Trace Element Concentration and Speciation in Selected Mining-Contaminated Soils and Water in Willow Creek Floodplain, Colorado

Table 6

Selected chemical and physical properties of study soils.

Soil	Depth	EC^a	pH	CEC-7^b	Base Sat.^c	Total C	Total N	Total S	Bray P-1	Fe^dd	Al^eo	Mnd	Sand	Silt	Clay	>2-mm fraction
	(cm)	dS/m		(cmol/kg)	(%)	%			mg/kg	%			%			(%)
Gravelbar	0–73	–^f	6.8	6.9	86	0.47	0.060	0.04	22.5	1.1	0.04	0.2	91.9	5.0	3.1	65
Cottonwood	0–90	–	5.4	15.2	47	1.19	0.134	0.04	21.4	1.0	0.07	tr	69.0	18.3	12.7	19
Spruce	0–10	–	6.4	12.9	85	2.05	0.308	0.14	23.9	1.3	0.07	0.1	73.1	17.0	9.9	24
	10–40	–	6.7	6.8	97	0.43	0.708	0.10	30.8	1.3	0.04	0.1	88.7	6.4	4.9	63
Railroad	0–61	–	5.9	7.0	19	0.52	0.035	0.22	13.9	1.6	0.05	0.1	80.3	13.8	5.9	59
	61–120	–	4.9	5.3	42	0.23	0.040	0.13	21.0	1.4	0.03	0.2	89.6	6.8	3.6	66
Western Channel	0–40	–	6.4	6.2	84	0.41	0.139	0.17	23.9	0.9	0.03	0.1	89.5	5.9	4.6	70
Salty	0–20	8.00	5.7	22.4	29	2.76	0.229	0.28	–	1.3	0.09	0.1	51.4	32.5	16.1	1
North	0–40	–	6.2	7.1	100	0.50	0.063	0.19	10.1	1.3	0.07	0.2	87.0	7.8	5.2	73
South	0–40	–	6.1	6.0	57	0.27	0.034	0.08	9.6	1.4	0.03	0.1	93.4	3.6	3.0	47
Denuded Mound	0–40	–	4.6	16.1	34	1.33	0.185	0.23	17.0	1.2	0.08	tr	55.8	28.5	15.7	3
Sedge Mound	0–40	–	5.6	23.1	100	2.43	0.246	0.13	26.3	1.0	0.07	tr	50.8	30.0	19.2	4

EC^a = electrical conductivity, saturated paste extract.
CEC-7^b= cation exchange capacity by NH4OAc, pH 7.
Base Sat.^c= base saturation by NH4OAc, pH 7.
Fe^d_d = dithionite-citrate extractable iron.
Al^e_o = ammonium oxalate extractable aluminum.
–^f = concentration below detection limits.