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Fs levels
Chemosphere 64 (2006) 579–587 www.elsevier.com/locate/chemosphere
Influence of a municipal solid waste incinerator on ambient air and soil PCDD/Fs levels Jeong-Eun Oh a, Sung-Deuk Choi b, Se-Jin Lee b, Yoon-Seok Chang a
b,*
Department of Environmental Engineering, Pusan National University, San 30, Jangjeon-dong, Geumjeong-gu, Pusan 609-735, Republic of Korea b School of Environmental Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang 790-784, Republic of Korea Received 25 March 2005; received in revised form 19 August 2005; accepted 3 November 2005 Available online 10 January 2006
Abstract To examine the influence of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) emissions from a municipal solid waste incinerator (MSWI) on the environment, we measured the levels of PCDD/Fs in ambient air and soil samples collected near a MSWI in Bucheon, Korea. The PCDD/Fs concentrations in the ambient air samples ranged from 0.22 to 1.16 pg I-TEQ m 3 (13.39–75.16 pg m 3), with an average of 0.66 pg I-TEQ m 3 (35.62 pg m 3). The soil samples contained between 1.25 and 74.98 pg I-TEQ g 1 (38.15–3303.33 pg g 1), with an average of 19.06 pg I-TEQ g 1 (1077.11 pg g 1). These levels were higher than those previously reported by other investigators in a number of surveys. The furan homologues predominated in the air samples and some soil samples, and the soil PCDD/Fs levels decreased with increasing distance from the MSWI. Comparison of the homologue patterns and a multivariate statistical analysis showed that PCDD/Fs emission from the MSWI directly affected the pattern of PCDD/Fs in air, while the PCDD/Fs patterns in soil differed according to the location relative to the MSWI, roads, and construction sites. These results collectively indicate that the MSWI was the major PCDD/Fs emission source in this area, but that unidentified combustion sources and vehicles might influence the environment to some extent. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: PCDD/Fs; Incinerator; Air; Soil
1. Introduction Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are extremely hazardous chemicals that form both naturally and during combustion (Hashimoto et al., 1990; Gribble, 1994; Brzuzy and Hites, 1996; Kim et al., 2003). These compounds are semi-volatile and hydrophobic, and they easily accumulate in the environment, especially in organic carbon-rich media such as soil and sediment (Schuhmacher et al., 1997). PCDD/Fs emitted into the atmosphere easily undergo dry and wet
*
Corresponding author. Tel.: +82 54 279 2281; fax: +82 54 279 8299. E-mail address: [email protected] (Y.-S. Chang).
0045-6535/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2005.11.012
deposition in the vicinity of the source, while low-chlorinated congeners can undergo long-range transport via air masses, global distillation and the grasshopper effect (Wania and Mackay, 1996). Many studies have evaluated the PCDD/Fs levels near emission sources, and their impact on the environment (Deister and Pommer, 1991; Jimenez et al., 1996; Schuhmacher et al., 1997, 1999, 2002; Wallenhorst et al., 1997; Domingo et al., 2000, 2001; Park et al., 2004). Incinerators can be an important source of PCDD/Fs pollution in Korea due to the policy on municipal wastes; the contribution of incineration to waste treatments increased from 5.5% in 1996 to 14.5% in 2003 (NIER, 2004). The first Korean national survey of PCDD/Fs emission from incinerators was launched in 1997 (Oh et al., 1999; Shin et al., 1999). This survey increased public awareness of PCDD/Fs
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contamination near incinerators. However, only a few studies have examined PCDD/Fs levels in the environment near incinerators, and most of these reports have focused on industrial waste incinerators (Park, 2001; Im et al., 2002; Park et al., 2004; Kim et al., 2005a,b). Here, we examined the concentrations of PCDD/Fs in ambient air and soil samples near a municipal solid waste incinerator (MSWI) located in a residential area, and used meteorological data, homologue pattern comparison, and multivariate statistical analysis to determine the relationship between PCDD/Fs emissions and the environment.
that the area within 1 km of the MSWI is likely to be under the direct influence of its PCDD/Fs emission (data not shown). In addition to this MSWI, a small-scale (<2 tons day 1) industrial waste incinerator (IWI) had been operated near the MSWI, but it was not in service during the study period. PCDD/Fs emissions from this IWI were never measured due to its small scale and irregular operation. There are no other incinerators in the study area (Fig. 1); the MSWI is likely to be the most significant source of PCDD/Fs. 2.2. Air and soil sampling
2. Materials and methods 2.1. Description of the study area Bucheon City, located west of Seoul, Korea, is a central industrial city in the Gyeongin industrial region. Our study area is located in the northern part of the city, where industrial and residential areas coexist (Fig. 1). More than 45 000 people live in the study area, which also contains few hundreds small-scale factories (metal and mechanical, chemical, assembly factories, etc.), which were not considered important PCDD/Fs sources. A MSWI located in this area was put into service in 1995 and has a treatment capacity of 200 tons day 1. In 1997, the PCDD/Fs emission from this incinerator was recorded as the highest in Korea (36.50 ng I-TEQ N m 3) (Oh et al., 1999, 2002). As a result of this, a selective catalytic reduction reactor and bag filter were installed in 1999, and the PCDD/Fs emission decreased to 0.003–0.006 ng I-TEQ N m 3 as measured in 2001–2003 (unpublished data). Atmospheric dispersion modeling (ISC3) indicates
Fig. 1 shows the air and soil sampling sites in relation to the MSWI. Ten air samples (A1–A10) at three sites were taken from August 1999 to November 2000 using high volume air samplers (DHA-1000S, SIBATA). Sampling was performed on the roof of three buildings over 10 m in height (a1, a2, and a3). Glass fiber filters and polyurethane foam plugs (PUF) were used to collect vapor-phase PCDD/Fs as well as airborne particles. The sampling time and air volumes were about 24 h and 1000–1500 m3, respectively (Table 1). Before sampling, the filter was baked at 450 °C for 12 h, and the PUF were pre-cleaned with methylene chloride in a Soxhlet apparatus for 24 h. Based on the ISC3 model result, nine soil samples were collected from within 1 km of the MSWI and one soil sample was taken at 2 km. The study area is highly developed with many paved roads, residences, industries and construction areas. This complicated soil sample collection; most of the samples were collected from the vicinity of driveways. For reference purposes, a background soil sample was collected at Mt. Dobong, a national park 30 km
Fig. 1. PCDD/Fs sampling sites and location of the MSWI in Bucheon, Korea.
J.-E. Oh et al. / Chemosphere 64 (2006) 579–587
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Table 1 Information on the air samples Sample #
Site
Sampling date
Sampling volume (m3)
Mean temperature (°C)
PCDD/Fs (pg I-TEQ m 3)
A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
a3 a1 a3 a1 a2 a1 a2 a1 a1 a1
08.19, 1999 08.17–08.18, 11.20–11.21, 11.07–11.08, 12.20–12.21, 12.18–12.09, 04.12–04.13, 04.11–04.12, 07.13–07.15, 11.03–11.05,
1636.0 1570.5 1100.1 1128.5 1133.3 1131.8 1039.4 1086.0 1592.3 1095.5
25.1 27.3 10.1 5.6 7.6 6.1 11.5 9.7 25.8 13.2
0.379 0.672 0.871 1.116 1.161 0.368 0.548 0.574 0.221 0.664
1999 1999 1999 1999 1999 2000 2000 2000 2000
Site: three air sampling locations noted in Fig. 1.
away from the study area. All soil samples were collected at a depth of 0–10 cm. Meteorological data (wind velocity, wind direction, and temperature) during the sampling period were obtained from the Korean Meteorological Administration (KMA) and used to make a wind rose diagram (Fig. 2) using the Grapher 4.0 software package (Golden Software Inc.). 2.3. Instrumental analysis Sample preparation was conducted according to US EPA method 1613. The solid samples were transferred to glass Soxhlet thimbles, then spiked with a mixture of 13 C12-labelled PCDD/Fs internal standards (1 ng) and extracted for 16 h with toluene. The extracts were washed with H2SO4 until they became colorless and were then washed with hexane-rinsed water for neutralization. Samples were cleaned by passage through a silica gel column (with layers of basic, neutral, acidic and neutral silica), followed by passage through an activated acidic alumina column capped with anhydrous Na2SO4. N2 gas was used to concentrate each sample, and 13C12-labelled PCDD/Fsrecovery standards (1 ng) were added before samples were 0 45
315
270
<=1 >1 - 2 >2 - 3 >3 - 4 >4 m/s
subjected to GC/MS analysis using an HRGC/HRMS (HP 6890/JMS 700T) with a DB-5MS column (60 m, 0.25 mm i.d., 0.25 lm film thickness). The temperature program of the capillary column was as follows: (1) 140 °C initial isothermal hold for 4 min; (2) increase at 15 °C/min to an isothermal hold at 220 °C for 3 min; (3) increase at 1.5 °C/min to an isothermal hold at 240 °C for 2 min; (4) increase at 4 °C/min to an isothermal hold at 310 °C for 6 min. The sample was introduced by splitless injection. The MS was operated at a resolution of 10 000 under positive EI conditions (38 eV electron energy), and the data were obtained in the single ion monitoring (SIM) mode. Two out of the three ions (M+, M+2, and M+4) were monitored. The toxic 2,3,7,8-substituted PCDD/Fs as well as tetra- to octa-chlorinated homologues were quantified based on isotope ratios within ±15% of the theoretical values and signal: noise ratios of P2.5. Recoveries of the 13C12-labelled PCDD/Fs-internal standards in the environmental samples were in the range of 50–120%, which satisfied the EPA method 1613 protocol. 2.4. Statistical analysis Cluster analysis and principal component analysis (PCA) were used to evaluate the similarities or differences of the PCDD/Fs homologue patterns in air, soil, and stack gas samples. Prior to analysis, the PCDD/Fs homologue levels were normalized with respect to the total PCDD/Fs concentration in the relevant sample. The statistical analyses were performed using the SIMCA-P 7.01 (U-metri) and SPSS 11.0 (SPSS Inc.) software packages.
