•Highest PAH concentrations were found in the mid-southern part of the YRD.•PAHs were from coal and biomass burning, petroleum spills, and/or vehicular emissions.•The PAHs in most sites were derived ...from the pyrogenic origin.•While the sites in the mid-southern part derived from the petrogenic sources.•The PAHs in soils in YRD were at low ecotoxicological contamination level.
PAH concentrations of 61 surface soil samples collected from the Yellow River Delta (YRD), China were measured to determine occurrence levels, sources, and potential toxicological significance of PAHs. The total concentrations of ∑PAHs ranged from 27 to 753ng/g d.w., with a mean of 118±132ng/g. The highest concentrations was found in the mid-southern part of the YRD (753ng/g), which was associated with the oil exploration. The ratios indicated that the PAHs throughout the YRD were mostly of pyrogenic origin; while various sites in mid-southern part in the region were derived mainly from the petrogenic sources. Multivariate statistical analyses supported that the PAHs in surface soils of the YRD were principally from the coal and biomass combustion, petroleum spills, and/or vehicular emissions. The toxic assessment suggested that the PAHs in soils were at low potential of ecotoxicological contamination level for the YRD.
Concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb), and zinc (Zn), grain sizes, and concentrations of organic carbon (Corg) were measured in 323 river ...sediment samples from the Pearl River Delta (PRD). Results showed that the heavy metal concentrations in the sediments ranged from 1.6–93 mg/kg for As, 0.04–9.3 mg/kg for Cd, 2–315 mg/kg for Cr, 1.1–352 mg/kg for Cu, 0.01–0.67 mg/kg for Hg, 11–221 mg/kg for Pb, and 11–1234 mg/kg for Zn. The highest values of As, Cr, Cu, Hg, Pb, and Zn appeared in the Beijiang River, whereas Cd was high in the Xijiang River. The overall sediment quality in the area with respect to metal concentrations generally met the primary standard criteria of China (Marine Sediment Quality), except for Cd and Cu. The spatial distributions of the heavy metals were influenced by both grain sizes and Corg concentrations. The Igeo geo-accumulation index indicated that there was no significant Cr, Cu, Hg, or Zn pollution, slight to moderate pollution by As and Pb, and moderate Cd pollution in the study area. Spatial distributions of an eco-toxicological index based on probable effect levels indicated that there was a 21% probability that the combination of the seven metals was exerting a toxic stress in the PRD river sediments.
•Heavy metal pollution was assessed in river sediments of the Pearl River Delta•Beijiang River had the highest values of As, Cr, Cu, Hg, Pb, and Zn•Slight to moderate pollution by As and Pb, and moderate Cd pollution appeared in the region.•A 21% probability of being toxic in the river sediments of PRD
Seven hundred and nine surface sediment samples, along with deeper sediment samples, were collected from Hebei Province along the coastal section of the Bohai Sea, China, and analyzed for grain size, ...concentrations of organic carbon (Corg) and heavy metals (Cu, Pb, Zn, Cr, Cd, As, and Hg). Results indicated that the average concentrations in the sediments were 16.1 mg/kg (Cu), 19.4 mg/kg (Pb), 50 mg/kg (Zn), 48.8 mg/kg (Cr), 0.1 mg/kg (Cd), 8.4 mg/kg (As), and 20.3 μg/kg (Hg). These concentrations generally met the China Marine Sediment Quality criteria. However, both pollution assessments indicated moderate to strong Cd and Hg contamination in the study area. The potential ecological risk index suggested that the combined ecological risk of the seven studied metals may be low, but that 24.5% of the sites, where sediments were finer and higher in Corg concentration, had high ecological risk in Hg and Cd pollution.
•Pollution in surface sediment of Hebei coasts, China was assessed.•Metal concentrations generally met the China Marine Sediment Quality criteria.•Metals Cd and Hg showed moderate to strong pollution in some stations.•About 25% of the sites had high ecological risk even at those lower concentrations.
