Research Environmental Impact and Human Health Risks of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in the Vicinity of a New Hazardous Waste Incinerator: A Case Study NU Ä R I A F E R R EÄ - H U G U E T , † M A R T IÄ N A D A L , † , ‡ M A R T A S C H U H M A C H E R , †,‡ A N D J O S EÄ L . D O M I N G O * , † Laboratory of Toxicology and Environmental Health, School of Medicine, Rovira i Virgili University, San Lorenzo 21, 43201 Reus, Spain, and Environmental Engineering Laboratory, Department of Chemical Engineering, Rovira i Virgili University, Sescelades Campus, 43007 Tarragona, Spain
The purpose of this study was to assess the environmental impact of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the vicinity of a new hazardous waste incinerator (HWI) 4 years after regular operation of the facility. A double approach was carried out. The PCDD/F congener profiles corresponding to environmental samples, soil and herbage, collected before the HWI (baseline) and 4 years after starting regular operations, as well as PCDD/F profiles of air emission samples, were compared. The potential health risks (carcinogenic and noncarcinogenic) due to PCDD/F exposure were assessed for adults and children living in the neighborhood of the facility. Human exposure to PCDD/Fs was mainly due to dietary food intake. Comparisons between the PCDD/F congener profiles corresponding to the baseline and current surveys, as well as data concerning the human health risk assessment, indicate that the HWI in question does not cause additional risks to the environment or to the population living in the vicinity of the facility.
Introduction Although incineration is considered by regulators to be a strategic option for waste reduction and disposal (1), public opinion shows concern about the installation of municipal, hazardous, and medical waste incinerators in most developed countries (2). Among the pollutants emitted by waste incinerators, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) have generated a lot of public concern, mainly because they are among the most toxic environmental compounds (3). Although PCDD/Fs are generally produced in many combustion processes (4), incineration has received prolonged special attention by scientists and politicians (5, 6). In 1996, the construction of the first, and so far the only, hazardous waste incinerator (HWI) in Spain was initiated. * Corresponding author phone: +34-977-759380; fax: +34-977759322; e-mail:
[email protected]. † School of Medicine. ‡ Department of Chemical Engineering. 10.1021/es051630+ CCC: $33.50 Published on Web 12/01/2005
2006 American Chemical Society
Regular operations were started 3 years later (1999). Because concern about the environmental and health risks associated with this HWI was remarkable among the population of the area, we initiated a wide environmental and biological monitoring program focused on assessing the influence of the new HWI on the environment and on public health. The first step was to carry out a baseline survey, which would be essential for future evaluations. Soil and herbage samples were collected and analyzed for PCDD/F concentrations (7), while samples of blood from people living near the HWI were also collected and analyzed for PCDD/Fs (8). PCDD/F dietary intake of the individuals living near the HWI was also determined (9). All these data constituted an essential basis to evaluate potential changes found in subsequent surveys. When assessing impacts due to PCDD/Fs, the analysis of congener profiles allows an easy visual estimation of the possible incidence of individual sources (10-12). However, complementary methodologies should be applied in order to quantitatively evaluate human health risks. In recent years, a number of studies on health risk assessment have been carried out around incinerators in various countries (3, 1317). The aim of the present study was to assess the impact of the PCDD/F emissions from the HWI on the environment and human health 4 years after starting regular operations in the facility. First, PCDD/F congener profiles, obtained through environmental monitors in the baseline (1997-1998) and 2003 surveys, were compared. Second, human health risks due to PCDD/F exposure were assessed for subjects living both nearby and far away from the HWI. Baseline data were also compared with those of the current (2003) survey.
