Table 2.

Concentration (mg·L⁻¹; Mean ± SD) of heavy metals (HM) in sediments and Average Values of Clay from Sedimentary Rocks (AVCSR) values in sediment samples collected from three sites (Indus Delta, Sandspit and, Miani Hor) in three different seasons (monsoon, post-monsoon and pre-monsoon).

HM	AVCSR, 2010	Sandspit					Miani Hor					Indus Delta
		Monsoon	Post-monsoon	Pre-monsoon	Average	%Δ#	Monsoon	Post-monsoon	Pre-monsoon	Average	%Δ#	Monsoon	Post-monsoon	Pre-monsoon	Average	%Δ#
Hg	0.4	12.8 ± 0.18a	10.8 ± 0.09b	10.1 ± 0.19bc	11.24 ± 1.40	2710	11.1 ± 0.19a	10.8 ± 0.09b	8.4 ± 0.11c	10.1 ± 1.46	2425	13.1 ± 0.14a	11.5 ± 0.13b	10.8 ± 0.09c	11.8 ± 1.17	2850
Cd	0.42	2.8 ± 0.08c	2.9 ± 0.12b	4.2 ± 0.08a	3.31 ± 0.76	688	1.50 ± 0.17c	1.77 ± 0.14b	2.2 ± 0.17a	1.82 ± 0.35	333	0.75 ± 0.01c	0.92 ± 0.03b	1.33 ± 0.18a	1.00 ± 0.30	138
As	13	20.5 ± 0.27b	16.8 ± 0.13c	21.8 ± 0.11a	19.70 ± 2.62	51	14.4 ± 0.36b	13.6 ± 0.28c	18.4 ± 0.24a	15.48 ± 2.60	19	16.1 ± 0.12b	15.3 ± 0.12c	17.3 ± 0.13a	16.24 ± 1.03	25
Pb	80	21.4 ± 0.30c	25.6 ± 0.24b	31.7 ± 0.22a	26.23 ± 5.20	− 67	1.73 ± 0.12c	2.1 ± 0.14b	2.53 ± 0.13a	2.12 ± 0.40	− 97.3	1.03 ± 0.06c	1.48 ± 0.11b	1.74 ± 0.07a	1.42 ± 0.36	− 98.2
Cu	250	4.8 ± 0.08c	5.6 ± 0.12b	6.1 ± 0.16a	5.50 ± 0.65	− 97.8	1.82 ± 0.1c	2.02 ± 0.08b	2.23 ± 0.13a	2.02 ± 0.21	− 99.2	1.88 ± 0.13b	2.03 ± 0.17b	2.24 ± 0.14a	2.05 ± 0.18	− 99.2
Cr	90	27.6 ± 0.26c	35.1 ± 0.19b	39.6 ± 0.36a	34.08 ± 6.03	− 62	2.59 ± 0.08c	2.86 ± 0.07b	3.21 ± 0.06a	2.89 ± 0.31	− 96.8	0.90 ± 0.01c	1.15 ± 0.12b	1.51 ± 0.14a	1.18 ± 0.32	− 98.7
Zn	165	4.9 ± 0.15c	5.7 ± 0.14b	9.1 ± 0.22a	6.57 ± 2.22	− 96.0	1.78 ± 0.13a	1.71 ± 0.11a	1.8 ± 0.1a	1.76 ± 0.05	− 98.9	1.08 ± 0.05b	1.11 ± 0.07a	1.74 ± 0.13b	1.31 ± 0.38	− 99.2
Fe	65,000	2001 ± 11.05a	1822 ± 8.60b	1772 ± 12.42c	1865 ± 120.5	− 97.1	1356 ± 11.37a	1292 ± 12.41b	1278 ± 3.79c	1309 ± 41.67	− 97.9	1114 ± 11.6a	1045 ± 8.06b	1010 ± 8.49c	1056 ± 53.15	− 98.4
Al	84,000	24.2 ± 0.22c	25.6 ± 0.32b	33.5 ± 0.35a	27.74 ± 5.00	− 99.9	13.1 ± 0.21bc	13.8 ± 0.16b	17.7 ± 0.17a	14.88 ± 2.47	− 99.9	29.1 ± 0.12c	33.2 ± 0.14b	35.7 ± 0.19a	32.68 ± 3.34	− 99.9
Se	0.17	0.063 ± 0.005b	0.074 ± 0.005b	0.085 ± 0.005a	0.074 ± 0.01	− 56	0.022 ± 0.008b	0.026 ± 0.005a,b	0.032 ± 0.008a	0.03 ± 0.01	− 82	0.06 ± 0.008b	0.08 ± 0.005a	0.08 ± 0.009a	0.07 ± 0.01	− 59
∑		2120	1950	1928	1999		1404	1341	1335	1360		1178	1112	1082	1124

^#%Δ is calculated by comparing average observed values with the limits described in AVCSR, 2010. ^ap < 0.001, ^bp < 0.01, ^cp < 0.05.