The partition of Be between soil and water

An extensive and systematic investigation of Be partition between solid and water was carried out using laboratory batch experiments with radioactive ⁷Be tracer. We found that: (1) Be is strongly held by the solid particles in natural environments under neutral conditions; (2) man-made δ-MnO₂ and in situ weathering products of andesite have the highest K_d (> 10⁶) while most mud, silt and clay minerals have K_d on the order of 10⁵; (3) K_d is high under neutral or alkaline conditions but decreases rapidly by four orders of magnitude between pH 6 and 2; (4) K_d decreases with increasing concentration of suspended particles; (5) dissolved organic matter in Taiwan Strait surface water does not seem to greatly affect the value of adsorption K_d; (6) adsorption of Be onto soil is a two-stage process and the second stage is ∼ 1000 times slower than the first; (7) the reaction of surface ion exchange seems to proceed at a faster rate in river water than in seawater, probably because of the high ionic strength of the latter; (8) the activation barrier of sorption reaction for Be seems to be ∼ 10 kcal.mol^-1 for river mud; and (9) the adsorption of Be onto soil seems to be a reversible process.