Materials and Methods Study Area and Sampling Sites. In 1999, the HWI in our study site (Constantı´, Catalonia, Spain) initiated regular operations. During the construction of the facility, a wide surveillance program was initiated. Forty soil and 40 herbage samples were used as environmental monitors of long- and short-term exposure, respectively. Thirty samples were collected in the rural area adjacent to the facility at different wind directions (N, NW, S, and E), whereas the remaining 10 samples were collected in urban zones (U). The sampling points were chosen according to the results obtained by applying the dispersion model ISC2 (US EPA). Data for modeling included, among other things, the stack height (32 m) and the meteorological conditions of the zone (7). Samples of blood obtained from subjects living in the vicinity of the HWI were used as a biological monitor of PCDD/F exposure. In 2003, samples of soil and herbage were again collected at the same sampling points and analyzed for PCDD/F concentrations. Methods about sampling and PCDD/F analyses were widely detailed in previous reports (18-20). Data Analysis. To establish pattern similarities among the samples as well as to identify hot spots near the plant, a self-organizing map (SOM) was applied to soil and herbage samples. This is a kind of unsupervised artificial neural network, originally created by Kohonen (21). SOM is a powerful “data mining”-based chemometric tool generally used to classify large amounts of data. Basis for data treatment and analysis can be found in previous studies (22, 23). In the present study, the Kohonen map was a 48 unit (8 × 6) rectangular grid. Both the learning and tuning phases consisted of 10 000 steps each. Health Risks. PCDD/F levels in air and soil samples collected in the vicinity of the HWI were used for health risk VOL. 40, NO. 1, 2006 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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FIGURE 1. Percentages of the contribution of the respective congener to total PCDD/Fs in stack gas samples collected in the HWI (2003 survey). assessment. Total human exposure to PCDD/Fs was estimated as the sum of two different routes: direct and dietary exposure. (1) Direct pathway. Total environmental exposure to PCDD/Fs was calculated as the sum of air inhalation, dermal absorption through soil and dust, and soil and dust ingestion. A worst case scenario was considered by assuming that the population was exposed for 24 h/day, and by equalizing indoor and outdoor exposure. To carry out the calculations of exposure through dermal contact and ingestion, PCDD/F concentrations in soil were previously determined (24). (2) Indirect route. Dietary exposure was considered an indirect pathway of exposure to PCDD/Fs. Recent data corresponding to PCDD/F intake from foodstuffs consumed by the population living in the area under potential influence of the HWI were used to evaluate dietary exposure to PCDD/ Fs (25). PCDD/F exposure was calculated as the average daily intake of I-TEQ equivalents per unit body weight. Details on parameters and equations used in the present study were previously given (26, 27). Human exposure was evaluated for individuals living at 500, 2500, and >4000 m from the HWI. The first two distances (500 and 2500 m) were selected as a representation of rural points located close to and far away from the facility, respectively. On the other hand, at 4000 m from the HWI there is an important urban nucleus (Tarragona). In turn, the potentially exposed population was classified into two subgroups: adults and children.
Results and Discussion Environmental PCDD/F Levels. Air emitted by the HWI was periodically sampled in the stack during the period 19992003. The average PCDD/F concentration was 0.025 ng I-TEQ/m3 (range: 0.009-0.036), which is clearly under the legal limit established by the European Union directive of 0.1 ng I-TEQ/m3 (7). Other investigators found similar stack concentrations of PCDD/Fs (28). The PCDD/F congener profile corresponding to air emission samples collected in 2003 in the HWI studied here is depicted in Figure 1. It can be observed that 1,2,3,4,6,7,8HpCDF was the predominant congener, accounting for approximately 30% of the total concentration. OCDD and OCDF also showed an important contribution. Karademir (28) found a similar trend, identifying 1,2,3,4,6,7,8-HpCDF as the most influent congener with respect to total concentration when the health risks due to PCDD/F emissions of a medical/hazardous waste incinerator were assessed. This investigator stated that emission rates of all PCDF congeners were notably higher than those of PCDDs. As described above, an environmental monitoring program around the HWI was carried out in 2003. Soil and herbage samples were collected at the same sampling points 62
