| 基于PMF模型的宁南山区小流域土壤重金属空间分布及来源解析 |
| 摘要点击 3671 全文点击 1191 投稿时间：2021-05-12 修订日期：2021-06-29 |
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| 中文关键词 土壤重金属 潜在生态风险 正定矩阵因子分析(PMF) 空间分布 宁夏 |
| 英文关键词 heavy metals in soil potential ecological risk positive matrix factorization (PMF) spatial distribution Ningxia |
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| 中文摘要 |
| 为探明宁南山区小流域土壤重金属污染分布特征及主要污染源，确保土壤环境质量.采集并测定了260个表层（0~20 cm）土壤样品重金属Pb、Ni、Zn、Mn、Cu、Cr和Cd.基于宁夏土壤背景值，通过单因素和Nemera综合指数评价土壤重金属污染现状，使用潜在生态风险指数对生态环境风险水平进行评价，利用正定矩阵因子分析法（PMF）和Kriging插值相结合的方法分析土壤重金属空间分布及来源.结果表明，ω（Pb）、ω（Ni）、ω（Zn）、ω（Mn）、ω（Cu）、ω（Cr）和ω（Cd）均值分别为31.42、36.22、62.89、546.18、22.26、61.90和0.18 mg·kg-1，除Ni外，其他元素通常比宁夏土壤背景值高，但低于农业土壤污染风险选择标准和绿色食品环境质量标准背景值.Nemera综合指数表明，轻度、中度和重度重金属污染占比分别为71.92%、19.23%和1.54%.潜在生态风险以轻微风险为主，所占比例为98.85%，此外还存在极少量中等潜在生态风险等级样点，占总样点数1.15%.来源解析表明宁南山区小流域土壤重金属主要来源为施肥和工业排放混合源（12.6%）、农业活动源（23.5%）、自然母质源（27.6%）、农药使用和矿业开发排放混合源（17.7%）和大气沉降源（18.6%）. |
| 英文摘要 |
| In order to ascertain the distribution characteristics of soil heavy metal pollution and main pollution sources in a small watershed in the southern mountainous area of Ningxia and to ensure the quality of the soil environment, the contents of heavy metals Pb, Ni, Zn, Mn, Cu, Cr, and Cd in 260 surface soil samples (0-20 cm) were collected and determined. Based on the soil background value in Ningxia, the soil heavy metal pollution status and potential ecological risk were evaluated through the single factor index, Nemera composite index, and potential ecological risk index, and the method of combining positive definite matrix factor analysis (PMF) and Kriging interpolation was used to analyze the soil heavy metal spatial distribution and source. The results showed that the average contents of ω(Pb), ω(Ni), ω(Zn), ω(Mn), ω(Cu), ω(Cr), and ω(Cd) were 31.42, 36.22, 62.89, 546.18, 22.26, 61.90, and 0.18 mg·kg-1, respectively. Except for Ni, the other elements were higher than the background value of Ningxia but lower than the background value of agricultural soil pollution risk selection criteria and green food environmental quality standards. The Nemera composite index showed that the proportions of mild, moderate, and severe heavy metal pollution were 71.92%, 19.23%, and 1.54%, respectively. The potential ecological risks were mainly minor risks, accounting for 98.85%. In addition, there were a very small number of samples with medium potential ecological risk levels, accounting for 1.15% of the total number of samples. Source analysis showed that the main sources of soil heavy metals in the small watershed in the mountainous area of southern Ningxia were mixed sources of fertilization and industrial emissions (12.6%), agricultural activity sources (23.5%), natural parent material sources (27.6%), mixed sources of pesticide use and mining development emissions (17.7%), and atmospheric deposition sources (18.6%). |
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