Article pubs.acs.org/est
Atmospheric PCDD/F Concentrations in 38 Cities of China Monitored with Pine Needles, a Passive Biosampler Pei Chen,†,‡ Jun Mei,†,§ Ping’an Peng,*,† Jianfang Hu,† and Deyi Chen† †
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China ‡ University of Chinese Academy of Sciences, Beijing 100049, China § Department of Chemistry, Guangdong Medical College, Dongguan 523808, China S Supporting Information *
ABSTRACT: Many studies have shown that pine needles are a good biomonitor for atmospheric concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). However, this biomonitor has not been tested in large areas, and the quantitative relationship between concentrations in pine needles and air has not been established. In the present study, we collected pine needles from 38 cities in China. The concentrations of 2,3,7,8-PCDD/ Fs were measured by gas chromatography combined with high-resolution mass spectrometry. The total PCDD/F concentrations ranged from 5.4 to 330 pg/g dry weight of pine needles. The pine needles from cities located in central China and three major city agglomerations contained high concentrations of PCDD/Fs, while those from cities in the west and on the coast contained relatively low concentrations. Primary emission and diffusion processes were the main controls of the PCDD/F concentrations in pine needles. Homologue profiles of PCDD/Fs in pine needles were characterized by PCDFs/ PCDDs >1 in the industrialized cities and penta- > tetra- and octa- for PCDFs and increasing concentration with increasing chlorine substitution number for
Table 2. Comparison of PCDD/F Concentrations in Pine Needles country
concentration
China
87−167 pg/g dw
China
5.39−330.01 pg/g dw
Korea
Japan
26.18−2087.68 pg/g dw 10.126−155.480 pg/g ww 27−110 pg/g ww
Germany
2.50−11.48 pg/g dw
Poland
5.09−151.3 pg/g ww
Austria
14.3−167.9 pg/g dw
Korea
TEQ 2.1 (mean) pg/g dwa 0.08−21.22 pg/g dwa 0.07−17.37 pg/g dwb 0.09−20.54 pg/g dwc 0.62−26.88 pg/g dwc 0.763−7.384 pg/g wwc
0.78−1.73 pg/g dwc 0.85−1.91 pg/g dwa 0.01−3.18 pg/g dwc 0.3−1.9 pg/g dwc
reference Chen et al., 200619 this study
Ok et al., 200218 Kim et al., 200528 Hanari et al., 200417 Rappolder et al., 200711
Bochentin et al., 200729 Weiss et al., 199713
a
WHO1998-TEF. bWHO2005-TEF. cI-TEF; dw = dry weight; ww = wet weight.
PCDDs. Hexa- and hepta-PCDFs in Cedrus deodara and Pinus massoniana contribute to the total concentrations of PCDD/Fs from 7.94 to 43.98% (mean of 25.92%) and 11.83 to 39.40% (mean of 25.22%), followed by octa-PCDDs, penta-PCDFs, and tetra-PCDFs, with mean values of 20.02, 19.77, and 9.08%. Samples from Qingdao are characterized by high contents of penta-PCDDs. A close look at Figure 3 indicates slight differences in homologues among the samples from different cities. The Cedrus deodara samples collected from the Yangtze River Delta site were dominated by OCDD/Fs and HpCDD/Fs, accounting for 25.20 and 28.01% of total PCDD/Fs, while those from Beijing and Tianjin were dominated by HxCDD/Fs and HpCDD/Fs, accounting for 24.69 and 24.54% of total 13338
dx.doi.org/10.1021/es303468y | Environ. Sci. Technol. 2012, 46, 13334−13343
Environmental Science & Technology
Article
Figure 3. Tetra-, penta-, hexa-, hepta-, and octa-PCDD/F composition in pine needles in Cedrus deodara (A) and Pinus massoniana (B).
PCDD/Fs. The Pinus massoniana samples from Jiangxi province were dominated by HpCDD/Fs, accounting for 37.35−42.09% of the total PCDD/Fs. Differences in source or transport, degradation, and accumulation processes could cause small differences in the homologues among the samples. The ratio of PCDFs to PCDDs is a source and degradation indicator. Fresh PCDD/Fs from combustion processes are high in PCDFs, while aged PCDD/Fs or those from sources other than combustion are high in PCDDs. Therefore, a high PCDFs/PCDDs ratio indicating that the PCDD/Fs in the pine needles were fresh produced31 and derived mainly from combustion. We plot total PCDD/F concentration against the PCDF/ PCDD ratio in Figure S2. It can be seen that most of the samples had ratios >1, indicating that the PCDD/Fs in the pine needles were fresh and derived mainly from combustion as there are more industrial activities in these cities. The samples with PCDFs/PCDDs