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of the baseline survey. In soils, mean concentrations of 1.59 and 0.77 ng I-TEQ/kg dry matter were found in the baseline and in the 2003 surveys, respectively. However, this difference was not statistically significant. Moreover, no significant differences in the levels of PCDD/Fs in soils were observed in relation to the distance from the HWI or to the wind direction. The PCDD/F congener profiles for soils collected in the baseline and current surveys in sampling points close to and far away from the HWI are depicted in Figure 2. OCDD was the predominant congener (>60% of the total PCDD/F concentrations), followed by 1,2,3,4,6,7,8-HpCDD, 1,2,3,4,6,7,8-HpCDF, and OCDF. Only the contribution of OCDD increased notably between the baseline and the current surveys, while the OCDF percentage over the total PCDD/F concentration decreased. However, these changes were not statistically significant. In general terms, profiles were very similar to those obtained in soils collected near various municipal solid waste incinerators (MSWIs) and other industrialized areas (29-31). In herbage, mean PCDD/F concentrations were between 0.31 and 0.22 ng I-TEQ/kg dry matter in the baseline and current surveys, respectively. Only PCDD/F levels from samples collected in urban zones (more than 4 km from the plant) seemed to increase in both surveys (24). The PCDD/F congener profiles for herbage samples collected near and far away from the HWI are depicted in Figure 3 (baseline and current surveys). In general terms, a congener profile different from that corresponding to soils was observed for herbage samples. Although the same and heaviest congeners were predominant, an important reduction of OCDD contribution was noted between the baseline and the 2003 surveys. In absolute terms, OCDD median concentration decreased from 3.14 to 1.40 ng I-TEQ/kg dry matter, while a similar tendency was not observed for the remaining congeners. Despite the difficulties in comparing different kinds of industries according to their PCDD/F fingerprints (32), OCDD has been considered a good indicator to assess pollution by MSWIs, as well as unleaded gas-fueled and diesel-fueled vehicles (33, 34). On the other hand, the contribution of several furans could be determined (up to 5% in relation to total concentration). Unlike soils, herbage has been generally used in short-term environmental monitoring programs (35). Consequently, light PCDD/F congeners, which suffer more degradation than the heaviest compounds, can be more easily detected. It must be noted that PCDD/Fs with seven or eight chlorine atoms are strongly associated to particles and, hence, are subjected to relatively slow reaction rates (36). Similar congener profiles were previously detected in vegetation grown in other unpolluted areas (37). Self-Organizing Maps (SOM). To identify the most environmentally impacted zones, a SOM was applied to both soil and herbage samples collected in both the baseline and the current surveys. The resulting Kohonen maps are depicted in Figures 4a and 5a (soil and herbage, respectively), while the component planes associated to the SOM obtained for soils and herbage are shown in Figures 4b and 5b, respectively. With regard to soils, most samples showed relatively low values, while none of the zones were identified with a special degree of pollution. Variables could be grouped into two classes according to the individual concentration of PCDD/F congeners. Three samples collected in the baseline survey (NW4, U4, and E5) were characterized by higher levels of light dioxins (TCDD and PeCDD) and all furan congeners (lower-right corner of Figure 4a,b ). On the other hand, three samples corresponding to the 2003 survey were associated to a higher concentration of hexa- to OCDD (lower-left corner of Figure 4a,b). Two of these samples were collected in an urban area at 5 km from the HWI (U6 and U7). In turn, sample N5 was collected at 2500 m north from the facility, opposite to the main wind direction. It indicates that the effect of
FIGURE 2. PCDD/F congener profiles in soil samples collected at distances less than and greater than 1.5 km from the HWI: baseline and current (2003) data.
