Hydrophobicity of Soil Colloids and Heavy Metal Mobilization

Drying of soil may increase the hydrophobicity of soil and affect the mobilization of colloids after re‐wetting. Results of previous research suggest that colloid hydrophobicity is an important parameter in controlling the retention of colloids and colloid‐associated substances in soils. We tested the hypothesis that air‐drying of soil samples increases the hydrophobicity of water‐dispersible colloids and whether air‐drying affects the mobilization of colloid‐associated heavy metals. We performed batch experiments with field‐moist and air‐dried (25°C) soils from a former sewage farm (sandy loam), a municipal park (loamy sand), and a shooting range site (loamy sand with 25% Corg). The filtered suspensions (