Heavy metal accumulation during the last 30 years in the Karnaphuli River estuary, Chittagong, Bangladesh

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Table 5 Contamination factor (CF) and Pollution load index (PLI) value of heavy metals in surface and core sediments

Site	Layer (cm)	CF _Cr	CF _Cu	CF _Ni	CF _Pb	CF _Zn	PLI
S1	0–5	1.01	0.62	0.62	1.06	0.63	0.76
S2	0–5	1.02	0.62	0.61	1.07	0.65	0.77
S3	0–5	1.28	0.98	0.74	1.04	0.78	0.94
S4	0–5	1.18	0.71	0.71	1.04	0.70	0.85
S5	0–5	1.17	1.00	0.73	1.10	0.69	0.92
C1	0–1	1.33	0.77	0.75	1.10	0.74	0.91
	2–3	1.33	1.06	0.86	1.12	0.82	1.02
	4–5	1.31	1.04	0.86	1.11	0.81	1.01
	6–7	1.04	0.54	0.60	1.01	0.53	0.71
	8–9	1.03	0.57	0.58	1.02	0.54	0.71
	10–11	1.19	0.80	0.73	1.12	0.70	0.88
	12–13	1.26	0.98	0.78	1.17	0.77	0.97
	14–15	1.35	1.04	0.84	1.12	0.86	1.03
	16–17	1.08	0.72	0.68	1.03	0.68	0.82
	18–19	1.55	1.76	1.00	1.20	1.22	1.32
	20–21	1.55	1.39	1.00	1.24	1.07	1.23
	22–23	1.45	1.27	0.93	1.19	0.93	1.14
	24–25	1.29	0.97	0.76	1.10	0.74	0.95
	26–27	1.14	0.78	0.68	1.12	0.71	0.86
	28–29	1.19	0.87	0.71	1.09	0.73	0.90
	30–31	1.15	0.81	0.69	1.07	0.67	0.86
	32–33	1.17	0.81	0.69	1.11	0.70	0.87
	34–35	1.13	0.82	0.69	1.06	0.70	0.86
	36–37	1.16	0.82	0.70	1.09	0.76	0.89
	38–39	1.17	0.91	0.70	1.14	0.68	0.90
	40–41	1.32	1.09	0.78	1.15	0.82	1.01
	42–43	1.36	1.10	0.84	1.08	0.93	1.05