The Arctic region is experiencing more rapid climate changes than the other parts of the world and serves as a sink for semi-volatile persistent organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), which can be utilized as molecular markers for pyrogenic carbon, such as black carbon (BC). As the sea ice retreats and increased terrestrial inputs with widespread wildfires, the PAH concentrations in the Arctic Ocean are rising. In this study, the sources and fates of PAHs together with BC in surface sediments from the East Siberian Arctic Shelf (ESAS) were analyzed. Positive matrix factorization (PMF) elucidated a mixed petrogenic and pyrogenic sources and distinct PAH fates associated with diverse input pathways including coastal permafrost erosion contribution (similar to 30%), petrogenic-related emission (similar to 34%), fossil fuel combustion (similar to 26%), and biomass burning (similar to 10%). Correlation analysis indicated that BC plays a key role in affecting the behavior and fates of PAHs. In the Chukchi Sea, PAHs are closely associated with soot-BC, whereas in the Laptev Sea (LS) and west East Siberian Sea (W-ESS), they exhibit a coupling process with char-BC. The presence of these carbonaceous materials in the sediments of CS is likely influenced by atmospheric deposition and biological activity, whereas the LS and W-ESS regions are mainly affected by long-distance river transport and direct deposition from coastal permafrost. As global warming continues, permafrost thawing induces the remobilization and retranslocation of PAHs, thereby becoming a significant PAH contributor and input pathway in the rapidly changing Arctic coastal margin.

To investigate the distribution, sources, influencing factors, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in East China Marginal Seas (ECMSs) sediments, we measured the concentrations of 16 PAHs in 104 surface sediment samples collected from the ECMSs in 2014 and 2016. Total PAH concentration ( n-ary sumation PAHs) ranged from 4.49 to 163.66 ng/g dry weight (dry w), with 65.98 +/- 33.00 (mean +/- SD) ng/g dry w. The highest PAH concentrations and total organic carbon were observed in areas with fine-grained sediments in the Bohai Sea (BS), Yellow Sea (YS), and coastal East China Sea (ECS), indicating the prominent influence of regional hydrodynamics and sediment properties. The dominant PAH congener in BS and YS was BbF, whereas coastal ECS was Phe. The heterogeneity of PAH sources implies that terrestrial PAH input and shelf mud deposition have crucial roles in the source-sink processes of PAHs in a strongly human-influenced marginal sea.

Ninety-six fine particulate matter (PM2.5) samples covering four seasons from October 2020 to August 2021 were collected at a 'super' site in Hangzhou, a megacity in eastern China. These samples were analyzed to determine the sources and potential cancer risks to humans of 16 United States Environmental Protection Agency priority polycyclic aromatic hydrocarbons (PAHs). The average concentrations of the PAHs in PM2.5 in autumn, winter, spring, and summer were 8.35 ± 4.90, 27.9 ± 13.6, 8.3 ± 5.97, and 1.05 ± 0.50 ng/m3, respectively, and with an annual average of 11.9 ± 13.2 ng/m3. The source apportionment by positive matrix factorization analysis indicated that, based on the yearly average, the major sources of PAHs were traffic emissions (38.2 %), coal combustion (28.9 %), coke (21.7 %), and volatilization (11.1 %). Strong correlations between high concentrations of carbonaceous aerosols and high-molecular-weight PAHs in winter could be attributed to incomplete combustion. Long-range transport of air from the sea to the southeast resulted in low concentrations of carbonaceous aerosols and low-molecular-weight PAHs in summer. Trajectory clustering and the potential source contribution function both indicated that the Yangtze River Delta was the main source region of PAHs for PM2.5 in Hangzhou in spring and summer. In autumn and winter, it was dominated by long-range transport from northern China. Lifetime lung cancer risk assessment revealed that the PAHs in PM2.5 impose moderate human health risks in Hangzhou due to traffic emissions. The results of this study provide important information for policymakers to establish abatement strategies to reduce PAH emissions in Hangzhou, and perhaps other urban centers across China.

A total of 84 PM2.5 (fine particulate matter) aerosol samples were collected between October 2020 and August 2021 within an urban site in Hangzhou, an East China megacity. Chemical species, such as organic carbon (OC), elemental carbon (EC), as well as char, soot, and n-alkanes, were analyzed to determine their pollution characteristics and source contributions. The mean yearly concentrations of OC, EC, char, soot, and total n-alkanes (∑n-alkane) were 8.76 ± 3.61 μg/m3, 1.44 ± 0.76 μg/m3, 1.21 ± 0.69 μg/m3, 0.3 ± 0.1 μg/m3, and 24.2 ± 10.6 ng/m3. The OC, EC, and ∑n-alkanes were found in the highest levels during winter and lowest during summer. There were strong correlations between OC and EC in both winter and spring, suggesting similar potential sources for these carbonaceous components in both seasons. There were poor correlations among the target pollutants due to summertime secondary organic carbon formation. Potential source contribution functions analysis showed that local pollution levels in winter and autumn were likely influenced by long-range transportation from the Plain of North China. Source index and positive matrix factorization models provided insights into the complex sources of n-alkanes in Hangzhou. Their major contributors were identified as terrestrial plant releases (32.7%), traffic emissions (28.8%), coal combustion (27.3%), and microbial activity (11.2%). Thus, controlling vehicular emissions and coal burning could be key measures to alleviate n-alkane concentrations in the atmosphere of Hangzhou, as well as other Chinese urban centers.

