敦化大桥泥炭记录的积累人为大气铅沉降

Cumulative,anthropogenic,atmospheric lead deposition recorded in Daqiao mire,Dunhua Basin,Changbai Mountains

分析了敦化大桥泥炭地裕家剖面自2 120a(B.P.)以来泥炭中的铅、锆元素含量,计算了该剖面铅的富集因子、沉降速率,以及岩石铅和人为铅的含量.结果表明,大桥泥炭地该时期总铅含量变化在1.81~7.35μg/g,平均值为4.24μg/g.富集因子揭示剖面上部60cm,相当于1 300a(B.P.)以来有外来的铅富集,其下几乎无富集.裕家剖面铅沉降速率为0.54~4.97mg/(m^2·a),呈现随深度加深而增加的变化趋势.铅沉降速率与大气灰尘沉降速率呈明显的正相关(r=0.948,n=14,P<0.01),表明铅主要来自于大气灰尘.铅沉降速率与岩石铅含量也呈明显的正相关(r=0.784,n=14,P<0.01),意味着大气沉降的铅主要来自于岩石风化后的自然产物,而人类活动造成的人为铅污染较少.大桥泥炭地积累的人为铅总量为0.729 3g/m^2.

The concentrations of lead,zirconium in the Yujia profile of Daqiao mire in Dunhua Basin were analyzed,the enrichment factor,accumulation rates,lithogenic and anthropogenic lead were calculated in this paper.The results show that the total contents of Pb within Yujia profile at Daqiao mire are 1.81～7.35μg/g,and average value is 4.24μg/g.The enrichment factors in the upper section of the profile（0～60cm,correspond to 0～1 300a（B.P.））are more than 1,while less than 1in the bottom section of the profile.It seems to indicate a weak lead move in profile.The range of the lead accumulation rates in Yujia profile is from 0.54 mg/（m^2·a）to 4.97 mg/（m^2·a）,and it becomes smaller with the depth decreasing.The lead accumulation rates and atmospheric dust accumulation rates show a significant positive correlation（r=0.948,n=14,P〈0.01）.It means Pb mainly comes from the atmospheric dust.The lead accumulation rates and lithogenic lead concentrations also show a significant positive correlation（r=0.784,n=14,P〈0.01）,indicating less lead contamination caused by human activity.The total accumulative,anthropogenic lead in Daqiao mires is 0.729 3g/m^2.The enrichment factors of lead in the Yujia profile reveal the most enrichment occured since 530a（B.P.）.