Analyzing the possible sources of heavy metals in farmland soil around Weihe coal-fired plant based on multivariate statistical analysis

Abstract

Contents of heavy metals Cu, Pb, Zn, As, Ni, Mn, V, Co and Cr in farmland soil around Weihe coal-fired plant were surveyed by applying X-ray fluorescence spectrometry to estimate the impact of coal-fired industrial activity on the surrounding soil environment. The possible sources of heavy metals analyzed in the soil were discriminated by utilizing multivariate statistical analysis methods, including principal component analysis, correlation analysis and cluster analysis, and the contribution of each source was apportioned applying principal component analysis subsequently multiple linear regression method. The results revealed that the content ranges of Cu, Pb, Zn, As, Ni, Mn, V, Co, and Cr were 18.1 to 45.9, 20.1 to 64.5, 38.7 to 69.7, 6.0 to 17.9, 23.9 to 39.1, 218.6 to 681.6, 64.5 to 104.2, 18.9 to 61.0, and 94.7 to 128.1 mg/kg with the average of 23.3, 28.3, 48.7, 9.4, 31.2, 564.7, 78.3, 29.1, and 110.7 mg/kg, respectively. Compared with the element background value of Shaanxi soil, the mean contents of Cu, Cr, Co, Pb, Ni and V were larger than their background values, while the mean contents of As, Zn and Mn were less than or close to their background values. Three main sources were discriminated for heavy metals investigated in the surrounding farmland soil of Weihe coal-fired plant. Zn, Cu, Pb, Ni and V derived from traffic and natural source. Co and Cr primarily derived from coal-fired plant discharge. Mn and As primarily came from natural source. The contributions of traffic and nature mixing source, natural source and coal-fired source to heavy metals in farmland soil around Weihe thermal power plant were 21.7%, 49.9% and 28.4%, respectively.