| Based on the information observed in the Xiaoqinghe estuarine in 2005 and 2006,and the data obtained in April, June, July and November, 2006, the state of eutrophication and persistent organic pollution in the Xiaoqinghe estuarine was discussed and the flux of pollutants transported into sea was estimated. Meanwhile the solidphase extraction of phthalate in water was researched. The main study and results are shown as followed:The Xiaoqinghe estuarine was seriously contaminated by nitrogen and phosphorus nutrients. The level of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) was far beyond the concentration of class IV seawater criteria. Furthermore, DIN contributes most to the eutrophication in all the pollutants, and the phosphorus is not the limited factor. In the Xiaoqinghe estuarine, the annual flux of COD and DIN into the sea was 1.3×10~4 t and 0.8×10~4 t. Though the pollutants involved with COD have been reduced to some extent after the treatment of Xiaoqinghe River for many years, the pollutants relating to DIN have the trend to increase.Nitrogen behavior in Xiaoqinghe estuary was non-conservative and the level of nitrite in the estuarine area was very high, reach to 0.3mg/L, and a strong positive correlation between nitrite and salinity was shown. The lower salinity area where is in the riverway and the water was greatly affected by the runoff and high levels of pollutants especially organic pollutants regenerated a lot of NH4+-N. Though the NH4+-N was partly transformed to nitrite and partly consumed by photoplankton, the concentration of NH4+-N would not be decreased and still surplus. The higher salinity area was located outside the gate of the estuarine and the DO can be replenished by the off sea. This added to the level of DO and enhanced the transformation rate of nitrite. And because of the lower concentration of NH4+-N, the depletion of NH4+-N appeared in the theoretical dilution line. C18 reversed-phase SPE cartridge was used in the experiment of enrichment behavior of 11 kinds of phthalic acid esters(PAEs) in water samples. Based on variance analysis and rationale analysis, the final SPE method was chosen: eluent intensity (hexane:acetone)20.5:1, pH=4.5,elution velocity 2mL/min and elution volume 5mL , the main effects has a relative strength of velocity > pH > volume > eluent intensity, and it clearly demonstrates that the pH and volume factors have positive effects, and velocity and eluent intensity factors have negative effects.Xiaoqinghe estuary was polluted by PAEs, the total PAEs (particulate and dissolved phase) flux was 2×10~4kg/a, the flux of the dissolved phase PAEs was 1.4×10~4kg/a and accounts for 71%. DMP and DBP were the primary ingredients in dissolved phthalate. DEHP was the main component in particulate phthalate. The content and component of PAEs in river water have pronounced seasonal variation. The phthalate level in the estuary was lower than that in river water, moreover the concentration of DMP decreased fastest as the waters transfer.Compared to other rivers in the world, Xiaoqing River was seriously polluted. The total PAHs (particulate and dissolved phase) flux was 3×10~3kg/a, the flux of the dissolved phase PAHs was 2.5×10~3kg/a kg/a and accounts for 83%.The content and component of PAHs in river water have pronounced seasonal variation. The level of PAHs with 2-3 rings decline with the rise of salinity, while PAHs with 5-6 rings showed a high concentration at station 2 as a result of the resuspension of the surface sediments. In the article, the main source of PAHs in Xiaoqinghe were estimated by the Characteristic-Ratio method.From the results, the main source of PAHs were the produce of burning matter at high temperature, such as the combustion of mineral and fossil fuel, vehicle emission, exhaust gas of burning rock oil, liquid waste.
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