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The distribution of polycyclic aromatic hydrocarbons (PAHs) and halogenated PAHs (HPAHs) in surface soils from the petroleum industrial area of the Yellow River Delta (YRD) in China were investigated. The total concentrations of 16 PAHs ranged from 19.6 to 1560 ng/g, while 22 HPAHs ranged from 2.44 to 14.9 ng/g. Moreover, a high degree of spatial distribution heterogeneity was observed for both PAHs and HPAHs, which is likely attributed to the distinct industrial activities in studied area. The combustion of biomass and petroleum were identified as primary sources of soil PAHs and HPAHs in the YRD. Furthermore, benzo[ b ]fluoranthene, benzo[ k ]fluoranthene, and benzo[ g , h , i ]perylene exhibited high ecological risks (with risk quotients of 1.47, 1.44, and 1.02, respectively) in specific sites within the YRD. Considering the high toxicity of HPAHs and their potential joint environmental effects with PAHs, continuous attention should be directed towards the environmental risks associated with both PAHs and HPAHs. [Display omitted] • Co-occurrence of PAHs and HPAHs was found in soil in Yellow River Delta. • Industrial activities resulted in spatial heterogeneity of PAHs and HPAHs in soil. • Biomass and petroleum combustion are primary sources of soil PAHs and HPAHs. • Benzo[ b ]fluoranthene poses high ecological risks in studied areas. [ABSTRACT FROM AUTHOR]

The Yellow River Delta (YRD) is the second largest petrochemical base in China and the impact of human activities has been continuously increasing in recent decades, however, the contamination status of seldom monitored trace elements (SMTEs) in YRD has rarely been reported. This study evaluated the levels, vertical distributions, contamination status and sources of SMTEs in soil samples of three different land use types in YRD. The results indicated that the vertical distributions of SMTEs contents showed a gradually upward increasing trend for the soil profiles of black locust forest, while the SMTEs contents displayed a gradually upward decreasing trend for the soil profiles of cotton field. However, the SMTEs contents in the oil field area showed no significant difference among different depths. The vertical distributions of SMTEs were very likely related to the anthropogenic disturbance in the later stage. The environmental pollution status assessment of SMTEs showed obvious enrichment of Cs, Sn, and U in the soils of YRD. Moreover, the potential source analysis based on multivariate statistical methods indicated that Ga, Rb, Cs, Sc, Sn, Tl, Be, Bi, Ca and Mo were clustered together and positively correlated with Al, Fe, Mg and K, and may be mainly associated with geochemical weathering process, while the Ce, La, Th, U, Nb, Ta, and Hf may be impacted by both natural process and human activities. Though the SMTEs pollution status was not very serious, our results highlighted the non-negligible influence of anthropogenic activities on vertical distributions of SMTEs in three different land use types from YRD. Our results provide valuable information for understanding the vertical distribution and pollution status of SMTEs in YRD. • Non-negligible influence of anthropogenic activities on vertical distributions of SMTEs in YRD • SMTEs displayed an upward decreasing trend for the soil profiles of cotton field. • Obvious enrichment of Sn, Cs and U was observed in YRD soils. • Sources of most SMTEs are mainly related to the geochemical weathering process. [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 environmental status of seldom monitored trace elements (SMTEs) has rarely been reported in the North Yellow Sea (NYS). This study investigated the levels, sources and ecological risks of 18 SMTEs in a 209-cm-long sediment core from NYS. The concentrations of SMTEs exhibited a gradual increasing trend in the upper 70 cm. Based on the assessment results of enrichment factor (EF), geo-accumulation index (I geo) and contamination factor (CF), obvious enrichment of Cs, Li, and U was observed for the NYS sediments, indicating possible anthropogenic sources, which are consistent with the geochemical background normalized patterns. Moreover, the pollution load index (PLI) values ranged from 0.93 to 1.24 and showed a steadily increasing trend in the upper 70 cm part, indicating gradual deterioration of environment in NYS. Combined with the multivariate statistical analysis results and PLI variations, the first principal component (PC1) with high positive loading on Be, Cs, Ga, Hf, In, Li, Nb, Rb, Sc, Ta and Tl was very likely an "anthropogenic factor". Therefore, the historical anthropogenic impact record in the NYS was reconstructed based on the PC1 scores, which indicated significant anthropogenic influence over the past 300 years. This study provides valuable information for understanding the pollution history of SMTEs and historical record of anthropogenic impact in the NYS. [Display omitted] • Concentrations of SMTEs in NYS showed an increasing trend towards the surface. • Obvious enrichment of Cs, Li, and U was observed for NYS sediments. • A 3500-year-long anthropogenic impact record in the NYS was reconstructed. • Significant anthropogenic influence was observed over the past 300 years. [ABSTRACT FROM AUTHOR]

