| Because of the developed economy, densely population in the Pearl River Estuary area, sewage and industrial waste water pollution discharge into the Pearl River Estuary, the eutrophication trend enhancement and heavy metal pollution is becoming more and more serious. Based on the Pearl River Estuary as the study area, in January 2015 and April for two observation of voyage, collected surface water and the surface sediment samples, the surface water of the Pearl River Estuary of nutrient content and surface sediment of heavy metal content were analyzed. Through the potential eutrophication assessment method to evaluate the degree of eutrophication of survey area; Respectively at the same time, the application of single factor pollution index method, the geological accumulation index method, potential ecological harm index method were used to assess the potential ecological risk of the pearl river estuary, the pollution and potential ecological risk of water and sediment were analyzed of pearl river estuary. The results can provide reference for the Pearl River Estuary area and nearshore environmental protection. Main conclusions are as follows:(1) The Pearl River Estuary waters DIN average content of 0.953 mg/L, the main DIN is NO3-N, the second is NH4+-N, and NO2--N is the minimum. The average content of PO43--P was 0.014 mg/L. SiO32--Si was 2.126 mg/L. Due to the impact of terrestrial runoff and sea water dilution and other factors, various trends are in line with the basic nutrients gradually decreasing from north to south. The average of the Pearl River Estuary waters Chl a content of 5.548 μg/L. As can be seen from the correlation analysis of Chl a and nutrients between NO3--N phytoplankton growth is the most important environmental factor.(2) Comprehensive two voyages, the Pearl River Estuary most sampling stations belong to the phosphorus limit potential eutrophication (VIp trophic level), each sampling station station of N/P values are universal greater than 60, and some even up to more than 200 stations, you can determine the Pearl River Estuary belong phosphorus limit potential eutrophication.(3) The average content in Pearl River Estuary of Cr, Cd, Cu, Pb, Zn,were 114.70mg/kg,0.80 mg/kg,58.73 mg/kg,80.01 mg/kg,191.57 mg/kg, respectively,are high in the "ocean sediment quality" (GB 18668-2002) first class sediment quality standard limits, but not exceeding the standard value of the second category; average Ni content of 51.89 mg/kg, due to the above criteria are not given Ni related evaluation criteria, so no comments. Trend six kinds of heavy metals are basically the same, lofty low coastal sea and western stations higher than the eastern station. Comparison with the results of other research areas, the Pearl River Estuary sediments high heavy metal content. Through six kinds of correlations of heavy metals found between them have some positive correlation, indicating that they have a certain degree of homology; principal component analysis, sources of heavy metals in surface sediments of the Pearl River Estuary primarily affected by human activities.(4)Accoding to single factor pollution index and integrated pollution index, potential ecological and geological index accumulated index rating Show sediment environment in this study area has been polluted to some extent, which is currently Cd in surface sediments of the Pearl River Estuary was the more polluting heavy metal pollutants, it is worth seriously enough and can take certain measures to control. |
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