Environ. Sci. Technol. 2003, 37, 1503-1508
Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans in the Air of Seveso, Italy, 26 Years after the Explosion E L E N A F A T T O R E , * ,† ANTONIO DI GUARDO,‡ GIULIO MARIANI,† ANDREA GUZZI,† EMILIO BENFENATI,† AND ROBERTO FANELLI† Department of Environmental Health Sciences, “Mario Negri” Institute for Pharmacological Research, Via Eritrea 62, 20157 Milano, Italy, and Environmental Research Group, DBSF, University of Insubria, Via J. H. Dunant 3, 21100 Varese, Italy
This study reports the current levels of polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in air at Seveso, where an explosion in a 2,4,5,-trichlorophenol production reactor occurred 26 years ago. The aims were to assess if residues of the 2,3,7,8-tetrachlorodibenzo-pdioxin (2,3,7,8-TCDD) released during the accident and still present in soil could contaminate the above air and to investigate other potential sources in the area. Long-term air collection was carried out in zones A and B in Seveso and in a reference location in Milan, and samples were analyzed for PCDD and PCDF concentrations by gas chromatography-mass spectrometry (GC-MS). Experimental results showed that no important contribution to the air concentrations is due to the soil contamination and that contemporary sources essentially control the atmospheric burden of PCDDs and PCDFs in the Seveso area. The theoretical release of 2,3,7,8-TCDD from the soils of zones A and B of Seveso was calculated using the SoilFug model. In the worst case, the model simulated an enrichment in atmospheric 2,3,7,8-TCDD concentrations of 4 and 22% for zones A and B, respectively. The investigation of the potential emission sources in the area indicated that combustion of wood residues from furniture factories may be an additional local source of PCDDs and PCDFs.
Introduction On July 1976 an explosion in the 2,4,5,-trichlorophenol production reactor occurred at the Givaudan-HoffmanLaRoche ICMESA chemical plant. The accident caused the emission of a vapor cloud containing an undefined amount of the 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) together with ethylene glycol, trichlorophenol, sodium chloride, and sodium hydroxide (1, 2). The toxic cloud spread and settled along a linear path of 6 km SE from the chemical plant causing a heavy contamination of the soil in Seveso, a small town located 30 km north of Milan. The area was subsequently divided into three risk zones: the zones A, B, * Corresponding author e-mail:
[email protected]; phone: +39-02-39014420; fax: +39-02-39001916. † “Mario Negri” Institute for Pharmacological Research. ‡ University of Insubria. 10.1021/es0261224 CCC: $25.00 Published on Web 03/12/2003
2003 American Chemical Society
FIGURE 1. Map of the Seveso area showing the zones A, B, and R. and R (Figure 1), with decreasing levels of contamination in soil. In zone A (87.3 ha, 706 inhabitants, deposition >50 µg of 2,3,7,8-TCDD/m2 of soil), where the ICMESA plant was located, population was evacuated, and the first 20 cm of soil was scarified. A part of this area has been recently converted into a park (Bosco delle Quercie); zone B (269 ha, 4613 inhabitants, deposition range of 5-50 µg of 2,3,7,8TCDD/m2 of soil) and zone R (1430 ha, 30 774 inhabitants, deposition
