PCDF pollution in soils and sediments from the Pearl River Delta of China

Chemosphere 75 (2009) 1186–1195

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PCDD/PCDF pollution in soils and sediments from the Pearl River Delta of China Sukun Zhang a,c, Ping’an Peng a,*, Weilin Huang b, Xiaoming Li a,c, Gan Zhang a a b c

State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Wushan, Guangzhou 510640, PR China Department of Environmental Sciences, Rutgers University, New Brunswick, NJ 08901-8551, USA Graduate School of Chinese Academy of Sciences, Shijingshan, Beijing 100049, PR China

a r t i c l e

i n f o

Article history: Received 27 May 2008 Received in revised form 9 February 2009 Accepted 10 February 2009

Keywords: PCDD/Fs Soils Sediments The Pearl River Delta China

a b s t r a c t This study reported detection of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) for 62 soil samples and 3 sediment samples collected from the Pearl River Delta, a rapidly industrialized and highly populated area of South China. The results show that the PCDD/F concentrations ranged from 97.6 to 9,600 ng kg 1 and that the average total concentrations of PCDD/Fs are 1311, 2504, 1320 and 2335 ng kg 1 (dw), and 1.24, 3.99, 4.80 and 2.63 ng WHO1998–TEQ kg 1 for the samples collected from remote mountains, suburban areas, industrial areas, and residential/commercial areas, respectively. The WHO1998–TEQ values calculated for 17 soil samples are higher than 4 ng kg 1 but lower than 20 ng kg 1, whereas the WHO1998–TEQ values calculated for the remaining 45 samples are lower than 4 ng kg 1. According to the Canada soil quality guideline, the PCDD/F concentrations in 27.4% of the tested soil samples in this study are greater than the Canadian background concentrations, and the PCDD/F concentrations for the remaining soil samples (73.6%) are lower than the Canadian background concentration. Ó 2009 Elsevier Ltd. All rights reserved.

1. Introduction Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/ Fs) are a group of 210 chlorinated organic compounds. These chemicals are mainly produced in incomplete combustion processes such as municipal and industrial waste incineration, automobile exhaust, or as unwanted byproducts during manufacture of various chlorinated chemical mixtures such as chlorinated phenols (UNEP, 1999; Quaß et al., 2000). They were shown to cause developmental toxicity, cancers, mutagenicity, and endocrine disruption for animals and human beings (UNEP, 1999; Eljarrat and Barceló, 2004). They are extremely stable under various environmental conditions and are among persistent organic pollutants (POPs). PCDD/Fs were detected in diverse environmental samples collected from different countries (Rappe and Kjeller, 1987; Dyke et al., 1997; Schmid et al., 2003; Eljarrat and Barceló, 2004). Soils and sediments are important environmental media acting as sinks for hydrophobic organic contaminants. PCDD/Fs associated with soils and sediments may be exposed to human beings via food chain. Quantifying the concentration levels of these chemicals in soils and sediments can provide important information for ecological and environmental risk assessment and for cost and benefit

* Corresponding author. Tel.: +86 20 85290126; fax: +86 20 85290117. E-mail address: [email protected] (P. Peng). 0045-6535/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2009.02.032

analysis during decision-making process in environmental remedy and risk control. This paper reported the concentrations of PCDD/Fs associated with soil/sediment samples collected from the Pearl River Delta of the Guangzhou-Shenzhen areas, Guangdong Province, China. The study was the first phase of an integrated research program initiated by the provincial government of Guangdong in an effort to evaluate the background concentrations of PCDD/Fs and their potential environmental impact on ecosystems and human health of one of the most rapidly developing regions of China. The data of PCDD/F concentrations in the environmental media in this area are relatively limited and the information produced will be used for strategic planning of future industrial development and urbanization of this region.

2. Materials and methods 2.1. Sample collection The study area is the Pearl River Delta (Fig. 1) including eight cities (Zhaoqing, Jiangmen, Guangzhou, Foshan, Zhongshan, Dongguan, Shenzhen and Zhuhai) of Guangdong Province, China. It covers an area of about 20,000 km2 with population of about 25 million. Three sediments and 62 soil samples were collected in the year of 2000 and stored in glass bottles at 18 °C. For assessing background concentrations for PCDD/Fs, we classified the sampling

S. Zhang et al. / Chemosphere 75 (2009) 1186–1195

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Fig. 1. Spatial distribution of total concentrations of PCDD/Fs.

locations (Fig. 1) to 4 categories: (1) residential and commercial areas (Site 4 8, 13, 39, 40, 42, 46, 60 and 63), (2) industrial areas (Site 9, 11, 44, 48 and 49), (3) suburban areas (Site 1 3, 10, 12, 14 29, 31, 33 36, 43, 45, 47, 50 52, 54 59, 61, 62 and 64), and (4) undeveloped and remote mountain regions (Site 30, 37, 53 and 65). The sampled industrial areas include coal-fired power plants, aluminum and steel factories, oil-refinery factories and glassworks. There is a coal-fired power plant on the east and a steel factory on the west of Site 9. There are many aluminum and steel factories around Site 11. Site 44, around which there were many industries including an oil-refinery industry on the north, was a banana-growing farm land. There is an industrial area on south of Site 48. At Site 49 there was a glasswork on the south. The three sediments were collected from Baishigang of Wushan, Guangzhou (Site 41), the Pearl River (Site 38) and the Wanshan

Archipelagos of Zhuhai (Site 32). All 65 samples were representative of different surface environments that have been polluted variously during rapid development and industrialization over the past two decades. The soil samples were taken from the upper 0 15 cm and each sample is a composite of 5 sub-samples collected within 1 km of diameter. The sediment sampling depth was 0–10 cm from the surface. After plant debris was removed, all the samples were air dried and ground to pass through a 0.05 mm sieve. 2.2. Materials, chemicals and sample extraction/cleanup The PCDD/PCDF standards including calibration standard solutions, 13C12-labeled recovery standards and surrogate standards complying with EPA method 1613B in nonane for PCDD/PCDF