FIGURE 3. PCDD/F congener profiles in herbage samples collected at distances less than and greater than 1.5 km from the HWI: baseline and current (2003) data. other local pollution sources, rather than that of the HWI, would be more important in these sampling points. A different pattern was given by applying the SOM algorithm to herbage samples. As it can be seen in the lowerright corner of the map and the component planes Figure 5a,b respectively), two samples were associated to the most volatile PCDD/F congeners. In contrast, two different samples presented relatively high levels of OCDF and heavy PCDDs (lower-left corner of Figure5a,b 5). However, none of these samples were collected near the HWI. Likewise, some particular samples of the baseline survey were affected by tetra-CDD/F and 1,2,3,7,8,9-HxCDF. In general terms, no clusters were identified according to the distance to the plant. Human Health Risks. In addition to the environmental survey, a biological monitoring program was carried out in the population living in the neighborhood of the HWI. Blood samples from 20 individuals living in areas under the potential direct influence of the HWI were collected and subsequently analyzed to determine the concentrations of PCDD/Fs in plasma. Mean PCDD/F levels decreased from 27.01 pg I-TEQ/g lipid (baseline survey) to 15.70 pg I-TEQ/g lipid (current survey). PCDD/F congener profiles for both surveys are depicted in Figure 6. OCDD was also the main contributor (approximately 70% of the total concentration) in both surveys, followed by 1,2,3,4,6,7,8-HpCDD and 1,2,3,6,7,8HxCDD. These results are in agreement with those recently reported by other investigators in various surveys (16, 38, 39).
In summary, no significant differences in PCDD/F congener profiles in soils and herbage were noted between the baseline and the current surveys. This would be an indicator that the HWI would not significantly impact its surrounding environment. On the other hand, and since the same lack of differences was also observed in the PCDD/F congener profiles found in blood samples from the non-occupationally exposed population living in the neighborhood of the facility, it can be also concluded that the HWI did not notably increase the health risks due to exposure to PCDD/Fs. To corroborate this, a human health risk assessment following a typical methodology was carried out. The results of the estimation of total PCDD/F exposure for adults and children living at 500, 2500, and >4000 m from the HWI are summarized in Table 1. With regard to PCDD/F concentrations in air, no significant differences were noted. Values of 47.5, 31.8, and 47.1 fg I-TEQ/m3 at distances of 500, 2500, and >4000 m from the HWI, respectively, were found (data from the Regional Government of Catalonia). On average, PCDD/F levels in soils increased directly in relation to the distance from the facility, with values of 0.59, 0.99, and 1.28 ng I-TEQ/kg dry matter at 500, 2500, and >4000 m from the plant, respectively (24). Analogous results were also observed in the baseline survey (7). These data would suggest that pollution far away from the facility might also be important due to the presence of other potential emission sources of PCDD/Fs (chemical industries, a big oil refinery, heavy traffic, etc.) located in the same area as the HWI. VOL. 40, NO. 1, 2006 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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FIGURE 4. Kohonen self-organizing map (SOM) (a) and component planes (b) for soil samples collected in the baseline and the current (2003) surveys. Y-axis in component planes shows the individual concentration of each congener (in ng/kg).
FIGURE 5. Kohonen SOM (a) and component planes (b) for vegetation samples collected in the baseline and the current (2003) surveys. Y-axis in component planes shows the individual concentration of each congener (in ng/kg). The total environmental PCDD/F exposure for the population living in the urban area (>4000 m) was slightly higher than that estimated for the subjects living near the HWI (500 and 2500 m). For adults, exposures of 6.78 × 10-6, 5.00 × 10-6, and 7.22 × 10-6 ng I-TEQ/kg/day were estimated at 500, 2500, and >4000 m, respectively. Inhalation was the main contributor pathway for direct exposure, followed by dermal contact, and then soil ingestion. The percentages of exposure through air inhalation, with respect to the total direct exposure, were 92, 84, and 86% at 500, 2500, and >4000 m, respectively. For children, environmental exposure accounted for 9.66 × 10-6, 7.37 × 10-6, and 1.03 × 10-5 ng I-TEQ/kg/day, respectively. The trend for the children’s 64
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environmental exposure to PCDD/Fs was similar to that found for adults, with the highest value corresponding to individuals living in urban zones. However, because of body weight differences, children seemed to be more environmentally exposed to PCDD/Fs. In addition, since children ingest a remarkably higher amount of soil particles than adults, total PCDD/F ingestion was more important. This route means 11.4, 17.8, and 14.5% for the three simulated scenarios (500, 2500, and >4000 m, respectively). Similar results were observed in adults and children living around a MSWI (13) and in adults living in the vicinity of a petrochemical area (27), both located near the HWI studied here.
