Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements（REE） and yttrium（REY）,with a growing interest in exploitation as an alternative to land-based REY resources.On the bas...Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements（REE） and yttrium（REY）,with a growing interest in exploitation as an alternative to land-based REY resources.On the basis of comprehensive geochemical approach,the abundance and distribution of REY in the ferromanganese nodules from the South China Sea are analyzed.The results indicate that the REY contents in ferromanganese deposits show a clear geographic regularity.Total REY contents range from 69.1×10^-6 to 2 919.4×10^-6,with an average value of 1 459.5×10^-6.Especially,the enrichment rate of Ce content is high,accounting for almost 60% of the total REY.This REE enrichment is controlled mainly by the sorption of ferromanganese oxides and clay minerals in the nodules and crusts.Moreover,the total REY are higher in ferromanganese deposits of hydrogenous origin than of diagenetic origin.Finally,Light REE（LREE） and heavy REE（HREE） oxides of the ferromanganese deposits in the study area can be classified into four grades： non-enriched type,weakly enriched type,enriched type,and extremely enriched type.According to the classification criteria of rare earth resources,the Xisha and Zhongsha platform-central deep basin areas show a great potential for these rare earth metals.展开更多
Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haiko...Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou,China.The results showed that the annual average concentration of total VOCs(TVOCs)was 11.4 ppb V,and the composition was dominated by alkanes(8.2 ppb V,71.4%)and alkenes(1.3 ppb V,20.5%).The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening.The greatest contribution to ozone formation potential(OFP)was made by alkenes(51.6%),followed by alkanes(27.2%).The concentrations of VOCs and nitrogen dioxide(NO_(2))in spring and summer were low,and it was difficult to generate high ozone(O_(3))concentrations through photochemical reactions.The significant increase in O_(3)concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast.Traffic sources(40.1%),industrial sources(19.4%),combustion sources(18.6%),solvent usage sources(15.5%)and plant sources(6.4%)were identified as major sources of VOCs through the positive matrix factorization(PMF)model.The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function(PSCF)and concentration-weighted trajectory(CWT)models.Overall,the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport,and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou,thereby reducing the generation of O_(3).展开更多
为研究济南市和青岛市臭氧(O_(3))浓度长期变化特征及其气象影响因素,基于2014—2021年近地面O_(3)连续8年观测资料和同期气象资料,揭示O_(3)浓度长期变化特征,分析O_(3)浓度与气象因子关系,阐明O_(3)主要输送路径和潜在源区.结果表明:...为研究济南市和青岛市臭氧(O_(3))浓度长期变化特征及其气象影响因素,基于2014—2021年近地面O_(3)连续8年观测资料和同期气象资料,揭示O_(3)浓度长期变化特征,分析O_(3)浓度与气象因子关系,阐明O_(3)主要输送路径和潜在源区.结果表明:①整体上,济南市O_(3)污染程度高于青岛市,2个城市O_(3)污染均集中在4—10月.长期趋势上,2014—2021年济南市O_(3)日最大8 h平均浓度第90百分位数(简称“O_(3)-8 h 90th浓度”)总体呈先升后降的趋势,峰值出现在2019年;青岛市2019年和2017年O_(3)-8 h 90th浓度相对较高,其他年份O_(3)-8 h 90th浓度差异不大.月变化上,济南市O_(3)-8 h 90th浓度季节性变化较明显,呈单峰状;而青岛市受雨季和清洁海洋气流稀释作用,其O_(3)-8 h 90th浓度呈双峰状.②高温、低湿、小风等不利气象条件下更易发生O_(3)污染.相对于青岛市,济南市O_(3)日最大8 h平均浓度(简称“O_(3)-8 h浓度”)与气象因子的相关性更密切,尤其是与日间(08:00—17:00)平均气温(简称“T8-17”)的相关性最强,T8-17>15℃时,T8-17每升高1℃,O_(3)-8 h浓度升高6.1μg/m^(3);青岛市O_(3)-8 h浓度随T8-17的升高总体呈波动式升高趋势,但升幅有限,T8-17每升高1℃,O_(3)-8 h浓度仅升高1.5μg/m^(3).③济南市受来自西南、南偏东南方向的气流影响时,O_(3)浓度平均值较高,分别为(113±51)(109±57)μg/m^(3);青岛市受来自内陆方向的西南气流影响时,O_(3)浓度较高,平均值为(106±45)μg/m^(3).2个城市O_(3)外来主要潜在源区具有一定同源性,主要为苏皖鲁豫交界中东部和鲁中地区.研究显示,2个城市O_(3)污染均以本地污染为主,污染联防联控区域需要重点关注苏皖鲁豫交界中东部及鲁中地区.展开更多
基金The National Natural Science Foundation of China under contract Nos 41376057,41306047,41676056the Spanish project SUBVENT under contract No.CGL2012-39524-C02
文摘Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements（REE） and yttrium（REY）,with a growing interest in exploitation as an alternative to land-based REY resources.On the basis of comprehensive geochemical approach,the abundance and distribution of REY in the ferromanganese nodules from the South China Sea are analyzed.The results indicate that the REY contents in ferromanganese deposits show a clear geographic regularity.Total REY contents range from 69.1×10^-6 to 2 919.4×10^-6,with an average value of 1 459.5×10^-6.Especially,the enrichment rate of Ce content is high,accounting for almost 60% of the total REY.This REE enrichment is controlled mainly by the sorption of ferromanganese oxides and clay minerals in the nodules and crusts.Moreover,the total REY are higher in ferromanganese deposits of hydrogenous origin than of diagenetic origin.Finally,Light REE（LREE） and heavy REE（HREE） oxides of the ferromanganese deposits in the study area can be classified into four grades： non-enriched type,weakly enriched type,enriched type,and extremely enriched type.According to the classification criteria of rare earth resources,the Xisha and Zhongsha platform-central deep basin areas show a great potential for these rare earth metals.
