| With rapid development of industrialization and urbanization in our country, the deteriorating air quality and frequent hazy weather have attracted widespread public attention. PM2.5, which is the priority air pollutant in many cities in China, has been included in group 1 as acknowledged carcinogens to human beings by the International Agency for Research on Cancer (IARC). Jinan, the capital of Shandong province, is a typical industrial city in our country, and is also faced with serious PM2.5 pollution. PM2.5-bound trace elements could cause serious damages to human health although they only account for a small proportion of PM2.5. To understand the pollution characteristics and health risks of PM2.s-bound trace elements in Jinan, one year PM2.5 sampling was conducted in an urban site in Jinan from January,2014 to January,2015, and 17 trace elements in PM2.5 were detected using ICP-MS. The present research discussed the component characteristics, pollution levels, pollution sources, and health risks of trace elements and put forward some suggestions about pollution control.The results of PM2.5 analysis showed that, daily concentration of PM2.5 in Jinan during the sampling period was 131.4μg/m3. The concentrations in heating period (HP) and non-heating period (NHP) were 163.2μg/m3 and 95.7μg/m3, respectively, and were 6.5 and 3.9 times than the safe level (25μg/m3) recommended by World Health Organization (WHO), respectively. The concentrations of PM2.5 in HP and NHP also exceeded the secondary standard value (75μg/m3) of "Ambient Air Quality Standard" in our country. The PM2.5 pollution in urban Jinan was very serious.Elemental analysis indicated that, the concentration of Fe was 1671.5ng/m3 and was highest among the 17 elements. Element Al, Mg, and Ca were not far behind and the highest four elements account for 78.3% of total elements (TEs). Except for Fe, Al, Mg, and Ca, Zn and Pb also showed high concentrations which reached 504ng/m3 and 181ng/m3. The other elements in decrease order were Ba>Mn>Cr>Cu>V>Ni> As>Sr>Se>Cd>Co. Compared with other sites, the major PM2.5-bound toxic elements in urban Jinan showed high levels in both China and worldwide. Among all the elements, the levels of Pb, Cr, and Zn were extremely high, and were much higher than other sites. These elements needed more attention.Correlation analysis and PMF results indicated that, the major sources of trace elements in PM2.5 in urban Jinan were coal combustion, industries, traffic, and soil dust. In HP, coal combustion account for 31.4% to 39.4% of TEs and was the largest pollution source, while followed by soil dust contributing about a quarter of TEs. The contributions of industries and traffic were about 20% and were lower than the other two sources. In NHP, the contribution of traffic reached 33.9% and was the highest. Coal combustion, industries, and soil dust accounted for 21.2%,26.6%, and 18.4% of TEs, respectively.Health risk assessment model recommended by US EPA was used to assess the health risks of toxic elements. The results indicated that, As, Pb, and Cr were the most dangerous elements in study area and have serious carcinogenic and non-carcinogenic risks. Co, Ni, Cu, Zn, and Cd were safe elements in PM2.5 which posed no risks to local residents. Toxic elements in PM2.5 could have serious threat on human health especially on children which was resulting from that the total risks of them far exceeded the safe values.The health risk assessment of pollution sources showed that, the risks of four major sources apportioned by PMF in decrease order were coal combustion, industries, traffic, and soil dust. Coal combustion, accounting for approximately 50% of total risks, could be regarded as the prior pollution source. Several measures such as energy structure adjustment could be used to reduce emissions of coal combustion in order to decrease the threat of toxic elements. |
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