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S. Zhang et al. / Chemosphere 75 (2009) 1186–1195

analysis were purchased from Cambridge Isotope Laboratory (Austin, Texas, USA), and were diluted to appropriate concentrations with nonane before use. All organic solvents used in either GC or pesticide free quality grades were purchased from Merck (Darmstadt, Germany) or Tedia (Fairfield, OH, USA). Tetradecane and nonane in GC grades were obtained from Fluka (Augsburg, Germany). Silica gel (neutral, Type 60 Å, 70–230 mesh), alumina (base, 150 mesh), and Florisil of the highest purity were obtained from Merck (KGaA, Darmstadt, Germany) or Aldrich (Milwaukee, Wisconsin, USA), and were activated before use at 170 °C for 5 h, at 500 °C for 8 h, and 140 °C for 24 h, respectively. All 65 soil/sediment samples (approximately 50.0 g each) were extracted with toluene for 72 h using Soxhlet/Dean-Stark (SDS) extractors. During extraction, activated copper was added to remove sulfur from samples. The extracts were further cleaned up with multi-step procedures include acid silica slurry, multilayered silica gel column, base aluminum column and Florisil column. The detailed procedures described in literature (Ren et al., 2007) were exactly followed in this study. 2.3. HRGC/HRMS measurement The PCDD/Fs were analyzed with a high resolution gas chromatograph/high resolution mass spectrometer (HRGC/HRMS) (Thermo Electron Finnigan MAT 95XP) with electric impact ionization and LOCK MID (Multiply Ion Detection) mode. The instrument had a mass resolution of 10000 and a capillary column (CP-sil 8CBMS, 60 m  0.25 mm i.d.  0.25 lm film thickness). The electron impact ionization energy was at 55 eV with a source temperature of 250 °C. The GC temperature was programmed from 90 °C (2 min) to 220 °C at 55 °C/min, to 275 °C (0 min) at 1.2 °C/min, and to 301 °C (0 min) at 1.7 °C/min. The injector temperature was kept at 250 °C and the HRGC/HRMS interface temperature was held at 250 °C. The results of method blanks showed no interference. The recovery efficiencies ranged from 40% to 88%, which met the recovery limit requirement of US EPA Method 1613B. The final reported concentrations of PCDD/Fs in the soil/sediment samples were calculated based on their measured concentrations and the recovery efficiencies of the recovery standards. The total concentrations of 25 PCDD/Fs were reported as the average sum of all the quantifiable homologues and congeners from tetra- to octal-chlorinated dioxins and furans. The criteria for identification of peaks on the chromatograms as PCDDs or PCDFs, including those non-2,3,7,8substituted compounds, are relative retention time on the GC column (CP-sil 8CB), abundance ratio of isotopic ions and window retention time limit. The LOD of 2,3,7,8-TCDD was approximately 0.08 ng kg 1 dw for the soil/sediment samples. Concentrations that were lower than 1/2 of LOD were assigned a value of zero when calculating the means. 2.4. Data analysis The method of nonparametric test analysis (Npar) was used for evaluating the dataset. All statistical calculations were performed with the statistical software SPSS, Version 11.5. We used Kruskal–Wallis H tests for K independent samples for data that do not follow normal distribution of PCDD/Fs. Two groups (P1 and P2) of PNpar were calculated. P1 was referred to the four categories of the 62 independent soil samples, and P2 was referred to the total 63 independent samples (62 soil samples +1 sample (the mean for all item of 62 soil sample)). The criterion used was PNpar > 0.05 for no significant differences and PNpar < 0.05 for significant differences.

