“…The mineral Fe oxyhydroxide colloids are stable, that is, they remain suspended, due to electrostatic and/or steric stabilisation because of adsorption of negatively charged OM on the Fe oxyhydroxide colloids (Buffle et al, 1998; Philippe & Schaumann, 2014). The Fe oxyhydroxide colloids in soil solution carry oxyanions such as phosphate (Missong et al, 2018), arsenate (Tindale et al, 2016) and trace metal cations (Hassellöv & von der Kammer, 2008; Regelink et al, 2011) and might as such facilitate the vertical transport of these associated elements to deeper layers (Warrinnier et al, 2019).…”