Impact of sulfate on the release of genotoxic metals from hardened cement pastes

We investigated the effects of environmentally relevant sulfate concentrations on the leaching behavior of certain metalloids in hardened cement pastes. In our study, different cement pastes made of Portland cement (CEM I), blast furnace slag cement (CEM III/A) and a sulfate-resistant cement (CEM I SR0) were cured for 28 days and leached with ultrapure water and with sulfate-containing water. The released concentrations of the most metals and metalloids were independent of the presence of environmentally relevant sulfate concentrations below 1 µg/L or even below the limit of quantification (LOQ). However, the contact to sulfate-containing water led to an increased chromium release from CEM I, compared to leaching in ultrapure water. Under the same conditions an increased release of vanadium was observed from CEM III/A. A micronucleus test of the selected eluates revealed genotoxic effects which can be very likely attributed to the presence of vanadate. We were further able to connect the different leaching behavior of cement in sulfate-containing water compared to ultrapure water to changes of the specific surface area of the hardened cement pastes.

Subjects

Chromium | External sulfate attack | Genotoxicity (micronucleus test) | Leaching hardened cement paste | Vanadium

DDC Class

600: Technology

Options

Impact of sulfate on the release of genotoxic metals from hardened cement pastes