Abstract:101 surface sediments and 102 surface seawater samples from the sea area of Beisidao marine ranch in Changdao island have been investigated, and the indicators, such as surface sediment type, particle size, surface sediment and seawater heavy metals have been analyzed and tested. The potential ecological risks of surface sediments in this area have been evaluated by single factor pollution index method, enrichment coefficient method and potential ecological hazard index method, The surface seawater pollution has been evaluated by seawater quality classification and single factor pollution index method. As showed by the results of surface sediments, the sediments are argillaceous sandy gravel, gravelly argillaceous sand, gravelly mud, gravelly argillaceous sand, sand, silty sand and sandy silt, with an average particle size of 2.44~5.44 Ф； Hg, Cu, Zn, Pb, Cd, As, Cr, sulfide and petroleum all meet the class Ⅰstandard and belong to clean sediments. The enrichment coefficients of Cr, Cu, Pb, Zn, Cd, Hg and As are less than 1, which is at the low pollution level. The single potential ecological hazard coefficient E ir of Cr, Cu, Pb, Zn, Cd, Hg and As is 0.56~30.71, and the average value of RI is 66.27, which is far lower than the standard value of low level ecological hazard. As showed by the results of surface seawater, 21 stations are polluted by Hg, which is slightly higher than the first standard and meets the second standard. They are mainly located in the northwest part, west and central part and northeast part of the study area, and the other indexes meet the first standard. The contents of Hg, Cu and Zn are in a relatively clean environment, and the contents of As, COD, petroleum, Pb, Cr and Cd are in a natural background environment. According to the analysis results of seabed sediments and seawater, it is concluded that the sediment and water quality environment of the marine pasture planning area in Beisidao marine ranch of Changdao Island is suitable for the construction of marine ranch.
