Comparison of TEQS Measured by Enzyme Immunoassay (EIA) and High Resolution Gas Chromatography and Mass Spectrometry (HRGC/HRMS) in Air Samples of a Residential Area and a Waste Incineration Site

Abstract

P-076 Introduction: Dioxin is the most toxic chemical ever studied until now and usually produced by certain industrial processes, including incineration. Polychlorinated dibenzo-p[r]-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in environmental matrices are mainly measured by analytical procedures, such as high resolution gas chromatography and mass spectrometry (HRGC/HRMS). Although being used by most dioxin laboratories, these methods are time consuming and expensive. To solve these problems, therefore, many new techniques have been developed, for example, the immunoassay and bioassay for PCDDs and PCDFs analysis. An enzyme immunoassay (EIA) was developed as an antibody-based screening method and is now commercially available (DF1 by CAPE Technologies, USA). TEQs measured by enzyme immunoassay may be affected by the concentrations of congeners of PCDDs and PCDFs. The concentration of dioxin congeners in the air of a residential area may be very different from that of an incineration site. Moreover, few studies have been conducted to compare the analytical methods for PCDDs and PCDFs in ambient air samples. Methods: This study compared the PCDDs and PCDFs toxicity levels in terms of TEQs in ambient air samples from a residential area and a waste incineration site using two analytical methods: EIA and HRGC/HRMS. The ambient air samples were collected using a high volume air sampler and extracted using a soxhlet extraction method. Results: For residential district samples, TEQs by EIA (EIA-TEQs) were higher than those by HRGC/HRMS (I-TEQs). For waste incineration site samples, on the other hand, EIA-TEQs were lower than I-TEQs. The ratios of EIA-TEQs to I-TEQs were 1.70 in the residential area and 0.70 in the incineration site, respectively. The concentrations and distribution of dioxin congeners in the air samples of the residential area were different from those of the waste incineration site. Conclusions: The findings of this study indicate that EIA is a complementary method to HRGC/HRMS, and a caution should be given to the interpretation of the measurements because the concentrations and distribution of dioxin congeners were highly different.