福建九龙江下游潮间带沉积物铅污染及同位素示踪

通过分析九龙江下游潮间带23个表层沉积物及周边地区典型端元组分的铅含量和铅同位素组成(206Pb/207Pb和208Pb/206Pb),以评估铅的空间分布,并采用铅同位素二元和三元混合模型探讨铅来源及各源的相对贡献率.结果表明,九龙江下游潮间带表层沉积物中铅含量范围为38.50~128.50mg/kg(平均80.60mg/kg),地质累积指数法、富集系数法和潜在生态危害指数法评价结果表明研究区沉积物中的铅为轻度~中等污染与轻度潜在生态危害.沉积物铅同位素组成中206Pb/207Pb和208Pb/206Pb的范围分别为1.1651~1.1924和1.9640~2.1071,大多数采样点处沉积物中的铅主要来源于九龙江上游铅锌矿和土壤母质,受汽车尾气的影响很小;九龙江河口上端沉积物Pb主要来源为铅锌矿、土壤母质和燃煤,相对贡献率范围分别为26.74%~56.61%、18.85%~19.91%和24.20%~58.53%;九龙江河口外端沉积物Pb主要来源有铅锌矿、土壤母质、燃煤和船舶油漆,相对贡献率分别为20.06%、13.75%、7.52%和58.67%;其余采样点处Pb主要来源为铅锌矿和土壤母质,相对贡献率范围分别为20.00%~95.62%和4.38%~80.00%.

Lead pollution and isotopic tracing in intertidal sediments of Jiulong River downstream

Lead isotopes have been widely applied to tracing lead sources in the environment. Lead concentration and isotopic compositions (206Pb/207Pb and 208Pb/206Pb) of 23 intertidal surface sediments collected from Jiulong River downstream and surrounding known sources were analyzed to assess the spatial variation of lead, and to discuss the lead sources and their relative contributions using the dual member model and the three-end member model of lead isotopic ratios. The results show that the range of lead concentration in the intertidal surface sediments of Jiulong River downstream was 38.50~128.50mg/kg with the mean value of 80.60mg/kg. According to geoaccumulation index, enrichment factor and potential ecological risk index, the lead pollution degree was mild to moderate and the potential ecological risk of lead was mild in the sediments. The ranges of lead isotopic ratios of 206Pb/207Pb and 208Pb/206Pb are 1.1651~1.1924 and 1.9640~2.1071, respectively. Lead pollutants in most studied sediments mainly came from Fujian Pb-Zn deposit and parent soil material while seldom from vehicle exhaust. At the upstream of Jiulong River estuary, lead in the sediments were mainly from Pb-Zn deposit, parent soil material and coal, with the contribution rates of 26.74%~56.61%, 18.85%~19.91% and 24.20%~58.53%, respectively. At the outer end of Jiulong River estuary, lead were mainly from Pb-Zn deposit, parent soil material, coal and marine paints, with the contribution rates of 20.06%, 13.75%, 7.52% and 58.67%, respectively. At other sampling sites, the sediment lead mainly derives from Pb-Zn deposit and parent soil material with the contribution rates of 20.00%~95.62% and 4.38%~80.00%, respectively.