3. Results and discussion 3.1. Concentrations of PCDD/Fs The spatial distribution and the total concentrations were shown in Fig. 1, and the average total concentrations of the 25 PCDD/F congeners and homologues and their minimum, 25.percentile, median, 75.percentile and maximum are summarized in Table 1 for the 3 sediments and 62 soil samples collected from the four different geographical areas. It is clear from the table and figure that the total PCDD/F concentrations for the 62 soil samples are in the range of 97.6–9600 ng kg 1 and 0.28–15.2 ng WHO1998–TEQ kg 1 (dry weight), with average values of 2299 ng kg 1 and 3.62 ng kg 1, respectively. The average total PCDD/F concentrations are 1311, 2504, 1320 and 2335 ng kg 1 (dw), and 1.24, 3.99, 4.80 and 2.63 ng WHO1998–TEQ kg 1 (dw) for the samples collected from remote mountains, suburban areas, industrial areas, and residential/commercial areas, respectively. The results of statistics analysis listed in Table 1 show that, for both the four groups of soil samples (P1) and five groups of soil samples (P2), the 1,2,3,7,8,9-HxCDD, 2,3,7,8-TCDF, 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, 1,2,3,6,7,8-HxCDF, 2,3,4,6,7,8HxCDF, 1,2,3,4,6,7,8-HpCDF, 1,2,3,4,7,8,9-HpCDF, OCDD, PeCDFs, HxCDFs, HpCDFs, OCDF, RPCDDs + RPCDFs and I-TEQ concentrations have no statistically significant difference (PNpar > 0.05). However, the results of statistics analysis indicate different congener distributions among the four groups of soil samples. For both P1 and P2, the calculated PNpar values for 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, 1,2,3,4,7,8-HxCDD, 1,2,3,6,7,8-HxCDD, 1,2,3,4,6,7,8-HpCDD, 1,2,3,7,8,9-HxCDF, TCDDs, PeCDDs, HxCDDs, HpCDDs, TCDFs, WHO1998–TEQ and WHO2005–TEQ are 60.05, suggesting statistically significant difference. For better comparison with literature data, we calculated I-TEQ, WHO1998–TEQ and WHO2005–TEQ values for the 65 soil/sediment samples. The data are listed in Table 2, along with the I-TEQ values calculated from typical concentration ranges reported in the literature for soils and sediments. It is apparent that our data were generally comparable to the literature data obtained from USA (Nestrick et al., 1986; US EPA, 1985, 1996, 200b; Birmingham, 1990; Pearson et al., 1990; Reed et al., 1990; MRI, 1992; BC Environment, 1995; NIH, 1995; Lorber et al., 1998; Rappe et al., 1997; Tewhey Associates 1997; Pinsky et al., 1998; Rogowski and Yake, 1999; US EPA, Region 8, 2000a; Petreas et al., 2003), Australia (Müller et al., 2004), Canada (Birmingham, 1990; Grundy et al., 1997; Tewhey Associates, 1997), South Korea (Im et al., 2002; Choi et al.,2003a,b), Japan (Sakurai et al., 1996; Ono and Ikeguchi, 2001; Seike et al., 2001), Russia (Amirova and Kruglov, 2002), New Zealand (Buckland et al, 1998), Europe (Fiedler et al., 1999) including German (Rotard et al., 1994; Umweltbundesamt, 2002), UK (Stenhouse and Badshaw, 1990; HMIP, 1995; Vizard et al, 2003) and other central European central countries (Eljarrata, 2005), and other places in China (Wu et al., 1997; Chen et al., 2003; Cheng et al., 2003; Han et al., 2006; Wong et al., 2007; Liu et al., 2008; Ma et al., 2008; Shen et al., 2009). Further inspection of Table 2 indicates that the samples collected in this study from background/remote/rural/forest, suburban/urban and general industrial areas had no differences in PCDD/F concentrations compared to those reported in the literature for industrialized and populated countries and districts, but are higher than the values reported for New Zealand, Australia, Russia and Canada. For soil samples collected from known emission sources, our data are far lower than the PCDD/F levels reported for e-waste recycling sites in Guiyu, Guangdong Province and Taizhou, Zhejiang Province, China. The soil samples collected from these heavily contaminated industrial sites have PCDD/F levels ranging from below 100 ng I-TEQ kg 1

Table 1 Average PCDD/F Concentrations in Soil/Sediment Samples ng kg Compound name

1

.

Remote mountain (n = 4)

Suburban area (n = 41)

Industrial area (n = 5)

P 25

MED

P 75

MAX

AVE

MIN

P 25

MED

P 75

MAX

AVE

MIN

P25

MED

ND ND ND 0.06 0.35 6.86 0.06 0.07 ND 0.09 0.06 0.06 ND 0.31 ND

ND 0.07 0.05 0.30 0.44 10.9 0.19 0.11 0.01 0.25 0.19 0.29 ND 0.82 ND

0.01 0.15 0.16 0.59 0.71 15.4 0.26 0.22 0.22 0.47 0.36 0.47 0.06 1.59 0.03

0.03 0.34 0.53 0.93 1.40 24.3 0.53 0.55 0.58 0.72 0.58 0.63 0.14 2.25 0.12

0.09 0.72 1.33 1.32 2.72 41.3 1.24 1.27 1.09 0.96 0.90 0.84 0.18 2.42 0.32

0.02 0.26 0.41 0.64 1.12 19.8 0.46 0.45 0.38 0.50 0.42 0.46 0.08 1.48 0.09

ND ND ND ND ND 9.50 0.07 ND ND 0.21 ND ND ND 0.96 ND

ND 0.30 0.43 0.83 1.30 28.8 0.41 0.37 0.43 0.56 0.42 0.55 0.09 1.77 0.12

0.05 0.55 0.76 1.22 1.88 37.9 0.56 0.62 0.57 0.95 0.62 0.76 0.28 2.58 0.21

0.16 0.87 1.94 2.44 3.98 87.9 0.93 1.08 1.04 1.20 1.05 1.26 0.50 3.45 0.38

6.18 4.75 12.2 9.22 12.6 383 4.72 8.45 10.7 11.6 12.7 17.2 13.6 41.5 17.5

0.28 0.76 2.07 2.01 3.17 67.4 0.86 1.03 1.11 1.38 1.16 1.48 0.88 3.97 0.70

0.03 0.28 0.32 0.58 0.41 12.6 0.54 0.48 0.52 0.49 0.47 0.47 0.33 1.57 0.12

0.10 0.73 1.06 2.83 1.72 50.8 0.72 0.74 0.69 0.63 0.56 0.72 0.36 1.74 0.14

0.15 0.77 1.58 2.92 4.03 56.9 0.86 0.93 0.83 1.33 0.65 0.73 0.56 2.58 0.33

TCDDs PeCDDs HxCDDs HpCDDs OCDD TCDFs PeCDFs HxCDFs HpCDFs OCDF RPCDDs + RPCDFs Ratio of RPCDFs/RPCDDs WHO1998–TEQ WHO2005–TEQ I-TEQ

