TY - JOUR

T1 - Amendment of arsenic and chromium polluted soil from wood preservation by iron residues from water treatment

A1 - Nielsen,Sanne Skov

A1 - Petersen,L. R.

A1 - Kjeldsen,Peter

A1 - Jakobsen,Rasmus

AU - Nielsen,Sanne Skov

AU - Petersen,L. R.

AU - Kjeldsen,Peter

AU - Jakobsen,Rasmus

PB - Pergamon

PY - 2011

Y1 - 2011

N2 - An iron-rich water treatment residue (WTR) consisting mainly of ferrihydrite was used for immobilization of arsenic and chromium in a soil contaminated by wood preservatives. A leaching batch experiment was conducted using two soils, a highly contaminated soil (1033mgkg−1 As and 371mgkg−1 Cr) and slightly contaminated soil (225mgkg−1 As and 27mgkg−1 Cr). Compared to an untreated reference soil, amendment with 5% WTR reduced leaching in the highly contaminated soil by 91% for Cr and 98% for As. No aging effect was observed after 103d. In a small field experiment, soil was mixed with 2.5% WTR in situ. Pore water was extracted during 3years from the amended soil and a control site. Pore water arsenic concentrations in the amended soil were more than two orders of magnitude lower than in the control for the upper samplers. An increased release of arsenic was observed during winter in both fields, mostly in the deepest samplers. This is likely due to the formation of a pseudo-gley because of precipitation surplus. Stabilization of arsenic and chromium contaminated soil using WTR is a promising method but the transformation of ferrihydrite in soil proves a concern in case of waterlogged soils. Still the amendment minimized the leaching of arsenic, even in cases of seasonal releases.

AB - An iron-rich water treatment residue (WTR) consisting mainly of ferrihydrite was used for immobilization of arsenic and chromium in a soil contaminated by wood preservatives. A leaching batch experiment was conducted using two soils, a highly contaminated soil (1033mgkg−1 As and 371mgkg−1 Cr) and slightly contaminated soil (225mgkg−1 As and 27mgkg−1 Cr). Compared to an untreated reference soil, amendment with 5% WTR reduced leaching in the highly contaminated soil by 91% for Cr and 98% for As. No aging effect was observed after 103d. In a small field experiment, soil was mixed with 2.5% WTR in situ. Pore water was extracted during 3years from the amended soil and a control site. Pore water arsenic concentrations in the amended soil were more than two orders of magnitude lower than in the control for the upper samplers. An increased release of arsenic was observed during winter in both fields, mostly in the deepest samplers. This is likely due to the formation of a pseudo-gley because of precipitation surplus. Stabilization of arsenic and chromium contaminated soil using WTR is a promising method but the transformation of ferrihydrite in soil proves a concern in case of waterlogged soils. Still the amendment minimized the leaching of arsenic, even in cases of seasonal releases.

KW - Arsenic

KW - Soil stabilization

KW - Wood preservation site

KW - Iron oxide

KW - Sorbent

U2 - 10.1016/j.chemosphere.2011.03.069

DO - 10.1016/j.chemosphere.2011.03.069

JO - Chemosphere

JF - Chemosphere

SN - 0045-6535

IS - 4

VL - 84

SP - 383

EP - 389

ER -