90 0%
4%
8% 12% 16%
3. Results and discussion 3.1. PCDD/Fs in ambient air samples
225
135 180
Fig. 2. Wind rose diagram reflecting the sampling period (August 1999– November 2000).
Comparisons of PCDD/Fs levels among the samples were based on the Toxic Equivalent Quantity (TEQ) of the 2,3,7,8-substituted PCDD/Fs (reflected as Toxic Equivalent Factors; TEFs) and the sum of all homologue concentrations (Table 2). Lohmann and Jones (1998) noted the
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Table 2 PCDD/Fs concentrations in the ambient air and MSWI samples (unit: air (pg I-TEQ m 3, pg m 3), MSWI (ng I-TEQ Nm 3, ng N m 3)) Isomer
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
MSWI
2,3,7,8-TeCDD 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 OCDD 2,3,7,8-TeCDF 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 OCDF
0.01 0.10 0.05 0.10 0.09 0.48 0.66 0.21 0.18 0.32 0.24 0.22 0.30 0.10 0.80 0.11 0.44
0.02 0.10 0.10 0.22 0.10 1.14 1.78 0.55 0.48 0.38 0.68 0.58 0.19 0.94 2.52 0.65 2.97
0.04 0.14 0.18 0.32 0.25 1.76 3.55 0.34 0.55 0.43 0.55 0.85 0.08 1.22 4.96 0.83 5.01
0.03 0.23 0.15 0.25 0.19 1.67 2.98 0.19 0.43 0.89 0.99 0.84 1.43 0.45 3.78 0.71 3.97
0.03 0.19 0.11 0.20 0.13 1.15 2.85 0.36 0.32 1.36 0.62 0.61 0.76 0.23 2.05 0.28 1.72
0.01 0.07 0.04 0.07 0.05 0.58 1.35 0.15 0.15 0.37 0.23 0.20 0.31 0.10 0.82 0.13 0.56
0.01 0.10 0.08 0.10 0.09 0.63 1.34 0.25 0.28 0.46 0.51 0.40 0.62 0.25 1.97 0.44 3.38
0.01 0.09 0.05 0.10 0.08 0.64 1.48 0.22 0.24 0.45 0.52 0.39 0.54 0.23 2.08 0.47 3.58
0.01 0.03 0.02 0.05 0.03 0.29 0.59 0.08 0.09 0.19 0.21 0.17 0.23 0.10 0.66 0.15 1.01
0.02 0.11 0.08 0.18 0.05 0.78 1.48 0.21 0.28 0.58 0.58 0.52 0.75 0.22 1.93 0.34 1.79
1.02 5.17 9.78 5.77 6.91 31.13 52.04 12.35 17.82 35.73 25.19 27.17 40.60 2.41 60.67 10.96 37.55
TeCDD PeCDD HxCDD HpCDD OCDD TeCDF PeCDF HxCDF HpCDF OCDF
2.06 1.84 1.74 0.95 0.66 5.91 3.75 2.46 1.38 0.44
3.28 2.83 2.83 2.38 1.78 7.38 7.28 7.65 5.43 2.97
5.00 4.65 5.99 3.58 3.55 15.66 13.58 9.81 8.33 5.01
3.13 3.63 4.58 3.00 2.98 9.19 9.51 9.30 6.76 3.97
2.26 3.33 3.01 2.20 2.85 6.60 8.09 6.31 3.34 1.72
0.71 1.12 1.20 0.99 1.35 2.33 2.71 2.20 1.52 0.56
1.57 1.68 1.73 1.14 1.34 5.70 4.90 4.38 3.68 3.38
1.27 1.41 1.48 1.13 1.48 3.93 3.86 3.98 3.97 3.58
1.22 0.75 0.79 0.64 0.59 2.87 2.05 2.01 1.45 1.01
3.11 3.49 2.05 1.34 1.48 7.65 6.69 5.83 3.21 1.79
79.95 109.89 129.83 64.00 52.04 653.19 586.34 283.15 107.79 37.55
0.38 21.19
0.67 43.81
0.82 75.16
1.13 56.05
1.16 39.71
0.37 14.69
0.57 29.50
0.54 26.09
0.23 13.38
0.67 36.64
36.50 2103.72
I-TEQ Total
MSWI emission data were obtained from Oh et al. (1999).
large variation of PCDD/Fs concentrations measured from ambient air across a number of surveys in various countries. In general, PCDD/Fs levels tend to be <0.01 pg I-TEQ m 3 in remote sites, 0.02–0.05 pg I-TEQ m 3 in rural sites, and 0.1–0.4 pg I-TEQ m 3 in urban/industrial sites. Recently, ambient air PCDD/Fs levels near three different MSWIs in Italy were found to be in the range of 0.010–0.337 pg I-TEQ m 3 (Caserini et al., 2004). In Korea, urban sites (Seoul, Incheon, Daejeon, Jeonju, Cheonan, and Gunsan) have reported PCDD/Fs ranges of 0.015–0.758 pg I-TEQ m 3 (Kim et al., 2001; Park and Kim, 2002), and air samples collected in the vicinity of an IWI showed PCDD/Fs values ranging from 0.195 to 0.301 pg I-TEQ m 3 (Kim et al., 2005a), while two industrial areas (Pohang and Yeosu) showed relatively low PCDD/Fs levels of 0.034–0.172 pg I-TEQ m 3 (Oh et al., 2001). According to the 5-year (1999–2003) nationwide survey conducted by the Korean National Institute of Environmental Research (http://www.nier.go.kr/nierdepart/eds/), the average PCDD/Fs levels in ambient air in Korea (n > 150) have decreased from 0.425 pg I-TEQ m 3 in 1999 to 0.271 pg I-TEQ m 3in 2003.The PCDD/Fs levels observed in this study ranged from 0.221 to 1.161 pg I-TEQ m 3 (13.39–75.16 pg m 3) with an average of 0.66 pg I-TEQ m 3 (35.62 pg m 3) (Table 2). These values are higher than those reported in the previous surveys, con-
firming the existence of one or more significant sources of PCDD/Fs in or near the study area. PCDD/Fs concentrations show seasonal variations (usually high in winter and low in summer), likely associated with combustion sources, temperature inversion conditions, and several loss processes including photolysis, chemical reactivity, wet and dry deposition, and scavenging by vegetation (Lohmann and Jones, 1998). Thus, identification of seasonal PCDD/Fs level variation in the atmosphere is important for a proper evaluation of the contribution from each source. As shown in Fig. 3, the seasonal variations in the PCDD/Fs levels were observed in our study area. The first four PCDD/Fs concentrations (Summer 1999–Spring 2000) are the averages of two measurements each. Since the operation of the MSWI and other incinerators is likely to be consistent year-round, domestic burning and other environmental factors might account for the observed seasonal variation. In addition, wet deposition by precipitation is likely to play a key role in the low levels of atmospheric PCDD/Fs seen during the summer. The Korean Meteorological Administration reported that summer (June–August) precipitation accounted for 62% and 59% of the total annual precipitation in the study area during the sampling period (August 1999–November 2000) and the last 30 years (1971–2000), respectively.
J.-E. Oh et al. / Chemosphere 64 (2006) 579–587 30 pg I-TEQ m-3 Temperature
1.2
25
15
0.8
10
0.6
5
Fa ll
m er 2
Su m
Sp rin g
W in t
Fa ll
Su m m
20 00
-10 00 0
0.0 20 00
-5
er 19 99
0
0.2
19 99
0.4
Temperature (°C)
20 1.0
er 19 99
PCDD/Fs (pg I-TEQ m-3)
1.4
Fig. 3. Seasonal changes in PCDD/Fs concentrations during the study period.
