长江典型江段水体PAHs的分布特征、来源及其生态风险

针对我国长江典型江段丰、平、枯不同时期的地表水,采用了固相萃取—气相色谱质谱联用(GC-MS)的分析技术,调查了16种优先控制多环芳烃(PAHs)的污染状况.研究了长江干流PAHs的污染水平和分布特征,并在定量分析的基础上评估了长江干流PAHs的来源和生态风险.结果显示,Σ₁₆PAHs浓度范围为2.22～1450.91ng/L,均值为107.04ng/L,其中,平水期武汉江段Σ₁₆PAHs浓度最高,均值为1050.64ng/L,长江干流PAHs污染状况与近5a国内其他水体相比处于中等偏低水平.空间分布上长江典型江段地表水中Σ₁₆PAHs从上游攀枝花江段到下游南京江段呈现出先上升后下降的趋势;时间分布上Σ₁₆PAHs的变化趋势为平水期(187.78ng/L)>丰水期(73.30ng/L)>枯水期(38.02ng/L).由同分异构比值法分析表明:在枯水期和平水期中,煤炭、生物质燃烧和石油源是长江干流PAHs的主要来源,而丰水期PAHs主要源于煤炭、生物质燃烧,其中南京江段PAHs的来源较为复...

Distribution characteristics,source and ecological risks assessment of PAHs in water bodies of typical sections of the Yangtze River

Sixteen priority polycyclic aromatic hydrocarbons(PAHs) were investigated in water samples (wet, normal and dry periods) in the main stream of the Yangtze River using solid-phase extraction (SPE) -gas chromatography-mass spectrometry (GC-MS) analysis technique. The pollution levels and distribution characteristics of PAHs were studied, the sources and ecological risks of PAHs were evaluated based on quantitative analysis. The results showed that the concentration of Σ₁₆PAHs was from 2.22 to 1450.91ng/L, the average concentrations of ΣPAHs was 107.04ng/L in the Yangtze River, among them, the concentration of Σ₁₆PAHs in the Wuhan river section was the highest during the normal period, with an average value of 1050.64ng/L. Compared with other domestic water bodies in the past five years, the PAHs pollution in the main stream of the Yangtze River was at a moderately low level. In terms of spatial distribution, the Σ₁₆PAHs in surface water of typical sections of the Yangtze River showed a trend of first rising and then falling from the Upstream Panzhihua section to the downstream Nanjing section, The variation trend of Σ₁₆PAHs in temporal distribution: normal period (187.78ng/L)>wet period (73.30ng/L)> dry period (38.02ng/L). The analysis by isomeric ratio method showed that coal, biomass burning and petroleum sources were the main sources of PAHs in the main stream of the Yangtze River in dry and normal periods, In the wet season, PAHs mainly originated from coal and biomass combustion, among them, the sources of PAHs in the Nanjing River section were more complex. The ecological risk assessment of PAHs was carried out using the Species Sensitivity Distributions (SSD) assessment method. The results showed that the PAHs in the surface water of typical sections of the Yangtze River had not yet caused significant negative impacts on aquatic organisms. The comparison of the results with historical data showed that the current ecological risk of PAHs in the main stream of the Yangtze River is lower than the ecological risk before the implementation of the Yangtze River protection policy.