Dissolved black carbon(DBC)includes the water-soluble component of black carbon and/or its degradation products.It is a hydrophobic organic compound due to its thick cyclic aromatic structure and can therefore be pres...Dissolved black carbon(DBC)includes the water-soluble component of black carbon and/or its degradation products.It is a hydrophobic organic compound due to its thick cyclic aromatic structure and can therefore be present as particulate DBC(PDBC)on suspended particulate matter or particulate organic matter.PDBC is not equivalent to particulate black carbon(PBC)and is thus often overlooked when researchers measure PBC in particulate matter using current conventional methods.Consequently,the amount of DBC in nature is likely underestimated in many studies and the reliability of current findings on the geochemical behavior of DBC is subject to challenge.In this study,we attempted to draw the solid-liquid partition coefficient(K_(d),PDBC/DBC)based on detailed data on PBC,DBC,particulate organic carbon,total suspended solids,dissolved polycyclic aromatic hydrocarbons,and particulate polycyclic aromatic hydrocarbons in the surface waters of the Bohai Sea.The obtained K_(d)was in the range of 0.018-0.072.Accordingly,the concentrations of PDBC were 1.637-6.449μg C L^(-1).The estimated inventory of PDBC on suspended particulate matter in the Bohai Sea was 2.049-8.194 Gg,which was lower than that of PBC(15.16 Gg)but of the same order of magnitude.These results indicate that PDBC is an important form of DBC in the Bohai Sea.Quantitative results of DBC fluxes between the dissolved and particulate phases will benefit our understanding of DBC transport and fates in the ocean.展开更多
溶解态黑碳(DBC),通常被认为是黑碳或降解产物中可溶解于水的组分.作为一类具有高疏水性稠环芳香结构的物质,DBC完全可能以吸附在悬浮颗粒物或颗粒态有机物的形式存在(PDBC),并且不等同于黑碳颗粒物(PBC).然而,目前环境样品中测量黑碳...溶解态黑碳(DBC),通常被认为是黑碳或降解产物中可溶解于水的组分.作为一类具有高疏水性稠环芳香结构的物质,DBC完全可能以吸附在悬浮颗粒物或颗粒态有机物的形式存在(PDBC),并且不等同于黑碳颗粒物(PBC).然而,目前环境样品中测量黑碳的主流方法,尤其是颗粒物的处理方式,并未对这一部分黑碳进行测定.因此,自然界中DBC的量在很多研究中有可能被低估,使得目前关于DBC地球化学行为以及定量研究结果的可靠性存疑.本研究基于之前在渤海工作的详细数据,包括PBC、DBC,以及颗粒有机碳含量、悬浮颗粒物浓度、多环芳烃含量,通过对比实测多环芳烃固液分布情况,圈定出渤海表层水体中PDBC固液分布系数(Kd)大致在0.018~0.072之间,含量在1.637~6.449μg C L^(-1)之间.同时,估算出渤海水体悬浮颗粒物上PDBC储量(2.049~8.194Gg),低于PBC储量(15.16Gg),却同属一个数量级,该结果表明,PDBC是渤海水体环境中DBC的重要存在形式.明确DBC在水体中的吸附解吸附过程是厘定DBC源汇定量关系以及完善海洋DBC迁移转化过程的重要一环.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.42076205)。
文摘Dissolved black carbon(DBC)includes the water-soluble component of black carbon and/or its degradation products.It is a hydrophobic organic compound due to its thick cyclic aromatic structure and can therefore be present as particulate DBC(PDBC)on suspended particulate matter or particulate organic matter.PDBC is not equivalent to particulate black carbon(PBC)and is thus often overlooked when researchers measure PBC in particulate matter using current conventional methods.Consequently,the amount of DBC in nature is likely underestimated in many studies and the reliability of current findings on the geochemical behavior of DBC is subject to challenge.In this study,we attempted to draw the solid-liquid partition coefficient(K_(d),PDBC/DBC)based on detailed data on PBC,DBC,particulate organic carbon,total suspended solids,dissolved polycyclic aromatic hydrocarbons,and particulate polycyclic aromatic hydrocarbons in the surface waters of the Bohai Sea.The obtained K_(d)was in the range of 0.018-0.072.Accordingly,the concentrations of PDBC were 1.637-6.449μg C L^(-1).The estimated inventory of PDBC on suspended particulate matter in the Bohai Sea was 2.049-8.194 Gg,which was lower than that of PBC(15.16 Gg)but of the same order of magnitude.These results indicate that PDBC is an important form of DBC in the Bohai Sea.Quantitative results of DBC fluxes between the dissolved and particulate phases will benefit our understanding of DBC transport and fates in the ocean.
文摘溶解态黑碳(DBC),通常被认为是黑碳或降解产物中可溶解于水的组分.作为一类具有高疏水性稠环芳香结构的物质,DBC完全可能以吸附在悬浮颗粒物或颗粒态有机物的形式存在(PDBC),并且不等同于黑碳颗粒物(PBC).然而,目前环境样品中测量黑碳的主流方法,尤其是颗粒物的处理方式,并未对这一部分黑碳进行测定.因此,自然界中DBC的量在很多研究中有可能被低估,使得目前关于DBC地球化学行为以及定量研究结果的可靠性存疑.本研究基于之前在渤海工作的详细数据,包括PBC、DBC,以及颗粒有机碳含量、悬浮颗粒物浓度、多环芳烃含量,通过对比实测多环芳烃固液分布情况,圈定出渤海表层水体中PDBC固液分布系数(Kd)大致在0.018~0.072之间,含量在1.637~6.449μg C L^(-1)之间.同时,估算出渤海水体悬浮颗粒物上PDBC储量(2.049~8.194Gg),低于PBC储量(15.16Gg),却同属一个数量级,该结果表明,PDBC是渤海水体环境中DBC的重要存在形式.明确DBC在水体中的吸附解吸附过程是厘定DBC源汇定量关系以及完善海洋DBC迁移转化过程的重要一环.
