The extension of chemical models for sea water to include trace components at 25°C and 1 atm pressure

Chemical models for sea water based on the Brønsted-Guggenheim hypothesis of specific ionic interaction and on the ionic interaction equations of Pitzer are extended to encompass a range of trace constituents. Conventional single-ion activity coefficients of 23 trace components in sea water are listed over a range of ionic strengths (0.2–3 M) together with the ionic interactions that have been accounted for in their calculation. It is suggested that these data might provide the basis of a coherent (hybrid) model for sea water incorporating many of the advantages of the ion-association and specific interaction models.