Distribution and sources of heavy metals in surface sediments，southwest sea area of Leizhou peninsula

　In order to understand the distribution characteristics and sources of heavy metals in surface sediments of the southwest sea area in Leizhou Peninsula, 40 surface sediment samples were collected in the sea area in October 2021, and 40 samples were analyzed by grain size analysis and heavy metal content test. Then, the heavy metal pollution status and geological risk level were evaluated by geo-accumulation index, pollution load index, potential ecological risk index, enrichment coefficient and principal component analysis method, and the source of heavy metals was analyzed and discussed. The results show that the surface sediment types in the southwestern sea area of Leizhou Peninsula are mainly silt and silty sand. The distribution of heavy metals has a certain correlation with the sediment particle size. The content of heavy metals is generally low. Pb, Zn and Hg all meet the first-class sediment standard. 39 station of Cd meets the first-class sediment standard. 38 stations of Cu and Cr meet the first-class sediment standard. 31 station of As meets the first-class sediment standard, and 9 station meets the second-class sediment standard. The areas higher than the first-class sediment standard are mainly distributed near the Liusha Bay and the bay mouth. The geo-accumulation index of Hg and As was high, and 20 stations reached mild pollution level or above. The heavy pollution areas were located in Liusha Bay and the western  coastal waters of Xuwen County. The potential ecological risk level of Hg 29 stations was relatively high, and 6 stations reached high risk. The sources of Zn, Cr, Cu and Ni are mainly from the material carried by the residual current of the Qiongzhou Strait. The main source of Hg is the material carried by the residual current of Qiongzhou Strait, and the secondary sources are industrial waste discharge and ship activities. The main sources of Pb and Cd were industrial waste discharge and ship activities, and the secondary source was the material carried by the residual current of Qiongzhou Strait. The source of As is the discharge of wastewater from aquaculture farms distributed along the coast.