Land application of microsized basalt particles: A perspective on their mobility in the soil environment

Abstract Application of basalt powder (BP) for agricultural soils has been increasingly encouraged owing to its positive effects on soil fertility and carbon sequestration capability. However, the onsite positive effects can be reduced if BP or its components are prone to dispersion and losses by surface run‐off or downward leaching. In this study, surface charge (SC), colloidal properties together with dispersion/aggregation phenomena of BP were determined in a systematic approach, considering co‐effects of pH and ionic strength, presence and variation of various common mono‐, di‐ and trivalent cations and anions. Possible scavenging abilities of BP for common environmental heavy metal pollutants such as Cu 2+ , Pb 2+ , Zn 2+ and AsO 4 3− were also elucidated. We found that BP possesses negative SC; hence, it is prone to dispersion in the environment with the predominantly negatively charged soil compounds. Cations tended to reduce negative charges of BP; hence, they facilitated BP aggregation. In contrast, anions showed opposite tendencies in which BP was favoured to disperse. We also found strong adsorption capabilities of BP for Pb 2+ , Cu 2+ and Zn 2+ as well as anionic AsO 4 3− , inferring that BP can act as a sink or interfere with the transport route of heavy metals in soil‐aquatic environments. In general, the findings suggest that our ambition to use engineered BP for boosting soil fertility and carbon sequestration also needs to consider the dispersibility of BP upon soil application since this process can enhance nutrient losses or heavy metal widespreads through co‐transports with BP.