0.70 0.44 0.86 14.8 681 1.06 2.98 0.45 0.34 0.30 895 0.004 0.36 0.62 1.55

2.27 1.01 3.84 20.5 1103 4.30 3.18 0.52 1.22 0.58 1195 0.0075 0.72 0.97 1.81

3.15 2.03 5.79 25.2 1286 6.67 4.70 2.17 2.37 1.15 1327 0.011 0.86 1.11 2.09

5.74 5.35 13.5 47.9 1409 12.0 7.83 4.06 3.42 1.71 1443 0.024 1.38 1.53 2.50

12.4 12.8 33.8 108 1650 24.1 12.9 4.85 4.04 1.94 1697 0.056 2.87 2.76 3.12

4.85 4.32 11.6 43.2 1226 9.61 6.31 2.41 2.28 1.14 1311 0.021 1.24 1.40 2.21

2.18 1.68 5.25 19.6 108 5.60 3.73 0.82 1.58 0.71 197 0.003 0.86 0.96 1.19

6.11 7.33 21.8 79.4 941 11.3 6.95 3.78 2.72 1.29 1136 0.012 1.69 1.78 2.57

10.6 12.4 35.1 125 1385 15.8 9.46 5.49 3.84 2.09 1621 0.026 3.10 3.30 4.19

15.6 19.8 79.7 226 2866 24.9 12.6 10.0 6.33 2.71 3263 0.049 4.09 4.56 7.06

114 66.5 153 773 9206 193 195 65.2 61.6 61.6 9595 0.47 15.2 14.7 15.9

15.5 16.5 50.4 175 2179 28.8 16.6 9.80 7.17 4.41 2504 0.056 3.99 4.08 5.47

7.78 9.13 14.6 35.4 173 15.3 7.58 3.30 2.57 1.13 273 0.013 1.42 1.30 1.44

12.5 12.3 38.6 116 410 17.4 8.75 3.96 2.64 1.46 811 0.034 3.33 3.40 4.02

12.8 15.3 62.0 134 1172 23.6 11.0 5.12 4.41 2.90 1416 0.093 3.35 3.59 4.67

MAX

AVE

Industrial area

2,3,7,8-TCDD 1,2,3,7,8-PeCDD 1,2,3,4,7,8-HxCDD 1,2,3,6,7,8-HxCDD 1,2,3,7,8,9-HxCDD 1,2,3,4,6,7,8-HpCDD 2,3,7,8-TCDF 1,2,3,7,8-PeCDF 2,3,4,7,8-PeCDF 1,2,3,4,7,8-HxCDF 1,2,3,6,7,8-HxCDF 2,3,4,6,7,8-HxCDF 1,2,3,7,8,9-HxCDF 1,2,3,4,6,7,8-HpCDF 1,2,3,4,7,8,9-HpCDF

Residential/commercial area (n = 12)

Soil samples (n = 62)

P 75

MAX

AVE

MIN

P 25

MED

P 75

MAX

AVE

MIN

P 25

MED

P 75

0.26 1.41 2.92 4.36 4.59 67.9 2.54 3.44 3.63 3.41 2.42 2.97 1.16 8.92 1.93

0.40 2.33 4.03 4.75 7.71 90.5 3.78 4.52 3.99 4.14 4.37 4.14 3.98 9.37 3.86

0.19 1.10 1.98 3.09 3.69 55.7 1.69 2.02 1.93 2.00 1.69 1.81 1.28 4.84 1.27

0.37 ND ND ND 0.21 0 ND ND ND ND ND ND ND ND ND

ND ND ND 0.44 0.61 10.3 0.28 0.22 0.4 0.35 0.33 0.25 0.11 1.32 0.05

1.41 0 0.13 0.33 0.95 1.29 0.47 0.43 0.56 0.73 0.57 0.64 0.47 2.1 0.16

0.03 0.81 1.20 1.82 2.73 46.4 1.17 0.71 1.28 2.29 2.17 1.31 1.17 9.12 0.58

0.11 1.63 3.65 2.99 5.63 101 5.35 3.22 4.35 4.29 5.63 5.01 7.59 14.6 2.13

0.03 0.42 0.88 1.25 1.96 32.6 1.05 0.78 1.05 1.35 1.49 1.19 1.15 4.67 0.50

ND ND ND ND ND 3.03 ND ND ND ND ND ND ND ND ND

ND 0.19 0.28 0.61 1.08 19.3 0.38 0.34 0.42 0.54 0.40 0.51 0.09 1.64 0.10

0.04 0.45 0.70 1.27 1.78 36.3 0.55 0.59 0.57 0.91 0.57 0.73 0.29 2.45 0.20

0.13 0.87 1.72 2.48 3.97 70.9 1.07 1.06 1.16 1.28 1.06 1.23 0.56 3.60 0.38

S. Zhang et al. / Chemosphere 75 (2009) 1186–1195

MIN Soil samplesa 2,3,7,8-TCDD 1,2,3,7,8-PeCDD 1,2,3,4,7,8-HxCDD 1,2,3,6,7,8-HxCDD 1,2,3,7,8,9-HxCDD 1,2,3,4,6,7,8-HpCDD 2,3,7,8-TCDF 1,2,3,7,8-PeCDF 2,3,4,7,8-PeCDF 1,2,3,4,7,8-HxCDF 1,2,3,6,7,8-HxCDF 2,3,4,6,7,8-HxCDF 1,2,3,7,8,9-HxCDF 1,2,3,4,6,7,8-HpCDF 1,2,3,4,7,8,9-HpCDF

6.18 0.21 4.75 0.69 12.2 1.73 9.22 1.86 12.6 2.85 383 56.7 5.35 0.94 8.45 1.02 10.7 1.12 11.6 1.37 12.7 1.22 17.2 1.39 13.6 0.91 41.5 4.02 17.5 0.67 (continued on next page) 1189

1190

Table 1 (continued) Compound name

TCDDs PeCDDs HxCDDs HpCDDs OCDD TCDFs PeCDFs HxCDFs HpCDFs OCDF RPCDDs + RPCDFs Ratio of RPCDFs/RPCDDs WHO1998–TEQ WHO2005–TEQ I-TEQ

Remote mountain (n = 4)

Suburban area (n = 41)

Industrial area (n = 5)

