东莞市PM1中重金属元素的污染特征及来源解析

采集了2011年8月—2012年7月间东莞市不同区域两点(A:生活区;B:工业区)的PM2.5～10、PM1～2.5和PM1样品,并用ICP-MS分析了颗粒物上Pb、Cu、Zn、As、Cd、V、Mn、Cr、Hg和Al等10种元素,重点研究了PM1中除Al外其它9种重金属元素的污染特征.分析结果显示,工业区B点PM1中的重金属污染明显较生活区A点严重,9种重金属元素在B点PM1中的浓度是A点的2.3～4.4倍.Zn和Pb是A、B两点PM1中主要的重金属元素,同时各重金属元素质量占PM1质量百分比范围为0.0008%～0.3530%.粒径分布、富集因子分析的结果显示,大部分重金属元素主要富集在PM1中,且主要受人为源的影响.因子分析源解析结果表明,A、B两点PM1主要来源于4类污染源:燃煤源、机动车/工厂燃油源、冶金化工源、土壤尘.污染源特征分析表明,偏北风时东莞地区PM1受局地源远距离输送影响更严重,偏南风时受本地污染源影响更严重.

Pollutioncharacteristics and source apportionment of heavy metals in PM1 at Dongguan, China

PM_2.5~10, PM_1~2.5 and PM₁ were sampled from August 2011 to July 2012 at different sites of A and B (A: living area; B: industrial area) in Dongguan, China. In addition, elemental compositions (Pb, Cu, Zn, As, Cd, V, Mn, Cr, Hg and Al) of ambient particles were determined using ICP-MS and characterization of heavy metals in PM₁ was performed. Our results showed that the concentrations of these heavy metals in PM₁ at B site were about 2.3~4.4 times those at A site, indicating that the heavy metal pollution in PM₁ at the industrial site was more serious than that at the living site. Among these nine heavy metals, Zn and Pb were the primary elements in PM₁. Heavy metals accounted for 0.0008%~0.3530% of PM₁ mass. Size distribution and enrichment factor analysis suggested that most of the nine heavy metals were mainly enriched in PM₁ and were primarily emitted by anthropogenic sources. Source apportionment analysis further revealed that PM₁ at both sites primarily originated from coal combustion, vehicle/industrial oil burning, metallurgic emission and soil dust. Moreover, PM₁ in Dongguan was mainly affected by non-local source with north wind and by the local sources with south wind.