Correlation between enzyme-linked immunosorbent assay (ELISA) for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents and gas chromatography/high-resolution mass spectrometry (GC-HRMS) toxic equivalents (TEQs) for 16 slum soil samples. (a) The theoretical ELISA values (TCDD equivalents), computed as the sum of the concentration of each congener (determined by GC-HRMS) multiplied by the corresponding cross-reactivity versus GC-HRMS TEQ values. (b) Experimental ELISA (University of California, Davis, UC Davis, CA, USA)-determined TCDD equivalents versus GC-HRMS TEQ values. WHO = World Health Organization.