LINKING PLANT-TISSUE CONCENTRATIONS AND SOIL COPPER POOLS IN URBAN CONTAMINATED SOILS

Copper tissue concentrations of radish (Raphanus sativa cv. Cherry Bel ie), lettuce (Lactuca sativa cv. Butter-crunch) and ryegrass (Lolium p erenne cv. Barmultra) grown in a greenhouse in urban contaminated soil s are compared to total, soluble and free ion copper pools. The tissue concentrations of copper vary between 8.1 and 82.6 mg Cu kg(-1) dry t issue and the total soil copper content varies between 32 and 640 mg C u kg(-1) dry soil. The linear regressions with cupric ion activity and total soil copper are both significant (p < 0.01), but cupric ion act ivity yields a higher level of statistical significance in every case. The results support the hypothesis that free metal in the soil soluti on is a better indicator of plant metal bioavailability than either to tal or soluble metal. (C) 1997 Elsevier Science Ltd.