It can be argued that two measurements per season are not sufficient to represent seasonality, but other studies for this area have shown high PCDD/Fs concentrations in winter (up to 1.33 pg I-TEQ m 3) and low concentrations in summer (0.522 pg I-TEQ m 3) (Lee et al., in preparation; Seo et al., 2001). These independent measurements suggest that the atmospheric levels of PCDD/Fs vary seasonally in the study area. 3.2. PCDD/Fs in soil samples A number of recent surveys have provided details on country, incinerator type, year, number of samples, and PCDD/Fs concentrations (Table 3) and have shown a wide range of PCDD/Fs concentrations in soil. Background levels seem to be about 0.1 pg I-TEQ g 1, while samples taken near incinerators have shown levels up to 3.7 ng I-TEQ g 1, a peak PCDD/Fs level found adjacent to an open burning-type IWI in Changwon City, Korea (Im et al., 2002). The PCDD/Fs concentrations observed in the present study (1.25–74.98 pg I-TEQ g 1) are higher than those found in soil samples collected near MSWIs in Italy, Spain, and Taiwan (Domingo et al., 2000, 2001;
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Schuhmacher et al., 2000; Cheng et al., 2003; Caserini et al., 2004), while they are consistent with those found near IWIs in Korea (Park, 2001; Park et al., 2004; Kim et al., 2005a,b). As shown in Table 4, the soil samples in the present study were found to contain between 1.25 and 74.98 pg I-TEQ g 1 (38.15–3303.33 pg g 1) of PCDD/Fs with an average of 19.06 pg I-TEQ g 1 (1077.11 pg g 1). This was substantially higher than the background soil PCDD/Fs concentration of 0.92 pg I-TEQ g 1 (157.56 pg g 1). These observed PCDD/Fs concentrations are mostly beyond the 5 pg I-TEQ g 1 limit that restricts the cultivation of certain vegetables but do not exceed the limit for the cultivation of other types of plants (40 pg I-TEQ g 1) (Boos et al., 1992). The highest soil PCDD/Fs level (74.98 pg I-TEQ g 1) was observed in sample S1, which was collected at the front gate of the MSWI. Sample S6, which was collected near the small-scale, inoperative IWI, had a high level of PCDD/Fs (45.17 pg I-TEQ g 1). The high levels of PCDD/Fs in soil samples collected adjacent to the two incinerators might be explained by transportation of waste, temporary storage of fly ash, or the presence of wastes in the incinerator yard, rather than gaseous transmission. 3.3. Influence of stack gas on air and soil 3.3.1. Levels of concentration It is important to identify the source of contamination and its influence on the environment. The general method for identifying the source of PCDD/Fs contamination is to compare the levels of PCDD/Fs with distance. If PCDD/Fs levels tend to decrease as the distance from a certain site increases, then the site can be considered a source of PCDD/Fs. As most of our sampling sites were within 1 km of the MSWI, we were unable to find a strong relationship between the soil PCDD/Fs levels and the distance from the incinerator (Fig. 4). However, we could clearly observe a trend of declining PCDD/Fs levels as the distance increased. High PCDD/Fs levels were detected in most soil samples taken from sites near the MSWI,
Table 3 Recent reports of PCDD/Fs concentrations in soil samples collected near incinerators Country
Location
Type
Year
Number of samples
Concentration (pg I-TEQ g 1)
Reference
Italy
Po Valley Veneto Adige Valley Hsinchu Catalonia Barcelona
MSWI MSWI MSWI MSWI MSWI MSWI
2000 2000–2001 2001 2001 1996–1997, 1999 1999
3 3 3 8 72 24
0.7–1.5 1.1–1.4 0.08–1.2 0.52–5.02 0.11–5.80 1.22–34.28
Buchon Gunsan Pyoungtak Pyoungtak Changwon and Masan Yangju
MSWI IWI IWI IWI IWI IWI
1999–2000 – 2002–2003 2002 – 2003
10 13 47 4 23 30
1.25–74.98 0.16–45.25 0.7–15.5 1.16–77.96 0.2–3720 0.10–35.19
Caserini et al. (2004) Caserini et al. (2004) Caserini et al. (2004) Cheng et al. (2003) Domingo et al. (2001) Domingo et al. (2000); Schuhmacher et al. (2000) This study Park (2001) Park et al. (2004) Kim et al. (2005a) Im et al. (2002) Kim et al. (2005b)
Taiwan Spain
Korea
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Table 4 PCDD/Fs concentrations in the soil samples (unit: pg I-TEQ g 1, pg g 1) S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
Background
2,3,7,8-TeCDD 1,2,3,7,8-PCDD 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 OCDD 2,3,7,8-TeCDF 1,2,3,7,8-PCDF 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 OCDF
0.69 5.22 7.68 16.16 7.94 180.24 622.92 5.69 8.57 73.97 29.22 46.03 134.28 27.09 333.03 67.48 430.18
0.24 2.86 0.84 1.18 0.89 14.34 324.07 3.26 2.94 4.46 5.54 4.10 6.56 2.01 25.16 6.59 37.36
0.44 0.71 0.51 1.16 0.97 12.36 51.58 3.94 3.03 3.82 4.12 3.17 3.66 1.35 12.69 2.24 11.08
0.09 0.36 0.16 0.22 0.19 3.04 14.90 2.39 1.06 2.92 1.67 0.89 0.92 0.47 3.36 0.95 6.70
0.47 2.07 0.77 1.30 0.54 15.02 235.81 5.89 4.93 4.65 5.62 4.74 6.88 2.44 23.72 4.94 30.90
0.64 5.43 8.68 11.99 8.21 113.82 367.80 7.61 13.85 27.30 34.87 42.38 87.96 17.72 320.05 39.99 419.59
0.30 0.93 0.92 1.85 1.14 14.87 159.87 7.96 4.34 13.19 9.61 6.62 8.19 3.39 27.90 4.79 34.71
0.51 3.26 2.36 3.70 2.48 31.59 111.23 6.66 7.75 11.89 11.26 11.18 17.78 4.64 63.80 9.50 70.61
0.03 0.20 0.13 0.04 0.11 0.64 5.79 1.52 0.93 1.26 1.07 0.41 0.47 0.32 1.00 0.23 1.83
0.87 3.38 2.40 4.15 2.26 28.07 196.48 9.04 10.32 14.00 15.51 15.36 19.71 4.80 68.13 7.06 57.32
0.02 0.17 0.14 0.36 0.46 3.98 109.86 0.76 0.38 0.54 0.52 0.39 0.61 0.18 1.80 0.44 8.32
TeCDD PeCDD HxCDD HpCDD OCDD TeCDF PeCDF HxCDF HpCDF OCDF
48.42 89.04 176.00 346.47 622.92 114.27 290.84 536.16 649.03 430.19
27.08 40.32 16.70 27.58 324.07 48.08 44.90 47.07 52.17 37.36
22.76 31.32 14.56 20.30 51.58 50.92 38.78 31.69 21.53 11.08
7.78 16.05 2.69 4.58 14.90 12.82 12.33 7.86 6.60 6.70
62.37 55.70 15.83 30.90 235.81 72.49 61.83 52.17 46.26 30.90
88.32 156.46 154.89 225.57 367.80 183.45 291.17 437.99 528.67 419.60
24.96 85.32 21.82 28.39 159.87 61.21 65.99 58.77 46.75 34.71
61.62 121.88 59.27 62.79 111.23 153.48 129.25 119.67 115.79 70.61
1.92 4.51 1.57 1.48 5.79 7.47 6.53 4.37 2.67 1.83
104.20 110.48 63.56 57.10 196.48 211.71 198.96 155.61 109.41 57.32
2.59 2.33 5.58 9.78 109.86 6.76 3.91 4.26 4.18 8.32
I-TEQ (pg I-TEQ g 1) Total (pg g 1)
74.98
7.31
5.08
2.57
7.60
45.17
12.22
15.71
1.24
18.69
0.92
3303.34
665.33
294.52
92.31
664.26
2853.92
587.79
1005.59
38.14
1264.83
157.57
80
PCDD/Fs in soil (pg I-TEQ g-1)
S1 60
S6 40
20
S8 S5 S3
0
0
S10 S7 S2
500
S9 S4
1000
1500
2000
Distance (m)
Fig. 4. Decline of PCDD/Fs levels in soil with increasing distance from the MSWI.
whereas the lowest PCDD/Fs level was observed in the sample taken from >1500 m away (S9). Even if the two samples (S1 and S6) collected from the incinerator gates were disregarded, the trend of declining PCDD/F levels with increasing distance from the MSWI is also seen in Fig. 4 (average value within 500 m: 8.92 pg I-TEQ g 1, within 800 m: 7.39 pg I-TEQ g 1, at 1.8 km: 1.25 pg I-TEQ g 1). These results indicate that the trend of declining PCDD/Fs levels with increasing distance from the
source are reliable, regardless of whether the source was dispersion of fly ash or stack emissions. When investigating the influence of an incinerator on the environment, it is important to consider wind direction. In the study area, the major winds blew in western, northern, and northeastern directions; eastern and southern winds were weak (Fig. 2). Interestingly, we did not observe a significant correlation between the major wind directions and PCDD/Fs levels in soil samples. For example, sample S8, which was collected at the northeast side of the MSWI, had a higher PCDD/Fs concentration (15.71 pg I-TEQ g 1) than did soil samples S3 (5.08 pg I-TEQ g 1), S4 (2.57 pg I-TEQ g 1), and S5 (7.60 pg I-TEQ g 1), which were collected at southern sites. However, it is possible that the MSWI continuously influenced the residential area to the south due to the major winds. 3.3.2. Comparison of homologue patterns In addition to comparing total concentration levels among soil samples, we also used homologue pattern comparisons to investigate the relationships between the incinerator and the environment. To compare the homologue patterns of each sample, soil and air data were normalized to the total PCDD/Fs; [PCDDs] + [PCDFs] = 1. For the incinerator data, we used the PCDD/Fs homologue values previously measured from this MSWI (Oh et al., 1999).
J.-E. Oh et al. / Chemosphere 64 (2006) 579–587
Similar homologue patterns were observed between the MSWI and ambient air samples (A1–A10; Fig. 5a). The tetra, penta and hexa-chlorinated furans were particularly dominant in these samples. Many studies have reported that PCDD/Fs homologue patterns are similar among the various thermal processes, and that PCDFs levels were higher than PCDDs levels in flue gases (Lohmann and Jones, 1998; Oh et al., 1999; Mamontov et al., 2000). The homologue patterns found in the air samples of this study were similar to those found in stack gas (Faengmark et al., 1994). Background air tends to have a typical homologue pattern of high chlorinated dioxins (e.g. OCDD) and generally low levels of chlorinated furans (Fiedler et al., 1996). As described previously, high levels of low-chlorinated furans indicate the presence of potential combustion sources of PCDD/Fs, such as an incinerator. In this study, OCDD accounted for 70% of the homologues in the background soil sample (Fig. 5b); this is a relatively a typical ‘background pattern’ (Fiedler et al., 1996). In contrast, most of the soil samples examined in this study had higher fractions of furans than those of the background soil sample, though OCDD remained dominant. Collectively, these results strongly suggest that both the soil and air samples have been affected by a PCDD/Fs source such as a MSWI.
