Distribution and sources of some metals in the sediment core from Xiangshan bay, East China Sea

Major and trace elements in marine sediment can reflect the sources of marine substances, environment and climate changes.In the present study, a sediment core was collected and the contents of metals in the core were analyzed using X-fluorescence spectrometer in order to investigate the temporal distribution of these elements in Xiangshan bay, East China Sea.Combined with the distribution of organic carbon, inorganic carbon, total nitrogen and grain size, the sources of metals in the core were discussed according to the enrichment factor and principle component analysis.The results show that the metal contents range from 0.45% to 0.52% for Ti, from 2.14% to 2.58% for K, from 2.48% to 3.13% for Ca, from 4.54% to 5.83% for Fe, from 546×10^-6 to 868×10^-6 for Mn, from 23×10^-6 to 37×10^-6 for Pb, and from 113×10^-6 to 130×10^-6 for Rb.They were comparable to those obtained from the other offshore regions of China.Lead was significantly enriched since 1980s, which is suggested to be influence by human activities in the recent years.No obvious enrichment was observed for K, Ca, Fe, Mn and Rb and their main sources are mineral particles derived from the erosion and weathering of the surrounding basement. Metals of Ti、K、Fe、Mn、Rb and Pb are prone to be enriched in the sediments rich in organic matters, while Ca is deposited as inorganic calcium carbonate in the core.Comparing with the annual change of precipitation during summer in the Yangtze valley, it is suggested that mineral sourced metals are good indicator for the abnormal precipitation in geological time.