1. ^aSchool of Public Health, University of California at Berkeley, Berkeley, CA, USA
2. ^bDivision of Environmental Health Laboratory Science, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
3. ^cXenobiotic Detection Systems, Inc., Durham, NC, USA
4. ^dDepartment of Laboratory Medicine, University of Milano-Biococca, School of Medicine, Hospital of Desio, Desio-Milano, Italy

Correspondence: Dr. Marcella Warner, School of Public Health, University of California, 2150 Shattuck Avenue, Suite 600, Berkeley, CA 94720-7380, USA. Tel.: +1-510-642-9544. Fax: +1-510-642-9083. E-mail: mwarner@calmail.berkeley.edu

Received 8 September 2003; Accepted 19 July 2004; Published online 22 September 2004.

Abstract

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) are widespread environmental contaminants that exist as complex mixtures and are frequently detected at part-per-trillion (ppt) levels in humans. Using isotope dilution high-resolution gas chromatography/ high-resolution mass spectrometry (HRGC/HRMS), we measure the PCDDs, PCDFs, and PCBs in serum of a population of 78 women residing in an area near Seveso, Italy where a TCDD explosion occurred in 1976 and where furniture is manufactured. The average total dioxin-like toxic equivalents (TEQ) of these women was 25.3 ppt, lipid-adjusted, comparable to other parts of Europe. TCDD levels, however, were higher among the few women who resided in the exposed area in 1976. We examined the possibility of using the CALUX (chemical-activated luciferase gene expression) bioassay to estimate total TEQ in a small volume of plasma from this population. A total of 32 archived plasma specimens were selected for CALUX bioassay, based on the distribution of Total TEQ by HRGC/HRMS. The CALUX bioassay was performed blind to HRGC/HRMS results with 2 ml plasma per replicate analysis. Of 32 samples, 10 were below detection limits in the CALUX bioassay. For the 32 samples, the CALUX-TEQ averaged 25.4 ppt, lipid-adjusted (range: 0–127.6) and was not significantly different from the HRGC/HRMS Total TEQ average of 31.2 ppt, lipid-adjusted (range: 12.7–88.3) (t=0.88, P=0.38), however, the two measures were not significantly correlated (R_s=0.04, P=0.82). More validation of the CALUX bioassay with larger sample volume is needed before application as an exposure measure in large-scale epidemiologic studies of health effects of dioxin-like compounds.