MIN

P 25

MED

P 75

MAX

AVE

MIN

P 25

MED

P 75

MAX

AVE

MIN

P25

MED

27.9 29.0 67.9 232 1262 63.8 34.2 19.3 16.5 10.1 1796 0.14 6.88 6.34 7.32

36.1 36.4 83.6 280 1899 67.2 39.6 28.8 17.0 14.1 2305 0.24 9.01 8.21 8.23

19.4 20.4 53.3 160 983 37.5 20.2 12.1 8.62 5.93 1320 0.11 4.80 4.57 5.14

0.18 0.37 0.20 0 2.71 3.03 81.9 0.44 0.35 0 97.6 <0.01 0.28 0.27 0.30

2.17 2.1 6.41 17.4 312 4.32 5.71 2.55 2.27 0.94 424 0.012 0.99 1.09 1.38

3.2 1.41 5.06 4.22 10.4 17 1026 12.2 9.26 3.69 1101 0.058 1.5 2.49 3.03

12.6 15.1 24.5 103 2525 14.9 13.1 15.8 11.6 4.64 3044 0.091 4.26 4.56 4.32

62.0 25.8 109 339 7398 171 49.8 37.4 24.2 31.5 7464 0.31 6.85 6.05 8.22

14.2 8.96 25.3 84.5 2140 26.6 12.9 9.98 7.38 5.44 2335 0.072 2.63 2.84 4.36

0.20 ND 0.86 7.83 81.9 0.44 0.35 ND 0.18 0.30 97.6 0.001 0.28 0.27 0.30

5.47 5.82 15.8 49.9 705 10.4 6.32 3.35 2.60 1.23 929 0.012 1.43 1.52 2.21

9.97 10.4 33.7 107 1295 15.1 9.23 4.96 3.65 1.86 1537 0.028 2.84 3.15 4.09

15.5 19.7 59.9 176 2487 23.9 12.9 10.2 6.73 3.32 3003 0.058 4.08 4.49 7.05

114 66.5 153 773 9206 193 195 65.2 61.6 61.6 9600 0.47 15.2 14.7 15.9

14.8 14.6 43.3 148 2014 27.8 15.5 9.54 7.01 4.52 2299 0.060 3.62 3.71 5.02

MIN

P 25

MED

P 75

MAX

AVE

Sediment samplesa 2,3,7,8-TCDD 1,2,3,7,8-PeCDD 1,2,3,4,7,8-HxCDD 1,2,3,6,7,8-HxCDD 1,2,3,7,8,9-HxCDD 1,2,3,4,6,7,8-HpCDD 2,3,7,8-TCDF 1,2,3,7,8-PeCDF 2,3,4,7,8-PeCDF 1,2,3,4,7,8-HxCDF 1,2,3,6,7,8-HxCDF 2,3,4,6,7,8-HxCDF 1,2,3,7,8,9-HxCDF 1,2,3,4,6,7,8-HpCDF 1,2,3,4,7,8,9-HpCDF

0.01 0.03 0.05 0.04 0.14 0.02 0.11 0.08 0.18 0.28 0.43 0.33 0.05 0.37 0.15

0.02 0.06 0.08 0.08 0.21 0.04 0.16 0.12 0.24 0.32 0.42 0.35 0.07 0.42 0.15

ND ND 1.07 0.99 2.64 61.9 0.31 ND ND 0.52 0.52 ND ND 1.87 0.17

0.06 ND 1.17 1.31 2.71 63.5 0.34 0.14 0.08 0.67 0.56 0.25 0.06 1.96 0.29

0.12 ND 1.28 1.63 2.79 65.2 0.37 0.28 0.17 0.82 0.61 0.49 0.12 2.04 0.40

0.24 0.11 1.64 2.26 3.29 105 1.90 1.29 1.18 4.23 1.09 1.71 0.73 12.0 3.05

0.37 0.23 2.01 2.89 3.79 146 3.43 2.29 2.20 7.63 1.56 2.92 1.35 22.0 5.70

0.16 0.08 1.45 1.84 3.07 90.9 1.37 0.86 0.79 2.99 0.90 1.14 0.49 8.64 2.09

TCDDs PeCDDs HxCDDs HpCDDs OCDD TCDFs PeCDFs HxCDFs HpCDFs OCDF RPCDDs + RPCDFs ratio of RPCDFs to RPCDDs WHO1998–TEQ WHO2005–TEQ I-TEQ

0.03 0.01 <0.01 0.01 0.48 0.03 0.25 0.19 0.30 0.22 0.28 – 0.03 0.05 0.45

0.05 0.02 0.01 0.01 0.58 0.04 0.26 0.26 0.34 0.24 0.41 – 0.04 0.09 0.57

6.45 10.1 69.1 219 1673 3.95 2.01 2.07 3.01 3.71 2003 0.75 1.50 1.84 3.06

7.71 10.9 73.3 223 1701 5.54 2.73 3.08 3.40 4.02 2035 0.93 1.76 2.08 3.24

8.97 11.7 77.6 227 1730 7.13 3.46 4.08 3.79 4.34 2067 1.12 2.02 2.32 3.42

18.8 17.6 81.9 316 2630 34.0 22.7 20.0 22.1 32.4 3190 3.50 4.13 4.39 6.44

28.7 23.6 86.2 405 3530 60.8 42.0 36.0 40.4 60.5 4314 5.88 6.23 6.46 9.46

14.7 15.1 77.6 283 2311 24.0 15.8 14.1 15.7 22.8 2794 2.58 3.25 3.54 5.31

Note: P1 = P1Npar (62 soil samples in 4 categories), P2 = P2Npar (63 samples (62 soil samples 4 categories +1 categories (the mean for 62 soil sample)), PNpar > 0.05 indicates no significant differences; PNpar < 0.05 indicates significant differences. a Results for soil/sediment are given as MIN = minimum; P25 = 25.percentile, MED = median; P 75 = 75.percentile; MAX = maximum; AVE = arithmetic mean in ng/kg (dw). n: number of samples.

