黄河三角洲丰水期上覆水中PAHs分布、来源及生态风险研究

摘要

作为世界上生物多样性最丰富的区域之一,黄河三角洲的生态环境日益受到关注,但目前对该区域主要河流上覆水中多环芳烃的研究较少,了解黄河三角洲上覆水中PAHs的分布、来源及生态风险,对于黄河三角洲水环境的管理及水生生物的保护具有重要参考意义.鉴于此,本研究采用气质联用法测定了该区域37个采样点上覆水中PAHs的质量浓度,并分别通过多环芳烃特征比值法和物种联合概率曲线分析了PAHs的来源和∑PAHs的联合生态风险.结果显示,黄河三角洲上覆水中PAHs质量浓度范围为0.05~4.05μg·L-1,平均值为0.59μg·L-1.Shapiro-Wilk检验质量浓度分布符合对数正态分布(P=0.993),方差分析显示其与黄河口水中∑PAHs质量浓度无显著差异(P=0.567).在检出的12种单体中,萘的质量浓度最高,为0~2.95μg·L-1;从环数占比来看,2-3环占比最高,为88.19%,未检测到6环单体.源解析结果显示,37个采样点中,17个采样点PAHs来源于石油排放,14个采样点PAHs来源于木材、煤的燃烧,6个采样点PAHs来源于石油类产品的燃烧.商值法生态风险分析显示,各单体风险商均小于1.联合概率曲线对PAHs联合生态风险评价显示,PAHs影响超过5%物种的概率为0.0082%.结果表明,丰水期黄河三角洲上覆水中PAHs质量浓度较低,其主要来源于石油排放,其次是木材、煤的燃烧,石油类燃烧来源占比最少;各单体不存在生态风险,∑PAHs的联合生态风险较低.%As one of the richest biodiversity zones in the world, the Yellow River Delta of China receives increasing attention for its ecological and environmental conditions. However, few studies on polycyclic aromatic hydrocarbons (PAHs) in overlying water have been reported for this area. It will have great significance to understand the distribution, source and ecological risk of PAHs in overlying water for the management of the water environment and the protection of aquatic life in the Yellow River Delta. In this study, the PAHs concentrations of 37 sample sites were measured by GC-MS method. The sources of PAHs were analysed by PAH diagnostic ratios and risk assessment was done by joint probability curves. The results indicated that the total concentrations of∑PAHs in the overlying water from the Yellow River Delta ranged from 0.05 to 4.05 μg·L-1 with a mean value of 0.59 μg·L-1, which has no significant differences from that in the Yellow River Estuary water (P=0.567). According to a Shapiro-Wilk test (P=0.993), the concentrations of ∑PAHs were log-normal distributed. Naphthalene had the highest density in the 12 detected PAHs, ranged from 0 to 2.95 μg·L-1. ∑PAHs were predominated by two- and three-ring PAHs and no 6-ring PAHs were detected. The source analysis of the samples from 37 sites indicated that 17 sample sites were polluted bypetroleum, 14 sample sites were polluted by combustion of grass, wood and coal, 6 sample sites were polluted by combustion of petroleum. Risk quotient of each PAH was lower than 1. The joint probability curves of combined PAHs shown that the probability for affecting 5% of species was 0.0082%. The results shown that the concentrations of PAHs were low; the PAHs mainly came from petroleum, followed by combustion of grass, wood and coal;there was no ecological risk of PAHs, and the joint risk of ∑PAHs was low in overlying water during flood seasons from the Yellow River Delta, China.