Chromium toxicity mediated by application of chloride and sulfate ions in Vertisol of Central India.

Chromium (Cr) is one of the toxic metals adversely affecting organisms including humans in the ecosystems, and it is present in considerable concentration in the tannery industrial effluent. Toxicity expression of Cr is suspected to be influenced considerably by other accompanying ions present in the effluent used for irrigation. In a screen house experiment, interactive effects of chloride and sulfate ions in a Vertisol on uptake of Cr by spinach crop were investigated and treatments imposed were three levels each of Cr (0, 50, 100 mg kg-1), chloride (Cl-) (0, 25, 50 mM kg-1), and sulfur (S) (0, 4, 8 mM kg-1) in possible combinations. Plant growth parameters and leaf Cr concentrations were recorded to find out the effect of anions on Cr dynamics in the plant. Increasing the concentration of Cl- ions in soil reduced the Cr concentration in both root and shoot. Similarly, increasing the concentration of S from 4 to 8 mM kg-1 also reduced the concentration and uptake of Cr. Application of sulfate ions augmented the plant growth and counters the negative effect of Cl- ions and Cr. Thus, the study revealed that the addition of S fertilizers could minimize the Cr toxicity in high Cr contaminated soils.