Trace Metal Content of Sediments Close to Mine Sites in the Andean Region

Table 1

Metal concentration (mg/kg), in sediment samples with grain size < 63 μm for mainstream of Llapa Subbasin with median, mean, standard deviation, and skew for Y1, Y2, and Y3 (mainstream points); threshold effect level (TEL), and probable below level (PEL).

	Y1	Y2	Y3	Y4	Y5	Median^a	Mean^a	SD^a	Skew^a	TEL	PEL
pH	7.30	7.60	7.68	—^c	3.44	7.60	7.53	0.2	−1.4	—	—
EC^b	31.00	35.00	38.00	734.00	212.00	35.00	34.67	3.5	−0.4	—	—
AI	13687.3	19378.5	12649	24522.7	15265.5	13687.30	15238.27	3622.9	1.6	—	—
As	5.28	2.5	53.88	22.65	350.73	5.28	20.55	28.9	1.7	5.9	17
Cd	2.4	4	3.1	3.7	11.3	3.10	3.17	0.8	0.4	0.6	3.5
Cr	5.4	6.8	4.3	5.7	5.5	5.40	5.50	1.3	0.4	37.3	90
Cu	10.3	133.1	63.4	502	446	63.40	68.93	61.6	0.4	35.7	197
Fe	12397.4	13930	14478	17810.4	24884.25	13930.00	13601.80	1078.4	−1.2	—	—
Hg	n.d.^d	1.02	n.d.	n.d.	1.26	0.00	0.34	0.6	1.7	0.17	0.49
Mn	749.3	1205.8	957.7	933.7	372.75	957.70	970.93	228.5	0.3	—	—
Ni	5.9	9.4	8.4	10.5	11.6	8.40	7.90	1.8	−1.2	—	—
Pb	8.1	20	8.9	9.5	35	8.90	12.33	6.7	1.7	35	91
Sb	0.9	1.2	1.2	1.2	4.75	1.20	1.10	0.2	−1.7	—	—
Sn	64.7	93.3	71.1	65.5	85.4	71.10	76.37	15.0	1.4	—	—
Zn	45	90.6	76	126.1	114.65	76.00	70.53	23.3	−1.0	123	315

^aCalculated for mainstream samples (Y1, Y2, Y3); ^bOhms*1000; ^cno available; ^dno detectable (n.d.).