TABLE 1. PCDD/F Exposure for Adults and Children Living at 500, 2500, and >4000 m from the HWI (2003 data)a rural
urban
500 m adults
>4000 m
2500 m children
adults
children
adults
children
Environmental Exposure 4.75E-05 3.18E-05 0.585 0.998 6.27E-06 8.25E-06 4.20E-06 5.52E-06 3.59E-07 3.12E-07 6.11E-07 5.33E-07 1.52E-07 1.10E-06 1.89E-07 1.32E-06
4.71E-05 1.282 6.22E-06 8.18E-06 7.86E-07 6.85E-07 2.15E-07 1.46E-06
total environmental exposure (ng I-TEQ/kg/day)
6.78E-06
intake of PCDD/F (ng I-TEQ/kg/day)
8.52E-04
total exposure (ng I-TEQ/kg/day)
8.59E-04
PCDD/F Cair (ng I-TEQ/m3) PCDD/F Csoil (ng I-TEQ/kg dry matter) PCDD/F Inh (ng I-TEQ/kg/day) PCDD/F Der total (ng I-TEQ/kg/day) PCDD/F Ing total (ng I-TEQ/kg/day)
a
9.66E-06
5.00E-06
7.37E-06
7.22E-06
1.03E-05
Dietary Exposure 3.24E-03 8.52E-04
3.24E-03
8.52E-04
3.25E-03
3.25E-03
8.60E-04
3.24E-03
3.25E-03
8.57E-04
C: Concentration; Inh: inhalation; Der: dermal contact; Ing: soil ingestion.
FIGURE 6. PCDD/F congener profiles in blood samples of individuals living in the vicinity of the HWI: baseline and current (2003) data. The percentage of direct exposure referred to total PCDD/ Fs ranged from 0.6 to 0.8% for adults and from 0.1 to 0.3% for children. As it was expected, dietary intake for both adults and children was clearly the main source of PCDD/F exposure, with >99%. (40). It can be concluded that total environmental PCDD/F exposure of the population living near and far away from the HWI is almost imperceptible when compared with the contribution of dietary intake of PCDD/Fs to the total daily exposure to these organic pollutants. Similar findings were also reported by other investigators near different incinerators (13, 26, 28). The noncarcinogenic risk was evaluated by dividing total PCDD/F exposure by the range of 1-4 pg I-TEQ/kg/day, which was established as a tolerable daily intake (TDI) by the World Health Organization (41). The risk index ranged between 0.21 and 0.86 for adults and between 0.81 and 3.25 for children. No differences were noted according to the analyzed scenario. In turn, the carcinogenic risk was calculated considering the value 1 × 10-3 as the upper bound cancer risk (42). For total PCDD/F exposure calculations, inhalation and dermal contact were assimilated to oral exposure. The cancer risk was calculated to be approximately 860. Taking into account a lifetime of 70 years (43), this level means 12 cases of cancers per year in an adult population of 1 million. Some authors have pointed to some relationships between the appearance of childhood cancers and some environmental carcinogens such as PCDD/Fs (44). Unfortunately, because of the lack of reliable data about metabolism
and the adverse health effects in children (45), carcinogenic risk could not be assessed for this population. The comparison of the PCDD/F congener profiles corresponding to the baseline and current surveys as well as the human health risk assessment suggests that the HWI studied here does not mean additional risks either to the environment or to the population living in the vicinity of the facility. In fact, according to the results of a number of studies carried out in recent years from various countries, it seems quite evident that the public concern over the health risks due to exposure to PCDD/Fs emitted by modern MSWIs may be scientifically unjustified (2). Because diet is the main route of human exposure to PCDD/Fs, only efforts to reduce emissions from all sources can significantly contribute to decreased environmental PCDD/F concentrations and, consequently, their levels in food. In summary, our opinion is that decisions about potential construction and/or location of HWIs should be based on technical reasons more than on political reasons. It shows the great importance of risk assessment and communication to address the gap between experts and the public regarding knowledge of technical topics.
