Abiotic soil changes induced by engineered nanomaterials: A critical review.
A large number of research papers on the fate of engineered nanomaterials (ENMs) in the soil-water system have appeared in recent years, focusing on ENM transport, persistence and toxicological impact. It is clear from these publications that soil is a major sink for ENMs, and that only a small portion degrades or is mobilized further into groundwater. However, to date, very few studies have examined the impact of ENMs on the natural soil-subsurface matrix and its properties. Moreover, it is now well accepted that chemical contaminants are capable of changing soil properties either by inducing direct chemical or physical changes, or through indirect changes by, e.g., influencing biological activity that in turn modifies soil properties. Here, we review studies on the deposition, retention, and accumulation of ENMs in soil, indicative of the extent to which soil acts as a major sink of ENMs. We then examine evidence of how these retained particles lead to modification of surface properties, which are manifested by changes in the sorption capacity of soil for other (organic and inorganic) solutes, and by surface charges and composition different than the natural surfaces. Finally, we demonstrate how this results in physical and hydrological changes to soil properties, including hydraulic conductivity, swelling capacity and wettability. The overall picture revealed in this critical review sheds light on a perspective that has received little attention thus far. These aspects of soil change, due to exposure and subsequent accumulation of ENMs, may ultimately prove to be one of the most important impacts of ENM releases to the environment.
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel. Electronic address: ishai.dror@weizmann.ac.il.
Ishai
I
Dror
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
Bruno
B
Yaron
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
Brian
B
Berkowitz
D004777:Environment; D019015:Geologic Sediments; D006812:Humic Substances; D049329:Nanostructures / Q000032:analysis* / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry; D013499:Surface Properties
D006812:Humic Substances; D012987:Soil; D012989:Soil Pollutants
Change in soil matrix; ENM related soil chemistry; ENM retention; Engineered nanoparticles (ENMs); Environmental contamination; Modified soil properties