Toxicity assessment of soil amended with tannery sludge, trivalent chromium and hexavalent chromium, using wheat, oat and sorghum plants

Abstract

This work assessed the effect of soil amended with tannery sludge (0, 500, 1000, 2000, 4000 and 8000 mg Cr kg −1 soil), Cr 3+ as CrCl 3·6H 2O (0, 100, 250, 500, 1000 and 2000 mg Cr kg −1 soil), and Cr 6+ as K 2Cr 2O 7 (0, 25, 50, 100, 200 and 500 mg Cr kg −1 soil) on wheat, oat and sorghum plants. Seed germination, seedling growth (root and shoot) and Cr accumulation in dry tissue were measured. Toxicological parameters; medium effective concentration, no observed adverse effect concentration and low observed adverse effect concentration were determined. Root growth was the most sensitive assessment of Cr toxicity ( P < 0.05). There was a significant correlation ( P < 0.0001) between Cr accumulation in dry tissue and toxic effects on seedling growth. The three Cr sources had different accumulation and mobility patterns; tannery sludge was less toxic for all three plant species, followed by CrCl 3·6H 2O and K 2Cr 2O 7.