Metal phase association of chromium in contaminated soils from an industrial area in Delhi

Abstract

The distribution and mobility of chromium in the soils of an industrial area was investigated to evaluate its vertical and lateral movement. Operational speciation was determined using five step Tessier scheme to fractionate the metal content in soil into (i) exchangeable (ii) carbonate bound; (iii) reducible; (iv) oxidisable and (v) residual phases. Chromium concentration in one of the studied sites was higher than its critical value (75-100 mg/kg) in soil. In every extraction test the concentration of chromium in secondary phases was higher in the upper horizons than in the lower ones. In a contaminated area chromium was mainly present in secondary phases i.e. in mobile and mobilizable phases. The reducible phase had high percentage of chromium in the contaminated area from where mobilisation can occur with change in environmental conditions. Thus, results from this study can indicate the bioavailability of chromium in this area. © 2004 2004 Taylor and Francis Group LLC.