Carbon and nitrogen stable isotopes are useful tracers for distinguishing marine and terrestrial plant sources of sedimentary organic matter(OM),and for identifying OM from different types of plants.By analyzing the c...Carbon and nitrogen stable isotopes are useful tracers for distinguishing marine and terrestrial plant sources of sedimentary organic matter(OM),and for identifying OM from different types of plants.By analyzing the carbon and nitrogen stable isotopes of marine and riverine sediments from Bohai Bay and its catchment,we were able to identify the source of OM in these sediments.The stable carbon isotope values of Bohai Bay sediments were between-22.94‰ and-23.90‰,while those of riverine sediments were from-24.45‰ to-32.50‰.Marine algae were the main source of OM in Bohai Bay sediments.However,lacustrine algae were the main source of riverine sediments,not terrestrial OM.The nitrogen isotopes in Bohai Bay sediments decreased in eastward direction,with increasing distance from the coastline,which suggested a higher degree of impact from human activities along the coast.展开更多
The sources and enrichment of organic matter in a sediment core in the first member of the Xiagou Formation(K_1g^1) from the Chang 2-2 borehole of the Jiuquan Basin,NW China,have been examined using Rock-Eval,maceral,...The sources and enrichment of organic matter in a sediment core in the first member of the Xiagou Formation(K_1g^1) from the Chang 2-2 borehole of the Jiuquan Basin,NW China,have been examined using Rock-Eval,maceral,carbon isotopes and biomarker data.This data indicates that highly variable organic matter sources and preservation conditions in response to climate change.TOC content,HI,and δ^(13)C value were strongly correlated with the abundance of gammacerane,woody organic matter content,steranes/hopanes ratio,and C_(29) sterane content.This correlation demonstrates the importance that the control of the salinity of the depositional environment and organic matter sources can have upon the enrichment,type,and carbon isotopic composition of organic matter.In the Jiuquan Basin's relatively high temperature and arid climate,high salinity lakes with high primary productivity of algae,planktons,and bacteria,and good organic matter preservation conditions(anoxic bottom water) resulted in the enrichment of isotopically-light algae-bacterial organic matter.In the Jiuquan Basin's regions with a relatively low temperature and wet climate,fresh lakes with low primary productivity of algae,planktons,and bacteria received significant terrigenous high plants input,resulting in the deposition of a low abundance of isotopically heavier terrestrial organic matter.展开更多
Population exposure to pollutants is important for studies on the exposure-response relationship. However, it is difficult to evaluate population exposure to non-conventional pollutants due to limited data on concentr...Population exposure to pollutants is important for studies on the exposure-response relationship. However, it is difficult to evaluate population exposure to non-conventional pollutants due to limited data on concentration levels and the movement patterns of inhabitants. In this study, an air dispersion model was used to simulate N, N-dimethylformarnide （DMF） concentrations, as a proxy to monitoring concentrations. A total of 1289 randomly selected household representatives were surveyed to obtain information on movement characteristics. Subsequently, population movement patterns were combined with DMF concentration levels on maps of 100 m× 100 m resolution to calculate population exposure. During 2008, the estimated population exposure to DMF ranged from 0.002 to 0.64 mg/m^3. The highest level of population exposure to DMF was found in the north and northwest sub-districts of the study area, ranging from 0.42 to 0.64 mg/m^3. The population exposure to DMF for different occupational groups indicated that retired people and farmers were vulnerable subpopulations among people highly exposed to DME This was mainly because they spent most time at home where the DMF concentration was high. As pollutant concentrations were divided into small grids, we found that exposure levels were substantially impacted by population movement characteristics.展开更多
基金Supported by the National Natural Science Foundation of China(No.41273068)the Tianjin Research Program of Applied Science and Advanced Technology(No.11JCZDJC24100)
文摘Carbon and nitrogen stable isotopes are useful tracers for distinguishing marine and terrestrial plant sources of sedimentary organic matter(OM),and for identifying OM from different types of plants.By analyzing the carbon and nitrogen stable isotopes of marine and riverine sediments from Bohai Bay and its catchment,we were able to identify the source of OM in these sediments.The stable carbon isotope values of Bohai Bay sediments were between-22.94‰ and-23.90‰,while those of riverine sediments were from-24.45‰ to-32.50‰.Marine algae were the main source of OM in Bohai Bay sediments.However,lacustrine algae were the main source of riverine sediments,not terrestrial OM.The nitrogen isotopes in Bohai Bay sediments decreased in eastward direction,with increasing distance from the coastline,which suggested a higher degree of impact from human activities along the coast.
基金financially supported by CNPC Major Science and Technology Project (NO. 2012E330)CNPC Fourth Petroleum Resources Assessment (NO. 2013E-050209)
文摘The sources and enrichment of organic matter in a sediment core in the first member of the Xiagou Formation(K_1g^1) from the Chang 2-2 borehole of the Jiuquan Basin,NW China,have been examined using Rock-Eval,maceral,carbon isotopes and biomarker data.This data indicates that highly variable organic matter sources and preservation conditions in response to climate change.TOC content,HI,and δ^(13)C value were strongly correlated with the abundance of gammacerane,woody organic matter content,steranes/hopanes ratio,and C_(29) sterane content.This correlation demonstrates the importance that the control of the salinity of the depositional environment and organic matter sources can have upon the enrichment,type,and carbon isotopic composition of organic matter.In the Jiuquan Basin's relatively high temperature and arid climate,high salinity lakes with high primary productivity of algae,planktons,and bacteria,and good organic matter preservation conditions(anoxic bottom water) resulted in the enrichment of isotopically-light algae-bacterial organic matter.In the Jiuquan Basin's regions with a relatively low temperature and wet climate,fresh lakes with low primary productivity of algae,planktons,and bacteria received significant terrigenous high plants input,resulting in the deposition of a low abundance of isotopically heavier terrestrial organic matter.
基金Project (No. 200809103) supported by the State Environmental Protection Commonweal Trade Scientific Research of Ministry of Environmental Protection of China
文摘Population exposure to pollutants is important for studies on the exposure-response relationship. However, it is difficult to evaluate population exposure to non-conventional pollutants due to limited data on concentration levels and the movement patterns of inhabitants. In this study, an air dispersion model was used to simulate N, N-dimethylformarnide （DMF） concentrations, as a proxy to monitoring concentrations. A total of 1289 randomly selected household representatives were surveyed to obtain information on movement characteristics. Subsequently, population movement patterns were combined with DMF concentration levels on maps of 100 m× 100 m resolution to calculate population exposure. During 2008, the estimated population exposure to DMF ranged from 0.002 to 0.64 mg/m^3. The highest level of population exposure to DMF was found in the north and northwest sub-districts of the study area, ranging from 0.42 to 0.64 mg/m^3. The population exposure to DMF for different occupational groups indicated that retired people and farmers were vulnerable subpopulations among people highly exposed to DME This was mainly because they spent most time at home where the DMF concentration was high. As pollutant concentrations were divided into small grids, we found that exposure levels were substantially impacted by population movement characteristics.
