基于正定矩阵因子分析模型的城郊农田重金属污染源解析

城郊农田是城市农副产品的重要生产基地,其土壤环境质量直接影响人群的健康状况.本研究采用200 m×200 m网格布点法采集DL市城郊农田表层土壤样品246个,分析土壤中重金属Cd、Hg、Zn、Pb、Cu、As、Ni、Cr和Mn的含量分布特征.运用正定矩阵因子分析法(PMF)对研究区9种重金属污染来源及其贡献率进行了解析.结果表明:工业污染源贡献率29.74%,农业与污灌复合污染源贡献率19.93%,自然母质源贡献率35.98%,大气沉降源贡献率14.35%.其中,Hg主要来源于大气沉降源,贡献率为67.23%;Pb、Cu和Zn主要来源于工业污染源,贡献率分别为67.58%、40.65%、35.51%;Ni、Cr和Mn主要来源于自然母质源,贡献率分别为68.82%、67.16%、72.32%;Cd、As主要来源于农业与污灌复合源的影响,其贡献率分别为71.30%、47.53%.由PMF模型解析结果可知,工农业生产等人为因素(64.02%)是造成城郊农田土壤重金属污染的主要来源.

Analysis of heavy metal pollution sources in suburban farmland based on positive definite matrix factor model

Suburban farmland is an important production base of urban agricultural products, and its soil quality affects human health directly. In this study, 246 surface soil samples were collected from farmland in the suburbs of DL City. The sample sites were arranged by 200 m×200 m grid method. The distribution characteristics of heavy metals, namely Cd, Hg, Zn, Pb, Cu, As, Ni, Cr and Mn, in the soil were analyzed. The Positive definite Matrix Factor analysis(PMF)was applied to analyze the sources and contribution rates of nine heavy metals in the study area. The results show that the contribution rate of industrial pollution source, the agricultural and sewage irrigation combined pollution source, the natural source and the atmospheric sedimentation source were 29.74%, 19.93%, 35.98%, and 14.35%, respectively. Among them, Hg mainly comes from the source of atmospheric deposition, with a contribution rate of 67.23%. Pb, Cu and Zn mainly come from industrial pollution sources, and their contribution accounts for 67.58%, 40.65% and 35.51%, respectively; Ni, Cr and Mn mainly come from natural parent materials with contribution rates of 68.82%, 67.16% and 72.32%, respectively; Cd and As mainly come from agricultural and sewage irrigation sources, and their contribution rates are 71.30% and 47.53%, respectively. According to PMF model analysis, industrial and agricultural production and other human factors(64.02%)are the main sources of heavy metal pollution in suburban farmland soil.