Risk assessment of contaminants leaching to groundwater in an infrastructure project

Possible risks posed by rebuilding of a road and railway within a contaminated area have been studied by assessing the mobility of metals in soil through analysis of field samples, leaching tests and calculations of distribution Kd coefficients. The results from the standardized leaching tests showed a very high release of Pb, but also high release of Zn, Cu, Ni and As. The site specific Kd values determined showed that Cr and Pb are the metals most strongly bonded in the soil, and that As is the most easily released. Input of humus colloids increased the leaching of Cu, Pb and Zn and show on potential risk with enhanced leaching if flooding of the river or excavation activities at the site. It was concluded that Pb and As constitute the highest risk of leaching from the landfill site