Historical Variation In Black Carbon And Heavy Metal Concentration And Sources To Northern China Sediments

Aerosol pollutants are the main pollutants in the atmosphere,it can reduce atmospheric visibility.And it has a direct impact on climate change.Moreover,aerosol pollutants are harmful to human health,as it can cause a variety of diseases.In the atmospheric aerosol,black carbon is one of the most important components.Combustion-derived black carbon(BC)is an important primary pollutant of fine particulate matter(PM2.5).BC(here can defined as elemental carbon(EC))can absorb light and contribute to warm the atmosphere,and cause global warming.Black carbon is one of the important material that causing global warming,which is consider to be second only to CO2.In a short period of time,black carbon emissions can effectively alleviate global warming.Therefore,it is very necessary to study the source and concentration of black carbon.With the development of economy,the concentration of heavy metals in the environment is becoming higher and higher.Heavy metals have a harmful effect on human health and ecosystem.Therefore,sources and emissions of heavy metals have been widely concerned.Heavy metals can cause serious damage to human health.In general,heavy metals can not be biodegraded,but it can be enriched.And it finally enter the body.Lake sediments are regarded as an ideal samples for researching environment and climate changes.So reconstructing BC and heavy metal(Zn,Ni,Cu,Pb,Co)100-year historical trends in North China Plain(NCP)is necessary for better comprehending its artificial effect and the change of historical energy structure.Three lake sediments were collected in this study.Distribution patterns for BC and heavy metal concentration were consistent in three profiles.During years 1900-2010,the BC concentrations in three cores increased from 0.17 to 1.28 mg g-1,0.21 to 2.59 mg g-1,and 0.16 to 1.85 mg g-1,and the ranges for the BC deposition fluxes were 0.1-4.7,0.1-8.2,0.2-7.4 g m-2 a-1,suggesting ten times jump of primary pollutants from pre-industrial levels to recent years.BC flux and heavy metal(Zn,Cu,Pb)showed two peaks with first one at 1970 to 1980.The second stage of increase occurred since 2000 year,with peak in about 2010 that were stronger than the past record.Residential energy consumption and biomass burning(low-temperature combustion source)were responsible for the BC increase in the 1970s.Fossil fuel combustion in industry,power,and transportation sectors(industrialization source)was negligible before 1990,however,such industrialization source increased significantly during 1990-2010 and it rivaled low-temperature combustion for BC emission in recent years(-2010).Both low-temperature combustion and industrialization sources had contributed to the strongest peak of BC in recent years.This study reconstructed sediment cores in North China Plain(NCP)and discussed the historical concentration and sources of atmospheric black carbon and heavy metal.It can provide the basis for understanding the historical pollution of the north China plain.