Acknowledgments This study was supported by the “Age`ncia de Residus”, Generalitat de Catalunya, Spain.
Literature Cited (1) Richter, S.; Johnke, B. Status of PCDD/F-emission control in Germany on the basis of the current legislation and strategies for further action. Chemosphere 2004, 54, 1299-1302. (2) Domingo, J. L. Human health risks of dioxins for populations living near modern municipal solid waste incinerators. Rev. Environ. Health 2002, 17, 135-147. (3) Ma, H. W. Using stochastic risk assessment in setting information priorities for managing dioxin impact from a municipal waste incinerator. Chemosphere 2002, 48, 1035-1040. (4) Abad, E.; Caixach, J.; Rivera, J.; Gustems, L.; Massague, G.; Puig, O. Temporal trends of PCDDs/PCDFs in ambient air in Catalonia (Spain). Sci. Total Environ. 2004, 334-335, 279-285. (5) Directive 2000/76/EC of the European Parliament and of the Council of 4 December 2000 on the incineration of waste, Official Journal of the European Communities; 2000. (6) Snary, C. Health risk assessment for planned waste incinerators: getting the right science and the science right. Risk Anal. 2002, 22, 1095-1105. (7) Schuhmacher, M.; Agramunt, M. C.; Rodriguez-Larena, M. C.; Diaz-ferrero, J.; Domingo, J. L. Baseline levels of PCDD/Fs in soil and herbage samples collected in the vicinity of a new hazardous waste incinerator in Catalonia, Spain. Chemosphere 2002, 46, 1343-1350. VOL. 40, NO. 1, 2006 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
9
65
(8) Schuhmacher, M.; Domingo, J. L.; Llobet, J. M.; Lindstrom, G.; Wingfors, H. Dioxin and dibenzofuran concentrations in blood of a general population from Tarragona, Spain. Chemosphere 1999, 38, 1123-1133. (9) Domingo, J. L.; Schuhmacher, M.; Granero, S.; Llobet, J. M. PCDDs and PCDFs in food samples from Catalonia, Spain. An assessment of dietary intake. Chemosphere 1999, 38, 35173528. (10) Im, S. H.; Kannan, K.; Giesy, J. P.; Matsuda, M.; Wakimoto, T. Concentrations and profiles of polychlorinated dibenzo-pdioxins and dibenzofurans in soils from Korea. Environ. Sci. Technol. 2002, 36, 3700-3705. (11) Lorber, M.; Pinsky, P.; Gehring, P.; Braverman, C.; Winters, D.; Sovocool, W. Relationships between dioxins in soil, air, ash, and emissions from a municipal solid waste incinerator emitting large amounts of dioxins. Chemosphere 1998, 37, 2173-2197. (12) Park, S.; Kim, S. J.; Kim, K. S.; Lee, D. S.; Kim, J. G. 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. 2004, 38, 3820-3826. (13) Domingo, J. L.; Agramunt, M. C.; Nadal, M.; Schuhmacher, M.; Corbella, J. Health risk assessment of PCDD/PCDF exposure for the population living in the vicinity of a municipal waste incinerator. Arch. Environ. Contam. Toxicol. 2002, 43, 461465. (14) Glorennec, P.; Zmirou, D.; Bard, D. Public health benefits of compliance with current E.U. emissions standards for municipal waste incinerators: a health risk assessment with the CalTox multimedia exposure model. Environ. Int. 2005, 31, 693-701. (15) Lim, Y.; Yang, J.; Kim, Y.; Chang, Y.; Shin, D. Assessment of human health risk of dioxin in Korea. Environ. Monit. Assess. 