雷州半岛西南海域表层沉积物中重金属分布及来源

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

    • 摘要: 为了解雷州半岛西南海域表层沉积物中重金属元素的分布特征及来源,于2021年10月在该海域采集表层沉积物样品40站位,对40件样品进行了粒度分析和重金属含量测试,然后利用地累积指数法、污染载荷指数法、潜在生态风险指数法、富集系数法和主成分分析法,评价了重金属污染状况、生态风险等级,对重金属物源进行了分析探讨。结果显示,雷州半岛西南海域表层沉积物类型主要以粉砂、粉砂质砂为主,重金属元素的分布与沉积物粒径具有一定的相关性,重金属元素含量整体较低,Pb、Zn、Hg均符合一类沉积物标准,Cd 39站位符合一类沉积物标准,Cu、Cr 38站位符合一类沉积物标准,As 31站位符合一类沉积物标准,9站位符合二类沉积物标准。重金属的分布与沉积物的平均粒径有一定的相关性,高于一类沉积物标准的区域主要分布于流沙湾及湾口附近。Hg、As地累积指数较高,20站位达到轻度污染水平及以上,污染较重区域均位于流沙湾及徐闻县西部近岸海域。Hg 29站位潜在生态风险等级为较高风险,6站位达到高风险。Zn、Cr、Cu、Ni来源主要为琼州海峡余流携带的海峡东口物质;Hg主要来源为琼州海峡余流携带的海峡东口物质,次要来源为工业废物排放和船舶活动;Pb、Cd主要来源为工业废物排放和船舶活动,次要来源为琼州海峡余流携带的海峡东口物质;As来源为沿岸分布的水厂养殖场废水排放。

       

      Abstract:  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.

       

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