基于APCS-MLR和PMF模型的燃煤电厂周边土壤潜在有毒元素(PTEs)污染特征与来源解析

为探究燃煤电厂周边土壤潜在有毒元素（PTEs）的污染特征及来源，以靖远电厂周边土壤为研究对象，分别采集了36个城市土壤样品和27个农田土壤样品，测定了As、Cd、Cr、Cu、Hg、Ni、Pb和Zn的含量.采用地累积指数法、单因子污染指数法和改进的内梅罗污染指数法对土壤PTEs污染特征进行评估，并利用相关性分析、绝对因子得分-多元线性回归（APCS-MLR）和正定矩阵因子分解（PMF）法定量解析PTEs污染来源.结果表明，除农田土壤As之外，靖远电厂周边土壤其余元素含量均值都高于甘肃省土壤背景值，其中Cd、Cr、Ni和Pb相对较为富集，Hg空间分异较大，受人类活动干扰显著.地累积指数法和单因子污染指数法结果显示，周边土壤污染以Cd、Cr、Ni和Pb为主，Hg的污染范围较广.改进的内梅罗污染指数显示，周边土壤为偏中度-偏重度污染，且城市土壤的综合污染程度高于农田土壤.源解析表明，城市土壤PTEs源自于交通燃煤混合源、交通工矿混合源和工业降尘源，APCS-MLR模型的贡献率分别为35.2%、25.1%和23.4%，PMF模型的贡献率分别为40.2%、12.4%和47.7%；农田土壤PTEs源自于工矿农业交通混合源和交通燃煤混合源，APCS-MLR模型的贡献率分别为40.3%和35.9%，PMF模型的贡献率分别为36.2%和18.0%.此外，PMF模型还识别了贡献率为48.5%的燃煤农业混合源.

Contamination Characteristics and Source Apportionment of Potentially Toxic Elements in Soil around the Coal-fired Power Plant Using APCS-MLR and PMF Models

To investigate the characteristics and sources of potentially toxic elemental contamination in soils around the coal-fired power plant, we selected the soil around the Jingyuan power plant as the object of investigation. Thirty-six and 27 soil samples collected from the urban and farmland areas were analyzed for PTEs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn), respectively. We employed the geoaccumulation index, single-factor pollution index, and improved Nemerow integrated pollution index to evaluate the contamination characteristics of PTEs, and combined correlation analysis with absolute principal component scores-multiple linear regression (APCS-MLR) and positive matrix factorization (PMF) receptor models were used to quantitatively analyze the pollution sources of PTEs. The results revealed that all the average concentrations of other soil metals around Jingyuan power plant exceeded their corresponding background values of Gansu Province, except for As, in agricultural soil, and Hg exhibited significant spatial non-homogeneity, and thus it was visibly affected by anthropogenic activities. The values of the single-factor pollution and geoaccumulation indices indicated that the soils of both sites were mainly contaminated with Cd, Cr, Ni, and Pb, and Hg contamination was reflected in wide areas for both sites. Additionally, the results of the improved Nemerow index demonstrated that the investigated soil was between moderately contaminated and heavily contaminated. Further, the comprehensive pollution degree of urban soil was higher than that of agricultural soil. Moreover, source apportionment revealed that PTEs in urban soil were derived from mixed sources of traffic activities and coal combustion, mixed sources of traffic activities and industrial and mining activities, and atmospheric deposition from industrial activities, with contribution rates of APCS-MLR of 35.2%, 25.1%, and 23.4%, respectively. The PMF contribution rates were 40.2%, 12.4%, and 47.7%, respectively. PTEs in agricultural soil were from one mixture source of industrial, mining, agricultural, and traffic sources, and the other mixed source was of traffic activities and coal combustion, with a APCS-MLR contribution rate of 40.3% and 35.9% and a contribution rate of PMF of 36.2% and 18.0%, respectively. In addition, another mixed source of agricultural activities and coal combustion was obtained using the PMF model, with a contribution rate of 48.5%.