Copper geochemistry and availability in cultivated soils contaminated by a copper smelter

Abstract

The average amounts of Cu forms in sixteen soils contaminated by the Glogow copper smelter (Poland) determined by means of the McLaren and Crawford sequential extraction were: Ex 0.078; AAC 11.76; PYR 69.36; OX 26.20 and RES 14.10 mg kg −1. The distribution of soil copper between different Cu fractions was not influenced by soil properties. The average total content of Cu amounted to 134.9 mg kg −1 and was highly correlated with the AAC, PYR and OX forms of Cu. Soil tests, in descending order, extracted the following amounts of Cu: HNO 3 108.6; Lindsay 50.0; Mehlich-1 46.2; HCI 44.5; Mehlich-3 11.1; NaNO 30.42 mg kg −1. All these tests were poorly related to soil properties but highly related to the total Cu content. The AAC and PYR Cu fractions influenced the amounts of Cu extracted by 1 M HCI, Mehlich-1 and Mehlich-3 extraction solutions. The other tests highly depended on AAC and RES copper fractions. Copper concentration in both roots and shoots of flax may be treated as indicative of its bioavailability from the soils studied. The 1 M NaNO 3 and Mehlich-3 chemical extractants seem to be the best predictors of plant-available copper.