3.3.3. Multivariate analysis Cluster analysis and principal component analysis (PCA) were used to verify the influence of the MSWI and the relationships among stack gas, ambient air, and soil samples (Fig. 6). The first principal component (X-axis: PC1) was found to account for 37.4% of the variance, and the second principal component (Y-axis: PC2) accounted for 31.2% (Fig. 6b). Cluster analysis revealed four large groups: Groups I and III contained the soil samples, Group IV contained the background soil sample, and Group II contained the remaining samples clustered into three subgroups consisting of the stack gas, ambient air samples, and remaining soil samples. These findings indicate that all air samples might be affected by the MSWI, whereas only a subset of the soil samples was affected. A large variation in homologue patterns was observed among the soil samples, including the background soil. Rescaled Distance Cluster Combine 0
(a)
MSWI Air
Fraction
0.25 0.20 0.15 0.10 0.05 0.00 4D
5D
6D
7D
8D
4F
5F
6F
7F
5
10
A5 A7 A6 A9 A10 A8 A1 A2 S3 S10 S9 S8 S4 A3 MSWI A4 S1 S6 S5 S7 S2 Back
0.35 0.30
585
15
20
25
(a) Cluster analysis
8F
0.8
4
(b)
III
Background soil Soil 0.6
c
S6
S1
A2
2
A1
t[2]
Fraction
A3 0.4
0
IV
I
S2
S7 S5
II
A9 A6 A8 A10
S8 S3
a
-2
A7 A5
S4
S10 S9
MSWI A4
b
0.2
-4
Background soil -5
0.0 4D
5D
6D
7D
8D
4F
5F
6F
7F
8F
Fig. 5. PCDD/Fs homologue patterns in each type of sample including the MSWI and ambient air samples (a), and soil samples collected near the incinerator and background soil (b).
-4
-3
-2
-1
0 1 2 t[1] (b) Principal component analysis
3
4
5
Fig. 6. Plot of cluster analysis (a) and principal component analysis (b) for the incinerator (MSWI), air (A1–A10), and soil samples (S1–S10).
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4. Conclusions
0.6 Group a Group b Group c
0.5
Fraction
0.4
0.3
0.2
0.1
0.0 4D
5D
6D
7D
8D
4F
5F
6F
7F
8F
Fig. 7. PCDD/Fs homologue patterns of each group in the soil samples.
Cluster analysis of the homologue patterns grouped the soil samples into four groups: a, b, c and background. Group a is the OCDD-dominant group containing soils in which the other dioxin-homologue fractions were lower than the furan fractions, i.e. their homologue patterns were intermediate between the patterns of background soils (Fiedler et al., 1996) and those affected by a combustion source (Fig. 7). Group b (containing members located in Group II) contained samples that were OCDD dominant and contained high levels of low-chlorinated furans. The dominance of low-chlorinated furans in soil, air and MSWI samples from Group II indicate the potential influence of incinerator PCDD/Fs emission on soil samples. However, high fractions of furans in soil samples can also come from other combustion sources, such as other combustion facilities or motor vehicles (Gullet and Ryan, 1997), the latter being likely since most soil samples were collected near the road. The soil samples in Group II seemed to be influenced by the MSWI, whereas the homologue patterns of the soil samples in Group b (located in Group II) had lower furan fractions and higher OCDD levels than did the air and MSWI samples in Group II. This may be explained by the observation that unlike the air, soil samples can accumulate contaminants (i.e. OCDD) over long periods of time. Interestingly, many of the Group b samples (S3, S4, S8, S9, and S10) were collected in the vicinities of driveways, suggesting that the Group b samples, especially S9, might be affected by emissions from both the MSWI and motor vehicles. The Group a soils (S2, S5, and S7) were also collected near driveways, but these driveways were near sites of frequent construction; deposition of construction dust could explain the relatively high OCDD fraction in these samples. Finally, Group III includes soil samples with high PCDD/Fs levels that were collected at the gates of the MSWI and IWI. As commented above, these soil samples do not seem to have been directly affected by stack gas emission, but they were likely affected by other local factors such as uncontrolled dispersion of fly ash and wastes.
We herein report the first comprehensive analysis of PCDD/Fs data for a complex, MSWI-containing industrial/residential area in Korea. The PCDD/Fs levels in both air and soil were higher than those reported by other investigators with soil PCDD/Fs levels decreasing with increasing distance from the MSWI. Homologue pattern analysis revealed that the high furan fractions in the stack gas were more similar to those found in the air samples versus soil samples. Our results revealed that PCDD/Fs emission from the MSWI more directly affected the pattern of PCDD/Fs in air, while the soil samples could be divided into groups according to distance from the MSWI and location related to roads and construction. Our results indicate that the MSWI was the major PCDD/Fs emission source in this area, but that unidentified combustion sources and vehicles might influence the environment to some extent. These results can be used as basic data for assessing risk of PCDD/Fs exposure in residents living near this MSWI and will form the basis for our future human risk assessment studies, which will seek to confirm the quantitative influence of this MSWI on the nearby residential area. Acknowledgements This work was supported by the Korea Science and Engineering Foundation (KOSEF) through the Advanced Environmental Monitoring Research Center (ADEMRC) at Gwangju Institute of Science and Technology (GIST), by the Brain Korea 21 Project, and by Pusan National University research Grant, 2004. The authors thank Dr. JinSoo Choi at ENBTECH, for his assistance in sampling and statistical analysis. References Boos, R., Himsl, A., Prey, T., Scheidl, K., Sperka, G., Glaeser, O., 1992. Determination of PCDDs and PCDFs in soil samples from Salzburg, Austria. Chemosphere 25, 283–291. Brzuzy, L.P., Hites, R.A., 1996. Global mass balance for polychlorinated dibenzo-p-dioxins and dibenzofurans. Environ. Sci. Technol. 30, 1797– 1804. Caserini, S., Cernuschi, S., Giugliano, M., Grosso, M., Lonati, G., Mattaini, P., 2004. Air and soil dioxin levels at three sites in Italy in proximity to MSW incineration plants. Chemosphere 54, 1279– 1287. 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. Deister, U., Pommer, R., 1991. Distribution of PCDD/F in the vicinity of the hazardous waste incinerator at Schwabach. Chemosphere 23, 1643–1651. Domingo, J.L., Schuhmacher, M., Mu¨ller, L., Rivera, J., Granero, S., Llobet, J.M., 2000. Evaluating the environmental impact of an old municipal waste incinerator: PCDD/F levels in soil and vegetation samples. J. Hazard. Mater. 76, 1–12. Domingo, J.L., Schuhmacher, M., Llobet, J.M., Muller, L., Rivera, J., 2001. PCDD/F concentrations in soil and vegetation in the vicinity of a municipal waste incinerator after a pronounced decrease in the emissions of PCDD/Fs from the facility. Chemosphere 43, 217–226.
J.-E. Oh et al. / Chemosphere 64 (2006) 579–587 Faengmark, I., Stroemberg, B., Berge, N., Rappe, C., 1994. Influence of postcombustion temperature profiles on the formation of PCDDs, PCDFs, PCBzs, and PCBs in a pilot incinerator. Environ. Sci. Technol. 28, 624–629. Fiedler, H., Lau, C., Kjeller, L.-O., Rappe, C., 1996. Patterns and sources of polychlorinated dibenzo-p-dioxins and dibenzofurans found in soil and sediment samples in southern Mississippi. Chemosphere 32, 421– 432. Gribble, G.W., 1994. The natural production of chlorinated compounds. Environ. Sci. Technol. 28, 310A–319A. Gullet, B., Ryan, J.V., 1997. On-road sampling of diesel engine emissions of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran. Organohalogen Compd. 32, 451–456. Hashimoto, S., Wakimoto, T., Tatsukawa, R., 1990. PCDDs in the sediments accumulated about 8120 years ago from Japanese coastal areas. Chemosphere 21, 825–835. Im, S.H., Kannan, K., Giesy, J.P., Matsuda, M., Wakimoto, T., 2002. Concentrations and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans in soils from Korea. Environ. Sci. Technol. 36, 3700– 3705. Jimenez, B., Eljarrat, E., Hernandez, L.M., Rivera, J., Gonzalez, M.J., 1996. Polychlorinated dibenzo-p-dioxins and dibenzofurans in soils near a clinical waste incinerator in Madrid, Spain. Chemometric comparison with other pollution sources and soils. Chemosphere 32, 1327–1348. Kim, B.-H., Lee, S.-J., Mun, S.-J., Chang, Y.-S., 2005a. A case study of dioxin monitoring in and around an industrial waste incinerator in Korea. Chemosphere 58, 1589–1599. Kim, E.-J., Oh, J.-E., Chang, Y.-S., 2003. Effects of forest fire on the level and distribution of PCDD/Fs and PAHs in soil. Sci. Total Environ. 311, 177–189. Kim, J.-G., Kim, K.-S., Kim, J.-S., Shin, S.-K., Chung, Y.-H., Chung, I.-R., 2005b. Source estimation of dioxins in soil using a congener pattern. J. KSEE 27, 316–322. Kim, Y., Lee, S.Y., Kim, M., Kim, S.D., 2001. The survey of PCDDs and PCDFs in the ambient air of the urban and industrial sites in Korea, 1998–1999. Chemosphere 43, 501–506. Lee, S.-J., Choi, S.-D., Oh, J.-E., Chang, Y.-S., in preparation. PCDD/Fs monitoring near a MSWI after the installation of flue–gas treatment system. Lohmann, R., Jones, K.C., 1998. Dioxins and furans in air and deposition: A review of levels, behaviour and processes. Sci. Total Environ. 219, 53–81. Mamontov, A.A., Mamontova, E.A., Tarasova, E.N., McLachlan, M.S., 2000. Tracing the sources of PCDD/Fs and PCBs to Lake Baikal. Environ. Sci. Technol. 34, 741–747. NIER, 2004. Occurrence and treatment of wastes in 2003. National Institute of Environmental Research, Seoul, Korea.
