Table 6.

Geo-accumulation index (I_geo) of trace metals in river sediments.

Stations		As	Se	Hg	Be	Pb	Cd	Co	Cr	Cu	V	Zn	Ni	Igeo Standard classes [62]
														Class	Sediment quality
South-West	A1	−1.78	1.20	0.14	−2.00	−0.82	0.62	−1.06	0.24	1.38	−2.59	1.78	0.08	<0	Practically unpolluted
	A2	−1.34	0.80	0.18	−1.35	−0.53	1.02	−0.76	0.29	2.15	−2.34	1.55	0.12	0–1	Unpolluted to moderately polluted
	A3	−1.33	0.29	0.30	−1.42	−0.72	0.77	−0.88	0.37	1.94	−2.38	1.59	0.22	2–3	Moderately to strongly polluted
North-West	B1	−2.59	−2.07	−1.64	−3.62	−3.03	−3.17	−2.90	−1.03	1.19	−4.60	0.95	−1.25	3–4	Strongly polluted
	B2	−2.56	−4.51	−1.56	−3.50	−2.85	−2.91	−2.60	−1.03	1.37	−4.32	1.02	−1.12	4–5	Strongly to extremely polluted
	B3	−2.17	−2.56	−1.52	−2.85	−1.47	−3.91	−2.11	−0.89	1.01	−3.60	1.11	−0.94	>5	Extremely polluted
South-East	C1	−1.77	−0.19	−0.59	−1.85	0.19	−2.68	−1.19	−0.09	1.66	−2.70	1.46	−0.43
	C2	−1.67	−0.24	−0.37	−1.44	−0.78	−3.17	−0.88	−0.05	1.80	−2.44	1.38	−0.33
	C3	−1.57	0.16	−0.29	−1.48	−0.75	−2.49	−0.83	−0.02	1.30	−2.31	1.50	−0.23
North-East	D1	−1.95	−1.72	−2.17	−2.16	−1.68	−2.32	−1.59	−0.81	1.43	−3.10	1.20	−0.84
	D2	−1.82	0.42	−1.93	−1.77	−0.44	−3.17	−1.12	−0.60	1.04	−2.69	1.31	−0.72
	D3	−1.56	−0.04	−1.85	−1.85	−1.33	−2.49	−1.31	−0.52	1.38	−2.70	1.29	−0.63