Metal solubility and transport at a contaminated landfill site - From the source zone into the groundwater

Sammanfattning

Risks associated with metal contaminated sites are tightly linked to material leachability and contaminant mobility. In this study, metal solubility and transport were characterized within a glass waste landfill through i) lysimeter-collection of pore water and standardized batch leaching tests, ii) soil profiles extending from the landfill surface, through unsaturated soil underneath, and into the groundwater zone, and iii) groundwater samples upstream, at, and downstream of the landfill. The soil analyzes targeted both pseudo-total and geochemically active concentrations of contaminant metals (As, Cd, Pb, Sb) and basic soil geochemistry (pH, org. C, Fe, Mn). Water samples were analyzed for dissolved, colloid-bound and particulate metals, and speciation modelling of the aqueous phase was conducted. The results revealed a highly contaminated system, with mean metal concentrations in the waste zone between 90 and 250 times the regional background levels. Despite severe contamination of the waste zone and high geochemically active fractions (80-100%) of all contaminant metals as well as elevated concentrations in landfill pore water, the concentrations of Cd and Pb decrease abruptly at the transition between landfill and underlying natural soil and no indication of groundwater contamination was found. The efficient cation retention is likely due to the high pH. However, the sorption of As and Sb is weaker at such high pH, which explains their higher mobility from the pore water zone into groundwater. The field soil:solution partitioning (Kd) displayed a high spatial variability within the waste zone (the highest Kd variability was seen for Pb, ranging from 140 to 2,900,000 1 kg(-1)), despite little variability in basic geochemical variables, which we suggest is due to waste material heterogeneity. (C) 2019 The Authors. Published by Elsevier B.V.

Nyckelord

Soil and groundwater metal pollution; Glass waste; Soil:Solution partitioning (Kd); Leachability; Mobility; Colloids

Publicerad i

Science of the Total Environment
2019, volym: 668, sidor: 1064-1076
Utgivare: ELSEVIER SCIENCE BV

SLU författare

• Berggren Kleja, Dan

  • Institutionen för mark och miljö, Sveriges lantbruksuniversitet
    
  • Statens geotekniska institut (SGI)

Globala målen (SDG)

SDG6 Rent vatten och sanitet för alla

UKÄ forskningsämne

Miljövetenskap
Geokemi

Publikationens identifierare

• DOI: https://doi.org/10.1016/j.scitotenv.2019.03.013

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/99643