干旱区生态环境知识资源中心

The concentrations of Be-10 and C-14 and values of delta C-13 in samples collected during a major dust storm in Beijing on 16-17 April 2006 were studied. The Be-10 concentrations ranged from 1.69 x 10(8) to 2.07 x 10(8) atom/g, C-14 ages for black carbon (BC) ranged from 3001 to 5181 yr BP and for total inorganic carbon (TIC) from 8464 to 9119 yr BP, and delta C-13 values for BC ranged from -23.15% to -23.80% and for TIC from -5.39% to -5.98%. A comparison of BC content and delta C-13 value between the dust, surface soil in the dust source region, and aerosols in Beijing indicated that BC in the dust deposited in Beijing is significantly incorporated by aerosol BC during the dust transportation. Based on the C-14 ages of BC, the proportion of fossil-fuel-derived BC was 0.35-0.49 of the total. In contrast to BC, the TIC deposited in Beijing can be firmly related to the source area and delta C-13 was not significantly modified during its transportation. According to the C-14 ages of TIC, the proportion of the secondary carbonate in the dust was from 0.63 to 0.70. The results confirm that C-14 of TIC is another useful tracer to indicate the source region of dust besides the content and delta C-13 value of TIC from the arid and semi-arid regions of China.