人类活动对查干湖PAHs沉积历史及来源的影响

Effects of human activities on sedimentary accumulation of PAHs in Chagan Lake

对查干湖湖心沉积岩芯中16种美国环保署(US EPA)优控多环芳烃(PAHs)含量进行分析,辅以210 Pb和137 Cs年代测定,重建查干湖1877—2017年PAHs沉积历史,通过正定矩阵因子分解模型(PMF)定量判别污染源,通过随机影响模型(STIRPAT)和通径分析方法定量分析人类社会经济参数与PAHs沉积历史的影响机理.研究表明:PAHs含量为305.90~1214.42 ng·g-1,3~4环为优势组分.140年来,PAHs含量变化总体表现为缓慢波动、剧烈波动、快速增加的趋势,20世纪60年代,沉积物中PAHs总量及各组分开始呈较频繁的波动性增大,于2011年达高峰值.查干湖沉积物中PAHs的来源为生物质及煤燃烧、化石燃料燃烧、交通源和石油泄漏,其中燃烧源为主要来源.松原市人口总量和第二产业占GDP比值每提高1%,沉积物中PAHs沉积通量将分别增加8.11%和2.98%,其中能源消费总量通过第二产业占GDP比值对PAHs沉积通量的影响最大.

Sixteen priority polycyclic aromatic hydrocarbons(PAHs)proposed by US EPA were analyzed using GC/MS method in a sediment core from Chagan Lake(CG)in northeast China.Based on 210Pb and 137Cs dating,the PAHs sedimentary history from 1877 to 2017 of Chagan Lake was reconstructed.The sources of PAH were identified by positive definite matrix factorization model(PMF),and the impacts of human activities on PAHs were investigated quantitatively by stochastic impacts by regression on population,affluence,and technology(STIRPAT)and path analysis.The results showed that the total concentrations of 16 PAHs ranged from 305.90 to 1214.42 ng·g-1 with 3 and 4 rings PAHs being predominant in the CG sediment core.The vertical distribution of total PAH concentrations showed slightly fluctuate,drastic fluctuate and rapidly increase within 140 years.In 1960s,the PAH concentrations started to increase frequently with the peak value at the early 21st.Source apportionment indicated that the PAHs in CG sediment core were mainly from biomass and coal combustion,petrochemical combustion,traffic combustion and petroleum.According to the STIRPAT model,for every 1%increase in the total population and the secondary industry ratio of Songyuan City,the PAH sedimentary flux increased by 8.11%and 2.98%respectively.Path analysis results also shown that total energy consumed had the greatest impact on PAH sedimentary flux by secondary industry ratio.The results indicate that the current study well reconstructed response of human activities to accumulation of PAHs.