Abstract

The teaching of chromium-copper-arsenic salts from old wood preservation sites is a threat to ground water at many places in Sweden. The installation of in situ reactive barriers is an attractive ''passive'' technique to prevent the further spreading of contaminants. The use of peat as a reactive barrier material has been suggested for heavy metals, but this material was expected to be unsatisfactory for arsenic (As). Therefore, the feasibility of using spodic B horizon material for the retention of arsenic was tested in laboratory column experiments. Contaminated soil was taken from an old preservation site and leached under conditions designed to imitate the field conditions. The arsenic load during the three-month duration of the test corresponded to a load at the field site during three years. The B horizon material proved to be efficient for retention of arsenic, despite the observation that As(III) dominated the As speciation. The As(III) concentration was reduced from 1 to 3 mg dm(-3) to < 0.02 mg dm(-3)). Pure pear was, as expected, not suited as a reactive barrier for As, and a mixed B horizon/peat reactive barrier also proved unsatisfactory for the removal of As. It is therefore important to separate the B horizon material from any peat that is used to sorb heavy metals. Before applying the B horizon reactive barrier technique in the field, the effect of the naturally occurring variability of the reactive compounds should be tested. The inclusion of oxidizing agents in the barrier could possibly improve the lifetime considerably. Furthermore, the influence of the flow rate should be evaluated since the kinetics of the arsenic adsorption is relatively slow.

Published in

Ground Water Monitoring and Remediation
1997, Volume: 17, number: 4, pages: 125-130
Publisher: GROUND WATER PUBLISHING CO

UKÄ Subject classification

Oceanography, Hydrology, Water Resources


Publication identifier

DOI: https://doi.org/10.1111/j.1745-6592.1997.tb01272.x

Permanent link to this page (URI)

https://res.slu.se/id/publ/69507