万宁小海表层沉积物中重金属物质的空间分布特征及生态风险分析

为了解万宁小海海域表层沉积物重金属污染状况，2020年5月在小海潟湖采集18个沉积物样品，采用电感耦合等离子体质谱法（ICP-MS）同时测定5种重金属含量，采用原子荧光光度计测定总汞和砷，并分析归纳出重金属分布特征。采用Hakanson的潜在生态风险指数法识别小海表层沉积物潜在生态风险程度，以及运用富集系数和地累积法进一步评价小海表层沉积物重金属的污染程度。结果表明：Cu、Pb、Zn、Cd、Cr、Hg和As含量平均值分别为7.26 mg/kg、27.08 mg/kg、75.06 mg/kg、0.16 mg/kg、38.43 mg/kg、0.054 mg/kg、4.66 mg/kg，均符合第一类海洋沉积物质量标准。7种元素的潜在生态风险程度依序为Hg＞Cd＞Pb＞As＞Cu＞Cr＞Zn，其中Hg和Cd为主要潜在生态危害因子，其综合潜在生态风险等级已达到中等级风险；富集系数评价和地质累积系数评价污染程度依次为：Cd＞Hg＞Pb＞Zn＞Cr＞As＞Cu；表层沉积物中TOC 含量与 Cu、Pb、Zn、Cd 和 Cr 含量具存在显著正相关，与粒度呈一定的负相关。

Spatial distribution characteristics and ecological risk analysis of heavy metals in surface sediments of Xiaohai lagoon of Wanning-sea

In order to understand the pollution of heavy metals in surface marine sedimentsof Xiaohai lagoon in Wanning. In May 2020， 18 sediment samples were collected in the lagoon..,The content of five heavy metals was determined by inductively coupled plasma mass spectrometry (ICP-MS),The content of Hg and As by atomic fluorescence photometer,Analyze the distribution characteristics of heavy metals.The potential ecological risk index method of Hakanson was used to identify the potential ecological risk degree of small sea surface sediments，The concentration coefficient and ground accumulation method were used to further evaluate the pollution degree of heavy metals in small sea surface sediments.。The results showed that the average concentrations of Cu、Pb、 Zn、 Cd,、Hg and As in the surface sediment were 7.26 mg/kg，27.08 mg/kg, 75.06 mg/kg, 0.16 mg/kg, 38.43 mg/kg，0.054 mg/kg and 4.66 mg/kg. The sediment quality of Xiaohai lagoon meet the first class of marine sediment quality standard. The potential ecology risk index of 7 elements was Hg＞Cd＞Pb＞As＞Cu＞Cr＞Zn. Hg and Cd were major potential ecology risk factors. The comprehensive potential ecological risk level in Xiaohai reached the medium level. The evaluation of Enrichment Index and Index of Geoaccumulation(Igeo) showed the following order: Cd > Hg > Pb > Zn > Cr > As > Cu. The correlation analysis of heave metals and TOC in the surface sediment showed that the TOC was positively correlated with Cu、Pb、Zn、Cd and Cr，and negatively correlated with granularity.Key words: Xiaohai lagoon ; Heavy metal ; Distribution ; Ecological risk