S. Zhang et al. / Chemosphere 75 (2009) 1186–1195

Sediment samples (n = 3) P1 P2

Table 2 Levels of PCDD/Fs in soil/sediment at different sites. Country

Sampling date, sites and type

New Zealand

Indigenous Forest Pasture lands Metropolitan centre Contaminated Rural Arable Plowland and rural/ suburban Forest Rural High density urban area Urbanized area Industrial areas Urban, near source

Europe

German

USA

Agriculture fields Urban

Australia

Canada

South Korea

Japan

Remote Agricultural Indust. Urban Background Remote soils Rural Urban Industrial sites Source Mountain Rural and urban sites Industrial Vicinity of major highways Farmland Rural Urban Industrial area

2 km to MSWs Urban background soil, 1994–1995 Near to solid waste Incinerator (4 samples) (252 samples) 1994 (36 samples) (36 samples)

Soil 1.06 0.17–1.99 0.54, 0.17–0.74 1.83, 0.26–6.67 332–98000 0.1–20 0.03–25 1.7, 0.3–3.7 35.9, 5.4–112 1, 0–26 3 (median), 0–112 2 (median), 0–88 4 (median), 0–72 4.0–60 4.0 356, 50–843 (WHO1998) 2.5, 0.1–6.0 3.0, 0.083–22.6 2.7, 0.11–5.7

2001(15 samples) (171 samples) (270 samples)

2.88, 1.77–5.51 9.4, 2–21 9.3 ± 10.2, 2–21

(14 samples) The North, Southeast and Southwest of Australia

10, 3–33 0.046, 0.0056–5.0 0.097, ND-4.0 1.3, 0.063–11 3.2, 0.023–42 3.58, 0.73–5.9
1996 (7 samples) 1996 (16 samples) 1996 (15 samples) 1999 1999 1999 (25 samples) 1985–1999

(21 samples) – – – –

Yarmouth Pole Yard Site located in Yarmouth, Maine – (30 samples) (47 samples) (20 samples) Open-burning of complicated industrial wastes Masan and Changwon, 1994 2002(25 samples) 2001–2002(25 samples) Paddy soil Playgrounds Between the Tokyo metropolitan and Kashima

1992–1998 (34 samples) (15 samples) Paddy field1993

9, 0.17–67 2.53

References Buckland et al. (1998)

Fiedler et al. (1999)

Rotard et al. (1994) Umweltbundesamt (2002)

Pinsky et al. (1998) Lober et al. (1998) US EPA reassessment (2000b) Rappe et al. (1997) US EPA (1985, 1996), Birmingham (1990), Pearson et al. (1990), Reed et al. (1990), MRI (1992), BC Environment (1995), Tewhey Associates (1997), Rogowski and Yake (1999), US EPA, Region 8 (2000a) Petreas et al. (2003) US EPA reassessment (2000b) US EPA (1985, 1996), Nestrick et al. (1986), Birmingham (1990), Pearson et al. (1990), NIH (1995), Rogowski and Yake (1999), US EPA, Region 8 (2000a) Lober et al. (1998) Müller J. (2004)

S. Zhang et al. / Chemosphere 75 (2009) 1186–1195

Near source Background Rural

I-TEQ (ng/kg)

Tewhey Associates (1997) Grundy et al. (1994) Birmingham (1990)

Im et al. (2002)

Choi et al. (2003b) Choi et al. (2003a) Seike et al. (2001) Ono and Ikeguchi (2001) Sakurai et al. (1996) (continued on next page)

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1192

Table 2 (continued) Country

Sampling date, sites and type

Russia

Background Urban Rural area Industrial urban areas Suburban/urban sites Urban Near source, near MSWI Control area

UK

China

Rural Source, E-waste recycling places Near source, E-waste recycling places

Near source, near to a large chemical Plant Suburban Residential/commercial area Industrial area Suburban Remote mountains Sediment Japan USA

Between the Tokyo metropolitan and Kashima Industrial area Florida Panhandle Bay systems

Huston Ship channel Spain China

Harbours of Almeria and Tarragona, the mouths of the Beso’s and Llobregat rivers in Barcelona Ya’er Lake The Pearl River

*

The sampling depth 0–100 cm.

Parkland Farmland Grassland Agricultural fields Ya’er lake The Pearl River Delta

(5 samples) 2002 (47 samples) >50samples (85 samples) 1990 (12 samples) (>27 samples) 2000 2004

2005

From large scale and household facilities Agriculture 2002, 12 samples 2002, 22 samples 2002, 12 samples 1997, 2 samples 1991–1994 (5 samples) (12 samples) (5 samples) (41 samples) (4 samples)

References

0.15–1.95 1.19–3.69 5.2, 0.78–17.5 6–1911 3–20 28.4, 4.9–87 0.524–5.02 0.565–1.69

Amirova and Kruglov (2002)

13.2–28.4 627–13900 129–213 18.22, 3.0–53.12 (WHOTEQ) 68.2, 47.25–89.14 14.93, 2.97–55.72 1.1, 0.42–2.3 0.87, 0.16–3.7 0.48, 0.086–0.64 0.11–0.49 0.11–0.15 0.9–7.8 4.36, 0.30–8.22 5.14,1.44–8.23 5.47,1.19–15.9 2.21, 0.36–2.87

HMIP (1995) Vizard et al. (2003) Stenhouse and Badshaw (1990) HMIP (1995) Cheng et al. (2003) Wong et al. (2007)

Liu et al. (2008)* Ma et al. (2009) Shen et al., 2009 Chen et al. (2003)

Wu et al. (1997) Han et al. (2006) This study

Lake Kasumigaura and Ono River, 1994 Perdido Bay, 2003 Eleven Mile Creek, 2003 Pensacola Bay, 2003 Santa Rosa Sound, 2003 Choctawhatchee Bay, 2003 Lower St. Andrew Bay, 2003 West Bay, 2003 Watson Bayou, 2003 Martin Lake, 2003 Deer Point Reservoir, 2003 St. Joe Bay, 2003 St. George Sound, 2003 2003 Suspend –

