广西钦州湾表层沉积物中重金属的分布、来源及污染评价

为系统研究广西钦州湾表层沉积物中重金属分布与来源及潜在生态风险，分别于2019年10月和2020年10月在钦州湾采集表层沉积物样品116件，测定7种重金属的含量，利用地累积指数和污染载荷指数对重金属污染现状进行评价，利用潜在生态风险指数分析其潜在生态风险，采用富集系数法和UNMIX模型对重金属的来源进行探讨。结果表明，钦州湾表层沉积物中As为 （10.18±4.61）μg/g，Cd 为（0.17±0.13）μg/g，Cr为（44.28±23.56）μg/g，Cu为（18.53±10.75）μg/g，Ni为（23.38±11.11）μg/g，Pb为（24.76±12.75）μg/g，Zn为（62.66±27.32）μg/g，重金属含量比其他海域低，与本区近15年的调查数据相比也有所下降，但Cd含量呈增加趋势。地累积指数和污染载荷指数显示，Cd处于较高污染水平，污染严重区域主要位于防城港近岸，说明人类活动对该区域Cd分布有较大影响，且Cd是影响污染载荷指数的主要元素；潜在生态风险指数法表明，Cd处于中等生态风险水平；富集系数显示，研究区沉积物中重金属分布受人类活动的影响较为显著，通过UNMIX模型识别出3个潜在污染源，源1代表以Ni为主的矿石燃烧源，源2代表船体涂料、养殖废水的排放源，源3代表防城港近岸工业污染及岩石自然风化源。

Distribution,source and pollution assessment of heavy metals in surface sediments of Qinzhou bay,Guangxi

In order to systematically study the distribution, source and potential ecological risks of heavy metals (HMS) in surface sediments of Qinzhou bay in Guangxi, In 2019 and 2020, 116 surface sediment samples were collected in Qinzhou bay, the concentrations of 7 kinds of HMS were measured, the status of HMS pollution was evaluated by Geo-accumulation index (I_geo) and pollution load index (PLI), the possible ecological risk was analyzed by potential ecological risk index (E_RI) method, and the source of HMS was discussed by enrichment factor (EF) and UNMIX model. The results showed that the average concentration of As in surface sediments of Qinzhou bay is (10.18±4.61) μg/g, Cd is (0.17 ±0.13) μg/g, Cr is (44.28±23.56) μg /g, Cu is (18.53 ±10.75) μg/g, Ni is (23.38±11.11) μg/g, Pb is (24.76±12.75) μg/g, Zn is (62.66±27.32) μg/g, which was relatively lower than that in the sediments of other areas, and it was decreased compared with the previous study in Qinzhou bay, except for Cd. The concentration of Cd was relatively increased. The I_geo and PLI showed that Cd was at a high pollution level and was the main element affecting PLI. The heavily polluted areas were mainly located near the coast of Fangcheng port. The E_RI also showed that Cd was at a medium risk level. The EF showed the characteristics of significant anthropogenic impact of HMs. The UNMIX model identified three potential pollution sources. Source 1 represents the ore combustion source dominated by Ni, source 2 represents the discharge source of hull coating and aquaculture wastewater, and source 3 represents the source of industrial pollution and natural weathering of rocks near the coast of Fangcheng port.