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Oh, J.-E., Lee, K.-T., Lee, J.-W., Chang, Y.-S., 1999. The evaluation of PCDD/Fs from various Korean incinerators. Chemosphere 38, 2097– 2108. Oh, J.-E., Choi, J.-S., Chang, Y.-S., 2001. Gas/particle partitioning of polychlorinated dibenzo-p-dioxins and dibenzofurans in atmosphere; evaluation of predicting models. Atmos. Environ. 35, 4125–4134. Oh, J.-E., Chang, Y.-S., Ikonomou, M., 2002. Levels and characteristic homologue patterns of polychlorinated dibenzo-p-dioxins and dibenzofurans in various incinerator emissions and in air collected near an incinerator. J. Air Waste Manag. Assoc. 52, 69–75. Park, J.-S., 2001. Characteristics of PCDD/DFs in emission gas of incinerator and environmental samples (MS thesis). Chonbuk National University, Jeonju, Korea. Park, J.-S., Kim, J.-G., 2002. Regional measurements of PCDD/PCDF concentrations in Korean atmosphere and comparison with gasparticle partitioning models. Chemosphere 49, 755–764. Park, S., Kim, S.-J., Kim, K.S., Lee, D.S., Kim, J.G., 2004. Influence of an industrial waste incinerator as assessed by the levels and congener patterns of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. Environ. Sci. Technol. 38, 3820–3826. Schuhmacher, M., Granero, S., Llobet, J.M., Kok, H.A.M.d., Domingo, J.L., 1997. Assessment of baseline levels of PCDD/F in soils in the neighbourhood of a new hazardous waste incinerator in Catalonia, Spain. Chemosphere 35, 1947–1958. Schuhmacher, M., Domingo, J.L., Granero, S., Llobet, J.M., Eljarrat, E., Rivera, J., 1999. Soil monitoring in the vicinity of a municipal solid waste incinerator: temporal variation of PCDD/Fs. Chemosphere 39, 419–429. Schuhmacher, M., Granero, S., Rivera, J., Mu¨ller, L., Llobet, J.M., Domingo, J.L., 2000. Atmospheric deposition of PCDD/Fs near an old municipal solid waste incinerator: levels in soil and vegetation. Chemosphere 40, 593–600. Schuhmacher, M., Rodriguez-Larena, M.C., Agramunt, M.C., DiazFerrero, J., Domingo, J.L., 2002. Environmental impact of a new hazardous waste incinerator in Catalonia, Spain: PCDD/PCDF levels in herbage samples. Chemosphere 48, 187–193. Seo, J.-H., Kwak, T.-H., Song, J.-O., Dong, J.-I., 2001. Improvement on air pollution control facilities for the removal of PCDD/Fs in MSW incineration plant. J. Kor. Solid Waste Eng. Soc. 7, 685–692. Shin, D., Choi, S., Oh, J.-E., Chang, Y.-S., 1999. Evaluation of polychlorinated dibenzo-p-dioxin/dibenzofuran (PCDD/F) emission in municipal solid waste incinerators. Environ. Sci. Technol. 33, 2657– 2666. Wallenhorst, T., Krau, P., Hagenmaier, H., 1997. PCDD/F in ambient air and deposition in Baden–Wurttemberg, Germany. Chemosphere 34, 1369–1378. Wania, F., Mackay, D., 1996. Tracking the distribution of persistent organic pollutants. Environ. Sci. Technol. 30, 390A–396A.
Influence of a municipal solid waste incinerator on ambient air and soil PCDD/Fs levels Jeong-Eun Oh a, Sung-Deuk Choi b, Se-Jin Lee b, Yoon-Seok Chang a
b,*
Department of Environmental Engineering, Pusan National University, San 30, Jangjeon-dong, Geumjeong-gu, Pusan 609-735, Republic of Korea b School of Environmental Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang 790-784, Republic of Korea Received 25 March 2005; received in revised form 19 August 2005; accepted 3 November 2005 Available online 10 January 2006
Abstract To examine the influence of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) emissions from a municipal solid waste incinerator (MSWI) on the environment, we measured the levels of PCDD/Fs in ambient air and soil samples collected near a MSWI in Bucheon, Korea. The PCDD/Fs concentrations in the ambient air samples ranged from 0.22 to 1.16 pg I-TEQ m 3 (13.39–75.16 pg m 3), with an average of 0.66 pg I-TEQ m 3 (35.62 pg m 3). The soil samples contained between 1.25 and 74.98 pg I-TEQ g 1 (38.15–3303.33 pg g 1), with an average of 19.06 pg I-TEQ g 1 (1077.11 pg g 1). These levels were higher than those previously reported by other investigators in a number of surveys. The furan homologues predominated in the air samples and some soil samples, and the soil PCDD/Fs levels decreased with increasing distance from the MSWI. Comparison of the homologue patterns and a multivariate statistical analysis showed that PCDD/Fs emission from the MSWI directly affected the pattern of PCDD/Fs in air, while the PCDD/Fs patterns in soil differed according to the location relative to the MSWI, roads, and construction sites. These results collectively indicate that the MSWI was the major PCDD/Fs emission source in this area, but that unidentified combustion sources and vehicles might influence the environment to some extent. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: PCDD/Fs; Incinerator; Air; Soil
1. Introduction Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are extremely hazardous chemicals that form both naturally and during combustion (Hashimoto et al., 1990; Gribble, 1994; Brzuzy and Hites, 1996; Kim et al., 2003). These compounds are semi-volatile and hydrophobic, and they easily accumulate in the environment, especially in organic carbon-rich media such as soil and sediment (Schuhmacher et al., 1997). PCDD/Fs emitted into the atmosphere easily undergo dry and wet
*
Corresponding author. Tel.: +82 54 279 2281; fax: +82 54 279 8299. E-mail address: [email protected] (Y.-S. Chang).
0045-6535/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2005.11.012
deposition in the vicinity of the source, while low-chlorinated congeners can undergo long-range transport via air masses, global distillation and the grasshopper effect (Wania and Mackay, 1996). Many studies have evaluated the PCDD/Fs levels near emission sources, and their impact on the environment (Deister and Pommer, 1991; Jimenez et al., 1996; Schuhmacher et al., 1997, 1999, 2002; Wallenhorst et al., 1997; Domingo et al., 2000, 2001; Park et al., 2004). Incinerators can be an important source of PCDD/Fs pollution in Korea due to the policy on municipal wastes; the contribution of incineration to waste treatments increased from 5.5% in 1996 to 14.5% in 2003 (NIER, 2004). The first Korean national survey of PCDD/Fs emission from incinerators was launched in 1997 (Oh et al., 1999; Shin et al., 1999). This survey increased public awareness of PCDD/Fs
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contamination near incinerators. However, only a few studies have examined PCDD/Fs levels in the environment near incinerators, and most of these reports have focused on industrial waste incinerators (Park, 2001; Im et al., 2002; Park et al., 2004; Kim et al., 2005a,b). Here, we examined the concentrations of PCDD/Fs in ambient air and soil samples near a municipal solid waste incinerator (MSWI) located in a residential area, and used meteorological data, homologue pattern comparison, and multivariate statistical analysis to determine the relationship between PCDD/Fs emissions and the environment.
that the area within 1 km of the MSWI is likely to be under the direct influence of its PCDD/Fs emission (data not shown). In addition to this MSWI, a small-scale (<2 tons day 1) industrial waste incinerator (IWI) had been operated near the MSWI, but it was not in service during the study period. PCDD/Fs emissions from this IWI were never measured due to its small scale and irregular operation. There are no other incinerators in the study area (Fig. 1); the MSWI is likely to be the most significant source of PCDD/Fs. 2.2. Air and soil sampling
2. Materials and methods 2.1. Description of the study area Bucheon City, located west of Seoul, Korea, is a central industrial city in the Gyeongin industrial region. Our study area is located in the northern part of the city, where industrial and residential areas coexist (Fig. 1). More than 45 000 people live in the study area, which also contains few hundreds small-scale factories (metal and mechanical, chemical, assembly factories, etc.), which were not considered important PCDD/Fs sources. A MSWI located in this area was put into service in 1995 and has a treatment capacity of 200 tons day 1. In 1997, the PCDD/Fs emission from this incinerator was recorded as the highest in Korea (36.50 ng I-TEQ N m 3) (Oh et al., 1999, 2002). As a result of this, a selective catalytic reduction reactor and bag filter were installed in 1999, and the PCDD/Fs emission decreased to 0.003–0.006 ng I-TEQ N m 3 as measured in 2001–2003 (unpublished data). Atmospheric dispersion modeling (ISC3) indicates
Fig. 1 shows the air and soil sampling sites in relation to the MSWI. Ten air samples (A1–A10) at three sites were taken from August 1999 to November 2000 using high volume air samplers (DHA-1000S, SIBATA). Sampling was performed on the roof of three buildings over 10 m in height (a1, a2, and a3). Glass fiber filters and polyurethane foam plugs (PUF) were used to collect vapor-phase PCDD/Fs as well as airborne particles. The sampling time and air volumes were about 24 h and 1000–1500 m3, respectively (Table 1). Before sampling, the filter was baked at 450 °C for 12 h, and the PUF were pre-cleaned with methylene chloride in a Soxhlet apparatus for 24 h. Based on the ISC3 model result, nine soil samples were collected from within 1 km of the MSWI and one soil sample was taken at 2 km. The study area is highly developed with many paved roads, residences, industries and construction areas. This complicated soil sample collection; most of the samples were collected from the vicinity of driveways. For reference purposes, a background soil sample was collected at Mt. Dobong, a national park 30 km
Fig. 1. PCDD/Fs sampling sites and location of the MSWI in Bucheon, Korea.
