Cr Migration Potential and Species Properties in the Soil Profile from a Chromate Production Site in the Groundwater Depression Cone Area.

Abstract

The relationship between the migration process and speciation distribution of Cr is important for the risk assessment in the underground environment. In this work, soil columns were collected from the chromate production site, with a 40-year operation, in the groundwater depression cone area of North China plain. The relationship between chromium pollution features and the geochemical properties of soil was established, and the migration risk of Cr(VI) was assessed based on the Nemerow composite index and Hydrus-1D model. The maximum total Cr concentration in the chromium slag dumping site reached 907mg/kg, and that in the chromate production workshop was more than 200mg/kg across the depth. The migration of Cr might be accelerated in the soil with abundant Mn (236-1461mg/kg) but scarce organic matters (< 0.45%). The Hydrus simulation indicated that Cr(VI) would reach a cumulative flux of 300-729mg/cm2 after 50years.