Abstract
Sediments sampled along a central flow line of the
leachate pollution plume at the Vejen Landfill,
Denmark, were characterized in detail with respect
to the forms and pools of Fe(ll) and Fe(lll). After
15 yr of leaching, redox reactions had diminished the
pool of iron(ll1) oxides and hydroxides in the reduced
zones close to the landfill, and the aquifer oxidation
capacity (OXC) related to iron oxides was depleted.
Less than 2% of the total Fe(ll) was recovered as dissolved
Fe(ll), whereas 1-20% was ion-exchangeable
on the sediments. The majority of the Fe(ll) was in
the solid state either as pyrite or in the ill-defined
fraction extractable by 5 M HCI. The total reduction
capacities (TRC) of these anaerobic sediments were
significantly elevated relative to the unpolluted sediments.
Samples from the oxidized, weakly polluted
part of the plume contained Fe(lll) minerals and
insignificant amounts of Fe(ll). This study presents
evidence of substantial iron reduction buffering the
reducing power of landfill leachate entering a shallow
aquifer. It is also proposed that reduced sedimentbound
iron species form in the plume, thereby
increasing the need for oxygen if the aquifer was to
be remediated.
Original language | English |
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Journal | Environmental Science & Technology (Washington) |
Volume | 29 |
Issue number | 1 |
Pages (from-to) | 187-192 |
ISSN | 0013-936X |
DOIs | |
Publication status | Published - 1995 |