Predicting environmental concentrations of Nitramines from sorption potentials to soils and dissolved organic matter

Potentially carcinogenic and persistent nitramines (RR’NNO2) are known to form from the amines used in PostCombustion CO2 Capture (PCCC). Formation occurs in the atmosphere through photo-oxidation of escaped amines [1]. Terrestrial exposure levels, following years of amine-based PCCC activity, depend on the biogeochemical processes governing mobility of the nitramines. The main aim of this study is to make an approximation of potential maximum terrestrial exposure concentrations of the nitramines. This will be pursued through laboratory experiments assessing maximum sorption potential of nitramines to soils with different physicochemical properties. Results will be assessed in relation to deposition scenarios based on current knowledge regarding atmospheric nitramine formation, transport, and deposition estimated from atmospheric dispersion models [2, 3]. Sorption is a generic term that covers all mechanisms resulting in the loss of compound from the aqueous phase to the solid phase. Common sorption mechanisms include specific binding to mineral components (e.g. hydrous oxides of iron and aluminum, and hydroxyl groups on clay minerals), and to organic functional groupsand complexed metals in the soil organic matter, or by lipophilic interactions. Accumulation of the nitramines in soils is the likely result if nitramines sorb strongly to soil. Moreover, the sorption of a chemical is known to provide a shielding effect against biodegradation thereby augmenting the concentration of nitramines [4].