Table 1. The multi-component mixtures of PAHs (benzo[a]pyrene (B[a]P), naphthalene (Nap), phenanthrene (Phe), and pyrene (Pyr)) and heavy metal/loid(s) (arsenic (As), cadmium (Cd), lead (Pb)) on activation of Nrf2 antioxidant pathway in ARE reporter-HepG2 cells.

Chemical mixtures	ECIR1.5 exp (μM)	95% CI	ECIR1.5 CA (μM)	95% CI	IPQ	Observed maximum induction ratio
Binary mixtures
As + Cd	0.70 ± 0.24	0.09–1.3	0.90 ± 0.21	0.39–1.4	0.29	2.4
As + Pb*	1.63 ± 0.31	0.87–2.4	2.33 ± 0.21	1.8–2.9	0.43	2.4
Cd + Pb	2.2 ± 0.44	1.17–3.2	2.0 ± 0.21	1.52–2.6	–0.09	1.7
B[a]P + As	0.67 ± 0.25	0.05–1.3	1.04 ± 0.31	0.27–1.8	0.78	3.3
B[a]P + Cd	0.45 ± 0.16	0.04–0.9	0.80 ± 0.34	0.04–1.7	0.81	3.0
B[a]P + Pb	1.11 ± 0.34	0.26–2.0	2.13 ± 0.25	1.5–2.8	0.92	3.3
B[a]P + Nap	1.86 ± 0.45	0.70–3.0	1.76 ± 0.45	0.64–2.9	–0.06	2.5
B[a]P + Phe	2.1 ± 0.74	0.25–3.9	1.73 ± 0.37	0.81–2.7	–0.21	2.4
B[a]P + Pyr	1.56 ± 0.80	0.17–3.5	1.88 ± 0.54	0.54–3.2	0.21	3.3
Ternary mixtures
As + Cd + Pb	1.87 ± 0.55	0.50–3.2	1.70 ± 0.36	0.80–2.6	–0.09	2.3
B[a]P + As + Cd*	0.45 ± 0.16	0.05–0.9	0.79 ± 0.19	0.29–1.3	0.74	5.0
B[a]P + As + Pb*	1.22 ± 0.33	0.41–2.0	1.77 ± 0.32	0.97–2.6	0.45	3.4
B[a]P + Cd + Pb	1.00 ± 0.09	0.77–1.2	1.60 ± 0.27	0.93–2.3	0.60	3.3
B[a]P + Nap + Phe	1.5 ± 0.16	0.02–3.0	2.1 ± 0.83	0.6–3.5	0.39	4.4
B[a]P + Nap + Pyr	1.37 ± 0.23	0.13–3.4	1.94 ± 0.14	0.66–3.2	0.42	4.7
B[a]P + Phe + Pyr	1.34 ± 0.22	0.02–3.3	1.87 ± 0.05	1.4–2.33	0.40	4.8
Quaternary mixtures
B[a]P + As + Cd + Pb*	0.77 ± 0.12	0.46–1.1	1.47 ± 0.25	0.84–2.1	0.91	5.1
B[a]P + Nap + Phe + Pyr	1.96 ± 0.07	1.31–2.6	2.06 ± 0.29	0.14–4.6	0.05	4.6
All seven chemicals	2.06 ± 0.40	0.18–3.7	1.87 ± 0.06	1.3–2.4	–0.09	6.0