Nanoparticle characteristics affecting environmental fate and transport through soil

Abstract

Nanoparticles are being used in broad range of applications; therefore, these materials probably will enter the environment during their life cycle. The objective of the present study is to identify changes in properties of nanoparticles released into the environment with a case study on aluminum nanoparticles. Aluminum nanoparticles commonly are used in energetic formulations and may be released into the environment during their handling and use. To evaluate the transport of aluminum nanoparticles, it is necessary not only to understand the properties of the aluminum in its initial state but also to determine how the nanoparticle properties will change when exposed to relevant environmental conditions. Transport measurements were conducted with a soil-column system that delivers a constant upflow of a suspension of nanoparticles to a soil column and monitors the concentration, size, agglomeration state, and charge of the particles in the eluent. The type of solution and surface functionalization had a marked effect on the charge, stability, and agglomeration state of the nanoparticles, which in turn impacted transport through the receiving matrix. Transport also is dependent on the size of the nanoparticles, although it is the agglomerate size, not the primary size, that is correlated with transportability. Electrostatically induced binding events of positively charged aluminum nanoparticles to the soil matrix were greater than those for negatively charged aluminum nanoparticles. Many factors influence the transport of nanoparticles in the environment, but size, charge, and agglomeration rate of nanoparticles in the transport medium are predictive of nanoparticle mobility in soil.

Metal‐based nanoparticles in soil: Fate, behavior, and effects on soil invertebrates

“…Positively charged Al 2 O 3 NPs (50,80, and 120 nm) demonstrated relatively low mobility [74] because of sorption to negatively charged soil surfaces. Conversely, Al 2 O 3 NPs (50 nm) with adsorbed phosphate, producing a net negative charge, showed reduced sorption to soil and hence higher mobility [73]. A similar effect of phosphate on CeO 2 NPs has also been noted [56].…”

“…The interaction occurring between particles and solid surfaces will control the transport of NPs through soils [73]. This interaction may be influenced by both environmental conditions and the physicochemical characteristics of the particles (Fig.…”

“…When the particle and the soil both have similarly charged surfaces, the repulsion between them will favor particle mobility as opposed to sorption. Where the particles and the soil have opposite charges, particles will be attracted to the soil and sorption may occur, thus decreasing mobility [73]. Although specific functional coatings may be applied to metal-based NPs during manufacturing, sorption of ions such as humic substances may occur in the environment, potentially involving partial or complete replacement of any manufactured coating.…”

Trace element concentrations in soils along urbanization gradients in the city of Wien, Austria

“…The pore size of alkaline soil is higher (>4 mm diameter) than in the case of non-alkaline soil (2 mm diameter) (Barral et al 1998;van der Wal et al 2007). The pore size of soil matrix may increase the effect of filtration which result the main elemental concentration between alkaline and non-alkaline soil (Darlington et al 2009). We used PI to assess the pollution level of soils in Wien.…”

Ecotoxicity test methods for engineered nanomaterials: Practical experiences and recommendations from the bench

“…Although this is also well known for traditional chemicals, some challenges relate specifically to ENMs. Natural soils represent a large and reactive sink, and recent studies have shown that natural soil will filter ENMs during transport through the soil matrix, particularly if the clay content or ionic strength is elevated [75][76][77]. Likely the bioavailability of ENMs to soil organisms, as for aquatic sedimentary tests, will differ for natural and artificial soils, and the method of dosing the soil will alter this bioavailability.…”