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Table 1 Information on the air samples Sample #
Site
Sampling date
Sampling volume (m3)
Mean temperature (°C)
PCDD/Fs (pg I-TEQ m 3)
A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
a3 a1 a3 a1 a2 a1 a2 a1 a1 a1
08.19, 1999 08.17–08.18, 11.20–11.21, 11.07–11.08, 12.20–12.21, 12.18–12.09, 04.12–04.13, 04.11–04.12, 07.13–07.15, 11.03–11.05,
1636.0 1570.5 1100.1 1128.5 1133.3 1131.8 1039.4 1086.0 1592.3 1095.5
25.1 27.3 10.1 5.6 7.6 6.1 11.5 9.7 25.8 13.2
0.379 0.672 0.871 1.116 1.161 0.368 0.548 0.574 0.221 0.664
1999 1999 1999 1999 1999 2000 2000 2000 2000
Site: three air sampling locations noted in Fig. 1.
away from the study area. All soil samples were collected at a depth of 0–10 cm. Meteorological data (wind velocity, wind direction, and temperature) during the sampling period were obtained from the Korean Meteorological Administration (KMA) and used to make a wind rose diagram (Fig. 2) using the Grapher 4.0 software package (Golden Software Inc.). 2.3. Instrumental analysis Sample preparation was conducted according to US EPA method 1613. The solid samples were transferred to glass Soxhlet thimbles, then spiked with a mixture of 13 C12-labelled PCDD/Fs internal standards (1 ng) and extracted for 16 h with toluene. The extracts were washed with H2SO4 until they became colorless and were then washed with hexane-rinsed water for neutralization. Samples were cleaned by passage through a silica gel column (with layers of basic, neutral, acidic and neutral silica), followed by passage through an activated acidic alumina column capped with anhydrous Na2SO4. N2 gas was used to concentrate each sample, and 13C12-labelled PCDD/Fsrecovery standards (1 ng) were added before samples were 0 45
315
270
<=1 >1 - 2 >2 - 3 >3 - 4 >4 m/s
subjected to GC/MS analysis using an HRGC/HRMS (HP 6890/JMS 700T) with a DB-5MS column (60 m, 0.25 mm i.d., 0.25 lm film thickness). The temperature program of the capillary column was as follows: (1) 140 °C initial isothermal hold for 4 min; (2) increase at 15 °C/min to an isothermal hold at 220 °C for 3 min; (3) increase at 1.5 °C/min to an isothermal hold at 240 °C for 2 min; (4) increase at 4 °C/min to an isothermal hold at 310 °C for 6 min. The sample was introduced by splitless injection. The MS was operated at a resolution of 10 000 under positive EI conditions (38 eV electron energy), and the data were obtained in the single ion monitoring (SIM) mode. Two out of the three ions (M+, M+2, and M+4) were monitored. The toxic 2,3,7,8-substituted PCDD/Fs as well as tetra- to octa-chlorinated homologues were quantified based on isotope ratios within ±15% of the theoretical values and signal: noise ratios of P2.5. Recoveries of the 13C12-labelled PCDD/Fs-internal standards in the environmental samples were in the range of 50–120%, which satisfied the EPA method 1613 protocol. 2.4. Statistical analysis Cluster analysis and principal component analysis (PCA) were used to evaluate the similarities or differences of the PCDD/Fs homologue patterns in air, soil, and stack gas samples. Prior to analysis, the PCDD/Fs homologue levels were normalized with respect to the total PCDD/Fs concentration in the relevant sample. The statistical analyses were performed using the SIMCA-P 7.01 (U-metri) and SPSS 11.0 (SPSS Inc.) software packages.
90 0%
4%
8% 12% 16%
3. Results and discussion 3.1. PCDD/Fs in ambient air samples
225
135 180
Fig. 2. Wind rose diagram reflecting the sampling period (August 1999– November 2000).
Comparisons of PCDD/Fs levels among the samples were based on the Toxic Equivalent Quantity (TEQ) of the 2,3,7,8-substituted PCDD/Fs (reflected as Toxic Equivalent Factors; TEFs) and the sum of all homologue concentrations (Table 2). Lohmann and Jones (1998) noted the
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Table 2 PCDD/Fs concentrations in the ambient air and MSWI samples (unit: air (pg I-TEQ m 3, pg m 3), MSWI (ng I-TEQ Nm 3, ng N m 3)) Isomer
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
MSWI
2,3,7,8-TeCDD 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 OCDD 2,3,7,8-TeCDF 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 OCDF
0.01 0.10 0.05 0.10 0.09 0.48 0.66 0.21 0.18 0.32 0.24 0.22 0.30 0.10 0.80 0.11 0.44
0.02 0.10 0.10 0.22 0.10 1.14 1.78 0.55 0.48 0.38 0.68 0.58 0.19 0.94 2.52 0.65 2.97
0.04 0.14 0.18 0.32 0.25 1.76 3.55 0.34 0.55 0.43 0.55 0.85 0.08 1.22 4.96 0.83 5.01
0.03 0.23 0.15 0.25 0.19 1.67 2.98 0.19 0.43 0.89 0.99 0.84 1.43 0.45 3.78 0.71 3.97
0.03 0.19 0.11 0.20 0.13 1.15 2.85 0.36 0.32 1.36 0.62 0.61 0.76 0.23 2.05 0.28 1.72
0.01 0.07 0.04 0.07 0.05 0.58 1.35 0.15 0.15 0.37 0.23 0.20 0.31 0.10 0.82 0.13 0.56
0.01 0.10 0.08 0.10 0.09 0.63 1.34 0.25 0.28 0.46 0.51 0.40 0.62 0.25 1.97 0.44 3.38
0.01 0.09 0.05 0.10 0.08 0.64 1.48 0.22 0.24 0.45 0.52 0.39 0.54 0.23 2.08 0.47 3.58
0.01 0.03 0.02 0.05 0.03 0.29 0.59 0.08 0.09 0.19 0.21 0.17 0.23 0.10 0.66 0.15 1.01
0.02 0.11 0.08 0.18 0.05 0.78 1.48 0.21 0.28 0.58 0.58 0.52 0.75 0.22 1.93 0.34 1.79
1.02 5.17 9.78 5.77 6.91 31.13 52.04 12.35 17.82 35.73 25.19 27.17 40.60 2.41 60.67 10.96 37.55
TeCDD PeCDD HxCDD HpCDD OCDD TeCDF PeCDF HxCDF HpCDF OCDF
2.06 1.84 1.74 0.95 0.66 5.91 3.75 2.46 1.38 0.44
3.28 2.83 2.83 2.38 1.78 7.38 7.28 7.65 5.43 2.97
5.00 4.65 5.99 3.58 3.55 15.66 13.58 9.81 8.33 5.01
3.13 3.63 4.58 3.00 2.98 9.19 9.51 9.30 6.76 3.97
2.26 3.33 3.01 2.20 2.85 6.60 8.09 6.31 3.34 1.72
0.71 1.12 1.20 0.99 1.35 2.33 2.71 2.20 1.52 0.56
1.57 1.68 1.73 1.14 1.34 5.70 4.90 4.38 3.68 3.38
1.27 1.41 1.48 1.13 1.48 3.93 3.86 3.98 3.97 3.58
1.22 0.75 0.79 0.64 0.59 2.87 2.05 2.01 1.45 1.01
3.11 3.49 2.05 1.34 1.48 7.65 6.69 5.83 3.21 1.79
79.95 109.89 129.83 64.00 52.04 653.19 586.34 283.15 107.79 37.55
0.38 21.19
0.67 43.81
0.82 75.16
1.13 56.05
1.16 39.71
0.37 14.69
0.57 29.50
0.54 26.09
0.23 13.38
0.67 36.64
36.50 2103.72
I-TEQ Total
MSWI emission data were obtained from Oh et al. (1999).
large variation of PCDD/Fs concentrations measured from ambient air across a number of surveys in various countries. In general, PCDD/Fs levels tend to be <0.01 pg I-TEQ m 3 in remote sites, 0.02–0.05 pg I-TEQ m 3 in rural sites, and 0.1–0.4 pg I-TEQ m 3 in urban/industrial sites. Recently, ambient air PCDD/Fs levels near three different MSWIs in Italy were found to be in the range of 0.010–0.337 pg I-TEQ m 3 (Caserini et al., 2004). In Korea, urban sites (Seoul, Incheon, Daejeon, Jeonju, Cheonan, and Gunsan) have reported PCDD/Fs ranges of 0.015–0.758 pg I-TEQ m 3 (Kim et al., 2001; Park and Kim, 2002), and air samples collected in the vicinity of an IWI showed PCDD/Fs values ranging from 0.195 to 0.301 pg I-TEQ m 3 (Kim et al., 2005a), while two industrial areas (Pohang and Yeosu) showed relatively low PCDD/Fs levels of 0.034–0.172 pg I-TEQ m 3 (Oh et al., 2001). According to the 5-year (1999–2003) nationwide survey conducted by the Korean National Institute of Environmental Research (http://www.nier.go.kr/nierdepart/eds/), the average PCDD/Fs levels in ambient air in Korea (n > 150) have decreased from 0.425 pg I-TEQ m 3 in 1999 to 0.271 pg I-TEQ m 3in 2003.The PCDD/Fs levels observed in this study ranged from 0.221 to 1.161 pg I-TEQ m 3 (13.39–75.16 pg m 3) with an average of 0.66 pg I-TEQ m 3 (35.62 pg m 3) (Table 2). These values are higher than those reported in the previous surveys, con-
firming the existence of one or more significant sources of PCDD/Fs in or near the study area. PCDD/Fs concentrations show seasonal variations (usually high in winter and low in summer), likely associated with combustion sources, temperature inversion conditions, and several loss processes including photolysis, chemical reactivity, wet and dry deposition, and scavenging by vegetation (Lohmann and Jones, 1998). Thus, identification of seasonal PCDD/Fs level variation in the atmosphere is important for a proper evaluation of the contribution from each source. As shown in Fig. 3, the seasonal variations in the PCDD/Fs levels were observed in our study area. The first four PCDD/Fs concentrations (Summer 1999–Spring 2000) are the averages of two measurements each. Since the operation of the MSWI and other incinerators is likely to be consistent year-round, domestic burning and other environmental factors might account for the observed seasonal variation. In addition, wet deposition by precipitation is likely to play a key role in the low levels of atmospheric PCDD/Fs seen during the summer. The Korean Meteorological Administration reported that summer (June–August) precipitation accounted for 62% and 59% of the total annual precipitation in the study area during the sampling period (August 1999–November 2000) and the last 30 years (1971–2000), respectively.