Unraveling the spatial-temporal distribution of delta superlobes precisely is particularly important and challenging in the Yellow River Delta Complex (YRDC). Previous research on this issue can be ...dated back to the early 1990s, when the paleoenvironmental reconstructions mainly hinged on the historical documents and geomorphologic analysis of well-developed cheniers from the west coast of Bohai Bay, and only few drilled cores with scant radiocarbon dates were available. To build a refined model of the Holocene stratigraphic architecture and reconstruct the sedimentary evolution of the YRDC, detailed sedimentological investigation of 12 boreholes, including 59 new AMS 14C radiocarbon dates, was combined with other published 25 cores and 174 AMS 14C dates therein. Age-depth curves were grouped by stratigraphic positions and facies characteristics of these 233 radiocarbon dated samples across different sectors of the YRDC, exhibiting consistent patterns that can be used to identify distinct phases of delta superlobe activities. Eight new superlobes with relatively accurate dating spans were, therefore, proposed in the YRDC. Our results demonstrate that very high aggradation rates almost invariably correlate with the onset of deltaic deposition. Age-depth patterns, thus, may be very useful to elucidate the complex sedimentary evolution of delta systems with multiple lobes.
•The Yellow River Delta Complex dataset includes 37 cores and 234 AMS 14C ages.•We reconstructed eight Yellow River and three Haihe River deltaic superlobes.•Age-depth patterns may be useful to elucidate complex deltaic evolution.•Reworked shell beds represent condensed horizons that mark deltaic superlobe boundaries.•A variety of factors controlled superlobe distribution in the Yellow River Delta Complex.
Heavy metals (As, Cd, Cr, Cu, Hg, Pb, Zn), organic carbon and grain size of 237 surface sediment samples and one sediment core, taken from the west Guangdong coastal region in January 2008, were ...analyzed to evaluate the spatial distribution and pollution status. Results show that the ranges of the measured heavy metal concentrations in sediments are as follows: 8.33–39.49mg/kg for As, 0.1–1.49mg/kg for Cd, 33–108mg/kg for Cr, 11.5–78.8mg/kg for Cu, 0.04–0.26mg/kg for Hg, 21–73mg/kg for Pb, 56–248mg/kg for Zn. The heavy metal enrichment is closely associated with Corg and grain size. Both the metal enrichment factor and geoaccumulation index indicate that there was no detected pollution on metals As, Cr, Cu, Pb in our study area and a slight to moderate contamination of Cd, Hg and Zn. However, As, Cr and Cu have showed a certain risk.
•There was no detected pollution on metals As, Cr, Cu, Pb.•A slight to moderate contamination was found on Cd, Hg and Zn.•Metals As, Cr and Cu have showed a certain risk.•Heavy metals have closely correlated to organic carbon.•Metal pollution has been assessed on west Guangdong coastal region.
A new 3D open-framework potassium ferrite, K2Fe4O7 (1), has been successfully synthesized under hydrothermal conditions. The framework of 1 consists of both FeO6 octahedral and FeO4 tetrahedral units ...with shared vertices and edges where there are 6- and 3-ring channels parallel to the trigonal a- and c-axes, enabling many highly mobile potassium ions to move quickly through the channels. The K+ ion conductivity of the polycrystalline sample was 5.0 × 10−2 S cm−1 at room temperature. Interestingly, conductivities along the a-axis direction in single crystal K2Fe4O7 reached 3.5 × 102 S cm−1 at 25 °C and 5.0 × 102 S cm−1 at 500 °C with an activation energy of 0.08 eV. The conductor possessed a wide voltage stability up to 5 V vs. K/K+. Using the K2Fe4O7 electrolyte, we demonstrate an all-solid-state potassium metal battery employing a Prussian blue cathode with a high charge/discharge rate of 250C (charge/discharge in 14 s, 1C = 87 mA h g−1).
