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Geochemical associations and availability of cadmium (Cd) in a paddy field system, northwestern Thailand.

Geochemical associations and availability of cadmium (Cd) in a paddy field system, northwestern Thailand.

Environmental pollution (Barking, Essex : 1987) (2014-02-08)

Peerapat Kosolsaksakul, John G Farmer, Ian W Oliver, Margaret C Graham

ABSTRACT

The Mae Tao watershed, northwest Thailand, has become contaminated with cadmium (Cd) as a result of zinc ore extraction (Padaeng deposit) in the nearby Thanon-Thongchai mountains. Consumption of contaminated rice has led to documented human health impacts. The aim of this study was to elucidate transfer pathways from creek and canal waters to the paddy field soils near Baan Mae Tao Mai village and to determine the relationship between Cd speciation in the soil and uptake by rice plants. Transfer mainly occurred in association with particulate matter during flooding and channel dredging and, in contrast with many other studies, most of the soil Cd was associated with exchangeable and carbonate-bound fractions. Moreover, there was a linear relationship between soil total Cd and rice grain Cd (R(2) = 0.715), but a stronger relationship between both the Tessier-exchangeable soil Cd and the BCR-exchangeable soil Cd and rice grain Cd (R(2) = 0.898 and 0.862, respectively).

MATERIALS

Product Number

Brand

Product Description

Sigma-Aldrich

Cadmium, powder, −100 mesh, 99.5% trace metals basis

Sigma-Aldrich

Cadmium, shot, 3 mm, 99.999% trace metals basis

Sigma-Aldrich

Cadmium, granular, 30-80 mesh, ≥99%

Sigma-Aldrich

Cadmium, granular, ≥99%, 5-20 mesh

Cadmium, foil, 6mm disks, thickness 0.25mm, as rolled, 99.9%

Cadmium, foil, not light tested, 50x50mm, thickness 0.01mm, 99.7+%

Cadmium, foil, light tested, 25x25mm, thickness 0.01mm, 99.7+%

Cadmium, tube, 500mm, outside diameter 2.29mm, inside diameter 1.27mm, wall thickness 0.51mm, 99.95+%

Cadmium, foil, 50mm disks, thickness 0.5mm, as rolled, 99.95%

Cadmium, foil, not light tested, 100x100mm, thickness 0.01mm, 99.7+%

Cadmium, foil, 150x150mm, thickness 0.5mm, as rolled, 99.99%

Cadmium, wire reel, 0.5m, diameter 0.70mm, as drawn, 99.99+%

Cadmium, foil, 25mm disks, thickness 0.25mm, as rolled, 99.9%

Cadmium, foil, 100x100mm, thickness 0.125mm, as rolled, 99.95%

Cadmium, foil, 25mm disks, thickness 0.5mm, as rolled, 99.95%

Cadmium, foil, 4mm disks, thickness 0.125mm, as rolled, 99.99+%

Cadmium, wire reel, 0.2m, diameter 0.5mm, hard, 99.99+%

Cadmium, foil, 15mm disks, thickness 0.25mm, as rolled, 99.95%

Cadmium, foil, 150x150mm, thickness 0.25mm, as rolled, 99.95%

Cadmium, foil, 10mm disks, thickness 0.25mm, as rolled, 99.9%

Cadmium, wire reel, 0.5m, diameter 1.2mm, as drawn, 99.99+%

Cadmium, foil, 10mm disks, thickness 1.0mm, as rolled, 99.95%

Cadmium, foil, 95x100mm, thickness 0.5mm, as rolled, 99.99%

Cadmium, foil, 100x100mm, thickness 0.25mm, as rolled, 99.99+%

Cadmium, foil, 300x1000mm, thickness 2.0mm, as rolled, 99.99%

Cadmium, foil, 4mm disks, thickness 0.125mm, as rolled, 99.95%

Cadmium, wire reel, 0.2m, diameter 0.5mm, hard, 99.95+%

Cadmium, foil, 50x50mm, thickness 0.125mm, as rolled, 99.99+%

Cadmium, foil, 50x200mm, thickness 1.0mm, as rolled, 99.999%

Cadmium, foil, 25mm disks, thickness 1.0mm, as rolled, 99.95%