Knapp et al. (2023): Quantifying CO2 Removal at Enhanced Weathering Sites: a Multiproxy Approach

William J. Knapp, Emily I. Stevenson, Phil Renforth, Philippa L. Ascough, Alasdair C. G. Knight, Luke Bridgestock, Michael J. Bickle, Yongjie Lin, Alex L. Riley, William M. Mayes, Edward T. Tipper IN: Environ. Sci. Technol., https://doi.org/10.1021/acs.est.3c03757

Tha authors studied a CO₂ mineralization site in Consett, Co. Durham, UK, where steel slags have been weathered in a landscaped deposit for over 40 years. The authors provide new radiocarbon, δ¹³C, ⁸⁷Sr/⁸⁶Sr, and major element data in waters, calcite precipitates, and soils to quantify the rate of carbon removal. They demonstrate that measuring the radiocarbon activity of CaCO₃ deposited in waters draining the slag deposit provides a robust constraint on the carbon source being sequestered (80% from the atmosphere, 2σ = 8%) and use downstream alkalinity measurements to determine the proportion of carbon exported to the ocean.

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