2004, 92, 211-228. (16) Pirard, C.; Eppe, G.; Massart, A. C.; Fierens, S.; De Pauw, E.; Focant, J. F. Environmental and human impact of an old-timer incinerator in terms of dioxin and PCB level: a case study. Environ. Sci. Technol. 2005, 39, 4721-4728. (17) Meneses, M.; Schuhmacher, M.; Domingo, J. L. Health risk assessment of emissions of dioxins and furans from a municipal waste incinerator: comparison with other emission sources. Environ. Int. 2004, 30, 481-489. (18) Schuhmacher, M.; Domingo, J. L.; Hagberg, J.; Lindstrom, G. PCDD/F and non-ortho PCB concentrations in adipose tissue of individuals living in the vicinity of a hazardous waste incinerator. Chemosphere 2004, 57, 357-364. (19) Schuhmacher, M.; Domingo, J. L.; Kiviranta, H.; Vartiainen, T. Monitoring dioxins and furans in a population living near a hazardous waste incinerator: levels in breast milk. Chemosphere 2004, 57, 43-49. (20) Agramunt, M. C.; Schuhmacher, M.; Hernandez, J. M.; Domingo, J. L. Levels of dioxins and furans in plasma of nonoccupationally exposed subjects living near a hazardous waste incinerator. J. Exposure Anal. Environ. Epidemiol. 2005, 15, 29-34. (21) Kohonen, T. Self-organizing formation of topologically correct feature maps. Biol. Cybern. 1982, 43, 59-69. (22) Giraudel, J. L.; Lek, S. A comparison of self-organizing map algorithm and some conventional statistical methods for ecological community ordination. Ecol. Modell. 2001, 146, 329339. (23) Nadal, M.; Espinosa, G.; Schuhmacher, M.; Domingo, J. L. Patterns of PCDDs and PCDFs in human milk and food and their characterization by artificial neural networks. Chemosphere 2004, 54, 1375-1382. (24) Nadal, M.; Bocio, A.; Dı´az-Ferrero, J.; Schuhmacher, M.; Llobet, J. M.; Domingo, J. L. Monitoring PCDD/Fs in soil and herbage samples collected in the neighborhood of a hazardous waste incinerator after five years of operation. Organohalogen Compd. 2004, 66, 1788-1795. (25) Bocio, A.; Domingo, J. L. Daily intake of polychlorinated dibenzop-dioxins/polychlorinated dibenzofurans (PCDD/PCDFs) in foodstuffs consumed in Tarragona, Spain: a review of recent studies (2001-2003) on human PCDD/PCDF exposure through the diet. Environ. Res. 2005, 97, 1-9. (26) Nouwen, J.; Cornelis, C.; De Fre, R.; Wevers, M.; Viaene, P.; Mensink, C.; Patyn, J.; Verschaeve, L.; Hooghe, R.; Maes, A.; Collier, M.; Schoeters, G.; Van Cleuvenbergen, R.; Geuzens, P. Health risk assessment of dioxin emissions from municipal waste
66
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(27)
(28)
(29)
(30)
(31)
(32)
(33)
(34)
(35)
(36)
(37)
(38)
(39)
(40) (41)
(42)
(43)
(44) (45)
incinerators: the Neerlandquarter (Wilrijk, Belgium). Chemosphere 2001, 43, 909-923. Nadal, M.; Schuhmacher, M.; Domingo, J. L. Probabilistic human health risk of PCDD/F exposure: a socioeconomic assessment. J. Environ. Monit. 2004, 6, 926-931. Karademir, A. Health risk assessment of PCDD/F emissions from a hazardous and medical waste incinerator in Turkey. Environ. Int. 2004, 30, 1027-1038. Domingo, J. L.; Bocio, A.; Nadal, M.; Schuhmacher, M.; Llobet, J. M. Monitoring dioxins and furans in the vicinity of an old municipal waste incinerator after pronounced reductions of the atmospheric emissions. J. Environ. Monit. 