The Distribution And Source Identification Of PAHs In The Sediments And Soils Around Poyang Lake

Polycyclic aromatic hydrocarbons(PAHs) is one kind of persistent organic pollutants(POPs).There are 16 kinds of PAHs in the 129 kinds of priority control pollutants list published by US EPA. PAHs are also the pollution substances which are most concerned by United Nations environment programme(UNEP) in order to evaluate the PTS areas. The benzo(a) pyrene(Bap) is the strongest carcinogen in PAHs, and it was listed in the China’s environmental air quality standards(state environmental protection administration, 1996). Due to the rapid development of society and economy, a large amount of pollutants discharged from the Poyang Lake ecological economic zone. High intensity of industrial and agricultural and transportation activities, the large numbers of vehicle emissions and the use of gasification of coal, oil, biomass and other energy lead to the high density of polycyclic aromatic hydrocarbons(PAHs) emissions in this area. Previous study showed that there are PAHs residues in the atmospheric medium and surrounding soil in Nanchang city, which is belongs to the Poyang Lake ecological economic zone. There are few studies on the characterization of PAHs in multi-media from a regional scale, and sediments and soils are the sink of PAHs. The main conclusions of this study are as follows:(1)The mean concentrations of ∑PAHs in the sediments of Poyang Lake were 745.80±1024.94?g·kg-1, with the concentrations of Nap was 2.24μg·kg-1, which was lower than the concentrations of other PAHs in Poyang Lake. And the concentrations of Phe was the highest when compared with other PAHs, and it was 1526.34 μg·kg-1. Concentrations of 2 rings, 3 rings, 4 rings, 5 rings and 6 rings of PAHs accounted for 0.04%, 32.45%, 33.79%, 22.45% and 11.27%, respectively. And ordered as follows: 4 rings>3 rings>5 rings>6 rings>2 rings. High rings of PAHs(≥) with high molecular weight accounted for 67.51% of the total contents of ∑PAHs.(2)The mean concentrations of ∑PAHs in the soils around Poyang Lake were 513.49±788.97?g·kg-1, which was lower than that in the sediments of Poyang Lake. Be the same to the sediments, the lowest concentrations of PAHs in soils from Poyang Lake was Nap(2 rings), which was 10.25 μg·kg-1. And the greatest concentrations of PAHs was Phe(3 rings), which is 1827.95μg·kg-1. Concentrations of 2 rings, 3 rings, 4 rings, 5 rings and 6 rings of PAHs accounted for 0.13%、30.85%、33.63%、24.56%和 10.82%, respectively. And ordered as follows: 4 rings>3 rings>5 rings>6 rings>2 rings. High rings of PAHs(≥4 rings) with high molecular weight accounted for 69.01% of the total contents of ∑PAHs.(3)Concentrations of ∑PAHs in differents regions from Poyang Lake ordered as follows: Poyang>Xingzi > Duchang> Hukou>Shatan bridge. And concentrations of ∑ PAHs in Poyang Lake with different landuse types ordered as follows: industrial soil>marsh soil>agricultural soil. The mean concentrations of ∑PAHs in agricultural soils were 214.40±107.14?g·kg-1, with the concentrations of lower rings(<4) of PAHs was much greater than that of higher rings(≥4 rings) of PAHs, which indicated that they were from the petroleum pollution. The mean concentrations of ∑PAHs in primary soils were 214.40±107.14?g·kg-1, with the concentrations of higher rings(≥4 rings) of PAHs was much greater than that of lower rings(<4) of PAHs, which indicated that they were from the combustion of fossil fuel, and it was different from the agricultural soils.(4)Principal component analysis(PCA) and Ratio analysis method were used to identify the sources of PAHs in Poyang Lake. And the results showed that the residues of PAHs in the sediments and sorrouding soils from Poyang Lake were mainly from the high temperature combustion, which accounted for about 72.97%. And there were still some other sources such as the emissions from vehicles exhaust and industry.