Propofol, one of the most widely used intravenous anesthetic in clinical practice, has been reported to impair cognitive and memory function. However, the toxicological effects of propofol on aquatic organisms are still poorly understood. This study explored the toxic effects of chronic propofol exposure (0.008, 0.04, and 0.2 mg L−1) on adult zebrafish from biochemical, transcriptional, and molecular level after 7, 14, 21 and 28 days of exposure. Results indicated that the reactive oxygen species (ROS) levels were significantly upregulated during the 28 days exposure period, and excessive ROS caused lipid peroxidation, resulting in increased malondialdehyde (MDA) contents in the zebrafish brain. In order to relieve the oxidative damage induced by the excessive ROS, the activities of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT)) were significantly activated, and detoxification enzyme (glutathione S-transferase, GST) activities showed an "activation-inhibition" trend. However, the antioxidant enzymes and detoxification enzyme system could not eliminate the excessive ROS in time and thus caused DNA damage in zebrafish brain. The olive tail moment (OTM) values displayed a "dose-response" relationship with propofol concentrations. Meanwhile, the transcription of related genes of Nrf2-Keap1 pathway was activated. Further molecular simulation experiments suggested that propofol could directly combine with SOD/CAT to change the activity of its biological enzyme. These findings indicated that zebrafish could regulate antioxidant capacity to combat oxidative stress at the early exposure stage, but the activity of antioxidant enzymes were significantly inhibited with the increase of propofol exposure time. Our results are of great importance for understanding toxicological effects of propofol on aquatic organisms. [Display omitted] • The activity of antioxidant enzymes in zebrafish brain was significantly inhibited. • Propofol triggered dose-dependent DNA damage and increased 8-OHdG content. • Nrf2/Keap1 signaling pathway was involved in the defense against oxidative damage. • Propofol preferentially interacted with SOD active center. • The environmental risks of propofol should be valued. [ABSTRACT FROM AUTHOR]

The marine environment of coastal Shandong Peninsula has been significantly influenced by anthropogenic activities due to the rapid industrialization and economic development in the past decades. However, the sedimentary records of PTEs in the North Yellow Sea have rarely been reported. In this study, a 209-cm-long sediment core was collected off the northern coast of Shandong Peninsula, analyzed for grain size and elemental compositions, and assessed using EF, I geo and several numerical Sediment Quality Guidelines (SQGs). The EF and I geo results suggested that sediment profile could be slightly to moderately polluted with As and Sb, while ecological risk assessment using SQGs showed that As, Cr, Sb and Ni in the sediment profile may have a moderate incidence of toxicity. Our results highlighted the nonnegligible ecological risk of Sb in sediments of North Yellow Sea, and great importance should be attached to the fact that many PTEs may also pose a potential ecological risk to the aquatic organisms, even though their concentrations meet the standards of the Marine Sediments Quality (MSQ). Moreover, the reconstructed PTEs record showed a dramatic increase over the past 250 years, which could be related to the intense anthropogenic activities since the Industrial Revolution. The multivariate statistical analysis results indicated that Co, Cr, Cu, Pb, Ni and Zn may be mainly related to the natural origin, while As and Sb could be influenced by both natural weathering sources and anthropogenic activities. This study provides more insights into the historical record of PTEs in the North Yellow Sea, and lays foundation for future comparison of PTEs sedimentary records. [Display omitted] • Historical records of PTEs increased dramatically over the past 250 years. • Ecological risk of Sb cannot be underestimated in the sediments of the Yellow Sea. • PTEs lower than MSQ standards may also pose ecological risk to aquatic organisms. • As and Sb could be derived from both natural and anthropogenic sources. [ABSTRACT FROM AUTHOR]

Ny-Ålesund has been significantly impacted by anthropogenic activities (e.g. coal mining, scientific research, tourist shipping) over the past 100 years. However, the studies of potential toxic elements (PTEs) contamination in Ny-Ålesund currently mainly focus on surface soil or surface fjord sediments, and little is known about the history and status of PTEs contamination over the past 100 years. In this study, we collected a palaeo-notch sediment profile YN, analyzed the contents of six typical PTEs (Cu, Pb, Cd, Hg, As, Se) in the sediments, and assessed the historical pollution status in Ny-Ålesund using the pollution load index, geo-accumulation index and enrichment factor. The results showed that the contents of PTEs over the past 100 years increased rapidly compared with those during the interval of 9400-100 BP. In addition, Pb, Cd and Hg showed a clear signal of enrichment and were the main polluters among the PTEs analyzed. The contamination was likely linked to gas-oil powered generators, coal mining, research station, tourist shipping and long-range transport of pollutants. Image 1 • Historical records of potential toxic elements (PTEs) in Ny-Ålesund was reconstructed. • The PTEs contents over the past 100 years increased rapidly compared with historical periods. • Pollution was mainly caused by gas-oil powered generators, coal mining, scientific research activities. We reconstructed the history and pollution status of PTEs contamination over the past 100 years in Ny-Ålesund and proposed its potential sources and transport pathways. [ABSTRACT FROM AUTHOR]

Heavy metal contaminants in Mirror Peninsula, East Antarctica, have rarely been studied and the source and influencing factors are poorly understood. We sampled a grid of 189 topsoil samples from Mirror Peninsula and analyzed the concentrations of Zn, Cu, U, Cr, Ga, Pb, Hg, Se and As; we also calculated the chemical index of alteration (CIA), a proxy of weathering. The results show that the distributions of Cr, Ga, Cu, and Zn are associated with weathering; the distributions of As and Pb are related to vehicle use and unloading activities at the wharfs, respectively; and the distribution of Hg is likely associated with both anthropogenic impacts and biological activity. The contamination level of these heavy metals in Mirror Peninsula is relatively low and within the controllable range. Both weathering processes and anthropogenic impacts can cause the enrichment of heavy metals; thus reliable source apportionment is crucial in studying heavy metal enrichment and contamination. Image 1093 • Heavy metal contamination levels of topsoils from Mirror Peninsula, East Antarctica, are within the controllable range. • The observed spatial distribution of heavy metal concentrations is related to logistical activities and vehicle use. • Biological activities, including biomagnification along the food chain, are another source. • Enrichment of heavy metal induced by weathering process should be eliminated as natural process. Heavy metal contamination in Mirror Peninsula falls within the controllable range and various factors contributed to the enrichment of heavy metals. [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]

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]