Suppression of arsenic leaching from excavated soil and the contribution of soluble and insoluble components in steel slag on arsenic immobilization.

A huge amount of soil is excavated by tunnel and road construction projects in urban, coastal, and mountainous regions. These projects enable the effective use of underground spaces, and generally, the excavated soil is expected to be reused after treatment, which is required due to the potential release of geogenic arsenic from the soil. The present study investigated the level of water-soluble arsenic and arsenic phases in excavated soil in order to identify how arsenic is immobilized by soluble calcium and insoluble components in steel slag.

The effects of redox conditions on arsenic re-release from excavated marine sedimentary rock with naturally suppressed arsenic release.

Massive quantities of marine sedimentary rock are excavated from urban coastal areas. The excavated rock often releases arsenic with concurrent oxidation of framboidal pyrite, but the arsenic release is naturally suppressed with subsequent atmospheric exposure. The present study evaluated the re-release of arsenic from excavated rock in which arsenic release has been naturally suppressed by the atmospheric exposure in the presence of sulfate ions under various redox conditions using the biological reduction method.

Arsenic release from marine sedimentary rock after excavation from urbanized coastal areas: Oxidation of framboidal pyrite and subsequent natural suppression of arsenic release.

Massive quantities of marine sedimentary rock are excavated from urban coastal areas for making underground spaces available for infrastructure projects globally. The excavated rock often contains low levels of framboidal pyrite, which can release arsenic (As) to levels that exceed environmental standards. In the present study, changes in As release and its phases were investigated during oxidation of framboidal pyrite in marine sedimentary rock following exposure to the atmosphere.