基于PMF模型解析九龙江河口表层沉积物重金属来源

为研究九龙江河口表层沉积物中重金属来源,分析测定了表层沉积物中15种重金属含量,并用正定矩阵因子分析模型(PMF)解析表层沉积物中重金属来源。结果表明,九龙江河口表层沉积物中大部分重金属相对福建省土壤环境背景值已存在一定程度的富集。各重金属在研究区域分布差异较大,其中Co、Rb和Th属于低分异; Be、V、Ni、Zn、Sr、Mo、Cd、Pb、Hg和U属于中等分异; Cr和Cu属于高分异。沉积物中重金属实测值与PMF模型预测值拟合曲线呈现较好相关性,PMF模型结果与铅同位素示踪结果相近,能满足研究需要。九龙江河口表层沉积物中重金属主要来源有自然源、化石燃料燃烧、农业活动和采矿活动,其对表层沉积物中重金属的综合贡献率分别为35. 6%、32. 5%、11. 2%和20. 7%。

Source Apportionment of Heavy Metals in Surface Sediments of the Jiulong River Estuary Based on Positive Matrix Factorization

In order to apportion sources of heavy metals in surface sediments of the Jiulong River Estuary, contents of fifteen heavy metals in surface sediments were determined and the Positive matrix factorization model (PMF) was used. The results showed that, compared with their background values in soils of the Fujian province, most heavy metals were enriched in the surface sediments and had different variation levels in the spatial distribution in the study area. Co, Rb and Th showed low variations; Be, V, Ni, Zn, Sr, Mo, Cd, Pb, Hg and U showed moderate variations; Cr and Cu showed high variations. This study showed that results of the PMF model were reasonable and met the research needs, since predicted values of the PMF model were consistent with measured values and results of the PMF model were consistent with those of the Pb isotope trace model. The results of PMF indicated that there were four major potential heavy metal sources, natural source, fossil fuel combustion, agricultural activities and mining activities, whose contribution rates were 35.6%, 32.5%, 11.2% and 20.7%, respectively. The natural source contributed most to Mo, U, V, Zn, Th and Rb with the contribution rates of 60.6%, 52.4%, 49.1%, 47.3%, 45.9% and 38.7%, respectively, the fossil fuel combustion contributed most to Be, V, Cr, Sr and Hg with the contribution rates of 40.7%, 46.6%, 62.0%, 50.8% and 43.3%, respectively, the agricultural activities contributed most to Cd with the contribution rate of 41.6%, and the mining activities contributed most to Ni, Cu and Zn with the contribution rates of 45.2%, 44.3% and 46.0%, respectively.