Distribution And Sources Of Polycyclic Aromatic Hydrocarbons (PAHs) In Sediment From Henan Reach Of Huaihe, Huanghe Water System , East China.

Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants, have two or more benzene rings, which are widespread environmental contaminanted that occurred in atmosphere, water, soil, sediment and organism. Owing to their low aqueous solubility and hydrophobic nature, PAHs tend to associate with particulate material, which will finally be deposited to soil and the underlying sediments of estuary, lake and marine . Numberous studies have been conducted to determine the partitioning of PAHs in sediment. Most of these studies show that organic matter plays an important role in adsorption of PAHs in sediments. Few studies have researched the association of PAHs in different size fractions of sediments, and these studies obtain conflicting conclusion from different origin sediments. In our study , sediments collected from Huaihe River, Yellow River and surface water of Xinxiang were sieved into five fraction , each of these size fraction were then analyzed for PAHs. The main conclusions in the paper were as follows:(1) Sonicate extraction was used to extract 16 polycyclic aromatic hydrocarbons in sediments with acetone: n - hexane (1: 1) mixed solvent. After the purification process by a silica gel column, the solution was passed to high performance liquid chromatography - fluorescent detector-ultraviolet detector for analysis. Standard addition recovery rate was determined with quartz sand as substrate. Standard addition recovery rate was performed over 16 polycyclic aromatic hydrocarbons with the detection limit ranging from 0.34 ng g^-1 to 1.52 ng g^-1, while in precision testing the relative standard deviationswas below 15% with recovery rate staying between 57.09% and 103.41%. (2) Henan reach of Yellow River: Sediments collected from Outlet of Luoyang Petroleum Factory and Huanghe-Ⅱwere analyzed for PAHs, TOC and BC in five size fractions. Total concentration ranges of PAHs were 223.7 ⁵00.68 ng/g and 83.28 ²45.0 ng/g respectively and varied largely among the different size fractions. High PAHs were associated with small size fractions(<65μm) while the 220¹25μm fractions contained the lowest∑PAHs. TOC show a significant positive correlation with PAHs in sediment samples both from outlet of Luoyang petroleum factory and Huanghe-Ⅱ, but BC show that only in sediment from outlet of Luoyang petroleum factory .(3) Henan reach of Huai River: Two sediment samples collected from Huangchuan Hydrological Station and Sanjian Estuary were analyzed in the same way as above. The concentrations of 16 PAHs in five size fractions ranged from 317.64 ²781.41 ng/g, 40.12¹86.12ng/g, respectively. The highest∑PAHs concentration was associated with >220μm fraction in sediment from Huangchuan Hydrological Station (2781.41 ng/g) but associated with <25μm fraction in sediment from Sanjian Estuary(186.12ng/g). While the 125⁶5μm fraction contained the lowest∑PAHs concentrations in both samples. Samples in first station were dominated by four or more ring PAHs, but the second station mainly made up of 2³ ring PAHs. TOC and BC were not important for PAHs distribution in these samples.(4) Surface water of Xinxiang: the two sediment samples were collected from Wei River and Meng Jiangnv River, which are important surface water in Xinxiang. Total PAHs concentrations ranged from 1074.29 ²780.89ng/g and 295.91²288.04 ng/g and varied largely among the different size fractions in these sediments. The highest∑PAHs concentration was associated with 220¹25μm fraction in both sediment stations. Samples from Wei River were dominated by four or more ring PAHs in five size fraction, but sediments from Meng Jiangnv River mainly made up of 2³ ring PAHs. Positive correlations between PAHs, TOC, BC were existed in all size fraction sediments from Meng Jiangnv River but not existed in sediments from Wei River.(5) According to diagnostic ratios and PCA, the contamination source of PAHs is mixed from pyrolytic(coal, wood combustion and traffic-ralated pollution) and petrogenic(spills of oil products) inputs, and has an advantage of pyrolytic PAHs in Yellow River, Huai River and Surface water of Xinxiang in Henan reach. In addition, HCA result suggested that pollute pattern of PAHs represented no visible areal variation in Henan. This conformed to the factual distribution of factories or corporations, which was dispersed and mixed in small towns and cities located near the rivers.(6) The potential ecosystem risk assessment indicated that the ecosystem risk of PAHs was relatively low in Henan Reach of the Yellow River, Huai River. But most of sediments from Surface water of Xinxiang had probably certain risk and it showed be noticed.