The porcine epidemic diarrhea virus (PEDV) is a member of the coronavirus family, causing deadly watery diarrhea in newborn piglets. The global pandemic of PEDV, with significant morbidity and ...mortality, poses a huge threat to the swine industry. The currently developed vaccines and drugs are only effective against the classic GI strains that were prevalent before 2010, while there is no effective control against the GII variant strains that are currently a global pandemic. In this review, we summarize the latest progress in the biology of PEDV, including its transmission and origin, structure and function, evolution, and virus-host interaction, in an attempt to find the potential virulence factors influencing PEDV pathogenesis. We conclude with the mechanism by which PEDV components antagonize the immune responses of the virus, and the role of host factors in virus infection. Essentially, this review serves as a valuable reference for the development of attenuated virus vaccines and the potential of host factors as antiviral targets for the prevention and control of PEDV infection.
Arbuscular mycorrhizal fungi (AMF) is presumably to be associated with carbon sequestration and nutrient acquisition through mineral weathering in wetland ecosystems. However, information on ...AMF-carbonweathering interactions is limited. Grain size, concentrations of nutrients, and the major components of 304 surface sediment samples and glomalin-related soil protein (GRSP) in 133 surface sediment samples were analyzed in various environments, including the upper delta plain wetlands (UDPW) and its adjacent shallow sea wetlands (SSW), to evaluate the relationship among the GRSP, carbon content, nutrients, and chemical index of alteration (CIA) in the wetlands of the Liaohe Delta (LHD). The concentrations of GRSP in surface sediments ranged between ~ 0.11 and 11.31 mg g−1, with an average of 2.30 ± 0.17 mg g−1, and were significantly affected by the vegetation types. The ratios of organic carbon in GRSP (GRSP-C) to soil organic carbon (SOC) varied from 0.71% to 25.34%, with an average of 10.34% ± 0.52%, indicating that the GRSP was an important carbon pool in sediments, and the carbon dynamics in these wetlands were closely related to human activities. Moreover, the CIA values ranged from ~ 18.97 to 68.75, and were significantly higher in the UDPW than in the SSW (p < 0.05), and were significantly correlated with the concentrations of GRSP (r² = 0.22 r = 0.43, p < 0.01). Meanwhile, both the CIA and GRSP were significantly correlated with SOC, Total Nitrogen, and Fe (r² > 0.17 r > 0.41, p < 0.01). The results indicate that AMF excursions in wetland ecosystems enhance carbon sequestration and mineral weathering, and in turn they alter retention of at least some nutrients.
River deltas have contributed to the regulation of atmospheric CO2 concentrations throughout Earth's history, but the capacity and controlling factors for deltas to serve as permanent carbon sinks ...over the long term are unclear. To address this issue, we carried out a high-resolution assessment of carbon burial in a well-dated sediment core (BXZK13) from the paleo-Yellow River delta on the west coast of the Bohai Bay. We found that the sedimentary environments in core BXZK13 since the Late Pleistocene (∼84 k cal yr B.P.) were divided into seven depositional units. The apparent mass accumulation rate (AMAR) of total organic carbon (TOC) and total inorganic carbon (TIC) varied significantly between depositional units. The average rates were highest in delta front deposits (TOC: 135 g m−2 yr−1, TIC: 333 g m−2 yr−1). Notably, the rates of carbon accumulation were dominated by TIC. The differences in the characteristics of TIC in the borehole compare to those of carbonates in Yellow River sediments and the positive correlation between TIC and Fe suggested that authigenic carbonate contributed significantly to long-term carbon burial in the delta. The apparent sedimentation rate (ASR) dominated the variations of the carbon AMAR, and the high clay and Fe content in the sediment enhanced TOC preservation and authigenic carbonate precipitation. Low concentrations of TIC were associated with several cold events, and there was a positive correlation between the chemical index of alteration and TIC. The implication was that climate may have affected the dynamics of inorganic carbon burial by regulating authigenic carbonate precipitation. These results enable a more thorough understanding of the factors that control long-term carbon sequestration, which is critical for both management purposes as well as assessment of the role of deltas in past and future climate change.
•The apparent sedimentation rate dominated the variations of carbon sequestration.•Carbon concentration was closely related to Fe, clay content and climate change.•Long-term carbon sequestration rates were much smaller than that in short-term.•Authigenic carbonate plays an important role in long-term carbon burial in deltas.