J.-E. Oh et al. / Chemosphere 64 (2006) 579–587 30 pg I-TEQ m-3 Temperature
1.2
25
15
0.8
10
0.6
5
Fa ll
m er 2
Su m
Sp rin g
W in t
Fa ll
Su m m
20 00
-10 00 0
0.0 20 00
-5
er 19 99
0
0.2
19 99
0.4
Temperature (°C)
20 1.0
er 19 99
PCDD/Fs (pg I-TEQ m-3)
1.4
Fig. 3. Seasonal changes in PCDD/Fs concentrations during the study period.
It can be argued that two measurements per season are not sufficient to represent seasonality, but other studies for this area have shown high PCDD/Fs concentrations in winter (up to 1.33 pg I-TEQ m 3) and low concentrations in summer (0.522 pg I-TEQ m 3) (Lee et al., in preparation; Seo et al., 2001). These independent measurements suggest that the atmospheric levels of PCDD/Fs vary seasonally in the study area. 3.2. PCDD/Fs in soil samples A number of recent surveys have provided details on country, incinerator type, year, number of samples, and PCDD/Fs concentrations (Table 3) and have shown a wide range of PCDD/Fs concentrations in soil. Background levels seem to be about 0.1 pg I-TEQ g 1, while samples taken near incinerators have shown levels up to 3.7 ng I-TEQ g 1, a peak PCDD/Fs level found adjacent to an open burning-type IWI in Changwon City, Korea (Im et al., 2002). The PCDD/Fs concentrations observed in the present study (1.25–74.98 pg I-TEQ g 1) are higher than those found in soil samples collected near MSWIs in Italy, Spain, and Taiwan (Domingo et al., 2000, 2001;
583
Schuhmacher et al., 2000; Cheng et al., 2003; Caserini et al., 2004), while they are consistent with those found near IWIs in Korea (Park, 2001; Park et al., 2004; Kim et al., 2005a,b). As shown in Table 4, the soil samples in the present study were found to contain between 1.25 and 74.98 pg I-TEQ g 1 (38.15–3303.33 pg g 1) of PCDD/Fs with an average of 19.06 pg I-TEQ g 1 (1077.11 pg g 1). This was substantially higher than the background soil PCDD/Fs concentration of 0.92 pg I-TEQ g 1 (157.56 pg g 1). These observed PCDD/Fs concentrations are mostly beyond the 5 pg I-TEQ g 1 limit that restricts the cultivation of certain vegetables but do not exceed the limit for the cultivation of other types of plants (40 pg I-TEQ g 1) (Boos et al., 1992). The highest soil PCDD/Fs level (74.98 pg I-TEQ g 1) was observed in sample S1, which was collected at the front gate of the MSWI. Sample S6, which was collected near the small-scale, inoperative IWI, had a high level of PCDD/Fs (45.17 pg I-TEQ g 1). The high levels of PCDD/Fs in soil samples collected adjacent to the two incinerators might be explained by transportation of waste, temporary storage of fly ash, or the presence of wastes in the incinerator yard, rather than gaseous transmission. 3.3. Influence of stack gas on air and soil 3.3.1. Levels of concentration It is important to identify the source of contamination and its influence on the environment. The general method for identifying the source of PCDD/Fs contamination is to compare the levels of PCDD/Fs with distance. If PCDD/Fs levels tend to decrease as the distance from a certain site increases, then the site can be considered a source of PCDD/Fs. As most of our sampling sites were within 1 km of the MSWI, we were unable to find a strong relationship between the soil PCDD/Fs levels and the distance from the incinerator (Fig. 4). However, we could clearly observe a trend of declining PCDD/Fs levels as the distance increased. High PCDD/Fs levels were detected in most soil samples taken from sites near the MSWI,
Table 3 Recent reports of PCDD/Fs concentrations in soil samples collected near incinerators Country
Location
Type
Year
Number of samples
Concentration (pg I-TEQ g 1)
Reference
Italy
Po Valley Veneto Adige Valley Hsinchu Catalonia Barcelona
MSWI MSWI MSWI MSWI MSWI MSWI
2000 2000–2001 2001 2001 1996–1997, 1999 1999
3 3 3 8 72 24
0.7–1.5 1.1–1.4 0.08–1.2 0.52–5.02 0.11–5.80 1.22–34.28
Buchon Gunsan Pyoungtak Pyoungtak Changwon and Masan Yangju
MSWI IWI IWI IWI IWI IWI
1999–2000 – 2002–2003 2002 – 2003
10 13 47 4 23 30
1.25–74.98 0.16–45.25 0.7–15.5 1.16–77.96 0.2–3720 0.10–35.19
Caserini et al. (2004) Caserini et al. (2004) Caserini et al. (2004) Cheng et al. (2003) Domingo et al. (2001) Domingo et al. (2000); Schuhmacher et al. (2000) This study Park (2001) Park et al. (2004) Kim et al. (2005a) Im et al. (2002) Kim et al. (2005b)
Taiwan Spain
Korea
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Table 4 PCDD/Fs concentrations in the soil samples (unit: pg I-TEQ g 1, pg g 1) S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
Background
2,3,7,8-TeCDD 1,2,3,7,8-PCDD 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 OCDD 2,3,7,8-TeCDF 1,2,3,7,8-PCDF 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 OCDF
0.69 5.22 7.68 16.16 7.94 180.24 622.92 5.69 8.57 73.97 29.22 46.03 134.28 27.09 333.03 67.48 430.18
0.24 2.86 0.84 1.18 0.89 14.34 324.07 3.26 2.94 4.46 5.54 4.10 6.56 2.01 25.16 6.59 37.36
0.44 0.71 0.51 1.16 0.97 12.36 51.58 3.94 3.03 3.82 4.12 3.17 3.66 1.35 12.69 2.24 11.08
0.09 0.36 0.16 0.22 0.19 3.04 14.90 2.39 1.06 2.92 1.67 0.89 0.92 0.47 3.36 0.95 6.70
0.47 2.07 0.77 1.30 0.54 15.02 235.81 5.89 4.93 4.65 5.62 4.74 6.88 2.44 23.72 4.94 30.90
0.64 5.43 8.68 11.99 8.21 113.82 367.80 7.61 13.85 27.30 34.87 42.38 87.96 17.72 320.05 39.99 419.59
0.30 0.93 0.92 1.85 1.14 14.87 159.87 7.96 4.34 13.19 9.61 6.62 8.19 3.39 27.90 4.79 34.71
0.51 3.26 2.36 3.70 2.48 31.59 111.23 6.66 7.75 11.89 11.26 11.18 17.78 4.64 63.80 9.50 70.61
0.03 0.20 0.13 0.04 0.11 0.64 5.79 1.52 0.93 1.26 1.07 0.41 0.47 0.32 1.00 0.23 1.83
0.87 3.38 2.40 4.15 2.26 28.07 196.48 9.04 10.32 14.00 15.51 15.36 19.71 4.80 68.13 7.06 57.32
0.02 0.17 0.14 0.36 0.46 3.98 109.86 0.76 0.38 0.54 0.52 0.39 0.61 0.18 1.80 0.44 8.32
TeCDD PeCDD HxCDD HpCDD OCDD TeCDF PeCDF HxCDF HpCDF OCDF
48.42 89.04 176.00 346.47 622.92 114.27 290.84 536.16 649.03 430.19
27.08 40.32 16.70 27.58 324.07 48.08 44.90 47.07 52.17 37.36
22.76 31.32 14.56 20.30 51.58 50.92 38.78 31.69 21.53 11.08
7.78 16.05 2.69 4.58 14.90 12.82 12.33 7.86 6.60 6.70
62.37 55.70 15.83 30.90 235.81 72.49 61.83 52.17 46.26 30.90
88.32 156.46 154.89 225.57 367.80 183.45 291.17 437.99 528.67 419.60
24.96 85.32 21.82 28.39 159.87 61.21 65.99 58.77 46.75 34.71
61.62 121.88 59.27 62.79 111.23 153.48 129.25 119.67 115.79 70.61
1.92 4.51 1.57 1.48 5.79 7.47 6.53 4.37 2.67 1.83
104.20 110.48 63.56 57.10 196.48 211.71 198.96 155.61 109.41 57.32
2.59 2.33 5.58 9.78 109.86 6.76 3.91 4.26 4.18 8.32
I-TEQ (pg I-TEQ g 1) Total (pg g 1)
74.98
7.31
5.08
2.57
7.60
45.17
12.22
15.71
1.24
18.69
0.92
3303.34
665.33
294.52
92.31
664.26
2853.92
587.79
1005.59
38.14
1264.83
157.57
80
PCDD/Fs in soil (pg I-TEQ g-1)
S1 60
S6 40
20
S8 S5 S3
0
0
S10 S7 S2
500
S9 S4
1000
1500
2000
Distance (m)
Fig. 4. Decline of PCDD/Fs levels in soil with increasing distance from the MSWI.
