Are Crop And Range Lands Being Contaminated With Cadmium And Lead In Sediments Transported By Wind From An Adjacent Contaminated Shallow Lake?
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H. O. Rubio, T. R. Saucedo, M. R. Bautista, K. Wood, C. Holguin & J. Jiménez
Soil contamination by cadmium (Cd) and lead (Pb) in range and crop lands can occur from polluted sediments carried by the wind. Soils samples were obtained in three different areas on the leeward (east) side of a shallow lake called the Laguna de Bustillos: (1) sediment in the shallow lake (S), (2) soil in the range area adjacent to the shallow lake (RA), and (3) soil in agriculture land (AL) adjacent to the range area. In each area, three composite soil samples were randomly collected at depths of 0-15, 15-30 and 30-50 cm. Therefore, 45 soil samples were analyzed as a 3 (area) x 3 (depth) factorial arrangement. The samples were air dried, passed through a 2.0 mm sieve, ground and passed through a 0.355 mm sieve, and digested with concentrated nitric acid. The metals Cd and Pb were determined using ICP optical emission spectrometry. In addition pH and CE were evaluated. Cadmium concentration was statistically different among areas and showed a strong interaction between depth x area. Maximum Cd concentration was found in S with 0.94 mg kg-1 in the surface horizon (0-15 cm). Lead concentration was different among areas and the interaction was not as strong as the one noted for Cd. Highest Pb concentrations were observed in the surface horizons (0-15 cm) of both S and RA with 74.19 mg kg-1 and 55.09 mg kg-1. Nevertheless, for the AL system the maximum Pb concentration was found in the subsurface horizon (30-50 cm) with 40.23 mg kg-1. It is concluded that Cd and Pb are contaminating the RA and AL through wind movement with Pb contamination being the worst. Keywords: cadmium, lead, soil contamination, laguna Bustillos, Chihuahua, México.
cadmium, lead, soil contamination, laguna Bustillos, Chihuahua, México.