Table 1.

Summary statistics of metal and metalloid concentrations in sediments (n = 250)

District	Statistics*	Co	Fe	Ni	Zn	Cu	Mn	Pb	Cr	Cd	As	Hg
Tarkwa Nsuaem (N = 57)	Mean	31.17	9299.74	21.16	26.67	529.89	420.58	52.21	31.71	0.15	8.47	6.98
	Std. Deviation	27.35	15058.20	8.76	11.95	1052.24	34.63	58.00	19.03	0.17	8.98	13.63
	Minimum	11.88	9.94	9.50	12.52	0.66	316.57	0.58	10.10	0.04	0.89	0.04
	Maximum	112.15	45736.53	37.61	54.42	4422.00	489.66	208.02	84.06	0.54	43.29	50.88
Bibiani (N = 83)	Mean	306.83	96.48	302.46	44.48	24152.16	27.31	20.71	20.10	295.63	10.18	45.16
	Std. Deviation	153.48	169.58	132.77	9.48	14669.93	6.32	2.40	9.76	431.59	5.09	19.47
	Minimum	96.46	12.58	98.80	25.30	4510.00	21.50	15.90	4.16	22.82	2.50	9.48
	Maximum	597.46	866.94	725.20	50.50	63220.00	35.30	25.80	38.28	1600.20	19.96	75.84
Amansie West (N = 30)	Mean	103.65	19.62	127.48	14.59	16137.55	24.81	22.71	5.97	73.56	1.97	21.65
	Std. Deviation	32.75	15.17	187.17	2.07	15661.63	4.98	2.68	2.83	56.65	1.52	22.06
	Minimum	55.46	6.57	37.28	9.50	1456.53	22.10	20.40	1.96	10.78	0.26	4.99
	Maximum	149.18	44.02	681.45	15.50	45626.31	37.60	30.50	9.72	183.56	5.35	69.96
Birim North (N = 30)	Mean	24.42	27.15	1.70	3.22	20.42	3.75	6.28	20.45	0.25363	360.57	397.36
	Std. Deviation	1.74	10.16	0.97	1.80	8.07	3.00	3.39	9.60	0.01	294.68	11.47
	Minimum	19.00	3.11	1.25	1.01	6.08	0.70	1.98	8.48	0.250	250.00	350.00
	Maximum	25.00	38.00	4.43	6.44	38.20	9.40	13.80	48.50	0.32	1490.00	400.00
Upper Denkyira (N = 50)	Mean	20.41	54792.35	9.52	21.84	3109.75	1926.77	610.86	4997.77	13.84	243.03	11.87
	Std. Deviation	1.64	110331.49	1.43	4.58	794.99	965.87	912.29	8835.89	34.73	244.19	8.70
	Minimum	14.10	1182.07	5.00	2.90	1848.48	703.45	0.01	15.00	0.01	33.34	3.71
	Maximum	20.90	487430.17	10.00	22.90	4959.74	4622.91	3002.79	38392.46	116.63	1010.83	34.99

*Concentration of As and Hg are in μgkg^?1.