whereas the lowest PCDD/Fs level was observed in the sample taken from >1500 m away (S9). Even if the two samples (S1 and S6) collected from the incinerator gates were disregarded, the trend of declining PCDD/F levels with increasing distance from the MSWI is also seen in Fig. 4 (average value within 500 m: 8.92 pg I-TEQ g 1, within 800 m: 7.39 pg I-TEQ g 1, at 1.8 km: 1.25 pg I-TEQ g 1). These results indicate that the trend of declining PCDD/Fs levels with increasing distance from the
source are reliable, regardless of whether the source was dispersion of fly ash or stack emissions. When investigating the influence of an incinerator on the environment, it is important to consider wind direction. In the study area, the major winds blew in western, northern, and northeastern directions; eastern and southern winds were weak (Fig. 2). Interestingly, we did not observe a significant correlation between the major wind directions and PCDD/Fs levels in soil samples. For example, sample S8, which was collected at the northeast side of the MSWI, had a higher PCDD/Fs concentration (15.71 pg I-TEQ g 1) than did soil samples S3 (5.08 pg I-TEQ g 1), S4 (2.57 pg I-TEQ g 1), and S5 (7.60 pg I-TEQ g 1), which were collected at southern sites. However, it is possible that the MSWI continuously influenced the residential area to the south due to the major winds. 3.3.2. Comparison of homologue patterns In addition to comparing total concentration levels among soil samples, we also used homologue pattern comparisons to investigate the relationships between the incinerator and the environment. To compare the homologue patterns of each sample, soil and air data were normalized to the total PCDD/Fs; [PCDDs] + [PCDFs] = 1. For the incinerator data, we used the PCDD/Fs homologue values previously measured from this MSWI (Oh et al., 1999).
J.-E. Oh et al. / Chemosphere 64 (2006) 579–587
Similar homologue patterns were observed between the MSWI and ambient air samples (A1–A10; Fig. 5a). The tetra, penta and hexa-chlorinated furans were particularly dominant in these samples. Many studies have reported that PCDD/Fs homologue patterns are similar among the various thermal processes, and that PCDFs levels were higher than PCDDs levels in flue gases (Lohmann and Jones, 1998; Oh et al., 1999; Mamontov et al., 2000). The homologue patterns found in the air samples of this study were similar to those found in stack gas (Faengmark et al., 1994). Background air tends to have a typical homologue pattern of high chlorinated dioxins (e.g. OCDD) and generally low levels of chlorinated furans (Fiedler et al., 1996). As described previously, high levels of low-chlorinated furans indicate the presence of potential combustion sources of PCDD/Fs, such as an incinerator. In this study, OCDD accounted for 70% of the homologues in the background soil sample (Fig. 5b); this is a relatively a typical ‘background pattern’ (Fiedler et al., 1996). In contrast, most of the soil samples examined in this study had higher fractions of furans than those of the background soil sample, though OCDD remained dominant. Collectively, these results strongly suggest that both the soil and air samples have been affected by a PCDD/Fs source such as a MSWI.
3.3.3. Multivariate analysis Cluster analysis and principal component analysis (PCA) were used to verify the influence of the MSWI and the relationships among stack gas, ambient air, and soil samples (Fig. 6). The first principal component (X-axis: PC1) was found to account for 37.4% of the variance, and the second principal component (Y-axis: PC2) accounted for 31.2% (Fig. 6b). Cluster analysis revealed four large groups: Groups I and III contained the soil samples, Group IV contained the background soil sample, and Group II contained the remaining samples clustered into three subgroups consisting of the stack gas, ambient air samples, and remaining soil samples. These findings indicate that all air samples might be affected by the MSWI, whereas only a subset of the soil samples was affected. A large variation in homologue patterns was observed among the soil samples, including the background soil. Rescaled Distance Cluster Combine 0
(a)
MSWI Air
Fraction
0.25 0.20 0.15 0.10 0.05 0.00 4D
5D
6D
7D
8D
4F
5F
6F
7F
5
10
A5 A7 A6 A9 A10 A8 A1 A2 S3 S10 S9 S8 S4 A3 MSWI A4 S1 S6 S5 S7 S2 Back
0.35 0.30
585
15
20
25
(a) Cluster analysis
8F
0.8
4
(b)
III
Background soil Soil 0.6
c
S6
S1
A2
2
A1
t[2]
Fraction
A3 0.4
0
IV
I
S2
S7 S5
II
A9 A6 A8 A10
S8 S3
a
-2
A7 A5
S4
S10 S9
MSWI A4
b
0.2
-4
Background soil -5
0.0 4D
5D
6D
7D
8D
4F
5F
6F
7F
8F
Fig. 5. PCDD/Fs homologue patterns in each type of sample including the MSWI and ambient air samples (a), and soil samples collected near the incinerator and background soil (b).
-4
-3
-2
-1
0 1 2 t[1] (b) Principal component analysis
3
4
5
Fig. 6. Plot of cluster analysis (a) and principal component analysis (b) for the incinerator (MSWI), air (A1–A10), and soil samples (S1–S10).
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J.-E. Oh et al. / Chemosphere 64 (2006) 579–587
4. Conclusions
0.6 Group a Group b Group c
0.5
Fraction
0.4
0.3
0.2
0.1
0.0 4D
5D
6D
7D
8D
4F
5F
6F
7F
8F
Fig. 7. PCDD/Fs homologue patterns of each group in the soil samples.
Cluster analysis of the homologue patterns grouped the soil samples into four groups: a, b, c and background. Group a is the OCDD-dominant group containing soils in which the other dioxin-homologue fractions were lower than the furan fractions, i.e. their homologue patterns were intermediate between the patterns of background soils (Fiedler et al., 1996) and those affected by a combustion source (Fig. 7). Group b (containing members located in Group II) contained samples that were OCDD dominant and contained high levels of low-chlorinated furans. The dominance of low-chlorinated furans in soil, air and MSWI samples from Group II indicate the potential influence of incinerator PCDD/Fs emission on soil samples. However, high fractions of furans in soil samples can also come from other combustion sources, such as other combustion facilities or motor vehicles (Gullet and Ryan, 1997), the latter being likely since most soil samples were collected near the road. The soil samples in Group II seemed to be influenced by the MSWI, whereas the homologue patterns of the soil samples in Group b (located in Group II) had lower furan fractions and higher OCDD levels than did the air and MSWI samples in Group II. This may be explained by the observation that unlike the air, soil samples can accumulate contaminants (i.e. OCDD) over long periods of time. Interestingly, many of the Group b samples (S3, S4, S8, S9, and S10) were collected in the vicinities of driveways, suggesting that the Group b samples, especially S9, might be affected by emissions from both the MSWI and motor vehicles. The Group a soils (S2, S5, and S7) were also collected near driveways, but these driveways were near sites of frequent construction; deposition of construction dust could explain the relatively high OCDD fraction in these samples. Finally, Group III includes soil samples with high PCDD/Fs levels that were collected at the gates of the MSWI and IWI. As commented above, these soil samples do not seem to have been directly affected by stack gas emission, but they were likely affected by other local factors such as uncontrolled dispersion of fly ash and wastes.
We herein report the first comprehensive analysis of PCDD/Fs data for a complex, MSWI-containing industrial/residential area in Korea. The PCDD/Fs levels in both air and soil were higher than those reported by other investigators with soil PCDD/Fs levels decreasing with increasing distance from the MSWI. Homologue pattern analysis revealed that the high furan fractions in the stack gas were more similar to those found in the air samples versus soil samples. Our results revealed that PCDD/Fs emission from the MSWI more directly affected the pattern of PCDD/Fs in air, while the soil samples could be divided into groups according to distance from the MSWI and location related to roads and construction. Our results indicate that the MSWI was the major PCDD/Fs emission source in this area, but that unidentified combustion sources and vehicles might influence the environment to some extent. These results can be used as basic data for assessing risk of PCDD/Fs exposure in residents living near this MSWI and will form the basis for our future human risk assessment studies, which will seek to confirm the quantitative influence of this MSWI on the nearby residential area. Acknowledgements This work was supported by the Korea Science and Engineering Foundation (KOSEF) through the Advanced Environmental Monitoring Research Center (ADEMRC) at Gwangju Institute of Science and Technology (GIST), by the Brain Korea 21 Project, and by Pusan National University research Grant, 2004. The authors thank Dr. JinSoo Choi at ENBTECH, for his assistance in sampling and statistical analysis. References Boos, R., Himsl, A., Prey, T., Scheidl, K., Sperka, G., Glaeser, O., 1992. Determination of PCDDs and PCDFs in soil samples from Salzburg, Austria. Chemosphere 25, 283–291. Brzuzy, L.P., Hites, R.A., 1996. Global mass balance for polychlorinated dibenzo-p-dioxins and dibenzofurans. Environ. Sci. Technol. 30, 1797– 1804. Caserini, S., Cernuschi, S., Giugliano, M., Grosso, M., Lonati, G., Mattaini, P., 2004. Air and soil dioxin levels at three sites in Italy in proximity to MSW incineration plants. Chemosphere 54, 1279– 1287. 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. Deister, U., Pommer, R., 1991. Distribution of PCDD/F in the vicinity of the hazardous waste incinerator at Schwabach. Chemosphere 23, 1643–1651. Domingo, J.L., Schuhmacher, M., Mu¨ller, L., Rivera, J., Granero, S., Llobet, J.M., 2000. Evaluating the environmental impact of an old municipal waste incinerator: PCDD/F levels in soil and vegetation samples. J. Hazard. Mater. 76, 1–12. Domingo, J.L., Schuhmacher, M., Llobet, J.M., Muller, L., Rivera, J., 2001. PCDD/F concentrations in soil and vegetation in the vicinity of a municipal waste incinerator after a pronounced decrease in the emissions of PCDD/Fs from the facility. Chemosphere 43, 217–226.
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