The production and use of intentionally-produced polychlorinated biphenyls (PCBs) in China have a short history compared with countries of North America and Europe, where technical PCB mixtures were manufactured in large amounts for decades before being banned. Unintentionally-produced PCB emissions increased dramatically in China, leading to unique profiles of PCB burdens. This study first time evaluated 208 individual PCB congeners at 94 sites from surface sediments of the East China Marginal Seas (ECMSs) and explored their sources. Non-technical PCBs transported from atmospheric transport and river discharge played a dominant role in most areas of the ECMSs, while historical residuals of technical PCBs occupied the fine-grained sediments in muddy areas of the central Yellow Sea (YS), regarding to the low sedimentation rate in the central YS. Furthermore, emissions from Taizhou located on the coast of the East China Sea (ECS), which is an important electronic waste dismantling site in East China, contributed additional technical PCBs to the inner shelf of the ECS. Our results indicate that non-technical PCBs have become the dominant PCB species in the ECMSs, and emphasize the synergistic effects of large riverine input, long-range atmospheric transport, and muddy shelf deposition on PCB source and sink of in marginal seas.

To investigate the air-sea gas exchange and its potential influence on the regional fate of polycyclic aromatic hydrocarbons (PAHs) in the East China Marginal Seas (ECMS), which consist of the East China Sea (ECS) and Yellow Sea (YS), we collected air and surface seawater samples of this area in the summer 2018 and winter 2019, respectively. Generally, PAHs underwent a strong volatilization process in the ECMS in both summer and winter. Good correlations between wind speed and the magnitude of air-sea gas exchange were found for low molecular weight PAHs, suggesting the rate of their air-sea gas exchange was influenced by the static stability of overlying atmosphere. However, such an influence for high molecular weight PAHs was constrained by their low Henry's law constant. Dissolved concentration of PAHs in surface seawater was another key factor regulating their air-sea gas exchange, which not only influenced the rate of air-sea gas exchange but also was involved in the exchange direction. Higher air-sea gas exchange fluxes of PAHs in winter were attributed to their increasing dissolved concentrations in seawater during this season. A mass conservation analysis revealed a huge volatilization loss of PAHs from seawater to atmosphere, suggesting air-sea gas exchange might be a key process to modulate the distribution and occurrence of PAHs in the ECS and YS. Such a loss of PAHs in seawater might be compensated by the sediment resuspension, which implied that the sedimentary deposit could serve as a secondary source of PAHs in seawater and overlying atmosphere. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous semi-volatile organic compounds that pose a substantial threat to human health and ecological safety due to their carcinogenicity, teratogenicity, and bioaccumulation. Air-sea gas exchange is a critical mass transfer process influencing the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) in marginal seas. We found that the air-sea gas exchange of PAHs was mainly controlled by their dissolved concentrations in seawater and the wind speed in the East China Marginal Seas (ECMS). Seasonal variation of air-sea gas exchange of PAHs was observed, especially in the Yellow Sea (YS). Influenced by a greater PAH input from Northern China and the ECMS cross-shelf circulation system, the volatilization fluxes of PAHs in the YS were higher in winter, despite of lower temperature. Besides, resuspension of PAHs from sediments contributed to the dissolved PAHs in seawater, which compensated the massive loss of PAHs from seawater triggered by air-sea gas exchange. Our study highlights the significant influence of air-sea gas exchange and the role of sediment resuspension on the regional fate of PAHs in this area. Air-sea gas exchange of PAHs is mainly controlled by dissolved concentrations in seawater and wind speedAir-sea gas exchange triggers a massive loss of PAHs from seawater in the East China Marginal SeasDissolved PAHs from sediment resuspension are a potential source of PAH volatilization at air-sea interface

通过文献梳理(包括网页文献、数据库文献和灰色文献)并结合我国2006—2021年《国家卫生统计年鉴》数据,对美国、英国和日本的公共卫生护士定义和发展状况进行总结,同时对我国承担公共卫生相关服务的各类护士的现状和发展趋势进行描述.在分析目前公共卫生护士发展问题的基础上,提出:明确公共卫生护士定义,界定新形势下我国公共卫生护士的职责及工作内容;重视公共卫生护理人才培养,开展岗前和岗位相结合的专业培训;尽快开展我国公共卫生护士现况调查,科学合理配置我国公共卫生护士资源等对策建议.

To elucidate the variations in the East Asian monsoon system during seasonal changes and their impacts on continental outflow of polycyclic aromatic hydrocarbons (PAHs), sixteen integrated air samples were collected during a research cruise covering the Yellow Sea (YS) and East China Sea (ECS) in mid-spring of 2017. The concentrations of total suspended particle (TSP), aerosol-phase PAH fractions, ratios of organic to elemental carbon (OC/EC) and gas-particle partitioning of atmospheric PAHs exhibited clear regional differences associated with variations in the monsoon regime. The total concentrations of 16 USEPA priority PAHs (Σ16PAHs) varied from 3.11 to 13.4 ng/m3 throughout the cruise, with medium-to-high molecular weight (MW) PAHs more enriched over the YS and north ECS than the south ECS. Together with the relatively low gaseous PAH fraction over the YS and north ECS (78 ± 4%) relative to the south ECS (95 ± 13%), this result indicates the pattern of regional atmospheric transport. The ratio of organic to elemental carbon varied significantly between the south ECS (lower than 4) and the YS and north ECS (greater than 4), indicating contributions from vehicle emissions and coal combustion or biomass burning, respectively, following different atmospheric input pathways of carbonaceous aerosols, as supported by backward trajectory analysis. Considering the gas-particle partitioning of PAHs, soot adsorption was the main partitioning mechanism in the study region; while high-MW PAHs in the YS and north ECS were influenced by both absorption and adsorption. The Koa absorption model provided better predictions for high-MW PAHs when continental air masses prevailed, despite underestimating the partition coefficients (kp) of low-MW PAHs. Meanwhile, predicted kp for medium MW PAHs was better estimated over the YS and ECS when Ksa was included.