Abstract
River sediment can act as a reservoir of the pollutants in the river. Some toxic pollutants, such as polycyclic aromatic hydrocarbons (PAHs) would be finally deposited in the sediment and cause ecotoxicity to living organisms and human beings. Therefore, the objective of this study was to determine the concentration distribution and possible sources of PAHs in the surficial sediment from Gao-ping River for providing data to understand the pollution potential of sediment in Taiwan. PAHs contents in surface water, pore water, suspended particles and sediment were analyzed to establish the relationship of PAHs among these media. Moreover, principal component analysis (PCA) and molecular indices were used to assess the factors that account for the distribution characteristics and to infer potential pollution of PAHs.The result showed the main compounds of PAHs in the water samples was naphthalene; the concentration of naphthalene ranged from 0.03 to 9.12 mg/L with the average value of 1.52 mg/L. The mean concentration of PAHs in sediment samples followed the order pyrene (21.77 ng/g), anthracene (21.66 ng/g-dw) and phenanthracene (20.09 ng/g-dw). The significant polluted stations are located in the tributaries stations, 7 (chang-nong) and 8 (jui-ru), and the estuary stations, 1 (shuang-yuan) and 2 (wan-da). For PAHs on the suspended particles, three- and four-ring PAHs, mainly phenanthrene, antracene and pyrene, were the most often detected PAHs in the suspended particles samples obtained in the sampling time of July 2000. Also, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene and chrysene were major components of the PAHs detected in the porewater. The concentrations ranged from 0.24 to 2.08 mg/L for two-ring PAHs, from 0.13 to 6.01 mg/L for three-ring PAHs, from 0.12 to 14.98 mg/L for four-ring PAHs and from 0.4 to 3.21 mg/L for five-ring PAHs.Six molecular indices were used for assessing possible sources. The obtained results of ratios of NaP/FL, Phe/Ant, and Pyr/BaA showed that petrogenic PAHs was dominant in sediment from Gao-ping River. Also, the result of the ratio of Chr/BaA depicts that some nature occurring PAHs also existed in the sediment. The analysis of PCA showed that swinery wastewater and fossil fuel industries would be the major source for PAH contamination in the sediment. These results are in well consistent with the analytical results of PAHs.