基金supported by the Major Program of Science and Technology of Hainan Province,China(No.ZDKJ202007)the Special Foundation of Government Financial of Hainan Province,China(No.ZC2018-196)the Youth Innovation Foundation of Hainan Research Academy of Environmental Sciences,China(No.QNCX2021002)。
文摘Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou,China.The results showed that the annual average concentration of total VOCs(TVOCs)was 11.4 ppb V,and the composition was dominated by alkanes(8.2 ppb V,71.4%)and alkenes(1.3 ppb V,20.5%).The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening.The greatest contribution to ozone formation potential(OFP)was made by alkenes(51.6%),followed by alkanes(27.2%).The concentrations of VOCs and nitrogen dioxide(NO_(2))in spring and summer were low,and it was difficult to generate high ozone(O_(3))concentrations through photochemical reactions.The significant increase in O_(3)concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast.Traffic sources(40.1%),industrial sources(19.4%),combustion sources(18.6%),solvent usage sources(15.5%)and plant sources(6.4%)were identified as major sources of VOCs through the positive matrix factorization(PMF)model.The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function(PSCF)and concentration-weighted trajectory(CWT)models.Overall,the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport,and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou,thereby reducing the generation of O_(3).
文摘为研究济南市和青岛市臭氧(O_(3))浓度长期变化特征及其气象影响因素,基于2014—2021年近地面O_(3)连续8年观测资料和同期气象资料,揭示O_(3)浓度长期变化特征,分析O_(3)浓度与气象因子关系,阐明O_(3)主要输送路径和潜在源区.结果表明:①整体上,济南市O_(3)污染程度高于青岛市,2个城市O_(3)污染均集中在4—10月.长期趋势上,2014—2021年济南市O_(3)日最大8 h平均浓度第90百分位数(简称“O_(3)-8 h 90th浓度”)总体呈先升后降的趋势,峰值出现在2019年;青岛市2019年和2017年O_(3)-8 h 90th浓度相对较高,其他年份O_(3)-8 h 90th浓度差异不大.月变化上,济南市O_(3)-8 h 90th浓度季节性变化较明显,呈单峰状;而青岛市受雨季和清洁海洋气流稀释作用,其O_(3)-8 h 90th浓度呈双峰状.②高温、低湿、小风等不利气象条件下更易发生O_(3)污染.相对于青岛市,济南市O_(3)日最大8 h平均浓度(简称“O_(3)-8 h浓度”)与气象因子的相关性更密切,尤其是与日间(08:00—17:00)平均气温(简称“T8-17”)的相关性最强,T8-17>15℃时,T8-17每升高1℃,O_(3)-8 h浓度升高6.1μg/m^(3);青岛市O_(3)-8 h浓度随T8-17的升高总体呈波动式升高趋势,但升幅有限,T8-17每升高1℃,O_(3)-8 h浓度仅升高1.5μg/m^(3).③济南市受来自西南、南偏东南方向的气流影响时,O_(3)浓度平均值较高,分别为(113±51)(109±57)μg/m^(3);青岛市受来自内陆方向的西南气流影响时,O_(3)浓度较高,平均值为(106±45)μg/m^(3).2个城市O_(3)外来主要潜在源区具有一定同源性,主要为苏皖鲁豫交界中东部和鲁中地区.研究显示,2个城市O_(3)污染均以本地污染为主,污染联防联控区域需要重点关注苏皖鲁豫交界中东部及鲁中地区.
