, PC1, and PC4 for predicting the As, Cd, Cr, Ni, Pb, and Zn contents, respectively, and there was a significant source-receptor coupling path. The results demonstrate the feasibility of using the HPO-ML approach in hyperparameter-limited conditions, which providing data-driven pathways and options to support the high-quality development of agriculture and the protection of farmland soil ecosystem. [ABSTRACT FROM AUTHOR]

Lanzhou New District is the first and largest national-level new district in the Loess Plateau region of China. Large-scale land creation and rapid utilization of the land surface for construction has induced various magnitudes of land subsidence in the region, which is posing an increasing threat to the built environment and quality of life. In this study, the spatial and temporal evolution of surface subsidence in Lanzhou New District was assessed using Persistent Scatterer Interferometric Synthetic Aperture radar (PSInSAR) to process the ENVISAT SAR images from 2003-2010, and the Small Baseline Subset (SBAS) InSAR to process the Sentinel-1A images from 2015-2016. We found that the land subsidence exhibits distinct spatiotemporal patterns in the study region. The spatial pattern of land subsidence has evidently extended from the major urban zone to the land creation region. Significant subsidence of 0-55 mm/year was detected between 2015 and 2016 in the land creation and urbanization area where either zero or minor subsidence of 0-17.2 mm/year was recorded between 2003 and 2010. The change in the spatiotemporal pattern appears to be dominated mainly by the spatial heterogeneity of land creation and urban expansion. The spatial associations of subsidence suggest a clear geological control, in terms of the presence of compressible sedimentary deposits; however, subsidence and groundwater fluctuations are weakly correlated. We infer that the processes of land creation and rapid urban construction are responsible for determining subsidence over the region, and the local geological conditions, including lithology and the thickness of the compressible layer, control the magnitude of the subsidence process. However, anthropogenic activities, especially related to land creation, have more significant impacts on the detected subsidence than other factors. In addition, the higher collapsibility and compressibility of the loess deposits in the land creation region may be the underlying mechanism of macro-subsidence in Lanzhou New District. Our results provide a useful reference for land creation, urban planning and subsidence mitigation in the Loess Plateau region, where the large-scale process of bulldozing mountains and valley infilling to create level areas for city construction is either underway or forthcoming. [ABSTRACT FROM AUTHOR]

Air quality is a vital environment variable which determines spatial accumulation of soil heavy metals. It is very important to estimate the contribution of air quality for soil heavy metals in oil mining area. For the end, we collected 116 samples from surface soil of oil mining in the Yellow River Delta (YRD) of China, and analyzed the content of As, Cr, Ni, Pb, and Zn. Furthermore, 40 monitoring stations data of air quality were collected in study area, including CO, NO 2 , SO 2 , O 3 , PM 2.5 , and PM 10. Spatial estimation and mapping of heavy metals in soil were carried out by hybrid geostatistical models, including multiple linear regression-ordinary kriging (MLROK), support vector machine-ordinary kriging (SVMOK) and random forest-ordinary kriging (RFOK). RFOK exhibited the highest estimation accuracy (R2) for As (65.76%), Cr (77.85%), Ni (61.47%), Pb (74.64%), and Zn (71.35%) in comparison with other models. And relative R2 of RFOK improved 30%, while MLROK and SVMOK increased over 100% for Zn (RI o = 121.90% and RI o = 121.64%) based on their original R2 of machine learning models. In addition, mapping results by RFOK showed the high concentrations of heavy metals were focused in the central and northeastern (As), northern (Cr), northeastern and northwestern (Ni), central and eastern (Pb), and northern (Zn). Especially, compared with vegetation index and topographic factors, PM 2.5 is the highest driving variable for As (18.34%) and Zn (12.91%), and CO is the most important variable for Cr (18.22%), Ni (14.28%). The above results indicated that there is a mechanism of sources-receptor relationship between air quality and soil heavy metals, that is, oil well and factory in study area discharge heavy metal particles into the atmosphere, and then enter the soil through atmospheric deposition and precipitation. Enlightened by this study, variable selection should be focused on important sources for the accumulation of heavy metals in study area, who must take decisions to prevent and to early warn heavy metals pollution in mine soil. [Display omitted] • Air quality data are used to predict the content of heavy metals in oil mining soils. • Random forest-ordinary kriging has the best predicted performance for soil heavy metals. • The high concentrations of soil heavy metals are the northern of study area. • Air quality variables have effective feasibility for predicting soil heavy metals. • PM (for As and Zn) and CO (for Cr and Ni) is the highest driving variable. [ABSTRACT FROM AUTHOR]

• DEHP presented low acute toxicity to adult zebrafish (Danio rerio) • DEHP induced oxidative stress, lipid peroxidation and DNA damage in zebrafish hepatic tissue. • Acetylcholinesterase (AChE) activity of zebrafish liver was significantly inhibited after DEHP exposure. • The ecotoxicological risk of adult zebrafish increased with increasing DEHP concentrations. Di-(2-ethylhexyl) phthalate (DEHP) has become a ubiquitous contaminant in aquatic environments due to its increasing utilization in recent years. Although its environmental risks to aquatic organisms have attracted widespread attention, the ecotoxicological effects and toxic mechanism of DEHP on zebrafish (Danio rerio) liver remain poorly understood. Herein, this study investigated the acute toxicity, oxidative damage, neurotoxicity, and DNA damage of DEHP on zebrafish at the individual, tissue, physiological and biochemical levels. Results showed that no evident lethal effects of DEHP on zebrafish were observed in all testing concentrations. But in the chronic toxicity test (28 days), superoxide dismutase (SOD) and catalase (CAT) activities in zebrafish liver mainly increased during the pre-and mid-exposure experiment and subsequently decreased after 28 days exposure, whereas the acetylcholinesterase (AChE) activities were always inhibited. By comparison, reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione S-transferase (GST) levels generally increased throughout the experiment, indicating that DEHP enhanced oxidative stress lipid peroxidation, and cytotoxicity of zebrafish liver. DEHP induced DNA damage in hepatocyte, which was positively correlated with changes in ROS levels (0.9874 ≥ R2 ≥ 0.7374). Based on the risk assessment results, the integrated biomarker response (IBR) values were positively correlated with the DHEP concentrations, suggesting that higher DHEP concentrations may cause much more serious detrimental effects to zebrafish liver. Overall, this study is of great significance for understanding the ecotoxicity and mechanism of DEHP on zebrafish. [ABSTRACT FROM AUTHOR]