0.95–37.2 14.75 18.977.5 23.8 13.6 11.6 1.88–7.2 0.79–32.7 14.8 20.0–21.7 17.45 2.91–10.9 0.506 0.9–139.8 0.09 –2.91 0.1–48

Sakurai et al. (1996) Hemming et al. (2003)

1991–1994 (4 samples) 1997 (4 samples) 2002 (2 samples)

128.3–890

Wu et al. (1997)

0.6–17.5 3.1–9.5

Zheng et al. (2001) This study

Suarez et al. (2006) Eljarrata et al. (2005)

S. Zhang et al. / Chemosphere 75 (2009) 1186–1195

Urban Rural

Rural area – – – – – Taiwan Hsinchu Guiyu, reservoir area Guiyu, Rice filed Guiyu in South China Places in South China Places in Eastern China

I-TEQ (ng/kg)

1193

O C

D

D

H pC D D s

H xC D D s

C D D s

TC D D s

Pe

WHO1998-TEQ<4

O C D F

C D Fs

H xC D Fs

H pC D Fs

WHO1998-TEQ>4

Pe

100 90 80 70 60 50 40 30 20 10 0

TC D Fs

Homologue percent(%)

S. Zhang et al. / Chemosphere 75 (2009) 1186–1195

Congener percent(%)

Fig. 2. PCDD/F homologue profile for the 62 soil samples.

WHO1998-TEQ>4

25

WHO1998-TEQ<4

20 15 10 5

D O

C

D

D

D

pC H

H

8-

9-

7,

8,

6,

7,

3,

4,

3, 1,

2,

2,

D

D

D

xC

xC H 8-

7, 1,

1,

2,

3,

6,

4, 3, 2,

1,

D

D D

H 87,

7, 3, 2,

1,

xC

D C

8-

8-

Pe

TC

D

D

D

F 7, 3,

F

D C O

D pC H

98, 7,

4,

2,

F D

D

pC

xC

87, 6,

3, 2, 1,

2,

3,

4,

3, 2,

1,

1,

H

H 98,

7,

6, 4,

F

F

F

xC H 8-

7,

7,

3,

6,

3, 2,

2, 1,

D

D

D

xC

8-

H 8-

7, 4, 3,

2, 1,

H

xC

C Pe 8-

7, 4, 3,

2,

F

F D

D C Pe

87,

3, 2,

1,

2,

3,

7,

8-

TC

D

F

F

0

Fig. 3. WHO1998–TEQ calculated for the PCDD/F congeners of the 62 soil samples.

(Ma et al., 2008) to 627–13,900 ng I-TEQ kg 1 (Wong et al., 2007) at e-waste sites of China, 3720 ng I-TEQ kg 1 in waste sites of South Korea (Im et al., 2002), 50–843 ng WHO1998 kg 1 near solid waste incinerator of USA (Lober et al., 1998), and 6–1911 ng ITEQ kg 1 in industrialized urban areas of UK (Vizard et al., 2003). There are no common international guidelines for PCDD/Fs in soils and sediments. The established guidelines vary among different country and also for different land uses of the same country. In general, the guideline levels for soils in agricultural and residential areas tend to be lower than the levels for soils of industrial areas (Environment Protection and Heritage Council, 2005). In Canada, USA, Japan, Finland, Germany, Italy, the Netherlands and Sweden, the guideline values are 4 ng kg 1, 1000 ng kg 1, 1 ng kg 1, 2 ng kg 1, 1000 ng kg 1, 5000 ng kg 1, 1000 ng kg 1 and 250 ng kg 1 (Ministry for the Environment, 2002), respectively. The Chinese government has not yet established a guideline on PCDD/F-contaminated soils and sediments for evaluating their environmental risks. In recent years, many countries have used the following guidelines (BLAG, 1992). Soils containing PCDD/Fs at 5 ng TEQ kg 1 or lower should be safe for all agricultural purposes. Soils with 5– 40 ng TEQ kg 1 are not restricted for cultivation of foodstuffs, but these soils should be avoided for agricultural uses if the PCDD/F levels in foodstuffs were found bioconcentrated. Soils with I-TEQ greater than 40 ng kg 1 should not be used for growing plants that accumulate PCDD/Fs. BLAG (1992) also recommended that remediation actions be required in playgrounds, residential and industrial areas if soil contains TEQ > 100, 1000, and 10,000 ng kg 1, respectively. In Canada, the guideline value is 4 ng TEQ kg 1 for all land use types including agricultural, residential/parkland, commercial and industrial uses. The 4 ng TEQ kg 1 guideline was set based on the mean background concentration of PCDD/Fs in representative Canadian soils. For residential/parkland use, exposure analysis shows that the estimated daily intake (EDI) for the most sensitive receptor was greater than the tolerable daily intake (TDI), and therefore according to CCME (the Canadian Council of Ministers

of the Environment) protocol, it is desirable to prevent or disallow any additional soil contamination above the background PCDD/F levels. The supporting documentation notes that the soil quality guidelines for PCDD/Fs are considered to be management levels, rather than the levels that are protective of human or environmental health because they are not effects based. However, due to the conservative nature of the TDI and EDI values and of the guideline derivation protocol, risks associated with ambient levels are considered to be minimal. According to the guidelines of US EPA (1993), sediments with TEQ of 0–10, 10–20, 20–30, 30–50, and 50–80 ng kg 1 can be classified as possessing no, lowest possible, possible, possible/probable and definite risk to aquatic organisms. The I-TEQs calculated for the three sediment samples tested in this study are lower than 10 ng kg 1, suggesting little or no risk to aquatic life according to the above US EPA guidelines. As shown in Table 1, the 62 soil samples tested in this study have the WHO1998–TEQ values ranged from 0.27 to 14.7 ng kg 1, with an average value of 3.71 ng kg 1. Among them, 45 samples have WHO1998–TEQ values lower than 4 ng kg 1. The remaining 17 samples have WHO1998–TEQ values ranging from 4.09 to 15.2 ng kg 1 with an average of WHO1998–TEQ value of 7.72 ng kg 1. Also shown in Table 1, the I-TEQ values calculated for the 62 soil samples range from 0.30 to 15.9 ng kg 1 (dw). Among the 62 soil samples, 36 (58.1%) have I-TEQ values <5.0 ng kg 1 (dw) with an average value of 2.57 ng kg 1 (dw), indicating no risk for all agricultural purposes (BLAG, 1992). The remaining 26 soil samples have I-TEQs below 40 ng kg 1 (dw) with an average value of 8.40 ng kg 1 (dw), which can be used for certain cropping with cautions. Our study indicates that no remediation action is necessary for all the tested soil samples. 3.2. Homologue and congener profiles We have further analyzed the homologue and congener distribution patterns of PCDD/Fs. For convenient comparison, the tested

