| Caofeidian inshore area is the key areas surrounding the reclamation project implementation. To explore the change of sedimentary environment in this area, the surface sediment samples collected from the Caofeidian inshore and adjacent sea in2013 were identified for Grain size, mineral and element composition and their distribution characteristics in order to investigate the impacts of large-scale reclamation engineering on the sedimentation environment and discussed the origin and environmental significance of Caofeidian inshore sediment.The surface sediments of Caofeidian inshore with obvious terrestrial is mainly affected by the common Luan River, Haihe River and the Yellow River, but in order to influence the Luanhe river dominated. The marine sediments dominated by silt(45.2%), followed by sand(30.2%), and clay was the least(24.6%); the overall performance of the different components of clay minerals wre illite(55.8%) > smectite(24.9%) > chlorite(9.9%) > kaolinite(6.7%) in Caofeidian inshaore; the average content of the detrital minerals was 11.70%, mainly in the mineral light, and the average content of the mineral light was 96.63%, the average content of heavy minerals was 2.17%, of which in Caofeidian inshore average content was 3.37%.Heavy mineral advantage minerals in the study area are mainly of hornblende, epidote and authigenic pyrite, which hornblende accounted for proportion in Caofeidian coastal reached the highest value(36.4%); light mineral advantage minerals mainly quartz, plagioclase and weathering debris, the proportion of quartz also in Caofeidian coastal reached the highest value(62.7%). Due to large-scale reclamation long-term implementation, nearly 10 years, sediments of Caofeidian inshare mainly changes from the silt and sand to sand in the east of Caofeidian, and on the west side of the Caofeidian is gradually smaller, the content of detrital minerals increased in sediments in the sea area of Laolonggou, and the particle size becomes larger. Also the reclamation project of long-term implementation of Caofeidian in surface sediments of the finer particles(< 63 μm) distribution were more obvious, especially on clay minerals(< 2 m) distribution is more significant. The distribution characteristics of illite, kaolinite and chlorite and reclamation in hydrodynamic change were closely related. To a certain extent, the results of the study can reveal the influence of thelong-term implementation of reclamation projects on the coastal sedimentary environment.To study on the distribution characteristics of elements, it shows that in the study area to C, N, S to represent biogenic element for a large number of elements, the contents of which were TC(1.83 mg / g) > TS(0.39 mg / g) > TN(0.13 mg / g). The average content of trace metal elements followed by Zn(71.02 mg / kg) > Cu(25.39 mg / kg) > Pb(20.91 mg / kg) > Cd(0.23 mg / kg), and the distribution characteristics,sediment grain size and total organic carbon of sediments and elements are closely related to, having the obvious correlation. Cd in the study area is the most serious pollution, the pollution level is higher, and the risk index is larger, some parts of the study area are the high risk area, so it should be given some attention to the pollution of Cd in the region. The accumulation index method of Pb in the study area shows that there are different degrees of enrichment in some sea areas, but the risk index is not high. Two kinds of metal elements(Cu and Zn) in the study area are relatively clean,the cumulative degree and risk index of them are lower. The reclamation project of Caofeidian inshore sedimentary environment have changed, it’s influence is obvious mainly in Laolonggou area and south and west of Caofeidian but the effect range is not large, only has certain influence on the distribution of grain size, mineral and element in the district Caofeidian inshore engineering. |
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