2002, 4, 395399. Cheng, P. S.; Hsu, M. S.; Ma, E.; Chou, U.; Ling, Y. C. Levels of PCDD/FS in ambient air and soil in the vicinity of a municipal solid waste incinerator in Hsinchu. Chemosphere 2003, 52, 13891396. Bakoglu, M.; Karademir, A.; Durmusoglu, E. Evaluation of PCDD/F levels in ambient air and soils and estimation of deposition rates in Kocaeli, Turkey. Chemosphere 2005, 59, 1373-1385. Buekens, A.; Cornelis, E.; Huang, H.; Dewettinck, T. Fingerprints of dioxin from thermal industrial processes. Chemosphere 2000, 40, 1021-1024. Cleverly, D.; Schaum, J.; Schweer, G.; Becker, J.; Winters, D. The congener profiles of anthropogenic sources of chlorinated dibenzo-p-dioxins and chlorinated dibenzofurans in the United States. Organohalogen Compd. 1997, 32, 430-435. Lee, W. S.; Chang-Chien, G. P.; Wang, L. C.; Lee, W. J.; Tsai, P. J.; Wu, K. Y.; Lin, C. Source identification of PCDD/Fs for various atmospheric environments in a highly industrialized city. Environ. Sci. Technol. 2004, 38, 4937-4944. Lorber, M.; Pinsky, P. An evaluation of three empirical air-toleaf models for polychlorinated dibenzo-p-dioxins and dibenzofurans. Chemosphere 2000, 41, 931-941. Alcock, R. E.; Sweetman, A. J.; Jones, K. C. A congener-specific PCDD/F emissions inventory for the UK: do current estimates account for the measured atmospheric burden? Chemosphere 2001, 43, 183-194. Martinez, M.; Diaz-Ferrero, J.; Marti, R.; Broto-Puig, F.; Comellas, L.; Rodriguez-Larena, M. C. Analysis of dioxin-like compounds in vegetation and soil samples burned in Catalan forest fires. Comparison with the corresponding unburned material. Chemosphere 2000, 41, 1927-1935. Chen, H. L.; Liao, P. C.; Su, H. J.; Guo, Y. L.; Chen, C. H.; Lee, C. C. Profile of PCDD/F levels in serum of general Taiwanese between different gender, age and smoking status. Sci. Total Environ. 2005, 337, 31-43. Lee, C. C.; Chen, H. L.; Su, H. J.; Guo, Y. L.; Liao, P. C. Evaluation of PCDD/Fs patterns emitted from incinerator via direct ambient sampling and indirect serum levels assessment of Taiwanese. Chemosphere 2005, 59, 1465-1474. Parzefall, W. Risk assessment of dioxin contamination in human food. Food Chem. Toxicol. 2002, 40, 1185-1189. van Leeuwen, F. X.; Feeley, M.; Schrenk, D.; Larsen, J. C.; Farland, W.; Younes, M. Dioxins: WHO’s tolerable daily intake (TDI) revisited. Chemosphere 2000, 40, 1095-1101. US EPA. Draft exposure and human health reassessment of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds, EPA/600/P-00/001; US Environmental Protection Agency: Washington DC, 2000. Schecter, A.; Olson, J. R. Cancer risk assessment using blood dioxin levels and daily dietary TEQ intake in general populations of industrial and non-industrial countries. Chemosphere 1997, 34, 1569-1577. Knox, E. G. Childhood cancers and atmospheric carcinogens. J. Epidemiol. Community Health 2005, 59, 101-105. Becher, H.; Steindorf, K.; Flesch-Janys, D. Quantitative cancer risk assessment for dioxins using an occupational cohort. Environ. Health Perspect. 1998, 106 Suppl. 2, 663-670.
Received for review August 17, 2005. Revised manuscript received October 3, 2005. Accepted October 28, 2005. ES051630+