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S. Zhang et al. / Chemosphere 75 (2009) 1186–1195

62 soil samples were grouped to two categories according to their WHO1998–TEQ values of greater or smaller than 4 ng kg 1. As shown in Fig. 2, OCDD and HpCDDs on average constituted 70– 88% and 4.4–10.5% of the total PCDD/Fs in all the tested soil samples. This homologue distribution indicated that soil-bound PCDD/Fs in this region are highly chlorinated, suggesting that the less chlorinated homologues may have undergone much faster degradation than the highly chlorinated ones and/or that the highly chlorinated homologues may be the dominant ones produced in the sources of the pollution. The contribution of each congener to the TEQ was calculated using the WHO 1998 toxicity equivalent factors (TEFs) and the analyzed concentrations in the 62 soil samples. As shown in Fig. 3, 1,2,3,7,8-PeCDD, 1,2,3,4,6,7,8-HpCDD, OCDD, 1,2,3,4,7,8-HxCDF on average constituted 20.6, 13.3, 3.06 and 4.08% of the WHO1998– TEQ in the 17 soil/sediment samples with the values >4 ng kg 1. 4. Conclusion In conclusion, the PCDD/F concentrations analyzed for the 65 soil/sediment samples collected from this fast developing region are within 97.6–9600 ng
kg 1. Among these soil samples, 17 have I-TEQ values >4 ng kg 1 but <20 ng kg 1, and 45 samples have WHO1998–TEQ values <4 ng kg 1. According to prior recommendations, the soils and sediments may possess no risk to cropping or aquatic lives from PCDD/Fs. The average total concentrations of PCDD/Fs are 1311, 2504, 1320 and 2335 ng kg 1 (dw), and 1.24, 3.99, 4.80 and 2.63 ng WHO1998–TEQ kg 1 for the samples collected respectively from remote mountains, suburban areas, industrial areas, and residential/commercial areas. Acknowledgements The authors thank Dr. Jianzhong Song for his assistance in sample collection. This study was funded by the Department of Science and Technology of Guangdong Province (Contract No 2002A3040102). References Amirova, Z., Kruglov, E., 2002. Monitoring of PCDD/Fs and PCBs in soils of Russian cities from Bryansk to Vladivostok. Organohalogen Compds. 57, 281–284. BLAG, 1992. Rechtsnormen, Richtwerte, Handlungsempfehlungen, Meßprogramme, Meßwerte und Forschungsprogramme. Bundesminister für Umwelt, Naturschutz und Reaktorsicherheit (Hrsg.), Bonn. BC Environment, 1995. Dioxins and Furans in the British Columbia Environment. Report prepared for the Environmental Protection Department, British Columbia Environment, Victoria, British Columbia. Birmingham, B., 1990. Analysis of PCDD and PCDF patterns in soil samples: use in the estimation of the risk of exposure. Chemosphere 20, 807–814. Buckland, S.J., Ellis, H.K., Salter, R.T., 1998. Organochlorines in New Zealand: ambient concentrations of selected organochlorines in soils. In: Ministry for the Environment, Wellington. Chen, Z., Li, W., Li, C., Huang, P., Liu, G., Zhou, Z., 2003. Background levels of PCDD/Fs in soil of Beijing area China. Organohalogen Compds. 62, 495–498. Cheng, P.S., Hsu, M.S., Ma, E., Chou, U., Ling, Y.C., 2003. Levels of PCDD/Fs in ambient air and soil in the vicinity of a municipal solid waste incinerator in Hsinchu. Chemosphere 52, 1389–1396. Choi, K., Kang, D., Yoon, J., Lee, C., Jeon, S., Na, J., 2003a. Environmental levels and trend of dioxins in the Republic of Korea. Organohalogen Compds. 62, 484–486. Choi, Y., Yun, J.S., Eom, J.H., Kim, M.Y., Kim, M.H., Ahn, S.G., Yu, M.J., 2003b. PCDDs/ PCDFs level of soil accumulation on the edges of major highways. Organohalogen Compds. 62, 423–427. Dyke, P.H., Foan, C., Wenborn, M., Coleman, P.J., 1997. A review of dioxin release to land and water in the UK. Sci. Total. Environ. 207, 119–131. Eljarrat, E., Barceló, D., 2004. Toxicity potency assessment of persistent organic pollutants in sediments and sludges. Handbook Environ. Chem. 5, 99–140. Eljarrata, E., Cal, A.D.L., Larrazabal, D., Fabrellas, B., Fernandez-Alba, A.R., Borrulld, F., Marced, R.M., Barcelo, D., 2005. Occurrence of polybrominated diphenylethers, polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls in coastal sediments from Spain. Environ. Pollut. 136, 493–501. Environment Protection and Heritage Council, 2005. National Dioxins Program – National Action Plan for Addressing Dioxins in Australia. URL: www.ephc.gov.au/pdf/EPHC/final_NAP_october_2005_rev.pdf.

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